Influence of diet on flatus volume in human subjects.

Ten flatulent but otherwise healthy subjects were studied while consuming two or three different diets. Flatus collections showed that a bean-containing, high crude-fibre diet produced more flatus (mean 49.4 ml/hr) than either a diet with a restricted crude-fibre content (mean 26.7 ml/hr) or a liquid chemically defined diet (mean 10.9 ml/hr). There was a close correlation between the crude-fibre content of the diet and the production of flatus. The results are consistent with the conclusion that flatus is not the result of swallowing air, but arises mainly from bacterial fermentation of indigestible carbohydrate, eg, cellulose, passing into the colon.