Diet free from gluten and casein helpful in irritable bowel syndrome

A new study finds that excluding foods containing gluten and casein from the diet can relieve the symptoms associated with irritable bowel syndrome.

Many irritable bowel syndrome (IBS) sufferers have discovered for themselves that removing wheat and dairy products from their diet helps to relieve their symptoms and make them feel better. Now, a new study has gone beyond anecdotal reports and shown that this approach is truly effective in more than half of patients who have both IBS and inflammatory bowel disease (IBD).

Researchers from New Zealand this week presented results of their three month long trial at the Australian Gastroenterology Week conference in Perth. The trial involved 100 participants who had been disgnosed with both IBS and IBD. The two conditions commonly occur together.

The participants each had their diets assessed to determine which foods appeared to trigger or exacerbate their abdominal symptoms. The most common culprits included those foods that contain wheat, dairy products, foods high in fructose (i.e. fruit), and foods high in galactans like legumes. Paticipants were then advised to avoid their particular trigger foods for a period of three months.

The study results showed that those patients who adhered to the avoidance diet had significant relief from their symptoms. The diet was particularly effective for abdominal pain, diarrhoea, bloating and wind.

Patients reported that the diet was relatively easy to stick to and that they were able to find tasty alternatives to the foods they normally ate.

It is reported that up to half of IBD patients also have symptoms consistent with IBS. With the success of this trial it is hoped that a dietary approach will be used much more widely to help relieve symptoms in patients suffering from both IBD and IBS.

Lead investigator Dr Richard Gearry, a consultant gastroenterologist at Christchurch Hospital said: "We don't want to prescribe drugs or perform surgery on patients who do not have inflammation as the cause of their symptoms."

"Therefore, if a patient with IBD has symptoms suggestive of IBS, or there is no evidence of inflammation, then using this dietary approach is appropriate."

The study did not investigate the reasons why these particular foods caused problems but previous research has provided a number of possible explanations.

Small Intestinal Bacterial Overgrowth (SIBO) has been strongly linked with IBS. SIBO describes a situation in which there are much higher amounts of certain bacteria in the small intestine than usual. Eating a diet high in foods that the bacteria can use as food results in high levels of fermentation in the gut with resulting symptoms such as gas, bloating, and abdominal pain. Foods such as those containing fructose and galactans, as well as a diet generally high in carbohydrate, can exacerbate SIBO.

The protein gluten, found in wheat and other grains, is well known for causing inflammation of the intestinal lining in susceptible indivuduals. The most severe form is when there is an immune response to the presence of gluten with the end result being severe damage to the intestinal lining. This is referred to as Celiac Disease. Research has suggested that milder irritation can also occur however in people who do not have Celiac Disease. IBS patient's intestines are known to be much more sensitive than healthy people's.

Gluten and the milk protein casein may also be a problem as they form substances related to opiate drugs when they break down. These substances may interact with the nervous system in the gut and trigger muscular contractions and cramping for example.