The Causes of Diabetes | Viva!

The Causes of Diabetes

The Causes of Diabetes

All in the genes?

Not really! Our genetic make-up plays an important role and a certain set of genes can make us more or less susceptible to developing diabetes. However, even if your genes do make it more likely that you will develop the disease, it doesn't mean you will.

Several gene variants have been identified as contributing to type 1 diabetes but only a small proportion of people with those genes go on to develop the disease - less than 10 per cent. It follows that environmental factors are necessary to trigger the reaction which destroys insulin producing cells.

Lifestyle and environment also play a huge role in the development and severity of type 2 diabetes. Even individuals with susceptible genes and many of those who have already developed the disease don't have to live with it for the rest of their lives.

The relative(s) with the particular type of diabetes Risk of type 1 diabetes Risk of type 2 diabetes
Diabetic mother
Diabetic father
Both parents diabetic
Diabetic brother or sister
Diabetic non-identical twin
Diabetic identical twin
Up to 30%








Lifestyle and environmental factors

Lifestyle is incredibly important and can significantly increase or decrease the risk of developing the disease. Even if both parents have diabetes, it doesn't necessarily mean their children will develop it too.


Type 1 diabetes

It has been known for years that type 1 diabetes is triggered by something in the person's environment. The conventional theory is that a viral or another infection might be the culprit, making the body attack its own insulin producing cells by mistake. There is, however, a more uncomfortable theory - that cows' milk is the main trigger and it has been increasingly accepted since it was first suggested in the early 1990's.

If an individual has a certain combination of genes, making them more susceptible to type 1 diabetes, the environmental trigger is the key which opens the door to the disease. But if the trigger is avoided, they may never develop diabetes. The theory is as follows.

A baby with a susceptible genetic make-up is exposed to cows' milk early in life, for example through infant formula. At the same time the baby's immune system might be weakened by a virus infection. When milk proteins reach the intestine, they are not fully digested and broken down into individual amino acids as they should be. (Amino acids are the building blocks of proteins.) Instead, they are only broken down into chains of amino acids and these fragments may be absorbed into the blood where the immune system recognises them as foreign intruders and attacks them.

Coincidentally, the structure of some of these dairy fragments is identical to the surface structure of the body's own insulin producing cells (ß-cells) in the pancreas and it cannot distinguish between the two. As a result, both pancreas ß-cells and milk protein fragments are attacked and destroyed by the immune system and the child becomes diabetic.

The process of ß-cell destruction can be fast and aggressive, when the disease develops within a few months or, more often, it can take as long as 10 years or more as the cells are gradually destroyed. Type 1 diabetes is irreversible as the cells cannot regenerate. So what exactly are the milk proteins responsible for this reaction? There are three which will trigger this immune system reaction:

1 Bovine serum albumin (BSA) 
Human milk also contains albumin but it is different in structure to cows' albumin. When a foreign body is identified in the blood stream the immune system reacts by producing antibodies to fight it, so the presence of particular antibodies is an indicator that there is something in the blood that shouldn't be. When scientists tested type 1 diabetics and healthy children for antibodies against BSA, the results were astonishing. All diabetic children had antibody levels as much as seven times higher than the healthy children. Other studies have followed and all but one have found that diabetic children have high levels of BSA antibodies in their blood.

2 ß-casein 
The structure of human ß-casein is similar to ß-casein from cows' milk but about 30 per cent is different, which is assumed to be the reason why the immune system attacks it. As with BSA, there are structural similarities between cows' milk ß-casein and the molecules on the surface of the insulin producing cells in the pancreas. It is this close similarity that causes the immune system to react and attack both the cows' ß-casein as well as its own pancreas cells by mistake.

3 Cows' insulin
Cows' insulin is present in formula milk and can trigger the formation of specific antibodies. Research shows that the immune system of babies given cows' milk formula as early as three-months old, reacts strongly against the cows' insulin and produces antiinsulin antibodies. This results in the body's immune cells attacking human insulin also.

An extensive study of children from 40 different countries confirmed a link between diet and type 1 diabetes. The study set out to examine the relationship between dietary energy from major food groups and the occurrence of the disease. Meat and dairy foods significantly increased the risk of type 1 diabetes whilst a diet based on plant foods resulted in a much reduced risk of this disease. The more meat and milk in the diet, the higher was the incidence of diabetes but the more plant-based foods that were eaten, the lower the occurrence.

In summary, an early exposure to cows' milk (via infant formula) puts susceptible children at high risk of developing type 1 diabetes. If a baby cannot be breastfed until at least six months old, a much better option is soya-based formula. It provides all the essential nutrients without triggering an immune reaction. More than 20 per cent of all US babies have been brought up on soyabased formulae for 40 years or more - that's millions and millions of children - with no adverse reactions.

Type 2 diabetes

Type 2 diabetes is closely linked with being overweight or obese - in fact, obesity is the main risk factor, particularly abdominal obesity where the weight sits around your waist.

According to the latest statistics, almost a quarter of adults in England (24 per cent of men and 25 per cent of women) are classified as obese. In addition, 42 per cent of men and 32 per cent of women classified as overweight.

The numbers of obese children are equally startling - 17 per cent of boys and 15 per cent of girls aged two to 15. With this rapidly rising number of overweight people, the risk of diabetes is ever-increasing.

An extensive, 21-year study involving over 25,000 adults found that diabetes is less frequent among vegetarians and vegans. Those on meat-free diets had a 45 per cent lower risk of developing diabetes compared to the population as a whole. Another long-term piece of research followed the eating habits of people for 17 years. It showed that eating just one serving of meat per week significantly increases the risk of diabetes. People following a low-meat diet had a 74 per cent increase in the risk of type 2 diabetes compared to vegetarians.

The big question is why? What makes animal products so damaging to health? The answer is simple - fat is the main culprit. Several studies revealed that in people with insulin resistance (one of the main problems in type 2 diabetes) microscopic drops of fat accumulate in body cells and interfere with their ability to react to insulin correctly. Even though their bodies might produce enough insulin, the fat inside cells blocks the necessary reactions. Muscle cells normally store small amounts of fat as an energy reserve but, as the research shows, in insulin-resistant people, fat can build up to levels 80 per cent higher than in other, healthy people. Slim people are not exempt because it takes years for diabetes and other symptoms to develop.

But it doesn't end here. An abundance of fat in the bloodstream also turns off some of those genes that normally help the body to burn fat! A high-fat diet, therefore, not only causes the body to accumulate fat in the muscle cells but also slows down its ability to burn that fat. The result is an inability to respond to insulin.

This paradox can be explained by our evolutionary history. When food was scarce, the bodies of our ancestors developed special mechanisms to store fat when they had the opportunity - it was vital for their survival. We live in a much different world now but our bodies are still ready to store fat at any time if we provide it for them.

The common diet in many countries, including the UK, is high in fat, animal products and sugary foods and low in complex carbohydrates. Not only is this responsible for ever-increasing numbers of overweight or obese people but it also increases the risk of diabetes and cardiovascular disease.