Megavitamin E supplementation in man.

To assess possible toxic and/or beneficial effects of vitamin E supplementation, a group of 28 adults voluntarily ingesting 100 to 800 IU/day of tocopherol for an average of 3 years were evaluated in this study. Half of the subjects claimed a feeling of improved health or well being, but no specific beneficial effects were noted consistently; the other half indicated no change in health status after beginning vitamin E supplements. No gross evidence of toxicity was apparent on reviewing past medical histories with the subjects. Plasma alpha-tocopherol was found to be elevated significantly in the group from 650 micrograms/100 ml (control mean) to 1,340 micrograms/100 ml; however, 25% of the values were within 2 SD of the control mean. Plasma alpha-tocopherol levels did not correlate with total daily dose but did relate to plasma triglyceride and cholesterol concentrations. Total plasma carotenoids were also significantly increased along with vitamin A levels; the former did not correlate with plasma vitamin E, whereas the latter showed a significant correlation. Laboratory screening for toxic side effects of vitamin E supplementation by performance of 20 standard clinical blood tests failed to reveal any disturbance in liver, kidney, muscle, thyroid gland, erythrocytes, leukocytes, coagulation parameters, or blood glucose. It is concluded that megavitamin E supplements in this group produced no apparent toxic side effects and that subjective claims for beneficial effects were highly variable.