Safeguarding Children's Health: Defeating Disease Through Vegetarian/Vegan Diets
A Major New Health and Nutrition Report For Healthcare Professionals and Parents
by Laura Scott, MSc Nutrition – Viva! Health Senior Nutritionist
Introduction by Professor Colin Campbell and Dr Anne Griffiths MB ChB
Professor Colin Campbell
Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry, Cornell University, USA and long time senior science advisor to the World Cancer Research Fund.
This report – summarising the scientific evidence favouring the health value of a plant-based diet for children – is well done. I have been on several 'expert panels' responsible for recommending health policy positions, both nationally and internationally, and although some may be more voluminous, none is more reliable. This well-referenced document draws heavily on conclusions drawn by other institutions and panels, who have represented considerable collective deliberation, to synthesize their views into a logical and responsible report. It is well nigh time to make clear to the public that even conservative science is strongly trending in the direction of a plant-based diet and a read of this report is a good place to start.
Dr Anne Griffiths MB ChB
Diploma from the Royal College of Obstetrics and Gynaecology and Member of the Royal College of General Practitioners. Has an MSc in Community Paediatrics and is Associate Specialist at the East Paediatric Team, Newcastle upon Tyne, UK.
VVF has brought together, in this report, the overwhelming evidence that vegetarian and vegan diets are not only healthy for children, but preferable to modern meat and dairy-based diets which are a major cause of chronic ill-health and premature death. Here we have the results from over 200 studies, which show conclusively the links between meat and dairy consumption with such diverse diseases as asthma, gastrointestinal problems, cancer, coronary heart disease, hypertension, diabetes and obesity.
This information should now be disseminated so that as many parents as possible can make informed choices about what they choose to feed their offspring. Some of us have long-standing beliefs about the importance of meat and dairy products in our diets. We need to challenge these, as individuals and societies. It is imperative that future generations reap the health benefits that a shift towards a plant-based diet can bring. Vegetarian and vegan diets need to be actively promoted as the best diet for all stages of life: pregnant mothers, babies, toddlers, children, adolescents, teenagers and adults. Meat has become the so-called “luxury” we can ill afford.
Vegetarian – a person who eats no red meat, white meat, fish or other aquatic animals (prawns, crabs, lobsters etc) or slaughterhouse by-products such as gelatine, animal fat, lard or rennet.
Vegan – a person who eats no animal products at all including red and white meat, fish and other water creatures, dairy products (eg cow's or goat's milk or derivatives such as yoghurt or cheese) or eggs.
The latest worldwide research on diet and health has led internationally renowned health organisations such as the World Health Organisation (WHO) to recommend a diet very different to the one the majority of people in the West eat today. Diets should be based more on foods such as fruits, vegetables and cereals and less on meat, fat, sugar and salt if killer diseases such as coronary heart disease, diabetes, obesity and cancer are to be reduced. This report documents the evidence which backs up this assertion and concludes that animal produce must be eliminated from the diet as early as possible to promote a long, healthy life. And the evidence is overwhelming.
Anthropological studies show that the diet which fuelled most of human evolution was low in fat, very low in sugar and high in fibre and other complex carbohydrates (3), so it is no great surprise that today's high-fat, high-protein, low-fibre diet causes so many health problems and the dietary trends are spreading worldwide. With increased prosperity, the global trend is towards an increasingly unsuitable and unhealthy diet. In less developed countries even modest increases in prosperity are accompanied by major changes in dietary patterns and a dramatic increase in the incidence of diet-related diseases. If such trends continue, the WHO predict a massive rise in cardiovascular disease and cancer in virtually every country in the world (4). So concerned is this august body they are argue for “intervention on a mass scale” to shift dietary patterns closer to a safer diet (5).
“Scientific data suggest positive relationships between a vegetarian diet and reduced risk for several chronic degenerative diseases and conditions, including obesity, coronary artery disease, hypertension, diabetes mellitus, and some types of cancer... Vegetarians often have lower morbidity and mortality rates from several chronic degenerative diseases than do non-vegetarians...Vegetarian diets offer disease protection benefits because of their lower saturated fat, cholesterol and animal protein content and often higher concentration of folate, antioxidants such as vitamins C and E, carotinoids and phytochemicals... vegetarian diets have also been successful in arresting coronary artery disease.” American Dietetic Association Position Paper on Vegetarian Diets, 1997 (182).
With economics and politics dominating food production systems throughout the world, we need to listen to independent bodies and their research to re-discover a diet that will give children a chance at a long and disease-free future. It is essential that healthcare professionals guide parents and guardians and encourage them to actively promote the best diet for their family. Although many families have information about food-related issues this does not necessarily mean that the advice is followed (6). It is VVF's hope that healthcare professionals the world over will take heed of the research published here and promote a diet that will help save lives.
June 2000 saw the publication of a national diet and nutrition survey. This survey looked into the eating habits of a representative sample of over 2000 young people aged 4 to 18 years. For most parents what this report reveals will come as no surprise and makes for grim reading. Roughly 80% of kids are guzzling away on white bread, savoury snacks, biscuits, chips and chocolate confectionery. Roughly 60-75% had not eaten any citrus fruits (oranges, kiwi fruits, berry fruits – all very rich in fibre and vitamin C) or leafy green vegetables (eg broccoli and greens rich in fibre and many minerals). Whilst girls were more likely to eat some salad vegetables, boys more often consumed convenience foods such as sausages, bacon, ham and pizza. When interviewed 1% of boys and 5% of girls reported to be vegetarian or vegan increasing to 10% of girls aged 15-18 years.
Protein intakes for all ages considerably exceeded the government recommended intakes (known as Reference Nutrient Intakes or RNI for short). Carbohydrates (sugar and starch) are our primary energy source but should be predominantly starchy foods like bread, cereals, pasta and rice rather than sugar-laden processed foods. Sugars in the form of table sugar, honey and in baked goods contributed 17% of energy intakes with the RNI set at only 11%. Fibre intake (the indigestible part of plant foods that helps keep the body regular or NSP (Non-Starch Polysaccharides)) was some 10-11g per day – the RNI being 18g for adults with children slightly less so relative to their body size. Not surprising then that a third of children recorded not having a daily bowel movement. Dietary saturated fats (mainly from animal products) accounted for some 14% of daily fat intakes with the RNI set at some 20% less than this at just 10-11%. Dairy products contributed some 30% of this type of fat and meat products contributed 17%. Saturated fat intakes are a major contributor to cholesterol levels so with 20% higher intakes of this type of fat then recommended it is of no surprise that approximately 10% of boys and girls had cholesterol levels at or above the recognised safe levels.
Looking at some specific vitamins, vitamin A intakes for 10-20% of boys and girls were lower than recommended. Beta-carotene intakes (the antioxidant or disease-busting form of vitamin A only found in plant foods) were found to be actually zero for 2% of boys and girls! Of particular importance here was the observation that since girls aged 15-18 were most likely to be vegetarian it was no surprise to find that this group had a diet richer in total carotene than other younger girls. Folate (a B-group vitamin rich in plant foods) was below the RNI for 1-4% of all sex/age groups. Over half the vitamin C intake was from fruit juice and soft drinks with 15% from potatoes and only 10-13% from fruits and nuts. Whilst fruit juices are rich in vitamin C they are devoid of any fibre and thus a far better source of this vitamin is from whole fruits and vegetables.
A number of mineral intakes were also a cause for concern. The intake of iron for girls above seven years was below the RNI with the oldest age group having an intake of only 58% of the RNI. Calcium intakes were likewise below the RNI for 11-18 year olds and zinc intakes were below the RNI for all ages. Magnesium intakes were some 20-50% below the RNI for various different age groups – a mineral found principally in foods of plant origin. Not surprisingly, given the sort of highly salted, processed foods eaten by children, sodium (salt) intakes were twice the RNI.
As far as physical activity was concerned – a key determinant along with diet for maintaining a suitable and stable body weight – 40% of boys and 60% of girls had less than the recommended one hour per day of moderate activity.
About a quarter of all children reported to be unwell on at least one day during the seven-day dietary recording period. Approximately 5% of children had been diagnosed as having food allergies by their GP with double this percentage as reporting undiagnosed unpleasant reactions to food.
What this survey reveals is that young children are eating a diet low in many of the vital health-promoting vitamins and minerals needed to help combat disease and high in disease-promoting foods such as high fat, high salt and high sugar convenience foods. Much of their daily nutrient intakes are gained not from the basic foods that provide them but from processed cereal, meat and dairy products that are themselves laden with harmful fats, sugar and salt. Fresh fruit and vegetable intakes are woefully lacking in the diet. The consumption of energy-giving starchy foods like unrefined cereals, breads, pasta, rice – the very foods that our diets should be primarily composed of – take a very poor secondary place in the diet. Meat and dairy products still take centre stage at every meal and children will undoubtedly suffer the consequences of this type of diet sooner rather than later in terms of their health and quality of life.
A recent report from the Cancer Research Campaign paints a similarly worrying picture of children's diets. One in 20 of the 2,635 children (aged 11-16) questioned by MORI claimed not to have eaten any vegetables in the previous week, with one in 17 not eating any fruit. Compared with the recommended intake of 35 portions of fruit and vegetables per week, most of the children had eaten fewer than 13 portions (273). Vegetarian children nearly always have higher fruit and vegetable intakes. A very recent study found that vegetarian preschool children had in several ways a more desirable nutritional profile than those consuming meat products. The research revealed that, compared to omnivore children, vegetarian children had lower intakes of total and saturated fat, cholesterol and sodium and higher intakes of beneficial nutrients like potassium and vitamins beta-carotene (the precursor to vitamin A), C and E. No surprises that these findings reflected a higher consumption of fruits and vegetables than their meat-eating counterparts (274).
An allergy is the term used to describe an adverse reaction to a substance from the body's immune system – the body's defence against foreign substances. Asthma (breathlessness with wheezing episodes), eczema (areas of red, itchy, flaky skin), rhinitis (constant runny or congested nose), hay-fever and urticaria (skin rashes) are said to be classical allergies. Food allergy is also included here where there is an immediate violent reaction to a food – eg to peanuts. Food allergy is distinct from food intolerance which is the term used to describe an adverse reaction to a food where the involvement of the immune system is unproven and reactions are usually slower. The most common food intolerance's are to foods that are eaten very regularly – two of the most common being cow's milk and wheat.
A recent paper in the European Journal of Clinical Nutrition found that a maternal diet rich in saturated fat during breastfeeding may be a risk factor underlying the later development of allergies (atopic sensitisation) of the infant. This was regardless of whether the mother herself was atopic or not. The effect of such a diet ends in infants whose sole source of energy and nutrients is breast milk during the period of rapid growth and development when the immune response is developing (1). Along with certain processed foods, saturated fats are predominantly found in foods based on animal products such as meat and cow's milk.
One in seven children (aged two to 15) now suffer from asthma – that's over 1.5 million sufferers and over 1500 people die each year in the UK as a result (7). There are many possible triggers for an asthma attack, from animal hair, environmental pollution to dust. Whilst food and drink are not considered common triggers for people with asthma, the British Allergy Foundation estimate that food and food additive allergy may be involved in 5-10% of asthmatics (8). The National Asthma Campaign is also aware that an allergy to dairy products can be a trigger for this debilitating disease (2). According to Dr Nand Kishore Sharma, “a milk drinker can never cure his asthma.” The mucous-forming quality of cow's milk seems to trigger asthmatic development (9).
In Sweden, doctors prescribed a vegan diet to twenty-four asthmatic volunteers. With only a few lapses, the volunteers followed the diet for a year and their health assessed. After one year 92% of patients reported an improvement in their condition and there was a significant decrease in asthmatic symptoms. This means that the decrease in symptoms was not down to chance or it just happening anyway but attributed to the change in the diet itself. In almost all cases, medication was withdrawn or drastically reduced. Some of the volunteers that had also suffered from rheumatic diseases found a lessening of these symptoms too (11).
Most cancers affect adults rather than children – and diet is a major contributory cause. However, there has been some research on childhood cancers looking at the different types of variables (a variable simply meaning any quality like age or type of food consumed that varies in each individual) associated with certain cancers. One study in particular found that brain tumours in young people to be significantly associated with (amongst other variables) maternal exposures during pregnancy to frequent consumption of cured meat. Cured meat products contain nitrosamines – the most potent nervous system cancer-causing agents known – and cooking such meats means that relatively high levels may be released in cooking fumes (12). In a separate study, a statistically significant (ie not due to chance) threefold increased risk of brain tumours in offspring was associated with low maternal intake of vitamin C during pregnancy. This means that there was an association for the offspring of women having low intakes of vitamin C of having a three times greater chance of brain tumour than women who had high intakes of vitamin C. This effect remained even after adjustment for other variables (13) – ie the association remained at this increased risk level even after taking into account other factors or variables that may have increased the risk for brain tumours. A vegetarian diet is naturally high in this antioxidant vitamin which can help to protect against cancer. Meat and dairy foods contain no vitamin C.
Diet has an enormous bearing on cancer according to the latest research (14) and it is therefore crucial that children are encouraged in healthy eating habits right from a very early age and that includes the removal of meat and dairy products from the diet. Indeed cancer specialist, Dr Rosy Daniel states that the main foods to cut out of your diet to prevent cancer are red meat and animal fats along with preserved foods and food additives. Thus she states that: “The best move for those who feel inspired to 'go the whole way' is to become completely vegan and eliminate animal products from the diet altogether.” (10). (See also Cancer section on how animal products affect cancer rates in adults).
There is growing concern about the effects of chemical pollutants on both adults and children. Many harmful substances like PCBs and dioxins are principally found in fatty foods – meat, dairy, eggs and oily fish. This is because fatty tissue has a tendency to 'soak up' and store these chemicals. Exposure to PCBs and dioxins are linked to immune system damage, some cancers and can negatively affect the intelligence of infants. Nursing infants especially may be exposed to an array of chemical pollutants from the breastmilk of their mothers. Hergenrather and colleagues analysed samples of breastmilk from vegan mothers. They found that the highest level of a number of chemicals in the breastmilk of vegan mothers was lower than the lowest level in the general population. For three chemicals, the mean levels found in the vegan mothers were only 1 to 2% as high as the average levels found in the non-vegetarian reference population (17).
