Development of an updated method for fecal bile acid analysis and its use in assessing alterations in fecal bile acid composition in the rat due to enzyme resistant potato starch
Abstract
An updated method for fecal bile acid analysis was developed. Individual steps (extraction of sterols using methanol:chloroform, enzymatic deconjugation, bile acid extraction with diethyl ether and ethyl acetate, purification using Sep-Pak C$\sb{18}$ cartridges and methylation of bile acid carboxyl groups with dimethoxypropane/HCl) yielded improved recoveries when compared to alternate methods commonly employed. Effects of two types of resistant starch, ungelatized (raw potatoes) and retrograded (cooked/cooled potatoes), on cholesterol and bile acid metabolism in the rat was examined. Serum cholesterol was significantly higher and liver cholesterol was significantly lower in response to the cooked potato diet compared to a cellulose control diet or the raw potato diet. Bile acid and total steroid excretion were significantly higher in rats fed the cooked potato diet compared to those fed the cellulose or raw potato diet. High excretion of lithocholic and hyodeoxycholic acids observed in rats fed cooked potatoes suggests changes in the production and pool size of chenodeoxycholic acid and its derivatives may be responsible for alterations in cholesterol and bile acid metabolism observed with resistant starch feeding.
Degree
Ph.D.
Advisors
Story, Purdue University.
Subject Area
Nutrition
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