Bile acids fecal

Colonic reabsorption of secondary bile acids seems to be clearly established. The presence of deoxycholic acid as a normal biliary constituent indicates that it has been absorbed from the colon. Furthermore, the human bile contains a variety of other bacterial transformation products such as lithocholic acid and other cholanic acids, some of which may have been further metabolized by the liver (44-47). In contrast to the case in some other mammalian species, human liver is not able to convert deoxycholic acid back to cholic acid. Colonic perfusion with different labeled bile acids has clearly shown that colonic absorption takes place in man (48). Administration of labeled cholic acid into the lumen of the large bowel during operation for cholecystectomy is followed by the appearance of labeled cholic acid and deoxycholic acid in the T-tube bile, the recovery from the T-tube being about 60% of the dose (49). This clearly shows that cholic acid is converted to deoxycholic acid in the human colon and that both of them are absorbed from the large bowel. Colonic reabsorption has been calculated to amount to 200 mg/ day (49). The colonic absorption of secondary bile salts could be even higher if the physical state of some bile acids were not unfavorable for absorption. Lithocholic acid, for example, is a very nonpolar compound and precipitates in the colonic content in addition, it and other secondary bile acids as well are partially associated with fecal debris and bacteria (41). As a result of poor absorption, the amount of secondary bile acids, other than deoxycholic acid, is usually low in human bile. After a continuous biliary drainage, secondary bile acids disappear from the bile in a few days (49-51). 

As already mentioned, some bile acids escape from the portal blood to the general circulation. Serum bile acid concentrations range normally from 30 to 230 / g/100 ml (52). Most of them are in conjugated form, the proportions of the individual bile acids being about the same as in the bile, viz. cholic, chenodeoxycholic, and deoxycholic acids are the major constituents. 

The methods available for the quantitation of bile acid metabolism in man have been reviewed recently by Hofmann et al. (53). The measurement can be performed by the following methods (a) fecal determination of bile acids, (b) fecal excretion of administered labeled bile acids, (c) isotope dilution, and (d) measurement of bile salt pool. 

Since urinary excretion (4) and output through the skin (54) of bile 

In contrast to many earlier studies using less specific procedures cf, 55), the chemical methods, which apparently give the most reliable results, have shown that the daily bile acid synthesis is normally relatively low in man, being about 250 mg/day (range from about 100 to 400 mg/day), i.e., about one-third of total cholesterol catabolism. Dietary factors, and especially body size and obesity, affect the values sensitively impaired liver function and hypercholesterolemia decrease, and malabsorption, especially ileal dysfunction, increases markedly the fecal bile acid elimination (11,62,63). Determination of the fecal bile salt excretion is a sensitive method for detection of ileal dysfunction (64). 

---

Moundras, C. Behr, S.R. Demigne, G. Mazur, A. Remesy, G. (1994). Fermentable polysaccharides that enhance fecal bile acid excretion lower plasma cholesterol and apolipoprotein E-rich HDL in rats. Journal of Nutrition, Vol. 124, No.ll, (November 1994), pp. 2179-2188, ISSN 0022-3166. 

SEETHARAMIAH G s, CHANDRASEKHARA N (1990) Effect of gamma oryzanol on cholesterol absorption and biliary and fecal bile acids in rats. Ind J Med Res, 92 471-5. 

Trautwein, E. A., Kunath-Rau, A., and Erbersdobler, H. F. (1999). Increased fecal bile acid excretion and changes in the circulating bile acid pool are involved in the hypocholester-olemic and gallstone-preventive actions of psyllium in hamsters. /. Nutr. 129, 896-902. 

B. S. Reddy and E. L. Wynder, Metabolic epidemiology of colon cancer. Fecal bile acids and neutral sterols in colon cancer patients and patients with adenomatous polyps. Cancer, 1977, 39(6), 2533. 

Neomycin - Orally administered neomycin increases fecal bile acid excretion and reduces intestinal lactase activity. 