The theory behind these differing results involves a consideration of food chains. Chemical pollutants that are fat-soluble accumulate at each stage in the food chain. Thus foods from the top of the chain like meat and dairy foods will have accrued and concentrated a larger measure of chemicals compared to plant foods at the very bottom
of the chain. Humans and thus nursing infants are regarded as living at the top of the food chain. A nursing infant will therefore be exposed to very high levels of chemicals accumulated from the maternal diet. Eating foods lower down in the food chain – plants – means that vegan mothers are likely to receive less chemical contaminants in their diet and their breastmilk will reflect this. Their nursing infants would, by extension, be similarly less exposed to harmful chemicals (17).
Chemical pollutants are now a major problem in the sea and the inclusion of fish in the diet is increasingly being seen as a risky business. Sea pollution means that farmed salmon and other oily fish like mackerel are now a reservoir of harmful toxins. Though now illegal, PCBs were once widely used and stay in the environment – including the seabed – for many years. These toxins bind to organic matter on the sea floor which is eaten and absorbed into the fatty tissue of small fish. These seabed feeders are in turn eaten by larger fish which accumulate the toxin load from these smaller fish. At each stage of the food chain toxins will be concentrated and increase.
The problem with chemical pollutants in the food chain is now extremely worrying. European Commission (EU) guidelines on safety limits for dioxins in foods means that a third of all Britons and half of all under-five's could be exceeding these safety limits (276, 277).
According to Dr Alan Gaby (President of the American Holistic Medical Association) cow's milk is probably the most common cause of infantile colic. So sensitive are some infants to cow's milk that they develop colic, even when exclusively breast fed, if their mother continues to consume any cow's milk in her own diet. Gaby
describes one study in which colic was cured in 68% of 19 breast-fed infants simply by eliminating cow's milk products from the mother's diet (20).
Crohn's disease often affects young people, causing pain after mealtimes and can also bring on a fever and mild diarrhoea. It is a chronic inflammatory bowel condition that affects 90,000 people in the UK and rates are rising rapidly. The condition is thought to be partly genetic but also partly dietary. Some researchers believe that the problem starts when infections or food sensitivities aggravate the digestive tract.
Crohn's disease is rare in Africa and rural Asia where diets are low in fat and high in fibre, more common in parts of Asia that have a Westernised diet and most common in North America and Northern Europe. A 19-year study in Japan suggests the strongest independent dietary risk factor for Crohn's is an increased intake of animal protein (22). The high fat, low-fibre, meat-based diets are believed to play a big part. One study found that when placed on a milk-free diet, one third of patients with Crohn's disease noticed a beneficial effect (23).
A report by Professor John Hermon-Taylor of St. George's Hospital Medical School, London, strongly supports the belief that bacteria responsible for Johne's disease (found in cattle) is the same bacteria that causes Crohn's disease – Mycobacterium avium subspecies paratuberculosis (MAP). Research is now suggesting that pasteurisation of milk – heating it to 72 degrees for 15 or 25 seconds – may not be enough to kill the bacteria (24).
Coronary heart disease (CHD) results from narrowing of the arteries and stiffening of the artery walls by hard fatty deposits – principally cholesterol. Blood supply to the heart muscles is then reduced and eventually they become short of blood, leading to a heart attack. Dietary cholesterol is only found in foods of animal origin and saturated fats (from processed foods and animal products) cause the liver to produce more cholesterol. The National Forum for Coronary Heart Disease Prevention states that: “in order to reduce the overall risk of coronary heart disease, healthy eating patterns should be established in childhood.” The report continues: “Children continue to eat more than the recommended percentage of energy in their diets from fat and consume less than the recommended amount of fibre. Several studies indicate that there has been no improvement in children's eating habits over the last ten years, with fat consumption at up to 43% of energy. The typical diet of school children in the UK is high in fat and sugar, low in fibre, low in iron and calcium and possibly low in folate. This means that children should be eating a diet which contains more bread, cereals and other starchy foods; more fruit and vegetables; and less fat, sugar and salty foods; and which is richer in minerals and vitamins.” (135). A vegetarian diet is ideal for promoting a healthy start in life and the sooner this diet is adopted, the better.
“The avoidance of meat is likely to reduce the risk of coronary artery disease, because meat is the major source of saturated fat”. “High consumption of red meat has adverse health consequences: thus vegetarian diets tend to impart health advantages.” Dr Walter C Willett, chairman of the Department of Nutrition at the Harvard School of Public Health and Professor of Medicine at the Harvard Medical School, one of the world's most distinguished experts on nutrition (251).
A study in the New England Journal of Medicine found that in autopsy studies of 204 children and young adults, aged two to 39, essentially all persons had fatty streaks in their aortas (the main artery from the heart to the body's tissues). The prevalence of fatty streaks in the coronary arteries (the arteries that carry blood to the heart) increased with age from approximately 50% at two to 15 years of age to 85% at 21 to 39 years. The study found that the same risk factors that encourage heart disease in older people – high cholesterol levels, overweight and high blood pressure – do the same in the young (136). A more recent study echoes this statement finding that early deposition of cholesterol in the walls of the arteries (atherosclerosis) is influenced by these risk factors for clinical Coronary Heart Disease (CHD) and that the long-term prevention of CHD must begin in adolescence or young adulthood (60).
The WHO reaffirms the importance of introducing a healthy high-fibre, low-fat diet early in a child's life, one of the major reasons being that it is known that the atherosclerotic process leading to heart disease starts in childhood (15).
But of course it is not only diet that influences the development of CHD. Exercise is also important. The National Forum for Coronary Heart Disease Prevention discovered that children's hearts are under a huge strain from a poor diet and lack of exercise. Only 4% of boys aged 11-16 and less than 1% of girls could sustain a heart rate of over 140 beats per minute for periods up to 20 minutes which is the recommended level for children (137).
As every parent is more than aware, sugar in the diet is the most important dietary determinant in the development of dental caries (tooth decay). The properties of different foods, including their stickiness and nutrient content can affect the rate at which caries are formed. The foods that can help reduce dental decay are starchy foods like rice, bread and potatoes and the less refined the better. Thus when children are given carbohydrates such as beans, oats, rice, wholemeal bread and fruit, they will tend to develop fewer and smaller cavities than children fed a more refined diet. Fresh fruit, even though it contains fruit sugars (fructose) has a low cariogenic potential (138). A typical vegetarian diet provides all these types of foods for children in abundance.
Diabetes mellitus is a group of disorders that all lead to elevation of glucose (sugar) in the blood due to inaction of insulin – a hormone produced by the pancreas that helps to take glucose out of the blood and into the body's cells. There are two types – Insulin-Dependent Diabetes Mellitus (IDDM) where there is an absolute deficiency of insulin and Non-Insulin Dependent Diabetes (NIDDM) where insulin
is still produced but insulin-sensitive cells become much less sensitive to it.
Although it is not a killer disease in itself, it is still a factor in the development of premature heart disease, kidney failure and blindness (25). Insulin-dependent diabetes mellitus (IDDM) is on
the rise (26) but the correct diet may help prevent this disease in some instances. (See Diabetes section on how animal products
There is increasing evidence from a number of studies to show that early exposure to cow's milk may be a trigger for IDDM. (139,222,227). In particular that cow's milk may destroy pancreatic beta cells (cells that secrete insulin) in genetically susceptible hosts, thus potentially increasing the risk for IDDM (223).
In 1994, Diabetes Care published a critical review and statistical analysis of cow's milk and IDDM by Hertzel Gerstein MD. His review showed that early cow's milk exposure may be an important determinant of subsequent IDDM and may increase the risk by about one and a half times. Dr Hertzel concluded that: "74-94% of the variation in diabetes incidence across countries may be related to differences in cow's milk consumption." (27).
Diseases of the middle ear are primarily a disease of childhood with as many as 1.5 million cases in Britain every year (30). They are often linked with a cold or other problems of the respiratory system. The avoidance of dairy produce is recommended by some nutritionists and may be particularly valuable (31).
According to the British Allergy Foundation: “...the food intolerance patient is often mildly addicted (often without realising it) to the food or foods causing the problem. The child with catarrh, recurrent ear infection, insomnia and irritability who craves regular milk, cheese and yoghurt is a good example. Night-time waking, only
settling after a drink of milk, is an even stronger clue! The complete disappearance of symptoms with milk avoidance (and recurrence with milk re-introduction) is then clear evidence of the relationship.” (36).
An allergy to cow's milk protein is the most common food allergy in childhood, affecting between four and 75 babies in every 1000 (32). It can cause a whole host of symptoms including eczema in a child but can also play a part in the development of eczema in adult life. A number of studies have therefore concluded that whole cow's milk should not be given during the first year of a baby's life in order to help prevent the onset of a number of diseases and conditions in childhood and adulthood (33,34).
In 1999 a government report stated that an astonishing 9.5 million people in the UK get food poisoning each year, at a cost of £750 million to the National Health Service. Amongst the groups most endangered by food poisoning are young children – especially under one's but anyone can suffer. Eating animal products causes 95% of all cases with meat being the main culprit as the bacterial micro-organisms responsible thrive on rotting flesh. Food poisoning can range from being quite mild to a cause of death from a heart attack or stroke. Abdominal pain is the first sign of poisoning with the pain becoming excruciating and may lead to explosive diarrhoea. Although the illness usually lasts for five to 10 days, most often it is a further one to two weeks before someone feels well again (35).
A very recent report in the New Scientist detailed results of a study from the Royal London School of Medicine which found that a staggering one in 10 British children are carrying superbugs resistant to one or more antibiotics. The proportion of adult carriers could be even higher. The researchers found that 11% of seven and eight year olds in the study population contained bacteria such as E. coli that were resistant to antibiotics that the children themselves had never previously been given (156). Once resistant, bacteria can easily spread from person to person and they can be picked up from food and agricultural sources. There is already strong evidence that feeding farmed animals antibiotics can lead to resistant strains of bacteria in the gut which can then be passed on to people by eating infected animal products. Farm use of antibiotics have caused antibiotic resistance to medical drugs in 3 types of food poisoning (Salmonella, Campylobacter and Escherichia coli) (41). Now researchers from the University of Illinois have discovered that bacteria in the soil and water beneath pig farms seem to be acquiring tetracycline resistance genes from bacteria originating in the pigs' guts. Once transferred, these resistance genes can persist and could potentially be passed on to humans through drinking water (236).
Escherichia coli (E. coli) is a normal inhabitant of the gastrointestinal tract of humans and animals. Whilst this bacteria colonises infants within hours after birth and performs vital functions throughout
life, some strains cause a wide range of diseases. The most serious form of E. coli is known as VTEC – verocytotoxin-producing Escherichia coli. Another name for this strain is E. coli 0157. It has been known since 1983 that Haemolytic Uraemic Syndrome (HUS) – a form of kidney disease – is a complication of a VTEC bacterial infection. The bacteria sticks to the gut and releases a chemical into the bloodstream which causes renal (kidney) failure. It is most likely to affect the young and the elderly. VTEC is now thought to be the biggest cause of acute (short term) renal failure in children. Farmed animals, in particular cattle, are thought to be the reservoir of infection (35).
“A diet free of meat, fish, milk and eggs is by far the safest and one that I highly recommend.” Emanuel Goldman Professor of Microbiology & Genetics (35).
Many children display intolerance to the proteins (casein) in cow's milk with symptoms initially restricted to diarrhoea and vomiting (37). Cow's have a four-stomach digestive system ensuring, amongst other things, that calves can deal with casein easily – but cow's milk is clearly not designed for humans. Because it cannot be readily absorbed by humans cow's milk remains undigested in the gut and begins to putrefy. This putrefaction in humans produces toxins and mucus and it clings as undigested matter to the lining of the intestines, preventing the absorption of vital nutrients in the body (29).
Although chronic diarrhoea is usually the most common gastrointestinal symptom of intolerance to cow's milk among children, a recent study in the New England Journal of Medicine found other consequences of feeding children cow's milk. This study reported on 65 children between 11 months and six years of age with chronic constipation who had been treated unsuccessfully with laxatives. Taking them off cow's milk and switching to soya milk cured 44 of the children. The authors concluded that in young children, chronic constipation could be a manifestation of intolerance to cow's milk (38).
A 1993 review study concluded that in some children whole cow's milk-induced gastrointestinal blood loss appears sufficiently great to be nutritionally significant and may contribute to the development of iron deficiency anaemia (40).
“Ideally the infant should be exclusively fed human milk for the first year of life... After the first year of life the child requires no milk of any type. The child, like us adults, can thrive without cow milk ever crossing his lips.” Frank Oski MD (1932-1996). Internationally recognised specialist in paediatric nutrition and former Director, Department of Paediatrics, Johns Hopkins University School of Medicine and Physician-in-Chief, the Johns Hopkins Children's Centre (281).
Along with Haemolytic Uraemic Syndrome (discussed above under Food Poisoning), Nephrotic Syndrome is another potentially serious kidney disease that may be related to the consumption of animal products. Nephrotic Syndrome is linked to cow's milk allergy. Children with the disease suffer from protein deficiency and severe fluid retention and may ultimately develop permanent kidney damage. In one study, allergy to cow's milk was found to be a cause of nephrotic syndrome in five out of the six children studied. Elimination of cow's milk from their diet resulted in a marked improvement (43).
Migraine is a common condition characterised by recurring intense headaches and affects around 10% of the population (44). Usually accompanied by nausea, vomiting and visual disturbances, a migraine can be terrifying, especially for young children. Meat, dairy products and eggs can all trigger a migraine (as can citrus fruits, wheat, nuts, coffee, tomatoes and chocolate). The Elimination Diet recommends abstinence from these foods for two weeks and then reintroducing them one at a time in order to assess which food or foods trigger the migraine attack (45).
The UK government has recognised that the prevalence of overweight and obesity in the population is increasing rather than declining (46). Body Mass Index (BMI) provides an estimation of an individual's level or risk of morbidity and mortality. BMI is calculated by dividing a person's weight (kg) by the square of his or her height (m). A BMI of 20-25 means that a person has a normal weight. A BMI of 25-30 indicates a person is overweight and a BMI of 30 and over indicates obesity. At least 10% of children in this country could be regarded as overweight (47). Two recent papers in the British Medical Journal make grim reading. The first study reported trends in overweight and obesity over 20 years in British children (four to 11 years) and found that in 1994 an average of 10% of boys and 14.5% of girls were overweight (39). A second study observed that one in five nine-year olds and one in three 11-year old girls are overweight (42). In 1998, the prevalence of obesity in England had trebled compared to 1980 to 21% of women and 17% of men. Currently, over half of women and about two thirds of men are overweight or obese (48). It is therefore vital for current as well as future health that weight problems are tackled early on.
