Brief Alert

Different Diet, Less Gas?

Source: King TS, et al. Lancet 1998;352:1187.

King and associates examined whether colonic malfermentation could be a factor in the pathogenesis of Irritable Bowel Syndrome (IBS). Six female IBS patients and six female controls were enrolled in a randomized, cross-over study in which subjects received either a standard diet (containing the usual Western foods) or an elimination diet for two weeks, followed by the alternate diet for two weeks after a two-week washout period. The elimination diet included fish and meat, but not beef, soy products replaced dairy products, and cereals other than rice were prohibited. There were also restrictions on yeast, citrus, caffeine, and tap water.

Toward the end of each two-week diet, fecal excretion of fat, nitrogen, starch, and nonstarch polysaccharide was measured, along with a 24-hour indirect calorimetry.

On the standard diet, colonic gas production of hydrogen was two times higher in IBS patients than controls, and excretion of hydrogen plus methane was nearly four times higher. While both IBS and control subjects had reduced gas production, especially of hydrogen, while receiving the elimination diet, the IBS patients had near-normalization of their gas excretion patterns. This was associated with significant improvement in their gastrointestinal symptoms. King et al speculated that the elimination diet favorably alters the activity of certain bacteria, thereby decreasing symptoms of IBS. (This brief alert was written by Carol Kemper, MD, Clinical Assistant Professor of Medicine, Stanford University.)