α-Tocopherol supplements and high-density-lipoprotein–cholesterol levels

Abstract

1. In a randomized, double-blind 6-month study, a-tocopherol (728 mg) or placebo were administered daily to seventy-eight volunteers (forty-nine men, twenty-nine women) to investigate the possible enhancing effect of vitamin E on plasma high-density-lipoprotein-cholesterol (HDL-C) levels. In addition, the available reported values from short-term (4-6 weeks) studies, as well as the 4-week results from the present study, were combined and analysed for factors which may modify the effect of a-tocopherol on HDL-C.2. No consistent effect of a-tocopherol on plasma HDL-C levels was observed either in the combined 4-week values or in the 6-month study. Further analysis of the combined short-term values and 6-month values indicated that, in subjects with low initial HDL-C levels, treatment with a-tocopherol or placebo did not produce significantly different HDL-C changes.Results of some preliminary short-term studies have suggested that administration of a large daily dose of a-tocopherol (545-728 mg) can increase the plasma levels of high-densitylipoprotein-cholesterol (HDL-C) (Herman et al. 1979;. In view of the reported attenuating effects of high HDL-C levels on the development of coronary heart disease and the relative difficulty in achieving a significant and reproducible rise in HDL-C by dietary or pharmacologic means, the reports on the effect of a-tocopherol on this lipid class attracted considerable attention. However, a series of other studies (Schwartz & Rutherford, 1981;Barboriak et al. 1982;Ehnholm et al. 1982;Howard et al. 1982; Kesaniemi & Grundy, 1982; Chapkin et al. 1983;Serfontein et al. 1983), employing relatively small groups of subjects, failed to confirm the general effectiveness of a-tocopherol on HDL-C levels. Few of the reports were based on controlled randomized trials that included a placebo group, and they used a short (4-6 weeks) treatment period.Therefore, we decided to study the effect of a-tocopherol on plasma HDL-C levels in a long-term, double-blind study using patients most likely to benefit from such a treatment, i.e. patients entering a cardiac rehabilitation programme. In addition, we have pooled available reported short-term values on the effect of a-tocopherol on plasma HDL-C in order to investigate the possible variables modifying such an effect. The findings of both the long-term and pooled-values studies indicate little or no consistent effect of oral a-tocopherol on plasma HDL-C levels. M A T E R I A L S A N D M E T H O D SLong-term study Subject selection. A group of forty-nine male patients (24-73 years of age), who were enrolled in a cardiac rehabilitation programme, volunteered for the study. A group of twenty-nine female subjects (24-71 years of age), who were spouses of the male patients, https://www.cambridge.org/core/terms. https://doi

Vegetarians have higher plasma alpha-tocopherol relative to cholesterol than do nonvegetarians.

“…This enhanced tocopherol status of vegetarians sug gests that their lipoproteins are better protected against lipid peroxidation, including the cholesterol moiety, which may explain, in part, their lower incidence of certain types of cancer and atherosclerosis [1,7,33]. Supplementation of hypercholesterolemic patients with vitamin E has been suggested for increasing plasma high-density-lipoprotein cholesterol and decreasing coronary heart disease risk [34,35], but could not be corroborated by others [36,37]. Vitamin E supplementation may also decrease risk of atherosclerosis by inhibiting platelet aggregation [38,39] and reducing the susceptibility of LDL to peroxidation [11,12], although the latter process also depends on the presence of other antioxidant molecules as well [40].…”

α-Tocopherol protects against diet induced atherosclerosis in New Zealand white rabbits

“…A single study using parallel groups with no supplement or supplemented with 100 IU ␣ -tocopherol/day detected a small decrease in HDL-C after supplementation (51). Other randomized, placebo controlled double-blind studies reported no significant change in plasma cholesterol concentration (43)(44)(45)(46)(47)(48). The pro-and anti-oxidant roles proposed for ␣ -tocopherol taken together with the results from clinical trials have generated some controversy regarding the clinical value of ␣ -tocopherol supplements (14-17, 52, 53).…”

“…One clinical trial of cholesterol lowering also observed reduced atherosclerosis progression in men who chose to consume high levels of ␣ -tocopherol supplements (39). Based on such suggestive observations, several randomized clinical trials have been conducted to determine whether supplementation with 50-800 IU ␣ -tocopherol reduces cardiovascular disease (CVD) (32,(40)(41)(42)(43) or risk factors for CVD (44)(45)(46)(47)(48).…”