Antioxidant vitamins and prevention of cardiovascular disease: epidemiological and clinical trial data.
Naturally occurring antioxidants such as vitamin E, beta-carotene, and vitamin C can inhibit the oxidative modification of low density lipoproteins. This action could positively influence the atherosclerotic process and, as a consequence, the progression of coronary heart disease. A wealth of experimental studies provide a sound biological rationale for the mechanisms of action of antioxidants, whereas epidemiologic studies strongly sustain the "antioxidant hypothesis." To date, however, clinical trials with beta-carotene supplements have been disappointing, and their use as a preventive intervention for cancer and coronary heart disease should be discouraged. Only scanty data from clinical trials are available for vitamin C. As to vitamin E, discrepant results have been obtained by the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study with a low-dose vitamin E supplementation (50 mg/d) and the Cambridge Heart Antioxidant Study (400-800 mg/d). The results of the GISSI-Prevenzione (300 mg/d) and HOPE (400 mg/d) trials suggest the absence of relevant clinical effects of vitamin E on the risk of cardiovascular events. Currently ongoing are several large-scale clinical trials that will help in clarifying the role of vitamin E in association with other antioxidants in the prevention of atherosclerotic coronary disease.
Marchioli
R
R
Laboratory of Clinical Epidemiology of Cardiovascular Disease, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Santa Maria Imbaro (Chieti), Italy. marchioli@cmns.mnegri.it
Schweiger
C
C
Levantesi
G
G
Tavazzi
L
L
Valagussa
F
F
D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000517:prevention & control*; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D016239:MEDLINE; D008297:Male; D016032:Randomized Controlled Trials as Topic; D014810:Vitamin E / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage*; D019207:beta Carotene / Q000008:administration & dosage
D000975:Antioxidants; D014815:Vitamins; D019207:beta Carotene; D014810:Vitamin E; D001205:Ascorbic Acid