Taking multivitamins will not help you live longer, according to a major study.
Regularly taking the supplements, which promise benefits such as stronger bones and improved immunity, has no positive effect on longevity, the research found.
In fact, using them daily was associated with a 4 per cent higher mortality risk, the analysis involving almost 400,000 health adults found.
The vitamins industry is estimated to be worth billions in the UK and US, with most buyers assuming that the supplements will protect and improve their health.
But the potential benefits and harms of additional vitamins and minerals remains unclear, often hindered by the fact that studies on the subject have not been big enough to be conclusive and by short follow-up times.
Led by researchers at the National Cancer Institute in the US, a team followed individuals 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, 164,762 of them died, with 49,836 deaths attributed to cancer, 35,060 to heart diseases, and 9,275 attributed to cerebrovascular diseases such as stroke and brain aneurysms.
Researchers assessed for other factors such as education level, whether those taking part were ever smokers, their body mass index, marital status, and alcohol and coffee intake.
They also looked for family histories of cancer and factored this into the findings, according to the research published in the medical journal 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.’
But the results do not necessarily mean that taking them is a waste of time. Research published earlier this year by Harvard University found that they can help slow cognitive deterioration – such as impaired memory, concentration and decision-making – that occurs with age.
Duane Mellor, a dietitian and senior lecturer at Aston Medical School, said: ‘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.’
In a commentary linked to the study, senior US doctors Neal Barnard, Hana Kahleova and Roxanne Becker said: ‘Refocusing nutrition interventions on food, rather than supplements, may provide the mortality benefits that multivitamins cannot deliver.’
It was suggested that some supplements may have an impact on drugs being taken, for example, vitamin K may reduce the efficacy of the anticoagulant warfarin.
Source Agencies
