Effect of oral supplementation with D-alpha-tocopherol on the vitamin E content of human low density lipoproteins and resistance to oxidation.
Twelve clinically healthy subjects participated in a vitamin E supplementation study. Eight were given daily dosages of 150, 225, 800, or 1200 IU RRR-alpha-tocopherol for 21 days (two persons per dose) and four received placebo. Prior, during, and after the supplementation period, alpha-tocopherol, gamma-tocopherol, and carotenoids were determined in plasma and low density lipoprotein (LDL). The maximum levels of alpha-tocopherol were 1.7- to 2.5-times the baseline values in plasma and 1.7- to 3.1-times in LDL. A high correlation existed between alpha-tocopherol in plasma and LDL. gamma-Tocopherol significantly decreased in plasma and LDL during vitamin E supplementation. No significant influence on the lipoprotein and lipid status and carotenoid levels of the participants occurred throughout the supplementation. The resistance of LDL against copper-mediated oxidation was also measured. The oxidation resistance of LDL was significantly higher during vitamin E supplementation. However, the efficacy of vitamin E in protecting LDL varied from person to person. The statistical evaluation of all data gave a correlation of r2 = 0.51 between alpha-tocopherol in LDL and the oxidation resistance as measured by the length of the lag-phase preceding the oxidation of LDL. No association was seen between levels of carotenoids and vitamin E in plasma and LDL. The present study clearly shows that in humans the oxidation resistance of LDL can be increased by vitamin E supplementation.
Dieber-Rotheneder
M
M
Institute of Biochemistry, University of Graz, Austria.
Puhl
H
H
Waeg
G
G
Striegl
G
G
Esterbauer
H
H
D000284:Administration, Oral; D000328:Adult; D002338:Carotenoids / Q000097:blood; D002784:Cholesterol / Q000097:blood; D003300:Copper / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005231:Fatty Acids, Unsaturated / Q000097:blood; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000737:chemistry*; D008297:Male; D010545:Peroxides / Q000097:blood; D016037:Single-Blind Method; D013997:Time Factors; D014810:Vitamin E / Q000097:blood / Q000494:pharmacology*
D005231:Fatty Acids, Unsaturated; D008077:Lipoproteins, LDL; D010545:Peroxides; D014810:Vitamin E; D002338:Carotenoids; D003300:Copper; D002784:Cholesterol