A vitamin E concentrate rich in tocotrienols had no effect on serum lipids, lipoproteins, or platelet function in men with mildly elevated serum lipid concentrations

Background: Tocotrienols, lipid-soluble antioxidants with vitamin E activit y, have been reported to lower LDL-cholesterol concentrations and platelet aggregation in men, but results are contradictory. Objective: To examine in detail the effects of a vitamin E concentrate rich in tocotrienols on serum lipoproteins and on platelet function in men at r isk for cardiovascular disease. Design: In this randomized, double-blind, placebo-controlled parallel trial , 20 men received daily for 6 wk 4 capsules, each containing 35 mg tocotrie nols and 20 mg alpha-tocopherol; 20 other men received 4 capsules daily, ea ch providing 20 mg alpha-tocopherol. All men had concentrations of serum to tal cholesterol between 6.5 and 8.0 mmol/L or lipoprotein(a) concentrations > 150 mg/L. Results: Compliance was confirmed by changes in serum tocopherol and tocotr ienol concentrations. Serum LDL cholesterol in the tocotrienol group was 4. 80 mmol/L before and 4.79 mmol/L after intervention, and increased from 4.7 0 to 4.86 mmol/L in the placebo group (95% CI for the difference: -0.54, 0. 19 mmol/L; P = 0.333). Also, changes in HDL cholesterol, triacylglycerol, l ipoprotein(a), and lipid peroxide concentrations did not differ between the groups. After adjustment for differences in initial values, no effects wer e found on collagen-induced platelet aggregation velocity, maximum aggregat ion, or thromboxane Bz formation in citrated whole blood. ATP release, howe ver, was lower in the tocotrienol group. Urinary thromboxane B-2 and 11-ket o-thromboxane B-2 concentrations and coagulation and fibrinolytic measures did not change. Conclusion: The tocotrienol supplements used had no marked favorable effect s on the serum lipoprotein profile or on platelet function in men with slig htly elevated lipid concentrations.