A few scientific abstracts on studies on antioxidants

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Observational Study (G):
In a study of 6,318 females and 4,909 males aged 45-64, vitamin C intake was inversely associated with carotid arterial wall thickness after adjustment for age, body mass index, fasting serum glucose, systolic and diastolic BP, HDL and LDL cholesterol, total caloric intake, cigarette use, race, and education
(Kritchevsky SB, Shimakawa T, Tell GS, et al. Dietary antioxidants and carotid artery wall thickness: the ARIC study. Circulation 92(8):2142-50, 1995).

Experimental Double-blind Study (M):
46 pts. received either ascorbic acid 2 gm daily or placebo. Ascorbic acid supplementation reversed endothelial vasomotor dysfunction in the brachial circulation, suggesting that increased oxidative stress contributes to endothelial dysfunction in these pts., and that endothelial vasomotor dysfunction may be responsive to antioxidants. (Levine GN, Frei B, Koulouris SN, et al. Ascorbic acid reverses endothelial vasomotor dysfunction in patients with coronary artery disease. Circulation 93(6):1107-13, 1996).

87,245 female nurses aged 34-59 were followed for 8 years. At the start of the study, they were free of diagnosed cardiovascular disease and cancer. During follow-up, there were 437 nonfatal MIs and 115 coronary deaths. Among women in the highest quintile of vitamin use, compared to those in the lowest, the multivariate relative risk of CHD was 0.66 for vitamin E, after adjustment for age, smoking, and other CHD risk factors. This reduced risk was only noted for vitamin E supplement use. While women who took vitamin E for short periods of time showed no protective effect, women who took the supplements for at least 2 yrs. had a 40% reduction in risk for developing coronary disease. Consumption of other antioxidants showed little effect on reducing risk. (Manson JE, Stampfer MJ, Willett WC, et al. A prospective study of antioxidant vitamins and incidence of coronary heart disease in women. Abstract. J Am Coll Nutr 11(5):609, 1992; Stampfer M, Hennekens C, Manson J, et al. Vitamin E consumption and the risk of coronary heart disease in women. N Engl J Med 328:1444-9, 1993).

In a study of 6,318 females and 4,909 males aged 45-64, vitamin E intake was inversely associated with carotid arterial wall thickness after adjustment for age, body mass index, fasting serum glucose, systolic and diastolic BP, HDL and LDL cholesterol, total caloric intake, cigarette use, race, and education. This relationship was only significant in women. (Kritchevsky SB, Shimakawa T, Tell GS, et al. Dietary antioxidants and carotid artery wall thickness: the ARIC study. Circulation 92(8):2142-50, 1995).

In a study of 87,245 U.S. female nurses ages 34-59 free of symptoms for heart disease, stroke, or cancer, during the follow-up (669,795 person-years), 552 cases of CHD were documented. Women in the highest quintile of antioxidant intakes (vitamins C & E and beta-carotene) had an age-adjusted relative risk of 0.49 when compared to women who consumed the least amt. of antioxidants. Results suggest that higher antioxidant intakes might reduce a woman�s risk for developing CHD and that �the antioxidant pool is a stronger predictor of CHD risk than each of the vitamins individually�. (Manson J, Stampfer M, Willett W, et al. Antioxidant vitamin score and incidence of coronary heart disease in women. Abstract. Circulation 86:675, 1992).

125 pts. with suspected acute MI received 50,000 IU vitamin A, 1000 mg vitamin C, 400 mg vitamin E and 25 mg beta-carotene or placebo daily for 28 days starting within a few hours of their symptoms. Ave. infarct size was significantly smaller in the supplemented gp. and total arrhythmias, poor left ventricular function and angina pectoris occurred less frequently. (Singh RB, Niaz MA, Rastogi SS, Rastogi S. Usefulness of antioxidant vitamins in suspected acute myocardial infarction (The Indian Experiment of Infarct Survival-3). Am J Cardiol 77(4):232-6, 1996).

63 pts. suspected to have an acute MI received vitamin A 50,000 IU, vitamin C 1000 mg, vitamin E 400 mg and beta-carotene 25 mg daily for 28 days. Compared to 62 pts. who received placebo. mean infarct size was significantly less. Serum glutamicoxaloacetic transaminase decreased by 45.6 IU/dl in the antioxidant grp. compared to 25.8 IU/dl in the placebo group. Cardiac lactase dehydrogenase increased slightly in the antioxidant grp. compared to the placebo group. The QRS score was significantly less in the antioxidant group. Angina pectoris, total arrhythmias, and poor ventricular outcome occurred less frequently in the antioxidant gp. and cardiac end points were significantly less. (Singh RB et al. Usefulness of antioxidant vitamins in suspected acute myocardial infarction. Am J Cardiol 77:232-6, 1996).

Pts. with acute MI who received supplementation with vitamin C and vitamin E showed a significant decrease in neutrophil free radical production while changes in free radical production were not significant in the unsupplemented group. Serum levels of lipid peroxides (TBARS) remained stable in the supplemented gp. but increased in the unsupplemented group. Ave. serum vitamin C levels were critically low within 24 h after acute MI but had increased significantly by the 14th day, even in unsupplemented patients. Ave. serum vitamin E levels remained stable in the unsupplemented gp., while serum vitamin E levels increased in the supplemented group. Results suggest that antioxidant supplementation is advisable in pts. with MI (Herbaczynska-Cedro K, Klosiewicz-Wasek B, Cedro K, et al. Supplementation with vitamins C and E suppresses leukocyte oxygen free radical production in patients with myocardial infarction. Eur Heart J 16:1044-9, 1995).

CH/IH/TT

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