FECAL PH, BILE-ACID AND STEROL CONCENTRATIONS IN PREMENOPAUSAL INDIANAND WHITE VEGETARIANS COMPARED WITH WHITE OMNIVORES

Faecal bulk, pH, water content, the concentrations of neutral sterols and bile acids and dietary intakes were measured in twenty-two Indian vegetarian, twenty-two white omnivorous and eighteen white vegetarian premenopausal women. Faecal bulk and water content were greater and pH lower in the Indian vegetarians. Total faecal animal sterol and copro stanol concentrations expressed on a dry-weight basis were lower in th e vegetarians compared with the omnivores. The faecal sterol concentra tions were correlated with dietary cholesterol intake. Primary bile ac ids were detected in six Indian vegetarians, two white vegetarians and two white omnivores; secondary bile acids were detected in all the wh ite omnivore and vegetarian subjects but not in two of the Indian vege tarians. Total faecal free bile acid and conjugated bile acid concentr ations were lower in the white vegetarians compared with the omnivores . Faecal lithocholic acid concentrations were lower in both Indian and white vegetarians. The lithocholic: deoxycholic acid ratio and copros tanol:total animal sterols ratio were significantly lower in the India n vegetarians compared with the omnivores. Both ratios were positively correlated with faecal pH. Stepwise multiple regression analyses were undertaken in order to identify which nutrients influenced faecal pH, lithocholic and deoxycholic acid concentrations. The intakes of starc h and dietary fibre were negatively associated with faecal concentrati ons of lithocholic and deoxycholic acid. Starch intake alone was negat ively associated with faecal pH. The results of this study confirm tha t diets high in dietary fibre decrease faecal bile acid concentrations and suggest that the complex carbohydrates present in Indian vegetari an diets influence faecal pH and inhibit the degradation of faecal ste roids.