Cholestyramine (Questran/ Questran Light Prevalite) [AntilipemiC/ Bile Acid Sequestrant] Uses Hypercholesterolemia Rx pruritus associated w/ partial biliary obst D associated w/ excess fecal bile acids ... 

Hemagglutinin activity. Saline extract of the dried seed, at a concentration of 10%, was active on the human red blood cells L Hypocholestrolemic activity. Fresh root, taken orally by human adults at a dose of 200 g/person, was active. Daily ingestion at breakfast for 3 weeks decreased cholesterol in serum by 11%, increased fecal bile acid and fat excretion by 50%, and increased stool weight by 25%° . 

Cholesterol level decrease. The husks and seeds were administered orally to six normal adult males and five adult males with ileostomy and six normal adult males and four adult males with ileostomy, respectively, at a dose of 10 g/day for 3 weeks. The husk had no effect on cholesterol or triglyceride concentrations in either normal or ileostomy subjects. Total and HDL cholesterol concentrations were reduced on average by 6.4 and 9.3%, respectively, in normal group after seed supplementation. No effect on fecal bile acid excretion in the normal subjects was found after both regimens. Ileostomy bile acids were increased (on average 25%) after seed supplementation, whereas no effect on cholesterol concentrations was found. These results suggest that psyllium seed may be more effective than the husk in... 

A. Southgate. The effects of two di- SO084 etary fiber supplements on gastrointestinal transit, stool weight and frequency, and bacterial flora, and fecal bile acids in normal subjects. Me- SO085 tabolism 1977 26(2) 117-128. 

Ebihara, K., Shiraishi, R., Okuma, K. (1998). Hydroxypropyl-modifled potato starch increases fecal bile acid excretion in rats. J. Nutri., 128, 848-854. 

Yao, H. T. and Chiang, M. T. (2006). Effect of chitosan on plasma lipids, hepatic lipid and fecal bile acid in Hamsters. J. Food Drug Anal. 14,183-189. 

Porter JL, Fordtran JS, Santa Ana CA, Emmett M, Hagey LR, Macdonald EA, Hofmann AF (2003) Accurate enzymatic measurement of fecal bile acids in patients with malabsorption. J Lab Clin Med 141 411-418... 

Octreotide 100 pg given subcutaneously to five healthy subjects 30 minutes before meals for 7 days increased fecal fat excretion however, steatorrhea occurred in only two cases fecal bile acid excretion fell to about 25% (35)... 

Another possible mechanism involves the effect of saponins on micelle formation. Saponins are known to alter the size or shape of micelles (Oakenfull, 1986 Oakenfull and Sidhu, 1983), an observation that is consistent with decreased bile acid absorption (Stark and Madar, 1993) and increased fecal bile acid excretion (Malinow et al., 1981 Nakamura et al.,1999). Saponins may also directly bind bile acids (Oakenfull and Sidhu, 1989), which would presumably interfere with micelle formation and decrease cholesterol absorption. Other studies have found that saponins decrease the absorption of fat-soluble vitamins (Jenkins and Atwal, 1994) and triglycerides (Han et al., 2002 Okuda and Han, 2001), indicating decreased micelle formation. However, direct evidence showing impaired micelle formation in vivo is lacking. Moreover, Harwood et al. (1993) reported no change in bile acid absorption or interruption of the enterohepatic circulation of bile acids in hamsters fed tiqueside, despite significant reductions in cholesterol absorption. 

Jenkins, K.J. and Atwal, A.S. 1994. Effects of dietary saponins on fecal bile acids and neutral sterols, and availability of vitamins A and E in the chick. J. Nutr. Biochem. 5, 134-137. 

