Dietary supplementation with orange juice and carrot juice in cigarette smokers lowers oxidation products in copper oxidised low density lipoproteins

Abstract

<h4>Objective</h4>Our objective was to evaluate the effect of daily supplementation with foods high in vitamin C and beta carotene on plasma vitamin levels and oxidation of low-density lipoprotein (LDL) in cigarette smokers.<h4>Subjects</h4>Fifteen normolipidemic male cigarette smokers who did not usually take vitamin supplements were recruited into the study.<h4>Interventions</h4>Throughout the study, subjects consumed a diet rich in polyunsaturated fatty acids, which provided 36% of energy as fat: 18% from meat, dairy products, vegetable oils, and fat spreads and 18% from walnuts (68 g/day). Subjects consumed a vitamin-free drink daily for 3 weeks; then for 3 weeks they consumed daily supplements of orange juice (145 mg vitamin C) and carrot juice (16 mg beta carotene).<h4>Results</h4>Vitamin-rich food supplements raised plasma levels of ascorbic acid (1.6-fold; P < .01) and beta carotene (2.6-fold; P < .01). Malondialdehyde, one end product of oxidation, was lower in copper-oxidized LDL after vitamin supplementation (mean +/- standard error = 65.7 +/- 2.0 and 57.5 +/- 2.9 mumol/g LDL protein before and after supplementation, respectively; P < .01). Rate of LDL oxidation and lag time before the onset of LDL oxidation were not affected by antioxidant supplementation.<h4>Conclusions</h4>In habitual cigarette smokers, antioxidant vitamins, which can be feasibly provided from food, partly protected LDL from oxidation despite a diet rich in polyunsaturated fatty acids.