Psychological damage can be inflicted early in childhood as a result of being overweight and this damage can last a lifetime. Healthy eating habits should be started early. The typical diet of school children in the UK is high in fat and sugar, low in fibre, low in iron
and calcium and possibly low in folate. “Diet in childhood may influence the development of dental disease, constipation and other bowel disorders, nutritional anaemia, obesity and overweight, and may increase the risks in adulthood of low bone mass, coronary
heart disease, stroke and some cancers including breast and bowel cancer.” So states the National Forum for Coronary Heart Disease Prevention (49).
The 1991 Bogalusa Heart Study showed that even mild obesity in childhood is related to higher levels of blood pressure, insulin and cholesterol and that to some extent these track into adulthood. There is evidence that fatty deposits and the development of atherosclerosis start in childhood and emphasise the need for preventative cardiology in early life (50).
Research is clear on how diet affects obesity: energy (food) intake exceeds energy output. Meat and dairy products all contain saturated fat. A much healthier source of energy comes from complex, slow-releasing carbohydrates and the good news is that vegetarians are on average leaner than omnivores (51, 52, 53, 54).
Rheumatoid Arthritis affects more than 750,000 people in the UK and one child in every thousand has arthritis. Dairy products, meat and eggs can all be common triggers for rheumatoid arthritis (as can corn, nuts and citrus fruits) in children and adults alike. In 1985 the Journal of the Royal Society of Medicine reported on the case of a 14 year old girl who had first been admitted to hospital at the age of eight due to pain and swelling of the wrist. During the following years she had been hospitalised nine times as the swelling and pain spread and been diagnosed with juvenile rheumatoid arthritis (JRA). At 14 she again presented at hospital and after tests, doctors advised her to avoid dairy products and the swelling disappeared within a week. By the end of three weeks the pain had also gone. The arthritis was to return just three times in this girl's life, each time after she'd eaten dairy products. Even a small piece of milk chocolate was enough to cause the painful symptoms to recur (61).
Researchers are currently investigating a link between cow's milk and SIDS, saying that some cot deaths may be as a result of an allergic reaction to cow's milk. Research at Southampton University has discovered certain proteins, released during an allergic reaction, in the blood of babies who have died with no apparent cause. Researcher Dr Andrew Walls said that cow's milk was “a promising line of research.” Although the number of babies dying from cot death has dropped in recent years, it still kills nearly 10 babies a week and is the leading cause of death among children aged under 12 months (62).
Many diet-related diseases and conditions begin in childhood but don't show themselves until much later. The 1997 Scientific Conference on Preventative Nutrition: Paediatrics to Geriatrics reported that similar dietary guidelines are appropriate for children (aged over two years) as well as adults in order to reduce the risk of cancer, heart disease, diabetes and obesity. These include choosing a diet with plenty of wholegrain products, vegetables and fruits and a diet low in fat, saturated fat and cholesterol (64). When you consider that the main source of saturated fats in the diet are processed foods and animal products – both meat and dairy – the arguments in favour of a vegetarian diet get stronger and stronger.
Experts worldwide now believe that over a third of cancer deaths – and possibly many more – may be linked to diet.
The percentages of cancer deaths attributable to various factors is shown below (65):
Food Additives 1%
One quarter of a million people in the UK discover they have cancer every year and it kills one in four. If the two main risk factors (diet and smoking) were noted and acted upon, it is estimated that two thirds of cancers could be prevented. In 1981 Professor Sir Richard Doll estimated that 35% of fatal cancers are linked to diet. He currently estimates that 20-60% of cancers might be reducible by practicable dietary means (66).
According to the WHO, evidence suggests a direct relationship between the risk of certain cancers and the level of total fat in the diet and that it may prove necessary to lower the upper limit for total fat [intake] from 30% to 25% or perhaps even 20% (67).
The EPIC (European Prospective Investigation on Cancer) Project initiated in 1993 is a multi-centred prospective study designed to investigate the relation between diet, nutrition, various lifestyle factors and the risk of cancer. Prospective studies record the diets of subjects and track their health over the coming years. The EPIC study is set against the background that the most consistent result of epidemiological (population) studies on food choices and cancer is that a diet rich in vegetables, fruit and more generally, in plant foods is associated with a reduced risk of many cancers (59). The study has 480,000 subjects in nine European countries including 60,000 participants in the Oxford Study for the UK element of the project. Data is now being prepared for analysis and the results will be compiled over the next year (86). (See section under Colorectal Cancer below for interim results from EPIC studies.)
Way back in 1892, Scientific American asserted that “cancer is most frequent among those branches of the human race where carnivorous habits prevail.” (68). More recently it has been found that the very process of cooking meat, particularly at high temperatures for long periods, produces carcinogens which are thought to increase certain cancers (69). As animal proteins are heated, they produce cancer-causing chemicals called heterocyclic amines. This phenomenon occurs in all meats and the level of heterocyclic amines is 15 times higher in chicken than beef (70), suggesting that chicken can no longer be viewed as a healthy food option.
Heterocyclic amines are most strongly linked to colon cancer but have also been linked to cancer of the breast, ovary and uterus. A 24-year Finnish study of nearly 10,000 people found that fried meat consumption was linked to higher risk of these hormone-related cancers in women (71).
In 1996, researchers at the American Institute for Cancer Research (AICR) presented new evidence on how fat affects cancer. Dr Laurence Kolonel from the University of Hawaii Cancer Research Centre and his team believe that fats (mainly of animal origin) in the diet produce bile acids in the intestinal tract that seem to promote colon cancer. Apparently eating high-fibre foods like fruits, cereals and vegetables can reduce the concentration of these bile acids and help prevent colon cancer (72).
High-fat diets also increase the amount of oestrogens (female sex hormones) in the blood. It is known that many breast tumours are fuelled by an excess of oestrogen. When women begin a low-fat diet, their oestrogen levels drop sharply and vegetarians have significantly lower oestrogen levels than omnivores (63,73,74).
Researchers in New York tested the effect of low-fat diets on immunity and found that people with a low-fat diet had more 'natural killer' cells than those on a high-fat diet. These cells seek out and destroy any abnormal cells that may turn cancerous. The authors of this paper state: “The enhanced natural cytotoxicity may be one of the factors contributing to the lower cancer risk shown by vegetarians.” (75).
Breast cancer has now taken over lung cancer as the most commonest cancer in the UK. In 1980 there were 25,000 cases each year but now there are 40,000 women each year being diagnosed with the disease. Asian countries have a much lower rate of breast cancer than Western countries but when Japanese girls are raised on Westernised diets, their rate of breast cancer increases dramatically. In the 1940s when breast cancer in Japan was rare, less than 10% of calories came from fat while today's Western diets have up to three or four times that amount (78). A Japanese study found the risk of breast cancer was eight and a half times higher in affluent women consuming meat every day than poorer women who did not eat meat daily (16).
Researchers in Buffalo, New York calculated what they believed to be the degree of risk posed by fat in the diet. For a woman with metastatic breast cancer where the disease has spread to other parts of the body, the risk of dying from the disease at any point in time increases 1.4-fold for each 1000g of fat consumed monthly (79). This means that the typical Western diet could lead to about a 40% higher risk of dying of breast cancer at any given point, compared to a low-fat vegetarian diet (80). The relationship between dietary habits and breast cancer was studied in 240 women aged 50-65. Results suggested that diets that are low in fat, high in fibre, carbohydrates and Vitamin A seem to help the prognosis while alcohol slightly worsens it (81). The World Cancer Research Fund echoes this view. The advice given in their information leaflets is that research has shown that cancers of the breast are more common in overweight women and a diet to lower cancer risk is low in fat, high in vegetables, fruits and wholegrains (82). Well-balanced vegetarian diets typically incorporate this way of eating as a matter of course. A diet rich in vegetable products, especially fibre, may lead to a later menarche (onset of menstruation) which is thought may lessen the risk of developing breast cancer later in life (83).
The association of cooked meat and thus exposure to heterocyclic amines formed during high-temperature cooking may also play an important role in the risk of breast cancer. This was the conclusion of a paper by Zheng et al who conducted a case-control study among members of the Iowa Women's Health Study. This study looked at a group of 41,836 women who had been followed over the years from 1986 for mortality, cancer incidence and diet eaten. During 1995 to 1996 Zheng and colleagues looked at all members of the original group who had been diagnosed with breast cancer (the cases), compared them to a random sample of women from the original group who were free of cancer (the controls) and looked at the intake and preparation of meats consumed by both groups over the years. This analysis found that risk of breast cancer was elevated with increasing intake of well done to very well done meat (56).
The role of cow's milk as a possible risk factor for breast cancer has also been investigated. There is increasing speculation that one particular hormone – Insulin-Like Growth Factor-1 (IGF-1) – may have a major role to play. IGF-1 is a naturally occurring compound that stimulates growth in children and declines as a child ages. IGF-1 also encourages breast cancer cells to multiply and cow's milk contains about 30 micrograms of IGF-1 in every litre (84). A recent paper published in 1997 in Medical Hypotheses put forward the view that regular cow's milk ingestion after the age of weaning may produce enough IGF-1 in mammary tissue to cause the cell cycle to supersede its boundaries of control, thus increasing the risk of breast cancer (18). A study published in The Lancet found that pre-menopausal women with even small increases in blood levels of IGF-1 have up to seven times the breast cancer risk of women with lower levels (85).
Professor Jane Plant was diagnosed as having breast cancer in 1987 and had five recurrences. She began to research the disease and came to the conclusion that cow's milk had a major part to play. Seven years on, and after removing dairy products from her diet, the cancer has never returned. Her book on the subject presents the argument that cutting out cow's milk dramatically reduces the body's exposure to antibiotics, biologically active chemicals and a powerful cocktail of hormones thought likely to promote breast – and prostate – cancer (19).
Colorectal cancer (also called bowel cancer) refers to cancer in the colon (first part of the large intestine) and rectum (last part of the large intestine). In 1991 in England and Wales over 27,700 people had large bowel cancer (248). In the Harvard Nurse's Health Study, it was found that women who ate more animal fat had a greater risk of bowel cancer (76) and similar results have been found for men. In one prospective study the dietary risk factors for colorectal adenomas – precursors of cancer – found a positive association with saturated fat but a negative association with fibre (77).
Contrary to claims that white meat is somehow healthier than red meat a 1998 prospective study (whereby subjects diets are recorded and their health tracked over the coming years) identified both red meat and white meat (fish and poultry) intake as important dietary risk factors for colon cancer. Researchers at Loma Linda University examined eating habits of 32,000 men and women between 1976 and 1982 and monitored cancers over the six years. Among those who avoided red meat but ate white meat less than once a week, colon cancer risk was 55% higher than for those who avoided both kinds of meat. Those who had white meat at least once a week had more than a three-fold risk of suffering colon cancer. Conversely eating legumes such as beans, peas or lentils at least twice a week was associated with 50% lower risk compared to never eating these foods (21). A paper in the American Journal of Epidemiology in 1998 makes two very interesting points. Firstly that it is the overall dietary intake pattern that is important with greater emphasis on fruits and vegetables that is associated with lower risk for colon cancer. Secondly that 'substituters' (people who use low-fat dairy products instead of high-fat ones, margarine instead of butter, poultry instead of red meat and wholegrains instead of refined grains) were at reduced risk for colon cancer but the reduction was not significant. The authors conclude that this was because many adopting these 'substituter' so-called 'healthier' diets were not increasing their vegetable consumption and this aspect of the diet is important in significantly reducing colon cancer risk (55).
Fibre or non-starch polysaccharides (NSP) are major constituents of a plant-based diet and it has been long thought that high-fibre diets offer a measure of protection against colon cancer. The reason for this centres around the digestion of dietary fat. Fat is broken down in the body by the secretion from the gallbladder of bile acids made in the liver. Bacteria in the intestines turn these bile acids into cancer-promoting substances (mutagens) called secondary bile acids. Meat – unlike plant foods – fosters the growth of bacteria that cause these disease-causing acids to form. Fibre actually changes the type of bacteria that are present in the intestine so the production of carcinogenic (cancer-causing) secondary bile acids is reduced (88). Fibre may also help both by diluting the presence of such harmful acids in the faeces and by greatly speeding up their passage through the colon.
Jerome J DeCosse, a surgeon at Cornell Medical Centre in the US gave a high-fibre grain supplement to patients with recurring polyps of the colon. Polyps are small growths that may go on to become cancerous but within six months in this study, the polyps became smaller and fewer in number (90). Virtually every food that comes from a plant contains fibre while food from animal sources contains no fibre at all.
However it may not be simply a matter of increasing fibre and still eating meat that will help reduce risks of colon cancer. A study by O'Keefe et al in 1999 found that the low prevalence of colon cancer in black Africans was not so much explained by dietary 'protective' factors including fibre but may be influenced by the absence of 'aggressive' factors such as excess animal protein and fat as well as differences in colonic bacterial fermentation (57).
Preliminary results from the EPIC study on the link between meat consumption and colorectal cancer are showing that a high intake of red meat and particularly of processed meat, are associated with a moderate but significant increased risk of colonic cancer (89). Overall first results suggest that frequent consumption of beef, veal, pork and lamb is associated with a 20-40% increase in colorectal cancer risk (87). This contradicts a recent review paper by Key, Davey and Appleby which found no association between a vegetarian diet and a reduced risk of colonic cancer (225).
A population-based case-control study of dietary factors and endometrial cancer published in 1993 revealed that women eating the most animal fat and animal protein had more than three times the risk of developing this particular cancer. High consumption of meat, eggs and fresh fish were all associated with elevated risk (105).
Non-Hodgkin's lymphoma – a form of cancer – occurs more frequently in individuals with a suppressed immune system. Some types of dietary fat and protein have been linked with a decreased immunological response. A recent study published in 1999 found that greater dietary intake of certain meats and fats was associated with a statistically significant increased risk of this form of cancer. Intakes of beef, pork or lamb were all implicated (113).
