Constipation is a condition in which bowel movements are infrequent or incomplete. While it is normal for some people to go to the toilet several times a day, others go less frequently. A change in the normal frequency of trips to the toilet can be an indicator of constipation. Similarly if you are going as frequently but having trouble passing stools, having to strain, this too may indicate constipation. Common symptoms include stomach ache and cramps, feeling bloated, nausea, a sense of fullness, headache, loss of appetite, fatigue and depression.
There are a number of factors that increase the risk of constipation, including:
- not eating enough fibre, such as fruit, vegetables and cereals
- a change in your routine or lifestyle, such as a change in your eating habits
- ignoring the urge to pass stools
- side effects of certain medication
- not drinking enough fluids
- anxiety or depression
- in children, poor diet, fear about using the toilet and poor toilet training can all be responsible
Source NHS Direct, 2012j.
In more detail, constipation may be caused by a range of factors including insufficient fluid in the diet, lack of fibre (fruit, vegetables and cereals) in the diet, lack of physical exercise, certain drugs (diuretics or painkillers, antidepressants and antacids that contain iron, calcium or aluminium), too much calcium or iron in the diet, pregnancy, an excessive intake of tea or coffee (this increases urine production and so decreases the amount of fluid in the bowel). Other factors include surgery, haemorrhoids (piles) and psychological problems such as anxiety. Constipation may be a symptom of another medical condition such as irritable bowel syndrome (IBS).
The link between constipation and cow’s milk intolerance was first made in medical literature in the 1950s (Clein, 1954). Since then, there have been numerous studies published confirming that this link exits. Researchers at the University of Palermo in Italy studied 65 children (aged from 11 to 72 months) suffering from chronic constipation (Iacono et al., 1998). All of these children had been treated with laxatives without success. After 15 days of observations (in a double-blind crossover study) each child received either cow’s milk or soya milk for two weeks, and then had a week off when they could eat and drink anything they wanted. Then the feeding order was reversed, so that the group that had previously drunk cow’s milk switched to soya and vice versa. The researchers (and children) were unaware of the order of treatment. Careful recordings of the bowel habits were made and a response to the treatment was defined as eight or more bowel movements during the two week treatment period. Results showed that 44 of the 65 children (68 per cent) had a response while receiving soya milk compared to none of the children receiving cow’s milk. The results were most dramatic in children who had frequent runny noses, eczema or wheezing, which may have been a symptom of milk allergy in these children. Sometimes however, constipation can be the only symptom of cow’s milk intolerance (or allergy).
In addition to cow’s milk intolerance, cow’s milk allergy in children can also cause chronic constipation. Some small-scale studies have observed how a cow’s milk protein-free diet can alleviate constipation in children with cow’s milk allergy (Daher et al.; 2001; Turunen, 2004). A larger randomised clinical study investigating the role of cow’s milk allergy as a cause of chronic constipation in two groups of 70 children (aged 1-13) with chronic constipation compared the effects of a cow’s milk free diet with cow's milk diet. All children had previously been treated with laxatives for at least three months without success. The test group received the cow’s milk-free diet for four weeks. After that they received a cow’s milk diet for two weeks. The control group received a cow’s milk diet for the whole six weeks. After four weeks, 56 patients (80 per cent) of the test group had responded in comparison to 33 (47.1 per cent) patients in the control group. In the test group after two weeks challenge, 24 out of 56 responders (42.8 per cent) developed constipation again. 80 per cent of the constipated children tested positive for cow’s milk allergy. The authors concluded that, in children, chronic constipation can be a symptom of cow’s milk allergy and suggest that an elimination diet is advisable in all children with constipation unresponsive to laxative treatment (Dehghani et al., 2012).
Cow’s milk protein-induced constipation in children is often associated with anal fissures (tears or ulcers that develops in the lining of the rectum or anus) and rectal eosinophilia (a condition in which abnormally high amounts of white blood cells called eosinophils are found in the gut lining. Eosinophilia occurs in a wide range of conditions including allergies such as asthma and cow’s milk allergy). In children with cow’s milk allergy, cow’s milk may lead to painful defecation, perianal erythema or eczema and anal fissures with possible painful faecal retention, thus aggravating constipation (Andiran et al., 2003). For this particular symptom (constipation), it has been reported that tolerance of cow’s milk may be achieved after an average of 12 months of strict avoidance (El-Hodhod et al., 2010). In other words, in children with cow’s milk allergy-induced constipation, reintroducing cow’s milk into the diet can trigger the constipation for an average time of up to one year. It is interesting that there is a persistent insistence on including a food in the diet that can cause such unpleasant and distressing symptoms when dairy food is not an essential component of the human diet.
Cow’s milk may lead to constipation by two distinct modes of action: cow’s milk intolerance or cow’s milk allergy. In either case, studies suggest that cow’s milk intolerance or allergy should be considered as a cause of constipation although the underlying mechanism still requires further investigation. In general it should be noted that dairy products supply children with unnecessary saturated fat while providing no dietary fibre whatsoever. Fibre is essential in the diet to maintain good bowel health through regular movements.