Effects of dietary fiber from wheat, corn, and soy hull bran on excretion of fecal bile acids in humans

Tempe consumption modulates fecal secondary bile acids, mucins, immunoglobulin A, enzyme activities, and cecal microflora and organic acids in rats

The present study investigated the effect of dietary tempe, a fermented soy product, on the colonic environment of rats fed high-fat (HF, 30 % fat; experiment 1) or low-fat (LF, 6 % fat; experiment 2) diets. Growing male rats were fed the experimental diets with or without 25 % tempe for 21 days. Tempe consumption slightly but significantly increased the growth of rats fed both the HF and LF diets (P < 0.05). With both the HF and LF diets, dietary tempe markedly reduced a harmful fecal secondary bile acid, lithocholic acid (a risk factor of colon cancer) (P < 0.05), and markedly elevated fecal mucins (indices of intestinal barrier function) and immunoglobulin A (IgA, an index of intestinal immune function) (P < 0.05). With the HF diet, dietary tempe increased cecal acetate, butyrate, propionate, and succinate concentrations (P < 0.05). Analysis of the profile of cecal microflora revealed lower Bacteroides and higher Clostridium cluster XIVa levels in the tempe group of rats fed the HF diet (P < 0.05). Compared with the control group, the fecal activity of β-glucosidase was markedly higher in the tempe group (P < 0.05), while that of urease was lower (P < 0.05) with both the HF and LF diets. The present results suggest that tempe consumption modulates the colonic environment in rats.

The clinical value of faecal bile acid determination in patients with chronic diarrhoea of unknown origin

To evaluate the diagnostic value of faecal total bile acid determination in adult patients with chronic diarrhoea, output and concentration of 3 alpha-hydroxy-bile acids were determined in 28 patients. The patients had normal results of primary biochemical, radiologic, and endoscopic examinations. Stools were sampled for 3 days while on a standardized diet. The patients were observed until final diagnosis was obtained; Crohn's disease was diagnosed in 5 cases, osmotic diarrhoea in 4, bacterial overgrowth in 3, laxative abuse in 2, other specific causes in 3, and persisting lack of specific diagnosis in 11. No difference in output or concentration of faecal bile acids was found between the groups. Six patients with high bile acid outputs benefited from treatment with cholestyramine. Accordingly, determination of total bile acids in stools cannot be recommended as a primary test in patients with chronic diarrhoea.