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

They promise health benefits by strengthening the immune system to strong bones.

But multivitamins do not help you live longer, according to a major study.

Regularly taking the supplements appeared to have no effect on people’s life expectancy, according to research among almost 400,000 healthy adults.

The analysis even showed that daily use of multivitamins was associated with a 4 percent higher mortality risk.

In Britain and the US, the vitamin industry is estimated to be worth billions, which are taken by people in the hope of improving their health.

But the potential benefits and harms of supplementing the diet with additional vitamins and minerals remain unclear, often hampered by the size of the study 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 years, who had no history of cancer or other chronic diseases, for more than twenty 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 period, approximately 164,762 people died, of which 49,836 deaths were attributed to cancer, 35,060 to heart disease and 9,275 to cerebrovascular disease.

Researchers assessed 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 incorporated this into the findings, according to the study published in JAMA.

Those who took multivitamins were also more likely to use individual supplements and had a lower BMI and better diet quality.

But no longevity benefits were found in those who took daily vitamins – in contrast, they were associated with a 4 percent increased risk of death.

The conclusion is: ‘The analysis showed that people who took daily multivitamins did not have a lower risk of death from any cause than people who did not take multivitamins.

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

But the results don’t necessarily mean that taking vitamins is a waste of time.

Research published earlier this year by Harvard University shows that they may help slow the cognitive decline that occurs with age.

Other research has suggested that they may help people feel healthier, although this could be the placebo effect.

Duane Mellor, a registered dietitian and senior lecturer at Aston Medical School, said: ‘It is not surprising to see that these do not significantly reduce the risk of mortality.

‘A vitamin and mineral supplement will not in itself solve an unhealthy diet, but it can help cover important nutrients if someone has difficulty getting them from their diet.

‘An example of this could be vitamin D, which adults in Britain are encouraged to take as a supplement in winter, or vegans and vegetarians who could benefit from supplementing with vitamin B12.’

Neal Barnard, Hana Kahleova and Roxanne Becker of the Physicians Committee for Responsible Medicine, Washington, wrote in an accompanying commentary: ‘Refocusing nutritional interventions on food, rather than supplements, may provide the mortality benefits that multivitamins cannot.

‘Vegetables, fruits, legumes and grains are staples in areas of remarkably long life known as the 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 affect other medications being taken. For example, vitamin K can reduce the effectiveness of the anticoagulant drug 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 that similar concerns may apply to copper supplementation, and that calcium and zinc may reduce the absorption of certain antibiotics