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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, RESULTS. Meshes: Adult, Ascorbic Acid, Beverages, Carotenoids, Cholesterol, Dietary, Citrus, Copper, Daucus carota, Diet, Diet Records, Fatty Acids, Fatty Acids, Unsaturated, Food, Fortified, Humans, Lipids, Lipoproteins, LDL, Male, Malondialdehyde, Middle Aged, Oxidation-Reduction, Smoking, beta Carotene.
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Does dietary supplementation with orange and carrot juice in cigarette smokers lower oxidation products in copper-oxidized low-density lipoproteins? Context: 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. Fifteen normolipidemic male cigarette smokers who did not usually take vitamin supplements were recruited into the study. 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). 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.
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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. Final Decision: yes