Supplementation with 3 compositionally different tocotrienol supplements does not improve cardiovascular disease risk factors in men and women with hypercholesterolemia

Abstract

Background: Tocotrienols have been reported to lower LDL-cholesterol and fasting glucose concentrations and to have potent antioxidant effects, but the results are contradictory. Objective: The objective was to study the relative effect of tocotrienol supplements of different compositions (mixed α-plus γ-, high γ-, or P25-complex tocotrienol) on blood lipids, fasting blood glucose, and the excretion of 8-iso-prostaglandin F2α, a measure of oxidative stress, in healthy hypercholesterolemic men and women. Design: This was a double-blind, randomized, parallel-design study in which subjects (n = 67 men and women) consumed 1 of 3 commercially available tocotrienol supplements or a safflower oil placebo for 28 d. Blood and urine samples were obtained before and after the 28-d supplementation phase for analysis of fasting blood lipids, glucose, tocotrienols and tocopherols, and 8-iso-prostaglandin F2α. Results: Overall, serum tocotrienols were increased in subjects who consumed tocotrienols, which showed that the putatively active components were absorbed. No significant differences in mean lipid or glucose concentrations were observed among the 4 treatment groups at the end of the 28-d supplementation phase. However, when the values were expressed as a percentage change from the concentrations during the presupplementation run-in phase, LDL cholesterol increased slightly (7 ± 2%) but significantly (P < 0.05) in the group consuming the mixed α- plus γ-tocotrienol supplement when compared with LDL cholesterol in the group consuming the P25-complex tocotrienol. Neither mean concentrations nor the percentage change in 8-iso-prostaglandin F2α differed significantly among treatments. Conclusion: Supplementation with 200 mg tocotrienols/d from 3 commercially available sources has no beneficial effect on key cardiovascular disease risk factors in highly compliant adults with elevated blood lipid concentrations.