Erythrocyte membrane fatty acid composition of smokers and non-smokers: effects of vitamin E supplementation

Objective: Adequate dietary intakes of vitamin E and essential polyunsaturated fatty acids are important to maintain cell membrane integrity, and deficiencies have been associated with smoking related cardiovascular disease. Sufficient vitamin E is required to prevent free radical mediated peroxidation of membrane lipids. Consequently, smokers may have a greater requirement for this antioxidant. To investigate, we assessed the concurrent influences of smoking, vitamin E supplementation and red blood cell (RBC) PUFA composition on the susceptibility of the cells to lipid peroxidation in adult males.

Design and subjects: Thirty 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, and their susceptibility to in vitro H2O2 induced lipid peroxidation.

Results: Concentrations of essential fatty acids (EFA) in RBC were lower in smokers than in non-smokers. Supplementation with vitamin E increased levers of RBC EFA in smokers to match those of non-smokers. Furthermore, the ratio of vitamin E to PUFA in RBC from smokers and non-smokers was inversely correlated with their susceptibility to peroxidation.

Conclusions: An adequate vitamin E to PUFA ratio is required to protect cell membranes from oxidative damage. The significant correlation between susceptibility to peroxidation and the PUFA content of RBC before supplementation suggests an inadequate intake of vitamin E in relation to PUFA intake. Moreover. the requirement for vitamin E appears to be greater in smokers than in non-smokers.