ERYTHROCYTE-MEMBRANE FATTY-ACID COMPOSITION OF SMOKERS AND NONSMOKERS- EFFECTS OF VITAMIN-E SUPPLEMENTATION

Objective: Adequate dietary intakes of vitamin E and essential polyuns aturated fatty acids are important to maintain cell membrane integrity , and deficiencies have been associated with smoking related cardiovas cular disease. Sufficient vitamin E is required to prevent free radica l mediated peroxidation of membrane lipids. Consequently, smokers may have a greater requirement for this antioxidant. To investigate, we as sessed the concurrent influences of smoking, vitamin E supplementation and red blood cell (RBC) PUFA composition on the susceptibility of th e cells to lipid peroxidation in adult males. Design and subjects: Thi rty male smokers and thirty male non-smokers were randomly ascribed to daily 280 mg vitamin E or placebo supplements for 10 weeks. RBC were analysed at weeks 0 and IO for fatty acid methyl esters, vitamin E, an d their susceptibility to in vitro H2O2 induced lipid peroxidation. Re sults: Concentrations of essential fatty acids (EFA) in RBC were lower in smokers than in non-smokers. Supplementation with vitamin E increa sed levers of RBC EFA in smokers to match those of non-smokers. Furthe rmore, the ratio of vitamin E to PUFA in RBC from smokers and non-smok ers was inversely correlated with their susceptibility to peroxidation . Conclusions: An adequate vitamin E to PUFA ratio is required to prot ect cell membranes from oxidative damage. The significant correlation between susceptibility to peroxidation and the PUFA content of RBC bef ore supplementation suggests an inadequate intake of vitamin E in rela tion to PUFA intake. Moreover. the requirement for vitamin E appears t o be greater in smokers than in non-smokers.