Dietary Psyllium Hydrocolloid and Pectin Increase Bile Acid Pool Size and Change Bile Acid Composition in Rats

Abstract

Bile acid composition, synthetic rate and pool size were determined in rats fed diets containing 5 g cellulose, 5 g pectin or 5 g psyllium hydrocolloid/100 g diet using the washout technique. Bile acid pool sizes were similar for pectin- and psyllium-fed rats, and both were higher than the pool size for rats fed cellulose (5.48 +/- 1.22, 4.70 +/- 0.71 and 1.77 +/- 0.41 mumol/100 g body wt, respectively). Bile acid secretion rates showed a similar pattern [1730 +/- 496, 1551 +/- 252 and 572 +/- 88 nmol/(h.100 g body wt)], as did basal synthetic rates [129 +/- 25, 126 +/- 42 and 87 +/- 18 pmol/(h.100 g body wt)]. Individual and total bile acid pool sizes were generally higher in animals fed the pectin- or psyllium-supplemented diet compared with rats fed cellulose. Pectin or psyllium consumption resulted in a lower hydrophobicity of the bile acid pool and a lower ratio of circulating 12 alpha-hydroxylated to non-12 alpha-hydroxylated bile acids compared with cellulose consumption. This reduced hydrophobicity has been shown to reduce feedback inhibition of bile acid synthesis and may be responsible for the larger bile acid pool size. Changes in the location of reabsorption of bile acids may also be responsible for changes in the pool size and composition. These changes are characteristic of greater sterol excretion.

Effects of dietary fibre- and polyphenol-rich grape products on lipidaemia and nutritional parameters in rats

“…As a result, the amount of bile acids that return to the liver decreases and this leads to an increased hepatic synthesis of bile acids from cholesterol, causing a higher expression of LDL receptors in the liver and therefore a reduction of serum cholesterol concentrations and LDL lipoproteins. 23,51 In conclusion, the intake of fractional grape pomaces rich in dietary ®bre and polyphenols increases stool weight and the amount of fat and protein excreted in faeces, but these materials do not show any important antinutritional effect as they did not affect negatively animal growth or protein ef®ciency of the diet in Wistar rats. The utilisation of grape fractions as a source of dietary ®bre lowers serum total cholesterol and LDL cholesterol concentrations in hypercholesterolemic rats.…”

Hypocholesterolemic Effects of Hydroxypropyl Methylcellulose Are Mediated by Altered Gene Expression in Hepatic Bile and Cholesterol Pathways of Male Hamsters

“…Both of these events can result in upregulation of cholesterol synthesis. Most SDF are fermented by intestinal bacteria to produce SCFA, which can affect hepatic cholesterol synthesis (5,6).…”

Effect of Dietary Fiber on Serum Bile Acids in Patients with Chronic Cholestatic Liver Disease under Ursodeoxycholic Acid Therapy

“…Pool sizes of chenodeoxycholic acid as well as synthesis and fractional turnover rates of cholic and chenodeoxycholic acid significantly increased during the treatment period [26]. Using a washout tech nique, increased total bile acid pools have also been found in rats during PHM treatment [27], The mechanisms leading to these remarkable changes are poorly under stood [28], but have been attributed to impaired intestinal bile acid absorption [26,27]. The increases of fasting serum bile acid levels as observed in the present study are in accordance with increased pool sizes, although we did not perform kinetic studies.…”