Dr Daniel Cramer of Harvard University found that in a case-control study a higher intake of dairy products was linked to a higher risk of ovarian cancer. In particular the milk sugar found in cow's milk – lactose – was thought to be the problem when it is broken down in the body to galactose. It is thought that the galactose damages the ovary (94). This of course means that if it is the milk sugar not the milk fat causing this particular problem a switch to low-fat cow's milk products may not help to lessen ovarian cancer. Ovarian cancer also seems to be more common in countries with a higher total fat intake (95).
Risk factors for pancreatic cancer were evaluated in a 20-year cohort study between 1966 and 1986. A cohort study is one in which two groups of people are selected on the basis of differences in their exposure to a particular agent – in this case dietary habits including meat consumption. This study of over 17,500 men in the United States revealed – after adjustment for other risk factors – that those who ate meat were three times more likely to develop cancer of the pancreas than those with low meat consumption (96).
International comparison studies have shown that as Japan's diet has Westernised, so the incidence of pancreatic cancer has increased. One particularly pertinent aspect of this Westernised diet is in terms of animal fat consumption that previously was very low. Consumption has steadily increased from a daily level of 6.5 grams of animal fat per person in 1955 to 27.6 grams in 1987 and animal protein consumption has doubled in these 30 years (98).
One in 12 men will develop prostate cancer at some point in their lives. The number dying from the disease has almost tripled in the past 30 years to 9,500 in 1998. By 2015, it is expected to overtake lung cancer to become the most common male cancer. Professor Jonathan Waxman who founded the Prostate Cancer Charity believes that dietary factors are very strongly implicated. The rise in meat consumption since World War Two is the main culprit but eating dairy products can also increase your chances of getting it due to the hormones in cow's milk. Vegetarians are half as likely to get it as non-vegetarians (91).
Research has shown that men who consume diets based on animal products tend to have more testosterone and oestrogens compared to men who eat plant-based foods. This increase may be due to over-production of these hormones in the body or, since fibre in the diet is essential for the normal excretion of sex hormones, a lesser ability to get rid of them. This hormonal boost can affect the prostate and, according to the Physicians Committee for Responsible Medicine, is probably the reason for increased cancer risk among those on a meat-based diet (101).
IGF-1 (Insulin-Like Growth Factor-1) – found in cow's milk – is already known to encourage breast cancer cell growth and may also be a risk factor for prostate cancer. A very recent study reported in the British Journal of Cancer found that vegan men had a significant 9% lower IGF-1 concentration compared to meat eaters and that this might reduce their risk of prostate cancer (97). Other studies have likewise found that cow's milk consumption is also very strongly implicated as a risk factor for prostate cancer (256, 257, 258).
An important study published in 2001 in the prestigious American Journal of Clinical Nutrition also gives weight to the theory that dairy products are risk factors for prostate cancer. A high calcium intake, mainly from dairy products, may increase risk by lowering concentrations of a form of vitamin D (actually a hormone) thought to protect against cancer of the prostate. Results here showed that men consuming two and a half or more servings of dairy products (a serving being 140 grams of cheese, 170 grams of yoghurt or 75 mls of cow's milk) a day appeared to be almost a third more likely to develop prostate cancer then those eating the lowest amounts (less than half a serving per day). The authors concluded that their results supported the hypothesis that dairy products and calcium are associated with a greater risk for this particular cancer (269).
Earlier in 1999 Grant used an ecologic (multi-country analysis) approach. Here mortality data from a particular year for various age groups in a number of countries (41 in this example) were compared with national consumer macronutrient supply values for a range of foods. Grant found that the non-fat portion of cow's milk had the highest association with prostate cancer. For an association to be causal (ie in this instance that the non-fat portion in milk actually causes prostate cancer) a number of criteria need to be satisfied including strength of the association, consistency and most important of all a likely mechanism to link the suspected agent with the observed effect. Grant concluded that for cow's milk the most likely mechanism may be related to calcium with high intakes suppressing conversion of one form of vitamin D to another form which has an anti-tumour effect for prostate cancer (270).
In 1993, American researchers analysed data from the prospective cohort Health Professionals Follow-up Study looking at diet and subsequent disease patterns. Of all the foods studied red meat represented the food group with the strongest positive association with advanced prostate cancer (99).
A lower risk of prostate cancer is associated with diets higher in rice, soya bean products and green and yellow vegetables (100). Not surprising then that vegetarians have been found to have low rates of prostate cancer (102) and increasing consumption of beans, lentils, fruits and vegetables are all associated with significantly decreased prostate cancer risk (103).
Uterine cancer is linked to diets that are high in fat and obesity (104). Vegetarians have been shown to eat a diet that is lower in dietary fat and have lower body weights than non-vegetarians (107).
Eating high fibre foods can reduce the concentration of destructive bile acids and help prevent cancer from developing by sweeping away toxins in the intestines before cancers can form. The link between higher fibre consumption and lower cancer risk is clear and has been reaffirmed in many studies. Fibre first received worldwide attention in the 1970s when international studies showed that in countries where diets included large amounts of fibre, there were fewer cases of colon cancer, diverticulitis and other intestinal diseases, haemorrhoids, hiatus hernia, appendicitis, varicose veins, gallstones and heart disease. Since then, many scientists have reached similar conclusions and have also found that diets high in soluble fibre (eg oats, soya beans, fruits and vegetables) appear to lower the risk of diabetes and may reduce levels of cholesterol in the blood. The World Cancer Research Fund recommends adults introduce children to fibre-rich foods at an early age to ensure they grow up enjoying and eating these foods (106).
Fruits and vegetables contain antioxidants such as beta-carotene (the precursor to vitamin A), and vitamins C & E which protect body cells against damage. The evidence is overwhelming that an abundant intake of fruits and vegetables can play an important role in reducing cancer risk (108). Members of the cruciferous family – broccoli, Brussels sprouts, cabbage and cauliflower – are widely regarded as potentially cancer preventative foods. A number of papers have looked at the issue and found strong evidence to support these beliefs (92, 93).
For these reasons, it is recommended we all eat at least five portions of different fruits and vegetables per day as well as more starchy carbohydrates. One portion is equivalent to one medium fruit like an apple, banana or orange, two smaller fruits like kiwis or plums, a cupful of berry fruits, a large bowlful of green salad or two
serving spoonfuls of most cooked vegetables and pulses like beans and lentils.
The World Cancer Research Fund (WRCF) states: “The emphasis of our meals needs to be reversed; it is plant foods that should be the focal point of our dinner plate, not meat and dairy products.” (109).
The WCRF also has this to say about some important vitamins and minerals from fruits and vegetables:
“Beta-carotene is the pigment that gives dark green, yellow and orange fruit and vegetables their colour. In the body it is converted to Vitamin A, which may well lower our risk of developing cancer, especially lung cancer (167).
Vitamin C is believed to protect against cancer of the oesophagus and stomach. It is found almost exclusively in fruits and vegetables (167).
Vitamin E may help in the prevention of stomach and throat cancers as well as other serious illnesses. It is present in moderate levels in most fresh fruits and vegetables and at higher levels in cereals (167).
Selenium is a mineral that can probably protect against colon, breast and possibly other cancers. Scientists say an adequate amount passes into fruit and vegetables from the soil in which they are grown” (167).
There has been much publicity in the lay press – both negative and positive – surrounding soya products and their effects on the body – no less so than in the area of cancer. Some studies point to the chemo-preventative nature of soya whilst other studies seem to point to the opposite effect. On balance research seems to be suggesting that soya foods can be a very valuable part of a varied vegetarian diet.
Soya beans contain all eight essential amino acids (building blocks of protein), have strong antioxidant properties, are very rich in soluble fibre, contain no cholesterol and are high in the essential fats which are often lacking in many people's diets. Studies have also demonstrated that soya lowers cholesterol levels and the large amount of evidence linking soya to good heart health has even led the FDA (the US Food and Drug Administration) to allow health claims on food products containing soya.
Soya beans are rich in a class of compounds called isoflavones. These act as weak oestrogens – hence the name also given to isoflavones – phytoestrogens or 'plant hormones'. Phytoestrogens appear to have both antioestrogenic and oestrogenic effects in the body – thus they act as oestrogen modulators. The prevailing thought is that these plant hormones exert antioestrogenic effects in a high-oestrogen environment (such as that exists in pre-menopausal women) and oestrogenic effects in a low-oestrogen environment (such as that existing in post-menopausal women). Thus phytoestrogens appear to normalise oestrogen in the body. At the present time the data so far produced is insufficient to conclude that soya is protective against cancer but the data certainly warrants further investigation of this relationship. Indeed one important researcher in the field of soya states that: “given the nutrient profile and phytochemical contribution of legumes, nutritionists should make a concerted effort to encourage the public to consume more beans in general and more soya foods in particular.” (110).
A study published in The Lancet in 1991 of women in Singapore found that soya protein had a significant protective effect against breast cancer. This was in strong contrast to the finding that red meat consumption was a significant predisposing risk factor for this type of cancer (111). Soya beans are a mainstay of Asian diets and may be one factor why cancer levels are lower than in the West (112).
A landmark study published in 1994 in the British Medical Journal found that vegetarians suffer 40% less cancer mortality than the population average, even with controls for smoking, body weight and socio-economic status (114). In the words of Professor Jane Plant a completely plant-only diet may confer even greater advantages: “Undoubtedly, the best anti-cancer diet would be completely vegan.” (58).
Coronary Heart Disease (CHD) is the cause of nearly a quarter of all deaths in England and persists as the UK's number one health problem with one in three men and one in four women dying from it. Treating CHD costs the NHS £500 million each year (115). According to the WHO's report on diet, nutrition and disease published in 1991, dietary factors clearly play a role in CHD: “All the available evidence suggests that, for cardiovascular disease and cancer, diet has an influence throughout the life cycle, even though the end-points are manifested in the adult.” (116).
World renowned heart surgeon Christiaan Barnard performed the world's first heart transplant in 1967. After 30 years of surgery he has come to the conclusion that most heart attacks are unnecessary – we have the power to prevent them. He states that our diet lacks sufficient fruits and vegetables, is not properly balanced and that we should live like the people of Crete. Here heart disease is almost unknown, and along with other dietary norms fruit and vegetables are the mainstay of the diet and their consumption of meat is 32% less than in northern Europe (121). This is of course the typical 'Mediterranean' diet that has many elements to it that support a far more healthier way of eating. Indeed two recently published articles in the British Medical Journal detailing the results of the WHO World Health Report 2000 clearly show that many of the countries performing best in terms of health of their populations are characterised by such diets (265, 266). A well-balanced vegetarian diet – by its very nature – is very much along the lines of a Mediterranean-type diet typified as it is by higher intakes of plant foods especially fruits and vegetables and of course zero meat consumption.
A number of studies have demonstrated that a vegetarian diet can lead to a much reduced risk of heart disease. A key paper published in 1998 concluded from a collaborative analysis of 76,000 men and women in five prospective studies that vegetarians have a lower risk of dying from ischaemic heart disease (IHD) than non-vegetarians (122). A similar review study in 1999 actually put a figure to this decreased risk. Here, compared with non-vegetarians, Western vegetarians were found to have a lower BMI, a lower plasma cholesterol concentration and lower mortality from ischaemic heart disease by about 25%. These findings led the authors to state that the evidence available suggests that widespread adoption of a vegetarian diet could prevent approximately 40,000 deaths from IHD in Britain each year (123). Faced with such clear evidence as this and a cash-strapped NHS it is a surprise that a vegetarian diet is not available by prescription! Indeed a recent comprehensive review of the beneficial and adverse effects of vegetarian diets in various medical conditions makes this exact point. The authors conclude that: “The burden of modern lifestyle diseases is enormous when the costs of investigation, diagnosis, treatment and primary and secondary prevention are included. Thus, dietary intervention with a vegetarian diet seems to be a cheap, physiological and safe approach for the prevention, and possibly management of modern lifestyle diseases.” Dr M Segasothy, NT Clinical School of Medicine of Flinders University, Australia (239).
A new piece of research published this year in the Journal of Clinical Pathology gives a clue as to one of the reasons why a vegetarian diet may lead to lower heart disease risk. Scottish researchers found that levels of salicylic acid in the blood of vegetarians were up to one and a half times significantly higher than in meat eaters. Some vegetarians had levels up to 12 times higher (253). Salicylic acid is the main component of aspirin – widely prescribed to reduce the risk of heart attacks – which helps fight the inflammation that causes most cardiovascular illness. Salicylic acid is also present in fruits and vegetables suggesting a high dietary intake may produce some of the same good effects as aspirin. Dr John Paterson who helped conduct the research states there is also evidence that aspirin can protect against bowel, breast and lung cancer as well as Alzheimer's disease. “It may be that salicylic acid in the diet can help prevent these diseases.” (252).
Another reason why vegetarians have a reduced risk of heart disease is thought to be caused by factors in the diet having a beneficial effect on vascular dilatory responses. Impairment of the ability of blood vessels to dilate or relax is an important early event in the lead up to plaques forming in vessels. A recent study reported in Atherosclerosis found that the vascular dilatory responses of vegetarians are better than omnivores. Just as importantly these effects are dependent on diet alone, independent of other known risk factors for atherosclerosis (clogged up arteries) such as smoking, diabetes, hypertension and ageing (261).
Whilst not the only factor in the causation of CHD cholesterol is still considered a prime indicator of risk for this disease. Dietary cholesterol is not an essential nutrient since the liver can make all that it needs. Cholesterol is transported in the bloodstream and supplied to different body tissues by five major classes of lipoprotein, (fat and protein complexes) the two most important being low-density lipoproteins (LDL-cholesterol) and high-density lipoproteins (HDL-cholesterol). LDL-cholesterol transports cholesterol to the arteries and plays a significant role in the metabolic processes leading to atherosclerosis. HDL-cholesterol – 'good cholesterol' – carries cholesterol to the liver so the body can get rid of it. Since LDL-cholesterol accounts for most of the total cholesterol in the blood, elevated total serum cholesterol is therefore regarded as a reliable indicator of the risk for developing atherosclerosis and CHD (120).
