Taking daily vitamin supplements doesn't help you live longer, review of 400,000 people finds

They promise health benefits from boosting the immune system to strong bones.

But multivitamins do not help you live longer, a major study has found.

Regularly taking the supplements was found to have no effect on whether people lived longer, according to the research involving nearly 400,000 healthy adults.

In fact, using multivitamins daily was associated with a 4 per cent higher mortality risk, the analysis found.

The vitamins industry is estimated to be worth billions in the UK and US, taken by people in the hope of improving their health.

The vitamins industry is estimated to be worth billions in the UK and US, taken by people in the hope of improving their health

But the potential benefits and harms of supplementing diet with additional vitamins and minerals remains unclear, often hindered by study size and short follow-up times.

Led by researchers at the National Cancer Institute in the US, researchers followed participants with an average age of 61, who had no history of cancer or other chronic disease, for more than 20 years.

They looked at their multivitamin use from 1993 to 2001 and again between 1998 and 2004 with a follow up period of up to 27 years.

During this time, some 164,762 people died, with 49,836 deaths attributed to cancer, 35,060 to heart diseases, and 9,275 attributed to cerebrovascular diseases.

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Researchers assessed for other factors such as education level, whether they were ever smokers, body-mass-index, marital status, alcohol and coffee intake.

They also looked for family history of cancer and factored this into the findings, according to the research published in JAMA.

Those who used multivitamins were also more likely to use individual supplements and have lower BMI and better diet quality.

But there were no longevity benefits found in those who took daily vitamins – in contrast, they were linked to a 4 per cent heightened risk of death.

It concludes: ‘The analysis showed that people who took daily multivitamins did not have a lower risk of death from any cause than people who took no multivitamins.

‘There were also no differences in mortality from cancer, heart disease, or cerebrovascular diseases.’

But the results do not necessarily mean that taking vitamins is a waste of time.

Research published earlier this year by Harvard University finding they can help slow the cognitive deterioration that occurs with age.

Other research has suggested they can help people to feel healthier, although it could be the placebo effect.

Duane Mellor, a registered dietitian and senior lecturer at Aston medical school, said: ‘It’s not surprising to see these do not significantly reduce the risk of mortality.

‘A vitamin and mineral supplement will not fix an unhealthy diet on its own, but it can help cover key nutrients if someone is struggling to get them from food.

‘An example of this might be vitamin D where adults in the UK are encouraged to take as a supplement in winter or vegans and vegetarians who might benefit from a supplement of vitamin B12.’

Writing in a linked commentary, Neal Barnard, Hana Kahleova and Roxanne Becker, of the Physicians Committee for Responsible Medicine, Washington, said: ‘Refocusing nutrition interventions on food, rather than supplements, may provide the mortality benefits that multivitamins cannot deliver.

‘Vegetables, fruits, legumes and cereal grains are staples in areas of remarkable longevity, known as Blue Zones—Okinawa, Japan; Sardinia, Italy; the Nicoya Peninsula, Costa Rica; the island of Ikaria, Greece; and Loma Linda, California.’

They suggested that some vitamins in the supplements may have an impact on other drugs being taken, for example vitamin K may reduce the efficacy of the anticoagulant warfarin.

And the inclusion of iron in a supplement adds to that in foods, increasing the risk of iron overload, which is associated with an increased risk of heart disease, diabetes, and dementia, the commentary continued.

The experts also said similar concerns may apply to copper supplementation, and calcium and zinc may reduce the absorption of certain antibiotics