It is probably fairly self-evident that what goes in to the digestive system must have a key role in determining how it works, in the same was as our lungs are affected by the quality of air we breathe. Proving this however is often difficult for scientists – diet is so dependent on personal tastes, social influences, mood, availability and much else, that proving something is unequivocally helpful is difficult. Here's a summary of the information available.


The Good


The disease with the strongest evidence base to support dietary change is Coeliac disease. In fact, dietary avoidance of gluten (wheat) is the cure of this otherwise potentially severe condition associated with diarrhoea, malnutrition and fatigue. It is important to remember that gluten can be found in the most surprising foods - stock cubes, soy sauce and hot chocolate for example.

Another recent positive dietary therapy is the use of the low FODMAPs diet for patients with the irritable bowel syndrome (IBS). “FODMAPs” is a medical acronym for different food chemicals that promote watery stools and flatulence. As such, IBS patients with diarrhoea and bloating can experience significant help with such a diet.


The Bad


If you suffer with gastro-oesophageal reflux (symptoms of heartburn and regurgitation) then fatty foods and excess alcohol can make things a lot worse. It is easy to see how that late-night kebab after a few drinks results in terrible heartburn in the small hours.

Skipping meals and eating “on the go” disrupts gut function and predisposes to constipation and indigestion.

Excessive amounts of coffee and alcohol can irritate the bowels. They encourage bowel movements which may lead to incontinence if consumed in large quantities.

Beyond what you eat, how you eat is also important. Skipping meals and eating “on the go” disrupts gut function and predisposes to constipation and indigestion.


The Ugly


For as many facts as there are, as many myths abound about the role of diet in gut function. For example, constipation is not always caused by low fibre intake. In a very common type of constipation, called slow transit (characterised by hard stools and infrequent urge to empty the bowel), reducing fibre often improves symptoms.

Whilst as many as 20% of people believe they are lactose intolerant, only 5% of the UK population is truly so. And avoiding milk deprives you of a key source of calcium to fight osteoporosis.

Finally, eating a late night meal is not more fattening: calories cannot tell the time. It has been shown that weight gain is not related to eating a heavy late night meal – weight gain is related to the total number of calories we eat, not when we eat them.