The foremost dietary determinant of total serum cholesterol is the intake of saturated fat. This type of fat is found principally in foods of animal origin and is particularly rich in the fatty portion of meat, eggs and milk products. Studies have suggested that whereas saturated fats elevate serum cholesterol levels, polyunsaturated fats (and possibly monounsaturated fats) actually lower levels (124). This is echoed by research showing that replacement of saturated fatty acids with almonds or walnuts (typical vegetarian staples which are high in polyunsaturated fats) lowers both total cholesterol levels and LDL-cholesterol levels. Compared with a reference population this study found that there were significant reductions of 7% and 10% respectively with almonds and 5% and 9% reductions respectively when walnuts were used in place of saturated fat (267). Saturated fat encourages the body to make more cholesterol than it needs and seems to prevent it from getting rid of the excess, leading to the narrowing of the arteries (118). Approximately 15% of dietary energy (calories) in the UK diet comes from saturated fat. Experts recommend that this be reduced to just 11% (125). A very recent literature review makes the point that the advice to reduce consumption of eggs – a major source of dietary cholesterol – may still be important in the prevention of coronary heart disease. The paper's authors also state that other major sources of dietary cholesterol – dairy fats and meat – are already considered as increasing the risk of heart disease because of their saturated, cholesterol-rich profiles and should likewise be reduced (268).
The WHO report in 1991 states: “Population data clearly associate a decrease in saturated fatty acid intake with a progressive fall in cardiovascular disease mortality... A value of 10% of energy has thus been fixed as the maximum upper limit for saturated fatty acids... Saturated fatty acids are not essential nutrients... The lower limit for saturated fatty acids is therefore zero.” (127).
This statement is lent support when one considers that from a public health standpoint, 'lean' red meat diets and white meat diets are both largely ineffective in reducing serum cholesterol concentrations. Hardly suprising when one considers that unlike fat, cholesterol is located mainly in the lean portion of meat. Low-fat vegetarian diets that forgo all meats can achieve serum total and LDL-cholesterol concentration falls of 23% and 32% respectively. These stand in stark contrast to many cholesterol-lowering programs that see serum cholesterol concentrations fall by only 5 to 6% (126). A recent study by Ashton and colleagues also highlights the greater benefits of plant sources of protein compared to protein from lean meats. Replacement of lean meat with tofu (soya bean curd) in this study found significantly lower total cholesterol and triglyceride (fat) levels compared with the lean meat diet (237).
There is increasing evidence to suggest that vegans may have an even greater advantage. Thorogood et al found that differences in total cholesterol concentration suggest that not only the incidence of coronary heart disease may be 24% lower in lifelong British vegetarians but 57% lower in lifelong vegans (131).
There is increasing speculation that cow's milk products may be playing a role in the high rates of CHD in Western countries. Research by Sacks et al has found that dairy products were the major sources of dietary saturated fat and cholesterol and that ingestion of fatty dairy products raises the LDL-cholesterol levels in the subjects followed (128). Way back in 1982 Segall made the compelling point that in Switzerland a falling cardiovascular mortality rate has been associated selectively with a fall in milk consumption, amounting to 46%, between 1951 and 1976 (129).
The theory that plasma homocysteine levels are directly associated with cardiac disease risk is one gaining considerable ground. This too may therefore be another factor why plant-based diets reduce CHD risk. Homocysteine is an amino acid found in high levels in foods of animal origin. A straightforward hypothesis would be that a vegetarian diet and more so vegan diet would have lower levels of this potentially damaging protein. Very recently DeRose and colleagues in Preventive Medicine published a study clinically demonstrating such an effect. In just one week on a vegan diet, as well as lifestyle interventions, subjects mean homocysteine levels fell 13% (130).
A study by Grant into possible dietary associations with CHD in 1998 found that milk carbohydrate (lactose) had the highest statistical association for CHD for males aged 35+ and females aged 65+. Non-fat milk was found to have the highest association for CHD for males aged 45+ and females aged 75+, while for females 65-74, milk carbohydrates (and sugar) had the highest associations. A number of possible mechanisms have been put forward for this, the most prominent of which is the plasma homocysteine hypothesis. Animal proteins contribute to homocysteine (Hcy) production and cow's milk lacks adequate B vitamins (vitamin B6, B12 and folic acid) to convert Hcy to less harmful products. Lactose and calcium in conjunction with Hcy from consumption of non-fat milk may also contribute to calcification (hardening) of the arteries (132).
Not only can a vegetarian diet lower the risks of getting heart disease in the first place it can also halt and reverse even severe CHD. Dr Dean Ornish and colleagues have demonstrated that a near-vegan diet (no animal products allowed except egg white and one cup per day of non-fat milk or yoghurt) caused a significant overall regression of coronary atherosclerosis in patients with moderate to severe coronary heart disease (119, 211).
“The Reversal Diet is a very low-fat vegetarian diet.. This is what the patients in our study consumed, whose coronary heart disease began to reverse. I am convinced that this is the world's healthiest diet for most adults, whether or not they have heart disease.” Dr Dean Ornish, Director of Preventive Medicine Research Institute, California, and the first clinician to offer proof that heart disease can be halted or even reversed on a vegetarian diet (282).
The evidence for a protective effect of a vegetarian diet for heart health is very clearly documented in an on-going landmark study – The China Health Study. This is a comprehensive survey of diet and mortality characteristics in 65 counties in rural China overseen by Professor Colin Campbell. All the evidence points to the conclusion that even small intakes of foods of animal origin are associated with significant increases in plasma cholesterol concentrations, which are associated, in turn, with significant increases in chronic degenerative disease mortality rates (117).
Fibre or NSP (Non-Starch Polysaccharides) is a collection of indigestible substances found in all plant cells. Hence virtually every food that comes from a plant will contain it and is why vegetarians have greater intakes than non-vegetarians do. Food from animal sources contains no fibre whatsoever. There are two types of fibre – soluble and insoluble. Soluble fibre is found in fruits and vegetables and the richest sources are vegetable protein foods like lentils, peas and beans. Oats are also rich in this type of fibre. Soluble fibre dissolves in the fluid of the gut and helps to maintain even blood sugar levels. It is also known to reduce cholesterol levels in the body. Insoluble fibre found in cereals, breads, rice, pasta as well as fruits and vegetable adds bulk to waste products ensuring easy passage of this waste through the digestive system.
According to the National Food Survey the average intake of fibre in the UK diet is 11.9 grams per person per day (133). Nutritionists are in agreement that adult diets should contain an average for the population of 18 grams of fibre per day (134).
Not surprisingly, vegetarian diets are found to be far richer in fibre than average meat-based diets (254).
Non-Insulin Dependent Diabetes (NIDDM) is much more common than the childhood-onset variety (IDDM). It is estimated that 150 million worldwide people have NIDDM with 5% or 22.5 million adults in Europe affected, including two million in the UK. The WHO estimates that by 2025 there will be at least 300 million sufferer's worldwide. The cost implications are truly staggering. In Europe and the US 10-15% of total health care expenditure goes on NIDDM and associated complications. This amounts to £2bn a year in the UK (216). By maintaining an appropriate weight, the risk of developing the disease is greatly diminished. Once again vegetarians – who as a group are typically leaner than omnivores – have a particular advantage in this aspect of health.
NIDDM, which usually starts in middle adulthood, is strongly associated with an increased risk of CHD as well as kidney, nerve and eye disorders. In pregnant diabetics the disease may have an adverse effect on the foetus. Approximately 80% of NIDDM sufferers are obese. The incidence rate is close to double in people who are only moderately overweight (226).
Vegetarians and vegans are less at risk from diabetes than meat-eaters as a 21-year study in America found. Over 25,000 adult Americans were studied and the results showed that people on meat-free diets had a 45% reduced risk of developing diabetes compared to the population as a whole. Meat consumption was positively associated with self-reported diabetes in both males and females (140).
NIDDM often improves with the right kind of diet and exercise. There is now very clear evidence that high-fibre, low-fat diets improve diabetic control (142, 228, 229) and can also lower insulin requirements (143). Significant reductions in fasting serum glucose (sugar) concentrations and body weight on a vegan diet can even occur in the absence of recommendations for exercise (141).
Diabetic neuropathy is characterised by numbness and shooting or burning pains in the lower limbs. 21 diabetics suffering this condition volunteered to follow a vegan, wholefood diet and exercise program for 25 days. Within four to 16 days, 17 of the patients reported that the characteristic pain of neuropathy had been completely alleviated and although the numbness persisted it was noticeably improved within the 25 days of the program (144).
A low-fat diet helps insulin work better because too much fat in the blood, or stored in the body, seems to inhibit absorption of insulin. A diet rich in complex carbohydrates and fibre means that the absorption of sugar is slow and steady, allowing it to pass into the bloodstream a little at a time rather than all at once. Thus dietitians recommend that wholegrain pasta, rice, bread and other complex carbohydrates as well as vegetables form the main part of any diabetic diet. All animal products contain a significant amount of fat and have no complex carbohydrates or fibre. A vegetarian diet is ideal for diabetics and can help minimise the doses of insulin needed and reduce the complications of the disease (28).
Diverticular disease is one of the most common disorders of the colon among elderly people in Western societies where small pouches (diverticuli) form in the wall of the intestine and become inflamed. Aldoori et al examined the association between diet and this disease using data from a prospective cohort of nearly 48,000 US men and a four-year follow up. A combination of total fat, red meat and a diet low in total dietary fibre was found to increase risk. The hypothesis for this was that under the influence of red meat, bacteria might produce a 'toxic metabolite' that weakens the wall of the colon and favours the formation of diverticuli. This may explain why vegetarians have a lower prevalence of diverticulosis than expected based solely on their higher fibre intake (238).
Fibromyalgia is a chronic pain disorder whereby muscle pain and tenderness occur over much of the body. Approximately 3 to 4% of women have the condition and the cause is likely to be in the unusual way the nervous system reacts to normal sensations. It occurs much less frequently in men (240). A Finnish group of sufferers when put on a vegan diet found that this animal-free diet alleviated the symptoms of fibromyalgia. It seems that certain foods aggravate the disease symptoms, the most common of which include chocolate, coffee, citrus fruits, alcohol and meat (241).
Although food poisoning is particularly serious for children, adults too of course can also be affected by contaminated food. Salmonella, Listeria, Staphylococcus, Campylobacter and Escherichia coli (E. coli) are all harboured in animal products. A well-publicised case of an E. coli outbreak occurred at the end of 1996 in Lanarkshire, Scotland. There were 272 confirmed cases and 450 people were thought to be affected. 27 people died as a result of this outbreak which was eventually traced to a butchers shop (35). As more meat and cow's milk is consumed and farming becomes more intensive, so the number of people being poisoned continues to rise. Way back in 1989, in response to national epidemics of foodborne infection with Salmonella and Listeria, the Secretary Of State for Health and the then MAFF (Ministry of Agriculture, Fisheries and Food) set up a study to investigate infectious intestinal (gut) diseases (IID). One important finding of this study was that a group of six foods was associated with a very consistent and statistically significant lower risk of IID – up to 70% less risk. Four of these foods would be everyday constituents of a vegetarian diet – pulses, salad, fruit and rice. Causal mechanisms for such an effect could include food consumption changing the intestinal flora (by exposure to other micro-organisms and fibre) or boosting general or specific immunity. Specific immunity could be boosted by repeated exposure to low dose of micro-organisms in food whilst general immunity could be boosted by ingestion of micronutrients, particularly antioxidants, in foods like fresh fruit andvegetables. This committee concluded by saying that the sorts of food already recommended for the prevention of heart disease and cancers – such as pulses, salads and fruit – may also have a protective effect against Infectious Intestinal Diseases (224).
Gallstones are composed chiefly of cholesterol crystals and are formed when bile becomes saturated with cholesterol. Women are far more likely to develop them than men and obese people are four times more likely to suffer (145).
The condition is far more common in affluent societies and in people who consume meat and dairy foods. In women, prevalence increases steadily from around 5 per cent in young adulthood to around 30 per cent in old age. Approximately one quarter of cases will require either surgical removal of the gallbladder or physical or chemical dissolution of the stones (146).
However, diet can prevent such drastic action. Fibre intake is effective in reducing cholesterol saturation of the bile since fibre can block the recycling of the bile acids from the intestine and increase the amounts of bile and metabolites excreted in the faeces. The WHO therefore recommends a starchy diet as a protective measure for this reason and because it may help reduce the problem of excessive weight (147).
A study in the British Medical Journal confirms this advice. This research found that non-vegetarians have about a two fold increase in risk of developing gallstones than vegetarians, even after controlling for potentially confounding factors. The main risk factors appear to be low fibre intake, saturated fat and cholesterol intake and obesity (148).
Hypertension (high blood pressure) has a number of possible causes including stress, alcohol, obesity and diet and increases the tendency for blockages to form in the arteries. Many people with high blood pressure do not even realise they are suffering from this condition. In 1997 one in 10 men and women aged 45 to 54 and four in 10 men and five in 10 women aged 75 and over in England had high blood pressure (249). Vegetarians suffer much less from hypertension than omnivores and adopting a vegetarian diet significantly lowers blood pressure in both normal and hypertensive individuals (149, 150, 151, 152). According to the Physicians Committee for Responsible Medicine: “This effect is independent of changes in body weight and salt or fat intake and is not fully accounted for by the presence or absence of any nutrient or group of nutrients.” (154).
Two studies looking at blood pressure changes that occur with vegan diets illustrate the exciting potential of plant-based diets in controlling hypertension.
As long ago as 1984, Lindahl and colleagues demonstrated the sort of changes that can occur on a vegan diet. 29 patients who had suffered from hypertension for an average of eight years, all of whom were taking medication, were put on a vegan diet for one year. In almost all cases medication was withdrawn or drastically reduced. A number of reported symptoms disappeared and there was significant decrease in both systolic (contraction of the heart) blood pressure and diastolic (resting period between heartbeats) blood pressure (153).
Much more recently in 1995 a study on the blood pressure-lowering effects of a vegan diet found that in just 12 days on such a diet beneficial changes in blood pressure were found. Blood pressure for all patients fell from 128/75 to 119/71 mm Hg (mercury) on average representing a 6% fall. Participants with higher blood pressures at the beginning of the trial had even greater reductions in blood pressure (155).
