Influence of metallic ions and adsorbents on cholesterol absorption

Abstract

Using the balance method and cholesterol-4-C14 as a tracer in rats, three adsorbents and several iron and aluminum compounds, all of which were known in vitro to adsorb or precipitate bile acids, it was found by examining the feces collected during the last 4 days of a 12-day feeding period that two ion-exchange resins, Deacidite and Zeokarb, definitely increased the excretion of radioactivity in the bile acid fraction of the feces, and increased the apparent absorption of cholesterol. Ferric glycerophosphate (5% by weight in the diet) had a similar effect. The evidence of increased absorption of cholesterol appears to be attributable only to a slower passage time through the ileum. Although the resinous substances as fed daily would adsorb in vitro 125 mg of sodium taurocholate, this was not accomplished in vivo. The inorganic compounds fed were more than adequate to precipitate, in vitro, all the bile acids in the total daily enterohepatic pool; this did not occur in vivo. It is pointed out that in the design of experiments to test the in vivo effectiveness of in vitro adsorbents and precipitants of bile acids, a feeding period of longer than 12 days will be required unless the test agent is practically 100% effective in vivo.