It is unclear if diet has much effect on the symptoms of IBS. Nevertheless, patients often associate their symptoms with specific foods (such as salads, fats, etc.). Although specific foods might worsen IBS, it is clear that they are not the cause of IBS. The common placebo response in IBS also may explain the improvement of symptoms with the elimination of specific foods in some people.
Dietary fiber often is recommended for patients with IBS. Fiber probably is of benefit in IBS patients with constipation, but it does not reduce abdominal pain. Lactose (milk sugar) intolerance often is blamed for diarrhea-predominant IBS, but it does not cause IBS. Because they both are common conditions, lactose intolerance and IBS may coexist. In this situation, restricting lactose will improve, but not eliminate the symptoms.
Lactose intolerance is easily diagnosed by testing the effect of lactose (hydrogen breath testing) or trying a strict lactose elimination diet. Intolerance to sugars other than lactose, specifically, fructose, sucrose, and sorbitol, may cause symptoms that are similar to IBS or make IBS worse. It is unlikely, however, that these sugars cause IBS.
Dietary fiber often is recommended for patients with IBS. Fiber probably is of benefit in IBS patients with constipation, but it does not reduce abdominal pain. Lactose (milk sugar) intolerance often is blamed for diarrhea-predominant IBS, but it does not cause IBS. Because they both are common conditions, lactose intolerance and IBS may coexist. In this situation, restricting lactose will improve, but not eliminate the symptoms.
Lactose intolerance is easily diagnosed by testing the effect of lactose (hydrogen breath testing) or trying a strict lactose elimination diet. Intolerance to sugars other than lactose, specifically, fructose, sucrose, and sorbitol, may cause symptoms that are similar to IBS or make IBS worse. It is unlikely, however, that these sugars cause IBS.