A study published in 2001 in Archives of Internal Medicine makes the compelling point that high blood pressure needs to be tackled early in life. This research tracked a cohort (group) of over 10,000 men aged 18 to 39 years from the Chicago Heart Association Detection Project in Industry. The authors concluded that in young adult men, blood pressure above normal was significantly related to increased long-term mortality due to CHD. Thus, population-wide primary prevention, early detection and control of hypertension are indicated from young adulthood on (219). A vegetarian diet can undoubtedly play a major role in helping to reduce the incidences of hypertension in the general population.
Lactase enzymes allow the digestion of lactose (milk sugar) to galactose and glucose (sugars). Whilst the majority of the world's adult population do not possess sufficient of these enzymes (see also under Lactose Intolerance section below), some populations are still able to break down lactose. There is clinical and experimental evidence that galactose arising from this breakdown may be toxic to ovarian germ cells. Dr Daniel Cramer of Harvard University has found significant correlations between a greater ability to digest lactose, greater cow's milk consumption, lower fertility rates and greater decline in fertility with ageing. The mechanism hypothesised for this is that the galactose resulting from the break down of lactose damages the ovaries (157). Whilst Dr Cramer's work makes no claims of causality between cow's milk consumption and reduced fertility it does highlight possible links, suggesting that lactose consumption and digestion may have potent negative effect's on human ovarian function. Cow's milk is indispensable for calves but its affect on human reproduction may not be so beneficial.
According to the American Dietetic Association: “A well-planned vegetarian diet may be useful in the prevention and treatment of renal [kidney] disease. Studies... suggest that some plant proteins may increase survival rates and decrease proteinuria [proteins in the urine]... and histological renal damage [kidney tissue damage] compared with a non-vegetarian diet.” (160).
Kidney stones affect three times more men than women and more whites than blacks or Asians. Between 30 and 50 per cent of people who have had a kidney stone will suffer a second one within five years but diet can reduce those odds dramatically. Drinking plenty of water and adopting a high potassium, low sodium (salt) diet can help. Plant foods such as fruits, beans and vegetables are all naturally high in potassium and low in sodium. Salt, sugar and animal protein are all implicated as problem foods. As Dr Neal Barnard states: “Animal protein is the worst enemy of people with a tendency toward kidney stones, or any kidney disease for that matter.” (161).
Animal protein tends to overwork the kidneys which in turn can cause a gradual decline in their ability to carry out their function in filtering waste from the body in the form of urine. Animal protein is high in sulphur-containing amino acids and these tend to leach calcium from the bones where it is excreted in the urine and may form stones. Meat and eggs contain two to five times more of these sulphur containing amino acids than are found in grains and beans (163). Vegetarian diets would therefore be expected to show less wear and tear on the kidneys than meat-based ones. A Harvard study found that intake of animal protein was directly associated with the risk of kidney stone formation. Researchers here found that an increase in animal protein from less than 50g per day to 77g per day was associated with a 33% increased risk of stones in men (164).
Research published in 1996 found that a vegan diet can be regarded as a valid alternative to the standard conventional low-protein diet (CLPD) that is the nutritional treatment for patients with chronic renal failure. The authors concluded that not only could the problems of poor palatability and high costs of the CLPD be solved by the vegan diet but that additional advantages came from such a diet too. Compared with the conventional diet the vegan diet offered a high ratio of unsaturated to saturated fatty acids, the absence of cholesterol and lower net acid production (165).
Lactose intolerance is the inability to digest lactose – the sugar found in cow's milk. Whilst infants, by necessity, nearly always have the lactase enzymes necessary to digest their mother's milk, these enzymes gradually diminish as they are weaned. This is the norm. Adults therefore have very little lactose and can experience a whole range of unpleasant digestive symptoms such as bloating and diarrhoea if cow's milk is drunk but not tolerated. Current estimates put a figure of some four to five million people in the UK being lactose intolerant (158). In the US it affects as many as 25% of the adult population (50 million) and a staggering 75% of the population worldwide are thought to be lactose intolerant! (159). Far from being an illness, lactose intolerance is now regarded as simply normal whilst those adults who retain the infant enzymes to digest milk are called “lactase persistent” (230). Far from being the most natural food in the world cow's milk is beginning to be seen as implicated in a whole host of disease conditions. Indeed very recent research is now suggesting that in a large majority of irritable bowel syndrome (IBS) patients – a commonly diagnosed functional bowel disorder – lactose intolerance is the primary cause of this debilitating condition. This led the authors of this piece of research to strongly recommended that lactose malabsorption is excluded before diagnosing IBS (259).
Not only can being overweight affect a patient's self-esteem and psychological state, it can kill. Obesity is a “risk factor for CHD and stroke and is associated with increased morbidity and mortality in many other diseases.” (166). Currently, over half of women and about two thirds of men are overweight or obese.
Along with CHD, the WHO states that obesity is linked to hypertension, diabetes, osteoarthritis, gallstones and other gastrointestinal disorders. Fat deposited abdominally is thought to be of particular concern. In addition, obese women face an increased risk of cancers of the gallbladder, breast (after menopause), and uterus; in men, obesity may increase the risk of cancers of the prostate and kidney. The importance of these health risks increase according to the severity of the obesity (168).
The advice to follow a low-fat, high-fibre diet and to embark on regular exercise does not seem as simple to follow as it is to prescribe. Psychologically, dieting has caused problems in many thousands of people and eating disorders have become associated with the dis-satisfaction felt with one's body. The WHO recognise the difficulty in encouraging obese people to slim: “In view of the great difficulty of treating obesity, a preventative policy seems the only long-term solution.” (169).
Encouraging children to eat a healthy diet all their lives is the best prevention against obesity and associated diseases. A vegetarian or vegan diet provides every nutrient necessary and plenty of complex carbohydrates without the excess fat – particularly saturated animal fat – that is so clearly associated with this condition. Quite simply non-meat eaters are thinner than meat-eaters! (260).
Osteoporosis – porous or brittle bones – is the major cause of bone fractures in the elderly and is characterised by loss of bone mass. The number of hip fractures in the elderly is increasing, reaching epidemic levels in many affluent countries. After the age of 50 osteoporosis will affect a staggering one in three women and one in 12 men in the UK. Worldwide about 1.7 million people, mostly post-menopausal women, suffer hip fractures annually.
Bone density increases in all parts of the skeleton during childhood and adolescence, with peak bone mass being reached by your mid-thirties. The normal rise in bone density is governed by genetic, hormonal, activity and nutritional factors and it is these factors that may prove very important in determining whether an individual will eventually develop osteoporosis (170).
Different sources of dietary protein have differing effects on bone metabolism. In 1992, Abelow proposed that acid production in the body from a high animal protein diet might lead to bone buffering and dissolution. His team found a strong, positive association between hip fracture rates and intakes of dietary animal protein in different countries (171). This reflects research findings from nearly 30 years ago which found that North Alaskan Eskimos that are very highly dependent on animal foods had an earlier onset and greater intensity of bone loss compared with a non-Alaskan reference population (172).
More recently in 2001, Sellmeyer et al carried out a prospective cohort study and likewise found that elderly women with a high dietary ratio of animal to vegetable protein intake had a greater risk of hip fracture than those with a low ratio. The authors concluded that this suggests an increase in vegetable protein intake and a decrease in animal protein intake may decrease bone loss (173).
The mechanism by which plant proteins – unlike animal proteins – seem to protect bone health is thought to centre around not only plant proteins having a lesser acidifying effect but also on the role of phosphorus. Zemel demonstrated that the lower level of sulphur amino acids coupled with the higher phosphorus content of soya for instance has a positive effect on calcium excretion such that calcium balance is maintained even when calcium intakes are modest (179).
The benefits of a greater emphasis on plant foods were demonstrated by a study published in 1999. This research observed that greater potassium and magnesium intake from high intakes of fruit and vegetables was associated with less decline in bone mineral density (BMD). These results suggest that alkaline-producing dietary components from a diet rich in fruit and vegetables contribute to the maintenance of BMD (174).
Despite our fixation with drinking cow's milk (principally for calcium) to prevent osteoporosis, comparisons between countries show that those with the highest calcium intakes actually have the highest risk of osteoporosis. Once again it seems that dairy products act in the same way as meat, being as they are acid-causing protein foods which may cause the loss of the very calcium that they supply (175). A number of studies have lent support to the view that drinking cow's milk may actually increase the risk of fracture. A study in 1994 of elderly men and women in Sydney, Australia showed that higher dairy product consumption was associated with increased fracture risk. Those with the highest dairy product consumption had approximately double the risk of hip fracture than those with the lowest consumption (176). The Harvard Nurses' Health Study followed over 77,000 women, aged 34 to 59 for 12 years. This piece of research found that those who derived more calcium from cow's milk actually had slightly, but significantly, more fractures than those who drank little or no cow's milk (177).
A study comparing more than 1,600 vegetarians and meat-eaters found that meat-eating women in their 80's had lost twice as much mineral content from their bones as had the vegetarians (178).
There are many excellent sources of calcium apart from cow's milk which don't have the disadvantages of this food – such as high protein content (decreasing the fat content of milk simply increases the protein content) and saturated fat. Dark green vegetables provide calcium which, except for spinach, appear to be of greater or equal bioavailability than that of cow's milk. Calcium absorption from kale for instance is higher than from cow's milk (180). Other good sources of calcium are watercress, broccoli, pulses, tofu, dried fruit (especially figs), nuts (especially almonds) and sesame seeds (tahini is sesame seed paste and an easily usable source of calcium). Natural daylight also helps the body produce Vitamin D, which encourages the storage of calcium. Being out in the sun is therefore important, as is keeping active which is vital for helping to keep bones strong. It is also very likely that a more plant-based diet will need less calcium in the first place. A paper by Nordin in the American Journal of Clinical Nutrition recently calculated that a reduction in animal protein intake from a reference value of 60 to 20 grams per day reduces the theoretical calcium requirement from about 750mg per day to 550mg per day (262). This reflects the view that high intakes of protein – in particular animal protein – encourage loss of calcium from the bone. If the animal protein is removed from the diet then less calcium will be required in the first place. Indeed in a study published in the American Journal of Clinical Nutrition, found that subjects on a vegetarian diet had less then half the calcium losses than those on a typical meat-based diet (162).
The Oxford Study – part of the EPIC study – published results in 1994 of its examination of the diets of 11,000 people over a period of 13 years and found that vegetarians have a 20% lower premature death rate than meat-eaters (181). Vegetarians live longer!
The American Dietetic Association states: “Studies indicate that vegetarians often have lower morbidity and mortality rates from several chronic degenerative diseases than do non-vegetarians” (182).
The people of Okinawa, a Japanese group of islands, are the longest-lived healthiest population in the world. Dr Makoto Suzuki, Professor and Head of Gerontology at Okinawa International University is the principal investigator on a 25-year study into diet, health and longevity. He, along with other scientists, have been investigating why the people of this island enjoy such good health. One of the keys to their longevity, apart from exercise and lifestyle factors is a diet based on wholegrains, vegetables, fruit and soya products. Indeed the islanders have one favourite recipe the scientific experts call 'immortal paté'. No surprises here – the paté is vegan and doesn't contain a speck of animal fat – meat or dairy! It is based simply on tofu (soya bean curd), miso (fermented soya bean paste), mushrooms and garlic (271).
Rheumatism is the term given to any painful state of the supporting structures of the body – bones, ligaments, joints, tendons or muscles. Arthritis is a form of rheumatism in which joints have become inflamed and refers to many different diseases. Rheumatoid Arthritis (RA) is an autoimmune disease whereby the immune system of the body attacks its own tissues – here its own cartilage and joint linings. Meat, dairy produce and eggs can all be triggers for arthritis and can also encourage hormone imbalances that may contribute to joint pain (183).
Several studies have looked at the effects of meat-free and dairy-free diets on RA. In one of the earliest studies, 60% of patients put onto a vegan diet felt better as a result. They experienced less pain and reported improved functional capacity (187). Kjeldsen-Kragh et al, assessed the effect of a vegetarian diet on RA in a randomised, single-blind controlled trial. This means that the participants in the trial are randomly allocated by a process equivalent to the flip of a coin to either one intervention (here, a vegetarian diet) or another (in this case the control group being 26 patients who ate an ordinary mixed diet throughout the whole study period). Single-blind normally means that subjects do not know which treatment they are receiving. In the case of dietary interventions this is obviously not possible, thus for this study single-blind refers to the fact that the clinical examinations done after starting the diet were performed by a single physician who did not know the group to which the patient had been allocated. 27 arthritic patients ate a gluten-free (gluten is a protein principally found in wheat) vegan diet for three and a half months after an initial seven to 10 day fast, then a lactovegetarian (vegetarian diet where cow's milk is included) diet for the remainder of one year. After just four weeks, patients on the vegetarian diet showed significant improvements in pain levels, number of tender and swollen joints, morning stiffness, grip strength and several blood chemistry parameters. In the control group of patients (ie those on the mixed diet), only pain scores improved. When the two groups were compared after 13 months, a statistically significant improvement was seen in the diet group for all indices except platelet count and haemoglobin (184).
A recent systematic review of controlled studies on vegetarian diets and RA supports the view that a short period of fasting followed by a vegetarian diet can cause clinically relevant long-term improvement in patients with RA. A systematic review is a summary of relevant literature in which evidence on the topic has been analysed in a systematic (ie standardised and objective) way and is given the greatest weight in the order of relative merit of the different types of study that can be carried out. The authors of this review concluded that vegetarian diets might be useful in the treatment of RA (185).
A recent paper in the British Journal of Nutrition took the ecological approach to study the links between diet and RA. Here, a measure of disease at the national level is compared statistically with various components of national consumer food supply for a number of countries. Fat from meat and offal was found to have the highest statistical association with the prevalence of RA. The statistical correlations for meat and offal were almost as high as those for their fat. Three possible factors that may contribute to the inflammation of RA were fat, iron and nitrite. The author concluded that “it is hypothesised that meat and offal may be a major factor contributing to the inflammation in RA.” (186).
A stroke is sudden damage to brain tissue caused either by a lack of blood supply or rupture of a blood vessel. The affected brain cells die and the parts of the body these cells control cease to function. A major reason why blood supply to the brain may be interrupted is due to the furring or hardening up of the arteries. This atherosclerotic process is accelerated in particular by hypertension and diabetes. As we have previously seen saturated animal fat is a prime cause of furred up arteries. Strokes cause about 12% of all deaths in England and about 30% of all people who have a stroke die within a few weeks. Of the remainder, about half will have significant continuing disabilities. It is estimated that approximately £1.6 billion is used in treating, rehabilitating and providing care for people who have suffered strokes in the UK (188). Since vegetarians typically suffer less from high blood pressure than meat-eaters and this is a major risk factor for a stroke, it would seem a sensible policy to encourage the adoption of such a diet in order to reduce the risk of this condition.
