The effect of fibre on gastrointestinal transit times in vegetarians and omnivores

Abstract

A pilot study has been carried out to investigate the effect of fibre on the gastrointestinal transit of a single unit and a multiple unit dosage form in vegetarians and omnivores, using the technique of gamma scintigraphy. Eight healthy male volunteers (four vegetarians and four omnivores) were studied after consuming a strict diet containing either 15 or 40 g dietary fibre per day. Gastric emptying of both types of dosage form was found to be unaffected by fibre content of the diet, however, small intestinal transit appeared to be longer in vegetarians than omnivores, irrespective of fibre intake. Transit time of the dosage forms within each region of the colon was highly variable, however, overall transit time in the vegetarians was slower than in the omnivores. The addition of supplementary fibre to the diet appeared to exert a ‘normalising’ effect on colonic transit, whereby initially rapid transit was retarded and initially slow transit accelerated. There appeared to be no definite relationship between transit time and laxation.