Clinical Briefs
With Comments from John La Puma, MD, FACP
Vitamin E and Serum Hormone Levels
June 2001; Volume 4; 71-72
Source: Hartman TJ, et al. Effects of long-term alpha-tocopherol supplementation on serum hormones in older men. Prostate 2001;46:33-4638.
It is known that alpha-tocopherol supplementation significantly reduced the risk of prostate cancer in the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study, and that sex hormones are thought to be involved in the etiology of prostate cancer. We examined whether long-term supplementation with alpha-tocopherol modified serum hormone levels.
Men who were cancer-free, consumed 90% of the study capsules, and had both baseline and follow-up blood available were eligible for the study. One hundred men who received alpha-tocopherol were matched by age, study center, and length of time between blood draws to 100 men who received placebo. Multivariate linear regression models, which allowed for a separate intercept for each matched pair, were used to evaluate the effect of alpha-tocopherol supplementation on follow-up hormone concentrations.
Compared to men who received placebo, we found significantly lower serum androstenedione (P = 0.04) and testosterone (P = 0.04) concentrations among men who received alpha-tocopherol, after controlling for baseline hormone level, follow-up serum cholesterol concentration, body mass index, smoking, and fasting time. Geometric mean (95% confidence interval [CI]) androstenedione concentration among men who received alpha-tocopherol was 145 ng/dl (CI 137-153 ng/dl) after adjusting for covariates, compared to 158 ng/dl (CI 148-167 ng/dl) among men who received placebo. Mean testosterone concentrations for men who received alpha-tocopherol and placebo were 539 ng/dl (CI 517-562 ng/dl) and 573 ng/dl (CI 549-598 ng/dl), respectively.
These results suggest that long-term alpha-tocopherol supplementation de- creases serum androgen concentrations, and could have been one of the factors contributing to the observed reduction in incidence and mortality of prostate cancer in the alpha-tocopherol treatment group of the ATBC Study.
Comment
Funded by the National Cancer Institute and the National Institutes of Health, this study adds fuel to the fat-soluble fire surrounding vitamin E. It is the supplement that is most closely associated with efficacy in prostate cancer, excepting PC-SPES (a mixture of eight herbs that causes estrogen-like adverse effects and PSA responses in patients with both androgen-dependent and refractory cancer). And these data, though few, support vitamin E use.
What is the mechanism? It is all hypothesis; synthesis, release, or destruction of androgen is somehow affected.
What is the downside of vitamin E use? Barrette reports: "In the ATBC study more episodes of hemorrhagic stroke were seen in those taking alpha-tocopherol than those not taking alpha-tocopherol.... (and) the incidence and mortality of subarachnoid hemorrhage were higher in the alpha-tocopherol subjects. However, the absolute rates were very low, e.g., 28 subarachnoid hemorrhage deaths in 14,238 taking alpha-tocopherol vs. 10 in 14,281 controls. Alpha-tocopherol also decreased the overall risk of the much more common cerebral infarction by 14% (95% CI, -25% to -1%; P = 0.03) and did not affect rates of intracerebral hemorrhage." (See Alternative Medicine Alert, Jan. 2001, pp. 1-5.)
In the Health Professionals’ Follow-up Study, a prospective cohort study of more than 40,000 men ages 40-75 followed for eight years, vitamin E intake and supplementation did not significantly affect hemorrhagic, ischemic, or total stroke rate.
Recommendation
Whether the benefit of vitamin E is limited to smokers is still up for debate. But with this writing, most men with prostate cancer can reasonably judge the benefit of the vitamin, 100 IU/d, to outweigh the risks.
June 2001; Volume 4; 71-72
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.