Whilst it is vitally important to determine the sorts of foods children should be encouraged to eat it is also important to look at why children may or may not eat certain foods. Three major determinants that affect children's food choice are parental food choices, food advertising and parental income.
Healthy food habits learnt early in childhood form the basis for continued healthy eating throughout life. Earlier experiences of a particular food are one major factor that affects children's food acceptance patterns. In other words teach children the importance of eating healthily when young and they are more likely to continue with their healthy eating pattern throughout life. Conversely, let children eat nutrient-poor foods from an early age and it is far more difficult to switch food preference patterns towards healthier options. It is interesting to note that humans seem to have a built-in bias to respond negatively to new foods but this can be reduced by repeated exposure to the novel food (189). So the message to parents is clear – it may well take a dozen or so attempts to get a child to accept an unfamiliar food but never give up introducing fresh fruits and vegetables into the diet!
No one can be in any doubt about the enormous influence that advertising has on everyone's life. Advertisers claim that adverts do not create a demand for product groups – ie a preference for high-fat foods over low-fat foods – rather they are designed instead to encourage brand switching by consumers. However, even at the tender age of three children demonstrate high recognition rates of brand logos for products – for instance properly matching the McDonalds arches to a hamburger! (190).
Sustain (formerly The National Food Alliance) published two reports concerning the issue of food advertisements and children. They found that in 1992 the advertising industry spent £523 million on advertising food and soft drinks. They also found that food advertising on television, particularly during children's programming, presents a grossly imbalanced nutritional message. Fatty and sugary foods account for a disproportionately large percentage of all food advertising while there are few adverts for healthier options (191, 192). And the link between television viewing and consumption of certain foods seems to be robust. Hitchings and Moynihan found that there was a relationship between foods for which children could remember the adverts of and the number of foods which the child ate (231). Of course television is not the only medium where food messages are displayed. Food advertising is found everywhere and increasingly schools are a rich avenue of indirect and direct food advertising.
Buying fresh fruit and vegetables can be costly for parents on low incomes and it is therefore not surprising that this limits intake. However, a healthy start in life is essential to the long-term well-being of children and new patterns of shopping may need to be learned. A major report published in 1994 concerning nutrition in low income families states: “It is widely recognised that members of poorer households in the UK and other European countries, in the United States and Australasia, are more likely to be ill, or to die in infancy, or at an early age when adult, then those in richer households.” (193). A good diet for children is clearly crucial.
The report went on to say that “Those who regularly cooked from fresh or raw ingredients, rather than opening packets or jars, or having 'something on toast' achieved healthier dietary variety for themselves and their children... Those who aimed to keep their children happy by buying what they like to eat had very unhealthy dietary patterns.” (194). This shows that despite what children may think, they don't always know what is best for them and sometimes a healthy diet must be encouraged or even insisted upon.
The report also discovered that those parents who expressed concern about providing a healthy diet for their children did make a considerable difference to their diet, despite being on a low income. That “even lone parents who were in the poorest categories but who said they looked for 'fresh' food in shopping had higher variety and healthy diet indices than those who did not.” (195). So, even on the lowest incomes, it is possible to make vast improvements in the diets of children. However, it has been shown that many low-income families simply cannot afford to risk changing their diets as the food may not be eaten. The ironic consequence of this is that children from low-income families often see themselves as eating more of what they enjoy than their affluent peers as mothers provide foods which they like in order to prevent waste (196). Whilst acknowledging this, strategies to help achieve healthier diets could include buying seasonal fruits and vegetables which are cheaper, buying from markets instead of supermarkets, buying basic raw ingredients (such as rice, pasta, beans and bread) instead of pre-packaged meals, limiting the amount of junk foods eaten (eg chips and burgers) and limiting more expensive foods eaten – for instance by substituting pulses like beans (soya, baked beans, kidney beans, chickpeas) lentils and peas in place of expensive meat and dairy products.
Not so! Take a look at how we have evolved alongside our close relative, the vegan gorilla, and then compare us to obligate carnivores such as tigers. We have no claws for ripping flesh, we do not have the type of canines necessary to tear flesh from bones and our jaw shape is entirely wrong for capturing and killing live prey. Very few of us have the speed necessary to catch any prey even if we wanted to but the truth is that most of us don't have that bloodlust either.
Professor Sanders Head of Nutrition at Kings College London states: “...meat is an optional rather than an essential constituent of human diets.” (255).
“Although human beings eat meat, we are not natural carnivores. No matter how much fat carnivores eat, they do not develop atherosclerosis [clogged up arteries]. When we kill animals to eat them, they end up killing us because their
flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.”
WC Roberts MD editor-in-chief of the American Journal of
Our intestines are certainly not appropriate for a meat-based diet. They are very long in relation to our body and this is because vegetable matter takes a long time to digest. The entire human digestive track (alimentary canal) is roughly eight to nine metres in length, most of its length taken up by the small intestine (duodenum and ileum) which are about six metres in length. In the course of its passage along the gut, food will typically spend three to five hours in the stomach, four hours travelling along the small intestine and from six to 20 hours in the large intestine. Carnivores on the other hand have a very short intestine, designed to absorb all the nutrients in the meat as quickly as possible.
American doctor, Neal Barnard, has looked at how humans have even survived the evolutionary change in our diet. If the dangers of meat-eating affected people before the age of reproduction, he says, we as a species would have to adapt to it but since its damage is usually done after the age of reproduction there is no imperative to change. Each generation must face its dangers over again as we do not seem to learn (197).
Zoologist Desmond Morris wrote in The Naked Ape: “We were driven to become flesh eaters only by environmental circumstances, and now that we have the environment under control, with elaborately cultivated crops at our disposal, we might be expected to return to our ancient primate feeding patterns.” (198). Meat eating is thought to have begun only in the last one-and-a-half million years. Colin Spencer – expert vegetarian cookery writer and one-time food columnist for The Guardian – puts this into context: “Contrasted with the life of an 80-year old human being it means that only in the last 15 years would meat have been eaten. For 65 years we were vegetarian.” And even when early humans started eating meat the bulk of the diet would still have been plant foods (250). One thing is certain, never in human history have we eaten as much meat as we routinely eat today and the consequences of this are all too apparent.
Drinking the milk of another species obviously could not occur until after animals were domesticated. The first evidence of milk production comes from about 4000 BC and so actually represents a very recent acquisition to the diet in evolutionary terms (217). Milk from a lactating mother is meant for babies – it's an odd concept for adults to drink it at all – and from another species too! Why not eat regurgitated food like many baby animals are weaned onto – an equally bizarre notion!
No mammal, including humans, are meant to drink milk after weaning. Therefore it is not surprising that lactose (milk sugar) maldigestion is the norm for adults of all mammalian species, including our own. The few who can digest cow's milk may be able to cope in the short-term with its digestion but may not be so well adapted to cope with the many possible long-term consequences – ovarian problems due to galactose, insulin dependent diabetes, rheumatoid arthritis, heart disease and obesity. It's a catalogue of disasters and yet we feed food designed for calves to children whenever possible because we are told it is good for them. The evidence does not support that view.
The WHO recommends a diet that “is characterised by frequent consumption of vegetables, fruits, cereals and legumes, and contrasts sharply with current diets drawing substantial amounts of energy from whole-milk products, fatty meats, and refined sugars.” (200).
Every macronutrient – protein, carbohydrate, essential fats and fibre and every micronutrient – vitamin and mineral – can easily be gained from a meat-free, milk-free diet – it is, after all, how we are designed to live. How would Martina Navratilova and nine-time gold medal Olympic runner Carl Lewis have attained the very highest sporting achievements if it were not perfectly possible – and a whole lot healthier – to get by without meat and cow's milk?
The Western diet consists of far too much animal protein and this is linked to many different diseases. Traditional rural Chinese diets consume far less animal protein than do Western countries. For example the proportion of total protein in China as animal protein is approximately 11% whereas in the USA it is roughly 70%. The reduced incidence of a number of common Western degenerative diseases seen in China appear to reflect this much lower intake of animal protein (201).
Vegetable protein is everywhere and it is impossible to suffer a deficiency, unless you go out of your way to do so! Protein can be found in all pulses (beans of all sorts, peas and lentils); grains and grain products such as breakfast cereals, bread, pasta, rice and oats; nuts and seeds. The WHO states: “Protein requirements are readily met in children and adults eating a varied diet based predominantly on cereals and pulses.” (202). Such diets typically provide 10-15% of their energy in the form of protein and are perfectly adequate. The humble soya bean – used in many soya products such as soya burgers, soya milk and tofu (soya bean curd) – is nutritionally equivalent to meat, containing as it does all the building blocks (amino acids) of protein.
Carbohydrates are our main and most important source of energy. There are basically three types of carbohydrate: fast-releasing (simple sugars) such as refined processed foods like table sugar, white flours, sweets and syrups; slow-releasing or complex carbohydrates such as wholegrains (oats, bread, rice, pasta, rye) and fibre – the indigestible part of fruits, vegetables and grains, essential for the digestive system to work properly. The WHO suggest we should all be eating far more carbohydrates (mainly slow-releasing ones) than we do – 55 to 70 per cent of our diet should ideally be made up of them. The WHO state that: “Studies have consistently shown that diets rich in starchy carbohydrates favour a lower incidence of several cancers, limit the occurrence of hyperlipidemia, and assist in the management of diabetes and other metabolic diseases. These diets also help to limit excessive weight gain... Foods rich in complex carbohydrates have beneficial effects on intestinal function, on the chemistry of the gut and on the physiology of the gut wall. In addition, starch foods from plants are an especially rich source of many minerals and vitamins, including essential fatty acids, calcium, zinc, iron and a variety of water-soluble vitamins, all known to have a clear and positive effect on health.” (218). A vegetarian diet – based as it is on carbohydrate-rich plant foods – is the perfect choice for providing the large amounts of carbohydrate human bodies need for good health.
Also known as non-starch polysaccharide (NSP), dietary fibre is an essential component of the diet. It refers to the carbohydrates that escape digestion in the mouth, stomach and small intestine and thus pass on to the colon. Although we gain no nutrients from it directly, it is essential for sweeping out the bowels and keeping them healthy. Through its effects on stool bulking, fibre helps to prevent constipation and haemorrhoids. By speeding up intestinal transit time, fibre may reduce the duration of exposure of intestinal tissues to noxious agents in the diet or secreted in the small intestine. Fibre also affects the rate of release and absorption of glucose and therefore has a role in the treatment of diabetes. Because fibre-rich food prolongs the time for gastric-emptying, and because fibre-rich foods tend to have a lower calorific density, diets rich in fibre may decrease the urge to eat and hence assist in appetite control (199). Fibre may also help reduce blood cholesterol. It isn't hard to find fibre – just eat a vegetarian diet and you will eat it in abundance. Fibre is only found in foods of plant origin – fruit, vegetables and wholegrains such as cereals, breads, pasta, rice and oats. Meat and dairy produce contain none.
Although fat is an essential component of the diet most Western diets contain far too much. Around 15 to 30 per cent of our energy should come from fat but the WHO states that it may prove necessary to lower the upper limit for total fat from 30 per cent of energy to 25 per cent or perhaps 20 per cent (204). Too much fat in the diet can cause excessive weight gain and there is no biological need for saturated (mainly animal) fat in the diet. Saturated fats increase cholesterol levels and can lead to heart disease and cancers. What we do need in the diet are the unsaturated, so-called essential fats. Vegetarian and vegan diets are rich in these essential fats – found abundantly in seeds, nuts, beans, avocados and vegetable oils.
Cow's milk does not have a monopoly on calcium. There are plenty of excellent sources of calcium from the plant kingdom and they have the added advantage that they don't come packaged with saturated fat. Good plant-derived sources of calcium are tofu (soya bean curd whereby cooked soya beans are precipitated with calcium sulphate), green leafy vegetables such as watercress, broccoli and parsley, nuts (especially almonds) and seeds (especially sesame). White flour is fortified with calcium in the UK so white bread can be an important source of this mineral and people living in hard water areas also obtain some calcium from tap water.
McCance and Widdowson's food tables provide details of exactly how much calcium is contained in these foods. Per 100g, dried, boiled soya beans contain 83mg of calcium; soya flour 210mg; tofu (steamed) 510mg; almonds 240mg; sesame seeds 670mg and tahini (sesame seed paste) 680mg. This compares to a calcium content per 100g of 57mg for eggs and 115 – 120mg for whole, semi-skimmed, skimmed or pasteurised cow's milk (203). Most calcium-enriched soya milks contain an equivalent level of calcium to cow's milk.
750 million people worldwide suffer from iron deficiency anaemia which usually occurs when the amount of iron absorbed by the body is insufficient to meet the body's demands. This can be due to insufficient iron in the diet, chronic blood loss or the most important factor – poor iron absorption (205). The American Dietetic Association and the British Medical Association both state that vegetarians are no more likely to suffer from iron deficiency anaemia than omnivores (208, 220). Indeed the China Health Study found that Chinese adults consume twice as much iron on their predominantly vegetarian diets than do American adults on their meat-based diets and iron status is not compromised (209). Care however must be taken whatever diet is consumed to ensure adequate iron status and this is especially so for women of childbearing years.
Iron-rich plant sources include wholegrains (such as wholemeal bread or brown rice), nuts, dark green leafy vegetables, pulses, dried fruits, seeds and black treacle. Many breakfast cereals are also fortified with iron. The absorption of plant sources of iron is also increased by vitamin C. Meat and dairy foods contain no vitamin C but of course this vitamin is abundant in vegetarian diets from fruits and vegetables.
