Pro-oxidant effect of vitamin E in cigarette smokers consuming a high polyunsaturated fat diet

Abstract

Dietary polyunsaturated fats and vitamin E are associated with reduced risk for atherosclerosis, but in smokers, they could promote lipid oxidation. Therefore, we examined the effects of a high polyunsaturated fat diet and vitamin E supplementation on measures of lipid oxidation in cigarette smokers. Ten subjects who smoked >1 pack of cigarettes per day were sequentially fed the following: a baseline diet in which the major fat source was olive oil, a diet in which the major fat source was high-linoleic safflower oil, and finally, the safflower oil diet plus 800 IU vitamin E per day. LDL oxidation lag time and rate and plasma total F2-isoprostanes and prostaglandin F2α (PGF2α) were determined after 3 weeks on each diet. The safflower oil diet increased total F2-isoprostanes from 53.0±7.2 to 116.2±11.2 nmol/L and PGF2α from 3.5±0.2 to 5.5±0.5 nmol/L, without changing LDL oxidation parameters. Addition of vitamin E prolonged mean LDL oxidation lag time but, paradoxically, further increased F2-isoprostanes to 188.2±10.9 nmol/L and PGF2α to 7.8±0.4 nmol/L. These data suggest that vitamin E may function as a pro-oxidant in cigarette smokers consuming a high polyunsaturated fat diet.