Effect of dietary supplementation with alpha-tocopherol on the oxidative modification of low density lipoprotein

• Published in: Journal of lipid research Vol. 33; no. 6; pp. 899 - 906
• Main Authors: Jialal, I, Grundy, SM
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.06.1992; American Society for Biochemistry and Molecular Biology; Elsevier
• Subjects: ADDITIF ALIMENTAIRE; ADITIVOS ALIMENTARIOS; administration & dosage; Administration, Oral; Adult; alpha-tocopherol; Analytical, structural and metabolic biochemistry; ANTIOXIDANTES; antioxidants; ANTIOXYDANT; beta Carotene; Biological and medical sciences; blood; Carotenoids; Carotenoids - blood; dietary supplements; drug effects; Fundamental and applied biological sciences. Psychology; HOMBRES; HOMME; Humans; Kinetics; lipid peroxidation; LIPIDE; LIPIDOS; LIPOPROTEINAS; LIPOPROTEINE; Lipoproteins, LDL; Lipoproteins, LDL - blood; Lipoproteins, LDL - drug effects; low density lipoprotein; Male; men; Middle Aged; OXIDACION; Oxidation-Reduction; Oxidation-Reduction - drug effects; OXYDATION; Placebos; Proteins; Single-Blind Method; Thiobarbiturates; Thiobarbiturates - blood; TOCOFEROLES; TOCOPHEROL; Vitamin E; Vitamin E - administration & dosage; Human; α-Tocopherol; Oxidation; Supplemented diet; Lipoprotein; Kinetics
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1016/S0022-2275(20)41515-9

Much data has accumulated supporting a proatherogenic role for oxidized low density lipoprotein (Ox-LDL). Micronutrient antioxidants such as alpha-tocopherol, the principal lipid-soluble antioxidant, assume potential significance because levels can be manipulated by dietary measures without resulting in side effects. Co-incubation of LDL in vitro with alpha-tocopherol inhibits its oxidative modification. Hence the effect of dietary supplementation with alpha-tocopherol on the time course of copper-catalyzed oxidation of LDL was tested in a randomized placebo-controlled single-blind study. Two groups of 12 male subjects were given either placebo or alpha-tocopherol (800 IU/day) for a period of 12 weeks. Alpha-tocopherol therapy did not result in any side effects or exert an adverse effect on the plasma lipid and lipoprotein profile. While the lipid standardized alpha-tocopherol levels were similar at baseline, the supplemented group had 3.3-fold and 4.4-fold higher levels compared to placebo at 6 and 12 weeks, respectively. In the 15 subjects in whom both plasma and LDL alpha-tocopherol levels were quantitated, there was a significant correlation (r = 0.79, P less than 0.0001). At baseline there were no significant differences in the time course curves of thiobarbituric acid-reacting substances (TBARS) activity or conjugated diene formation between the alpha-tocopherol and placebo groups. However, at both 6 and 12 weeks the mean levels of TBARS activity and conjugated diene formation were lower in the alpha-tocopherol group; the most significant differences were manifest at the 3-h time point. Also at both 6 and 12 weeks the mean rate of oxidation was lower in the alpha-tocopherol group.2+_