PROBUCOL TREATMENT DECREASES SERUM CONCENTRATIONS OF DIET-DERIVED ANTIOXIDANTS

The effect of probucol, which is both a cholesterol-lowering drug and an antioxidant, on the serum concentrations of diet-derived antioxidan ts vitamin E, beta-carotene, lycopene, and vitamin A was studied in 30 3 hypercholesterolemic subjects. In a 3-year, double-blind, randomized trial we investigated to determine whether combined treatment with di et, cholestyramine, and probucol could reduce the progression of femor al atherosclerosis. Serum and lipoprotein antioxidant levels were meas ured by reverse-phase high-performance liquid chromatography. Cholesty ramine significantly lowered serum concentrations of vitamin E by 7%, beta-carotene by 40%, and lycopene by 30% (all P < .001) due to impair ment of gastrointestinal absorption and to serum cholesterol lowering. Probucol reduced serum vitamin E by 14% (P < .001) secondary to chole sterol and triglyceride lowering. The carotenoids were reduced by prob ucol by 30% to 40% (P < .001) most probably due to reductions in lipop rotein particle size and to competition with these substances for inco rporation into VLDL during its assembly in the liver. This study shows that the use of a lipid-soluble antioxidant and cholesterol-lowering drug may have unfavorable effects on blood levels of diet-derived anti oxidants.