Vitamin E and heart disease

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Information Section-i+ Chem. Toxic. Vol. 34. No. 9

30 mg j-carotene and 25,000 IU retinyl palmitate/ day had any benefit, and that the regimen may even have had adverse effects. A total of 9420 of the participants received the active treatment and the group was followed for an average of 4 yr. The relative risks of lung cancer and death from lung cancer in the treated group compared with the placebo group were 1.28 (95% CI 1.04-1.57) and 1.46 (95% CI 1.07-2.00), respectively. The all-causes mortality rate was 17% higher in the treated than the placebo group and the rate of cardiovascular disease in the treated subjectswas also somewhat higher (RR 1.26, 95% CI 0.99-1.61). No differences in the death rates from cancersother than lung cancer were found (Omenn et al., New England Journal of Medicine 1996, 334, 1150). A study of almost 34,500 post-menopausal women from Iowa, USA has identified an inverse association between vitamin E consumption and the risk of death from coronary heart disease (CHD). Over approximately 7 yr of follow-up 242 of the women died of CHD. The relative risks of death from CHD from the lowest to the highest quintiles of vitamin E intake were 1.0, 0.70, 0.76, 0.32 and 0.38 (P for trend = 0.004) in the 21,809 women who did not take supplements. No association was found between death from CHD and the intake of vitamin E from supplements, or vitamin A, retinal, carotenoid or vitamin C intake from foods (Kushi et al., New England Journal of Medicine 1996, 334, 1156). Another US double-blind trial has reported that 12 yr of supplementation with 50 mg /?-carotene on alternate days produced practically no effect on the overall incidences of cancer or cardiovascular disease or in overall mortality. The trial involved a total of just over 22,000 male physicians, half of whom received the /I-carotene, half a placebo control (Hennekens et al., New England Journal of Medicine 1996, 334, 1145). Investigators from the Rowett Research Institute in Scotland have published data to support the hypothesis that the well established association between a high intake of fruit and vegetables and a low incidence of certain cancers may be due to the dietary antioxidants present in these foods. Using an assaythat detects specificDNA damage (oxidation of pyrimidine moities), they found a markedly reduced level of DNA damage in the white blood cells of a group of 50 men (aged 50-59 yr) who supplemented their diet for 20 wk with vitamin C (100 mg/day), vitamin E (280 mg/day) and /?-carotene (25 mg/day), than in a similar group who received no vitamin supplementation. The protective effect was seen both in smokers and non-smokers (Duthie et al., Cancer Research 1996, 56, 1291).

study in a rural Chinese population where 3318 men and women were persuaded to take either a supplement or a placebo daily for 6 yr. A significantly reduced stroke mortality was seen in the men (RR 0.42, 95% CI 0.19-0.93) but not in the women (RR 0.93, 95% CI 0.44-l .98). Among survivors, elevated blood pressure was less common in men (RR 0.43. 95% CI 0.28-0.65). Again no similar effect was seen in women (RR 0.92; 95% CI 0.68-1.24) (Mark et al., American

Journal

of Epidemiology

1996, 143,

658). Vitamin E and heart disease A British study has concluded that a-tocopherol supplementation substantially reduces the rate of non-fatal heart attacks in patients with established heart disease, with beneficial effects apparent after 1 yr of treatment. In a double-blind study, 1035 patients were given either 400 or 800 IU cc-tocopherol/day (268 or 537 mg/day). A further 967 patients received placebo capsules. The median follow-up time was 510 days. a-Tocopherol significantly reduced the risk of non-fatal myocardial infarction [14 P. 41 events; RR 0.23, 95% CI 0.1 I-0.47) but had no effects on cardiovascular deaths, of which there was a slight, but non-statistically significant excessin the treated group (27 11.23; RR 1.18, 95% CI 0.62-2.27) (Stephens et al., Lancer 1996, 347, 781). Salt and blood pressure Reanalysis and updating of data from Intersalt, a study of 10,074 men and women aged 2&59 yr in 32 countries, has confirmed the association between median daily urinary sodium excretion (a measure of salt intake) and blood pressure. In addition, higher urinary sodium was found to be associated with substantially greater differences in blood pressure in middle age compared with young adulthood. For example, in men and women aged 4G59 yr, systolic pressure was estimated to be 4.6-7.8 mm Hg higher per 100 mmol greater sodium excretion/day, whereas the corresponding figure in 2&39-yr-olds was 1.84.3 mm Hg. The investigators feel “these results support recommendations for reduction of high salt intake for prevention and control of adverse blood pressurelevels” (Elliott et al., British Medical Journal 1996, 312, 1249). Low fruit and vegetable intake and other bad habits

American researchershave looked at the association between fruit and vegetable intake and other health-linked habits in a study of nearly 22,000 adults. Consumption of fruit and vegetables was lowest among those who also reported that they were sedentary, heavy smokers, heavy drinkers or had Vitamin/mineral supplements and cerebrovascular never had their blood cholesterol level checked. The disease investigators warned that it is therefore important to Multivitamin/mineral supplements may reduce account for possible confounding between fruit and stroke death rate. This is a possible conclusion of a vegetable intake and other behavioural factors in