Effect of cyclodextrin on plasma lipids and cholesterol metabolism in the rat

beta-Cyclodextrin (beta-CD) is a bile acid and sterol sequestrant produced by enzymatic modification of starch; this product has the potential to decrease plasma cholesterol. In contrast to the sequestrants having resin- or saponin-like properties, beta-CD is rapidly broken down by the large intestine microflora. beta-CD effects on cecal fermentations and lipid metabolism were thus investigated in rats adapted to semipurified diets containing 0%, 2.5%, or 5% beta-CD. In rats fed beta-CD diets, there was an enlargement of the cecum together with a dramatic increase in the cecal concentration of propionic acid (even with the 2.5% level, in moderately acidic pH conditions). Propionic acid produced in the cecum was readily absorbed and entirely taken up by the liver, whereas there was no significant acetic acid uptake. Dietary beta-CD was highly effective in enhancing bile acid entry into to the cecum: the cecal bile acids pool was 2.2 and 3.6-fold enlarged in rats fed the 2.5% and 5% beta-CD diets, respectively. The solubility percentage of bile acids decreased to approximately 25% in rats fed the beta-CD diets (v 51% in controls); the cecal concentration of soluble bile acids was thus relatively low in these animals. The fecal excretion of steroids was strongly enhanced by beta-CD, and bile acids excretion was practically proportional to the dietary beta-CD level. There was a net lipid-lowering effect of beta-CD, even at the 2.5% level. The effect was more pronounced on triglycerides than on cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)