effect of a natural high-fiber diet on serum lipids, fecal lipids, and colonic function

Diets composed of natural foodstuffs were used to assess the effects of fiber on serum lipids and colonic function in 46 healthy volunteers. The 2 groups started on a high- or low-fiber diet and changed after 3 weeks. Half the subjects were on high or low cholesterol for the duration of the experiment. Measurements were done on serum cholesterol, fecal mass, steroids, electrolytes and intestinal transit time. The fat and cholesterol intake in the high-fiber diet was less than planned, which may account for part, but certainly not all, of the decrease in serum cholesterol levels. The high fiber diet also increased average fecal weight and decreased intestinal transit time.