Antioxidants and coronary heart disease

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.

Antioxidant vitamins and prevention of cardiovascular disease: laboratory, epidemiological and clinical trial data

Naturally occurring antioxidants like 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 epidemiological studies strongly sustain the 'antioxidant hypothesis'. To data, 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 scant data from clinical trials are available for vitamin C. As for 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 daily) and the Cambridge Heart Antioxidant Study (400-800 mg daily). Currently ongoing are several large-scale clinical trials that will help in clarifying the role of vitamin E in the prevention of atherosclerotic coronary disease.

Down's syndrome, dementia, and superoxide dismutase

Mental handicap includes specific behavioural phenotypes apparently caused by single enzyme errors or deletions, for example, compulsive self-mutilation and hypoxanthine-guanine phosphoribosyl transferase deficiency in the Lesch-Nyham syndrome. In Down's syndrome, the possession of additional genetic material is found to be linked to various physical abnormalities (premature cataract formation and hypothyroidism). These close associations between types of behaviour, illnesses, and known genetic abnormalities offer promising avenues for research. In this article we concentrate on the well known link between Down's syndrome and presenile dementia.