BMJ  2005;330 (5 March), doi:10.1136/bmj.330.7490.0-f

Filler

POEM^*

Vitamin E isn't helpful and may be harmful

Question In patients with or without heart disease, does vitamin E supplementation decrease mortality?

Synopsis The antioxidant property of vitamin E has led many to use it to prevent cardiovascular or cancer related mortality. However, several studies and several previous meta-analyses have shown either no benefit or a slight increase in mortality with its use. The authors of this study performed a literature search in the usual way, searching Medline, the Cochrane clinical trials database, and reference lists and files. They included 19 randomised studies of almost 136 000 patients, comparing vitamin E users with a control or placebo group for at least one year; trials included at least 10 deaths. Study participants varied and comprised elderly patients, healthy adults, and patients with cardiovascular disease. Study results were analysed by intention to treat. The method of data extraction was not explained, and studies were not graded or selected on the basis of quality. In the studies the baseline death rate was approximately 10%. Overall, there was no difference in all cause mortality between the control group and placebo group, but when low dose vitamin E was compared with high dose vitamin E (less than 400 IU/day v 400 IU/day or more), differences were found. In the studies of lower doses, there was no benefit or detriment to vitamin E supplementation (relative risk 0.98; 95% confidence interval 0.96 to 1.01). When high dose supplementation was studied separately, the risk was slightly but significantly higher in the supplemented group, with a number needed to harm of 250 (143 to 998). The effect of vitamin E supplementation was not different when the results were evaluated by patients' sex or average age, or by the length of follow up.

Bottom line Vitamin E supplementation does not decrease all cause mortality in patients with or without pre-existing heart disease. At higher doses it can actually be harmful, although the deleterious effect is small (number needed to treat to harm = 250).

Level of evidence 1b (see www.infopoems.com/levels.html). Individual randomised controlled trials (with a narrow confidence interval).

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Miller ER 3rd, Pastor-Barriuso R, Dalal D, Riemersma RA, Appel LJ, Guallar E. Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005;142: 37-46[Abstract/Free Full Text].

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^* Patient-Oriented Evidence that Matters. See editorial ( BMJ 2002;325: 983[Free Full Text])

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Rapid Responses:

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Ignoring data isn't helpful and may be harmful

P. David Mitchell
bmj.com, 4 Mar 2005 [Full text]

The truth about Vitamin E - Vitamin E is safer than implied

Neil E. Levin
bmj.com, 4 Mar 2005 [Full text]

"Comparing vitamin E users" proves nothing.

Barry Savage
bmj.com, 11 Mar 2005 [Full text]

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