Influence of fasting on circulating levels of alpha-tocopherol and beta-carotene. Effect of short-term supplementation

We investigated the influence of fasting on the levels of alpha-tocopherol in plasma, erythrocytes and platelets, and on plasma beta-carotene. Six app arently healthy adults were subjected to 17-h feed-fasting experiments at v arious days before, during and after supplementation with alpha-tocopherol (455 mg/day, 41 days) and beta-carotene (25 mg/day, 24 days). Adipose tissu e alpha-tocopherol and beta-carotene were measured at regular intervals. Su pplementation increased alpha-tocopherol and beta-carotene in all compartme nts, except for beta-carotene in adipose tissue. Discontinuation caused a r apid return to baseline, except for adipose tissue alpha-tocopherol and pla sma beta-carotene. Pasting caused linear increases of free fatty acids, con sistent (but small) increases of plasma alpha-tocopherol and inconsistent i ncreases of plasma beta-carotene. There were no fasting-related changes in other compartments. We conclude that fasting is unable to increase alpha-to copherol and beta-carotene in circulating lipoproteins and cells to a consi derable extent, both at baseline levels and after short-term supplementatio n. Maintenance of high levels may necessitate regular high oral intakes. (C ) 1998 Elsevier Science B.V. All rights reserved.