Iron status is also affected by the consumption of cow's milk. A review of published work relating to the association between feeding infants cow's milk and intestinal bleeding was carried out by Sullivan in 1993. He concluded that in some subjects whole cow's milk induced gastrointestinal blood loss appears sufficiently great to be nutritionally significant and may contribute to the development of iron deficiency anaemia (232). Other studies have also led researchers to state that cow's milk may increase the risk of poor iron status in young children (233, 234). High levels of calcium in dairy products are also known to interfere with the absorption of iron from the diet. Hallberg et al investigated this effect and found that milk and cheese can reduce iron absorption by around half (235). As far as iron status is concerned therefore dairy products can amount to a negative triple whammy – milk contains no iron itself, it can lead to intestinal bleeding and the calcium in dairy foods can reduce the amount of iron absorbed from those foods in a meal that do contain iron.
Whilst iron from plant sources (non-haem iron) has always been viewed as an inferior source to haem iron from meat, there may in fact be an advantage in deriving dietary iron from plants rather than meat. Red blood cells need some iron to carry oxygen but excesses can be risky and it may not necessarily be the case that the more iron we consume the better. Iron is known to act as a potent free radical that can damage body cells and may increase the risk of plaque formation in the arteries. A number of studies have found support for the hypothesis that excess dietary iron intake is a risk factor for coronary heart disease (206, 207). A team from Harvard investigated the type of dietary iron that may be a problem. Researchers here found an increased risk of myocardial infarction (heart attack) among men with higher intakes of haem iron – largely from red meat – and higher body iron stores. There is clearly a level at which body iron stores are at an optimum. Haem iron is absorbed regardless of iron status, potentially encouraging iron overload. Non-haem iron from plants on the other hand is efficiently regulated such that absorption is increased or decreased depending on body stores at any particular time (210). This means the body can absorb more iron when it needs it and less when it doesn't rather than having it pass straight into the bloodstream to excess.
Iodine is needed for the thyroid gland. This gland produces hormones that are essential for normal growth and physical and mental development. Cow's milk provides vegetarians with iodine partly because cattle feed contains this mineral. For vegans, dark green vegetables and Vecon vegetable stock supply iodine and sea vegetables such as dried seaweed are very rich sources.
Zinc is involved in a huge number of enzyme systems. These include growth, immunity, protein synthesis, energy metabolism, red-blood cell synthesis and antioxidant functioning. Good sources of zinc are pulses, wholegrains, leafy green vegetables, nuts and seeds.
Vitamin A is needed for the growth and normal development of tissues, vision and healthy skin. This vitamin comes in two forms – as the pre-formed vitamin A and as beta-carotene – a pre-cursor form of vitamin A which has antioxidant – disease-busting – properties. The beta-carotene form of vitamin A is only found in foods of plant origin especially orange, red and green-coloured fruit and vegetables – it is not found in foods of animal origin. Vegetarian and vegan diets therefore have ample amounts of beta-carotene and the body converts beta-carotene to vitamin A when required. Excess vitamin A e.g. from liver, can be toxic but vitamin A toxicity can never occur where it is derived from plant sources as the body regulates how much beta-carotene needs to be converted to vitamin A.
B1 (Thiamin) is found in plenty of plant foods including wholegrains such as wholemeal bread, yeast extract, brazil nuts, sunflower seeds, oats, black treacle and fortified breakfast cereals. When wheat flour is refined to make white flour, thiamin is lost which is why white flour in the UK is fortified with this vitamin. It is needed by the body to release energy from carbohydrates and fats.
B2 (Riboflavin) is also widely available in plant foods such as yeast extract, wholegrains including wholemeal bread, almonds, seeds, black treacle and dates. Riboflavin is also needed by the body to help release energy from fats, carbohydrates and protein. The UK recommended daily intake is 1.3 mg, although the average Chinese daily intake is 0.8 mg and there is no evidence of deficiency (212).
Niacin is another B-vitamin also needed to release energy from foods and for maintaining skin health. It is found in yeast extract, wholegrains including wholemeal bread, dates, nuts and seeds, peas and potatoes.
B6 (Pyridoxine) is required for protein metabolism and the production of red blood cells. It is easily obtained in the diet from wholegrains including wholemeal bread, avocados, bananas, prunes, beans, dried fruits, seeds and nuts.
Folate (Folic Acid) is required for protein synthesis, formation of blood, metabolism of DNA (the human genetic blueprint) and helps prevent neural tube defects in the developing foetus. It is found widely in a vegetarian diet in dark green leafy vegetables, pulses, avocado, nuts and beansprouts. A 1993 study found that children in all age and sex groups appeared to have lower intakes than recommended (213). A vegetarian diet can easily provide all that is needed. In fact, the American Dietetic Association states that vegetarian diets often have higher concentrations of folate (214) – hardly surprising since the major sources of folate are from plants.
Vitamin B12 (Cobalamin) is required for the maintenance of a healthy nervous system and normal blood formation. The recommended daily intake in the UK is just one and a half micrograms per day and a whole lifetime's requirement adds up to about one seventh the size of an average aspirin tablet (215). Deficiency is actually very rare. It is synthesised naturally only by micro-organisms (mainly bacteria) in the soil and in the intestines of ruminant animals, such as cattle and sheep. The liver has stores of B12 lasting up to 3 years and the body is also very efficient at reabsorbing it so little is lost from the body. This vitamin is therefore partly supplied by dietary intake and partly by this recycling.
Traces of this vitamin may be found on poorly washed vegetable produce where bacteria in the soil particles are found but this is obviously not a reliable source in developed countries. However it is easily obtained in a vegetarian diet and in a vegan diet as many everyday food items such as breakfast cereals, yeast extracts, some margarines and soya milks have been fortified with this vitamin. New research from the Framingham Offspring Study – a prospective study into risk factors for heart disease – makes a very interesting point about best sources of vitamin B12. Results suggest that vitamin B12 from fortified breakfast cereals, supplements and dairy products may be more efficiently absorbed in the body than foods traditionally viewed as the best sources – meat, poultry and fish. The theory put forward here is that such foods are cooked before eaten and the heat effectively destroys the vitamin (272).
Primates (including humans) – along with guinea-pigs – are the only animals which cannot synthesise vitamin C (ascorbic acid) in the body and a daily dietary source is therefore essential. It is required for healthy skin, teeth, bones and connective tissue, an aid to iron absorption, wound healing and proper functioning of the immune system. In a vegetarian diet ensuring adequate vitamin C intake is no problem whatsoever as it is found abundantly in all fruits and vegetables. Especially good sources are dark green leafy vegetables, tomatoes, berries and blackcurrants, kiwi and citrus fruits. Potatoes contain useful amounts of this vitamin in the average diet also. Since cooking destroys this vitamin, vegetables should be only lightly cooked or better still steamed and eating some raw vegetables is advised. Meat and dairy foods contain no vitamin C whatsoever.
Vitamin D acts as both a vitamin and a hormone (a chemical messenger) that helps keep blood calcium at optimal levels and supports bone health during growth and throughout life. Along with vitamins A, E and K, vitamin D is fat-soluble which means there must be a source of fat in the diet for these vitamins to be absorbed. The main source of vitamn D is not actually from food but that manufactured inside the body from the action of sunlight on the skin. In the UK, vitamin D is made during the sunnier months of April and October and stored in the liver, thus ensuring adequate amounts of it are available year round. Although certain algae produce the vitamin the main food sources are margarines and breakfast cereals which have been fortified with it. Cow's milk is another source of the vitamin – not because it is naturally present but because cow's milk also has this vitamin added to it (275).
Discovered in the 1980s, free radicals are thought to play a part in causing some 60 diseases and are capable of wreaking havoc on healthy cells. Free radicals are unstable molecules, produced by everyday processes such as breathing and digestion whereby an electron is removed from the molecule, destabilising it. This molecule tries to regain its stability by snatching an electron from another molecule but this sets off a chain reaction in which the DNA may be damaged. Free radicals can also be created as a result of cigarette smoking, pollution, ultraviolet light, stress and cooking, in particular cooking red meat. The remedy for free radicals is antioxidants.
Beta-carotene, vitamins C and E have antioxidant properties and are vital in preventing a whole range of diseases. None of them can be found in meat or cow's or goat's milk but are available abundantly in plant foods. Flavenol has also been added to the list of antioxidants and again this cannot be obtained from meat but rather only from red fruits and vegetables. A particular example is lycopene found in tomatoes – especially rich when tomatoes have been processed into tomato paste.
This report makes it abundantly clear that a vegetarian diet is amply able to provide all the nutrients the body requires and may confer significant health advantages over diets predominantly based around animal products. For parents, of course, the number one consideration will be whether vegetarian diets are safe. With this in mind a look at published research concerning vegetarian diets and children should put every parents mind at rest.
“Children who grow up getting their nutrition from plant foods rather than meats have a tremendous advantage. They are less likely to develop weight problems, diabetes, high blood pressure, and some forms of cancer.” Dr Benjamin Spock, (1904-1998) Paediatrician, Medical Teacher and Researcher and author of “Dr Spock's Baby and Child Care” which has sold 50 million copies worldwide since its first publication in 1946 (280).
An early review of the literature on vegetarian diets and children was published in 1988 in the American Journal of Clinical Nutrition. This review found that infants who are breast-fed by women eating balanced vegan and vegetarian diets thrive in early infancy. Appropriate vegetarian diets were also found to adequately provide for each phase of growth in children. Unsurprisingly this review went on to say that such diets during childhood, where they are low in total and saturated fats, may be beneficial in reducing the risks associated with high blood fat levels and also help children maintain their ideal body weight (242).
O'Connell et al reported in 1989 on a study to examine the effects of a vegetarian diet on child growth, height and weight of children aged four months to 10 years – known as The Farm Study. The actual vegetarian diet the children followed was a vegan one with the authors concluding that the growth of these children was similar to that of the reference (comparison) population and that there was no evidence of abnormality (243).
“The vegetarian diet is adequate for the nutritional needs of infants.” British Medical Association Report 1986 – Diet, Nutrition and Health (220).
A more recent review of the diets and growth of children reared on vegetarian diets was carried out in 1995 by Sanders. Not only did the author find that children can be reared successfully on vegetarian and vegan diets but that such diets of schoolchildren were found to have a similar nutrient content to meat-based diets. An analysis of the data comparing vegan and omnivorous children revealed some interesting results. The vegan children had energy, protein, vitamin D and B-vitamins (including vitamin B12) intakes that were virtually the same. The differences in nutrient content illustrate the potential benefits a plant-based diet can have. Fat intake was lower in the vegan children, vitamins A (as beta-carotene), C and E intakes were higher and fibre, iron and folate intakes were nearly double. Although lower rates of growth have been reported in some vegan children during the first few years of life catch-up growth occurs by the age of 10. Thus the author states that: “A vegetarian diet, if properly selected, can meet all of the requirements of the growing child.” (244).
And more recently in a 1999 paper Professor Sanders states that: “Well-balanced vegetarian diets are able to support normal growth and development.” (255).
Nathan, Hackett and Kirby conducted a one-year observational case-comparison study of the growth of vegetarian children (seven-11 years) compared with a matched control group of omnivorous children. Height, weight, upper arm skinfold thickness and mid-upper arm circumference measurements were taken and results suggested that children who followed a meat-free diet grew at least as well as children who ate meat (245). A review by two of these authors – Nathan and Hackett – and Burgess in 1998 concluded similarly that vegetarian diets can be adequate for children. Lacto-ovo-vegetarian children were found to consume diets closer to recommendations than omnivores and their pre-pubertal growth was at least as good. An important point made in this paper was that anaemia is probably the main risk of poor dietary selection but that this applies also to children brought up on an omnivorous diet. The authors also note that although vegetarian diets need to be well planned to ensure all nutrients are provided this comment is equally applicable to omnivorous diets (246).
The growth and physical fitness of Flemish vegetarian children, adolescents and young adults was assessed in a recent 1999 study and found that vegetarian children were physically as fit as the reference group and that the growth and maturation status of the vegetarian population were within the normal range. An interesting result from this study was that the vegetarians performed better in a step test than did the reference group. This test is used to predict maximal oxygen consumption capacity and led the authors to suggest that the vegetarian subjects had better cardio-respiratory endurance (247).
The most recent research on plant-only diets for infants and children was published in the June 2001 issue of the Journal of the American Dietetic Association. The first of these papers on vegan infants stated that appropriately planned vegan diets can satisfy nutrient needs of infants. Further that the American Dietetic Association and The American Academy of Paediatrics both state that vegan diets can promote normal growth (263). The second paper dealing with vegan children takes this one stage further by stating that diets of vegan children meet or exceed recommendations for most nutrients and vegan children have higher intakes of fibre and lower intakes of total fat, saturated fat and cholesterol than omnivore children. The authors conclude that not only can vegan diets be adequate for children at all ages but that such diets may reduce the risk of some chronic diseases of adulthood that have their origins in childhood. Finally the authors state that since vegan children are exposed to a greater variety of whole plant foods this may help to establish healthful lifelong eating habits (264).
All the evidence suggests that not only is an animal-free diet the healthiest diet for children (and adults) but that animal products are positively an unhealthy choice and can increase the risk of many fatal diseases and conditions.
Professor Colin Campbell, Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University and long time senior science advisor to the World Cancer Research Fund and organiser of the largest study into diet and health – The China Health Study – couldn't put it any plainer. He believes that humans are a vegetarian species whose risk of disease is increased by eating meat and animal products. And it's not simply good enough to put some elements of a vegetarian diet into practice – “the closer one approaches a total plant food diet, the greater the health benefit.” (279). That: “Animal foods, in general, are not really helpful and we need to get away from eating them.” (221).
A diet free from animal produce is perfect for every stage of life: pregnant mothers, babies, toddlers, children, adolescents, teenagers and adults of all ages. It can prevent many diseases, cure many more and extend life. And why? Because it is the most natural diet in the world – it's how we're meant to live.
Recommend foods for lifelong vitality, not foods to die for.
Organisations providing consumer information on meat and dairy foods are there for one reason and one reason only – to make money. As a charity VVF exists solely for an entirely different reason – to educate. VVF provides access to the mass of scientific research – much of which is little-publicised – concerning the potential health problems of diets based on animal products. In so doing, consumers are then able to make informed choices as to the diet best able to support good health throughout life. Parents, guardians and healthcare professionals have of course an additional reason as to why they need to get this choice right – others are under their care. The promotion of this report will not serve to increase the profit margins of a humble charity but will, if translated into sound nutritional advice, save lives – your own and those under your care. The same cannot be said of the huge and powerful bodies promoting meat and dairy products which are profit – not health – driven.
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