Conjugated bile salts are normally absorbed in the terminal ileum. Disease of the terminal ileum (eg, Crohn s disease) or surgical resection leads to malabsorption of bile salts, which may cause colonic secretory diarrhea. The bile salt binding resins cholestyramine or colestipol may decrease diarrhea caused by excess fecal bile acids (see Chapter 35 Agents Used in Hyperlipidemia). The usual dose is 4-5 g one to three times daily before meals. Side effects include bloating, flatulence, constipation, and fecal impaction. In patients with diminished circulating bile acid pools, further removal of bile acids may lead to an exacerbation of fat malabsorption. These agents bind a number... 

Increased fecal bile acid excretion in transgenic mice with elevated expression of human phospho lipid transfer protein. Arterioscler. Thromb. Vase. Biol. 23, 892-897. 

Dietary Fat and Fiber and Bile Acid Excretion. In order to understand the specifics of the mechanisms whereby dietary fat influences colon cancer, the effect of type and amount of dietary fat on biliary and fecal bile acids was studied in rats (40,47,48). These... 

Miettinen, T.A. and Tarpila, S. 1977. Effect of pectin on serum cholesterol, fecal bile acids and biliary lipids in normolipidemic and hyperlipidemic individuals, Clin. Chim. Acta., 79 471—417. 

Calvert RJ, Klurfeld DM, Subramaniam S, et al. 1987. Reduction of colonic carcinogenesis by wheat bran independent of fecal bile acid concentration. J Natl Cancer Inst 4 875-880. 

The role of dietary fat in cancer development may be a result of its influence on fecal bile acid concentrations. The release of bile acids is stimulated following ingestion of dietary fat. These acids are then converted by colonic flora to secondary bile acids, which are associated with bowel mucosal irritation and cell proliferation responses and may promote tumor growth. ... 

Decreases fecal bile acids decreases bowel tansit time direct binding to fecal mutagens dilution of fecal material... 

Decreases fecal bile acids reduces consumption of heterocyclic amines and other carcinogens that are produced through meat preparation and processing techniques Inhibit COX-2 induce apoptosis via 15-10X-1 Increases levels of intracellular folate... 

In addition to bile and serum bile acids, fecal bile acids can be estimated by the enzymatic method, provided that they are first extracted to remove interfering lipids. Methods for this purpose are continually being simplified and improved (B16, D6, V3). Enzymatic determination of fecal extracts slightly underestimates total bile add excretion, since 3-keto bile acids and bile acids which are sul ted at the 3a position occur in feces and are not... 

G14. Grundy, S. M., Ahrens, E. H., and Miettinen, T. A., Quantitative isolation and gas-liquid chromatographic analysis of total fecal bile acids. J. Upid Res. 6, 397—410 (1965). 

Shaikh, B., Pontzer, N. J., Molina, J. E., and Kelsey, M. I., Separation and detection of UV-absorbing derivatives of fecal bile acid metabolites by bigh-performance liquid chromatography. Anal. Biochem. 85, 47-55 (1978). 

M4. Makita, M., and Wells, W. W., Quantitative analysis of fecal bile acids by gas-liquid chromatography. Arud. Biochem. 6, 523-530 (1963). 

Although small amounts of the biliary bile acids, 3a,7 ,12a-trihydroxy- and 3a,la-dihydroxy-5)3-cholestan-26-oic acids, were detected, the major fecal bile acids were their 7-deoxy derivatives, 3 ,12 -dihydroxy- and 3a-hydroxy-5 8-cholestan-26-oic acids. Small amounts of 3j8,7a,12a-trihydroxy-5 -cholestan-26-oic acid, 3a,7 -, 3j8,7 -and 3jS,12a-dihydroxy-5)S-cholestan-26-oic acids, and 3 8-hydroxy-5j3-cholestan-26-oic acid were found as well [75]. Since intestinal bacterial in mammals are known to 7a-dehydroxylate C24 bile acids and to interconvert a- and j8-hydroxyl groups (Chapter 12), these C27 bile acids may be products of the intestinal flora in the alligator. 

---