Vitamin C and Heart Disease

Beta-carotene has recently been reported to reduce the incidence of cardiovascular disease events and angina in the Physician’s Health Study, while vitamin E has been shown to reduce the rate of restenosis after coronary angioplasty, which increases the interest in antioxidants as nutrients in heart disease. Recently the First National Health and Nutrition Survey found that men and women with the highest vitamin C intakes, at 50+ mgs per day and regular vitamin C containing supplements, had 25 and 45% lower coronary heart disease mortality rates, respectively, than subjects with the lowest vitamin C intake, which was less than 50 mgs per day. It is noted that, since known risk factors for coronary heart disease explain approximately 50 to 60% of coronary heart disease incidence, the possibility that antioxidant nutrients (such as vitamin C) influence the development of coronary heart disease cannot be ruled out. Vitamin C is a unique antioxidant. Vitamin C maintains the integrity of blood vessels, enhances the catabolism of cholesterol, is involved in the rate limiting enzyme, and converting cholesterol to bile acids. There is some evidence that vitamin C supplementation in individuals with cholesterol over 200 mgs can lower cholesterol levels. Vitamin C may also be directly related to high density lipoprotein. Vitamin C, even though a water soluble antioxidant, is a potent inhibitor of lipid peroxidation. Vitamin C has a greater effect on LDL oxidation than beta- carotene or vitamin E. Vitamin C preserves the ability of beta-carotene and vitamin E to inhibit lipid peroxidation. Vitamin C can regenerate oxidized vitamin E. Vitamin C promotes the production and inhibits the degradation of endothelial prostacyclin. This vitamin has a powerful antiplatelet and vasodilatory effect. Two to three gms a day of vitamin C have been shown to reduce platelet aggregation or adhesiveness. Groups at high risk for coronary artery disease such as men, smokers, diabetics, hypertensives and the elderly often have reduced vitamin C levels. Lower vitamin C levels are often seen in the elderly, resulting from poverty, institutionalization, and social isolation. There is evidence that the obese have lower vitamin C levels. Vitamin C is inexpensive, readily available, and generally nontoxic. The author cautions that, while the whole role of antioxidants in heart disease is a promising area of research, the causal relationship of antioxidant deficiency and heart disease has not been proven. Further rigorous randomized, blinded, and secondary prevention trials are warranted.