Advantage of taking daily vitamin supplements may be all in the mind

THE health benefits of taking multivitamins have more to do with positive thinking than any physiological effects, research suggests, after scientists found no difference in the health of users and non-users.

Regular users of multivitamins or mineral supplements reported 30 per cent better overall health than nonusers, according to a study published in the journal BMJ Open. But when the researchers looked at health outcomes, no difference between the two groups was found.

It is estimated around one in three British adults takes some form of nutritional supplement, the most popular being multivitamins, followed by vitamin C. The vitamin sector was valued at around £424 million last year, according to the IRI.

The researchers, from Harvard University, said previous research had failed to identify measurable health benefits associated with daily consumption of multivitamins among those without any known vitamin or mineral deficiencies. Their study compared selfreported and clinically measurable health outcomes among users and nonusers of multivitamins and minerals (MVM) in the US.

A sample of 21,600 adults who were asked about their use of supplements in the 2012 annual National Health Interview Survey, and were asked to selfevaluate their health, was used.

They were also questioned on five psychological, physical, and functional health outcomes including a subjective assessment of health, their history of 10 long term conditions such as diabetes or asthma, and the presence of 19 common health conditions in the last 12 months, such as infections or memory loss.

Around one in five said they regularly took multivitamins or supplements. The regular users were significantly older, had higher household incomes than non-users, and were also more likely to be women, educated, married and to have health insurance.

On the self-evaluation section, regular takers reported 30 per cent better overall health than those who did not take MVMS.

Better self-reported overall health for regular takers was consistent across all race, sex, and education groups, as well as in the under-65s and those on low household incomes, the study found.

However, the findings also revealed that users and non-users did not “differ in various psychological, physical and f unctional outcomes”, which the researchers say supports previous findings that multivitamins “do not improve overall health in the general adult population”.

The researchers put forward two explanations for their results. Firstly, that regular users believe in the effectiveness of these multivitamins by “harbouring a positive ex pectation regarding the health benefits”.

Alternatively, they propose MVM users are just inherently more positive about their personal health.

There is a growing body of evidence which supports the “power of positive thinking” when it comes to improving health, the researchers said.