These results suggest that exercise, such as walking, and a high intake of dietary fiber, such as rice, were useful in the maintenance of defecation.

The gastrointestinal transit time of food was determined by x-ray fluoroscopy using barium sulfate in rats fed with diets of various dietary fiber contents, and the effects of dietary fiber on the transit time, properties of feces, and fat absorption were examined. In 4-and 16-month-old rats fed with the diet for 3 and 15 month, respectively, the transit time of the cecum and colon in those receiving 20 and 40% wheat bran diets was shortened compared with that in the 0% group. The fecal pellet number and volume increased as the wheat bran content of the diet increased. In another experiments, the daily total fat excretion was found to be the greatest in rats receiving 15% pectin diet, followed by rats receiving 15% cellulose and non-fiber diets, respectively. These results suggest that shortening of the transit time through the cecum and colon with increase of fecal volume and suppression of fat absorption all participate in the mechanism of the inhibitory action of wheat bran on carcinogenesis and on the development of diverticulum of the large intestine, dietary fiber; wheat bran; transit timeThe effects of dietary fiber (DF) on gastrointestinal function, which have been described in many reports, include its action in shortening the gastrointestinal transit time of food, especially large intestine transit time, which has received attention as a major factor for the development of colonic carcinomas, and also for the development of diverticulum in the large intestine (Burkitt 1971;Burkitt et al. 1972). In the present study, we measured the transit time of food through each of the esophagus, stomach, and small and large intestine in rats fed with wheat bran by x-ray fluoroscopy using barium sulfate to examine the effects of dosage and administration period of wheat bran on the transit time. The changes in fecal properties induced by wheat bran administration and the effects of pectin