Careless use of vitamins could lead to early death, warn scientists

CARELESS use of vitamins, taken by millions in the belief that they promote good health, could be causing thousands of premature deaths, scientists said yesterday.

A study investigating whether antioxidant vitamin supplements can prevent cancer found that rather than saving lives they seemed to increase overall risk of death.

Although the effect was small, it amounted to 9,000 premature deaths among every million supplement users.

The researchers, led by Dr Goran Bjelakovic, from the University of Nis, Serbia and Montenegro, wrote in the Lancet medical journal: "Our results for the detrimental effect of antioxidant supplements on mortality were unexpected."

However, they warned that the findings were preliminary, and may partly be due to people taking vitamin doses above recommended levels.

The scientists pooled the results of 14 trials involving a total of 170,000 participants which recorded cancers of the gullet, stomach and intestine, bowel, pancreas and liver. Analysis showed no protective effect from taking supplements of beta-carotene, vitamins A, C and E, and selenium, alone or in combination.

In half the trials, there was a small but statistically significant increased risk of premature death among those taking supplements.

Two combinations of supplements were associated with increased mortality.

The risk of death was 30% higher for people taking beta-carotene and vitamin A than for those not taking the combination.

In the case of people taking beta-carotene and vitamin E, relative risk was raised by 10%.

Beta-carotene is a nutrient found in yellow and orange vegetables and fruit that can be converted to vitamin A in the body.

Four trials suggested that selenium was associated with a reduction in cancer risk, but the authors said this may have been the result of poorly conducted studies.

Most people who take vitamins will be taking reasonable doses, but the new findings suggest many could be at risk.

In a commentary accompanying the Lancet paper, Professor David Forman, of the University of Leeds, and Professor Douglas Altman, from Cancer Research UK, wrote: "The prospect that vitamin pills may not only do no good but also kill their consumers is a scary speculation given the vast quantities that are used in certain communities."

But they said the death rate analysis was incomplete and should not at this stage be seen as "convincing proof of hazard".

They added: "In the event that a hazard is established from a complete review, these researchers will need to identify which specific interventions are associated with any risk."

Last year, the British Food Standards Agency warned high doses of certain vitamins and minerals may have irreversible harmful effects.