As conventional medicine main-tains that there's no cure, many sufferers have to resort to self-help remedies. One of the most popular-mainly because it is the most aggressively marketed-is yoghurt, as it is supposed to repopulate the gut with 'good' bacteria.
Yet, a new report suggests that, for some IBS sufferers, yoghurt may be the worst thing they could eat, and it may even worsen the condition. The IBS Treatment Center in Seattle, WA, says that a substantial minority of cases are due to a food allergy, and one of the most common food allergens is dairy.
Dr Stephen Wangen, the Center's chief medical officer, commented: "A large number of our patients who experience IBS are actually suffering from a dairy allergy but don't realize it. Yogurt, although it is fermented, is still a dairy product and can be a potent trigger of their digestive problems. For these people, the consumption of yogurt, even brands with high probiotic bacteria content, is inadvisable" (Townsend Letter, 2008; June: 35).
Some advertisements for yoghurt suggest that the products are good for IBS, and can help to reduce bloating and constipation often within two weeks. But the Center says it regularly sees IBS sufferers who have tried a yoghurt-based preparation and who report either that they have not seen any benefits or even that they are feeling worse.
And, says Wangen, determining whether or not you have a dairy allergy can be more complicated than you might think. Dairy intolerance isn't the same as lactose intolerance, which is an enzyme deficiency and more easily treated. Dairy is present in lots of foods and, as whey powder and casein, is used in many processed foods such as cakes, biscuits and chocolate.
Overall, a food-elimination diet may be an effective way of treating IBS. In one study of 20 female IBS sufferers, their symptoms improved over a year with taking a probiotic while following a food elimination/ rotation diet. However, the changes in diet appeared to have a more sig-nificant effect than taking the pro-biotic (J Am Coll Nutr, 2006; 25: 514-22).
A review that evaluated 46 studies involving dietary approaches to IBS concluded that, while food allergies can exacerbate symptoms, they were not the cause of the problem. Food elimination can, at best, ameliorate the worst of the discomfort and pain, but cannot eliminate the underlying cause (J Clin Gastroenterol, 2005; 39 [5 Suppl 3]: S243-6).
Although the reports on the effect-iveness of probiotics in treating IBS are mixed, Wangen believes that this is only to be expected, as not every IBS sufferer needs a probiotic and, even when the patient does, the best dosage and form will vary from one person to another.
Lactobacillus is one of the exciting probiotics that may prove helpful in IBS, says a study from the Mauriziano Hospital in Turin, Italy (Minerva Gastro-enterol Dietol, 2008; 54: 287-93). One Korean study of L. acidophilus vs a placebo in 40 IBS sufferers found that the probiotic reduced abdom-inal pain and discomfort by 20 per cent (Dig Dis Sci, 2008; 15 February; e-published ahead of print).
Another strain, L. rhamnosus, was effective in treating an IBS-like condition known as FAPD (functional abdominal pain disorder) in 104 children. The children taking the probiotic reported a far greater reduction in pain than those given a placebo (Aliment Pharmacol Ther, 2007; 25: 177-84).
Yet another probiotic, Bifido-bacterium infantis, was tested in 362 female sufferers with some success (Am J Gastroenterol, 2006; 101: 1581-90), while B. animalis decreased bloating and discomfort in 274 IBS sufferers with constipation (Aliment Pharmacol Ther, 2007; 26: 475-86).
A combination capsule containing both Lactobacillus and Bifidobac-terium, together with Enterococcus, eased IBS symptoms in 85 patients in Hangzhou, China. The effects, however, were gradual, and showed no further improvement after two weeks (J Zhejiang Univ Sci B, 2006; 7: 987-91).
Despite these successes, the jury is still out. One double-blind study of 40 IBS patients found no effects on bloating, diarrhoea or constipa-tion vs a placebo, although the probiotics did result in "a significant decrease in abdominal pain" (Korean J Gastroenterol, 2006; 47: 413-9).
Furthermore, a meta-analysis of 20 trials, involving 23 probiotic treatments and 1404 subjects, found the evidence to be inconclusive. Although most of the studies reported less abdominal pain compared with placebo, few mentioned any other benefits. How-ever, many of these studies were poorly designed (World J Gastroenterol, 2008; 14: 2650-61).
Finally, a comparison of a pro-biotic dietary supplement and a placebo in 116 IBS patients could find no differences between the two in terms of abdominal pain and diarrhoea (Gastroenterol Clin Biol, 2008; 32: 147-52).
Overall, probiotics may have a part to play in treating IBS symptoms, but whether or not it works depends on the strain, the dose and viability. In short, it's not a self-help therapy.