Effect of cholestyramine on the absorption of vitamin D3 and calcium

Abstract

The absorption of 10 μg doses of vitamin D₃-³H in rats was found to be decreased by the addition of cholestyramine to the diet in an amount sufficient to cause steatorrhoea. Studies in vitro suggested that the effect of cholestyramine was due to its known ability to bind bile salts and thus disrupt micelles containing vitamin D. The absorption of 1 mg ⁴⁷calcium chloride was similar in both control and cholestyramine-fed rats, whether estimated by the whole body counting or the faecal excretion technique. These findings show that the administration of cholestyramine causes a reduction in the absorption of vitamin D₃-³H but not of radiocalcium.