VITAMIN-E SUPPLEMENTATION IN ELDERLY LOWERS THE OXIDATION RATE OF LINOLEIC-ACID IN LDL

Oxidation of LDL-linoleic acid (LDL-LA), a major substrate for lipid p eroxidation, may be counteracted by the antioxidant vitamin E. In a 3- month randomized double-blind placebo-controlled trial in 83 apparentl y healthy Dutch elderly, aged 67-85 years, the direct protective effec t of 100 IU vitamin E on the rate of oxidized LDL-LA was studied. The oxidation of LDL-LA was measured by its disappearance after a 5-h in v itro Cu-oxidation of LDL isolated from 1 mi plasma. In the vitamin E g roup, the decrease in oxidized LDL-LA of 10.4% (p < 0.05) was signific antly different (p < 0.05) from the smaller 4.6% (p < 0.01) decrease i n the control group. Moreover, within the vitamin E group the decrease was even more marked over tertiles of cc-tocopherol to LDL-LA ratio w ith a significant difference in decrease (p < 0.05) from the lowest co mpared to the highest tertile of, respectively, 18.4% [-24; -2%] (medi an and range) and 2.0% [-16; 34%]. In conclusion, supplementation with 100 IU vitamin E in elderly is beneficial in lowering the rate of oxi dation of LDL-LA. The protective effect of vitamin E might best be mon itored by using the ratio of alpha-tocopherol to LDL-LA as this reflec ts the degree of a-tocopherol available to protect the amount of LDL-L A present. (C) 1997 Elsevier Science Ireland Ltd.