Retinol, vitamin D, carotenes and alpha-tocopherol in serum of a moderately hypercholesterolemic population consuming sitostanol ester margarine

Abstract

We have shown earlier that sitostanol ester margarine lowers serum cholesterol by inhibiting cholesterol absorption so that, theoretically, there could be interference with the absorption of fat-soluble vitamins. Accordingly, we investigated whether sitostanol ester margarine affects the serum levels of vitamin D, retinol, alpha-tocopherol and alpha- and beta-carotenes during 1-year treatment in 102 subjects and 49 controls with moderate hypercholesterolemia. The vitamins were assayed at baseline on home diet, on margarine alone, after 1 year's consumption of sitostanol ester margarine and after an additional 2 months on home diet. In the sitostanol group, serum plant sterols, indicators of cholesterol absorption efficiency, were reduced up to -38% in relation to controls from home diet (P < 0.01) indicating that cholesterol absorption was markedly reduced. Vitamin D and retinol concentrations and the ratio of alpha-tocopherol to cholesterol were unchanged by sitostanol ester. Serum beta-carotenes and alpha-carotene concentration but not proportion were reduced in the sitostanol group from baseline and in relation to controls (P < 0.01). Retinol and vitamin D were unassociated with serum cholesterol, plant sterols or other vitamins, whereas alpha-tocopherol and carotenes were significantly associated with serum plant sterols suggesting that the higher cholesterol absorption efficiency, the higher the alpha-tocopherol and carotene levels in serum. We conclude that sitostanol ester did not affect vitamin D and retinol concentrations and alpha-tocopherol/cholesterol proportion, but reduced serum beta-carotene levels. Alpha-tocopherol and carotenes, but not vitamin D and retinol, were related to serum cholesterol and cholesterol absorption.