Plasma alpha-tocopherol, beta-carotene, and retinol levels in the institutionalized elderly individuals and in young adults.

We investigated the plasma levels of alpha-tocopherol, retinol, and beta-carotene in the institutionalized elderly individuals and in young adults, together with assessment of the influence of plasma lipids for beta-carotene and alpha-tocopherol, and the effect of retinol binding protein (RBP) on retinol levels. Although plasma alpha-tocopherol levels in elderly females were significantly higher than in elderly males, there was no significant difference in the ratio of plasma alpha-tocopherol to total lipids between males and females or between the young adults and the elderly subjects. However, the plasma beta-carotene level in elderly females did not differ from those in elderly males after correction for the difference in plasma lipids levels, while a significant higher level was observed in the young females even after this correction. Thus, plasma beta-carotene levels appear to depend not only on plasma lipids, but also on other factors, while the plasma alpha-tocopherol level depends entirely on plasma lipids. A higher plasma retinol level was observed in young males than in young females, with the level in young females not differing from that in elderly subjects of both sexes. This difference in retinol levels was dependent on changes in RBP, because the ratio of retinol to RBP did not differ between males and females or between the young adults and elderly.