Thursday, November 11, 2004

Death by supplement

Can overdoing vitamin E cause an early death?

'High dose vitamin E death warning', reports BBC News. A new study from Johns Hopkins University suggests that taking high doses of vitamin E may actually increase death rates by four per cent, while taking lower doses could reduce mortality. Lead author Dr Edgar Miller said: 'If people are taking a multivitamin, they should make sure it contains no more than a low dose of vitamin E. Our study shows that use of high-dose vitamin E supplements certainly did not prolong life, but was associated with a higher risk of death.'

The level of 'excess' deaths in this study is too small to be regarded as practically significant. The risk of death in the groups not taking vitamin E was 10.22 per cent - the risk in the high vitamin E groups was 10.61 per cent. Hardly a startling difference. For those taking low-level vitamin E supplements, there appeared to be a protective effect - but it was very small indeed.

Besides the very small effect measured, the authors of the study admit that there may be other limitations in their work: vitamin E was taken with other vitamins in some studies but not others; many of the study groups were people with pre-existing chronic diseases; the actual intake of vitamin E may have varied, with some people taking high doses for a period then not taking the vitamin at all.

It would be better to see this study as confirmation of earlier work that showed no protective effect from high doses of vitamins. Speaking on the BBC science programme Horizon, Catherine Collins, chief dietician at London's St George Hospital, said: 'For most people there's absolutely no benefit in taking high dose vitamin supplements. At best they are a waste of money and at worst they could seriously affect your health.' Vitamins are essential for good health, but we need only very small amounts to survive, which the vast majority of us get quite easily even if we eat nothing but so-called 'junk' food.

What the reporting of this study illustrates, however, is that if we fret about what we eat, we will frequently find ourselves caught between one health panic and another.

High dose vitamin E death warning, BBC News, 11 November 2004

The truth about vitamins, BBC News, 16 September 2004

Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase All-Cause Mortality, Annals of Internal Medicine, Vol 142 Issue 1

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