Power of positivity: Health benefits of multivitamins ‘may all be in the mind’

BOSTON — The health benefits of taking multivitamin supplements may be all in the mind, according to a new study. People’s positive expectations could be behind the benefits of multivitamin and mineral tablets as there is no hard evidence otherwise, researchers suggest.

A number of clinical trials have “failed” to find any measurable health benefits from taking vitamin or mineral supplements. That led Harvard University’s Dr. Manish Paranjpe to examine whether the subconscious is behind health improvements among those taking the popular supplements.

“The effect of positive expectations in those who take multivitamin or mineral supplements is made even stronger when one considers that the majority of them are sold to the so-called worried-well,” says Paranjpe in a statement. “The multibillion-dollar nature of the nutritional supplement industry means that understanding the determinants of widespread multivitamin or mineral use has significant medical and financial consequences.”

For the study, researchers collected data on 21,603 adults in the United States who took part in the 2012 National Health Interview Survey. Of the sample, 4,933 people reported taking multivitamin or mineral tablets regularly.

Participants were asked to self-evaluate their health and quizzed over five physical, psychological and functional health outcomes. Questions included whether people needed help with routine daily activities and if they had a history of ten long term health conditions, including high blood pressure, asthma, diabetes, and arthritis.

They were also asked if they had suffered from a health condition in the past 12 months. Such conditions include infections, memory loss, neurological and musculoskeletal problems and psychological distress.

People who take multivitamin supplements believe they’re healthier

“Regular multivitamin or mineral supplement users reported 30 percent better overall health than those who didn’t take them,” says Paranjpe. “But there was no difference between those who did and didn’t take them in any of the five psychological, physical or functional health outcomes assessed.”

In-depth analysis shows that people who popped multivitamin or mineral supplements tended to believe they were in better health, regardless of their race, sex, education, age and incomes. Researchers offer two possible explanations for the findings. Either people who regularly take supplements simply believe they will give them a health boost, or they are generally more positive about their personal health, regardless of what they take.

There is a growing body of evidence the power of positive thinking can improve various health conditions.

“This is an observational study, and so [we] can’t prove a causal relationship between use of multivitamin and mineral supplements and subjectively assessed health,” says Paranjpe. “What’s more, subjectively assessed health is not always reliable, and we didn’t track changes in health before and after taking supplements over the long term. Nevertheless, the lack of any difference in the health outcomes assessed is in line with other studies indicating that multivitamin or mineral supplements don’t improve overall health in the general adult population.”

Study results are published in The BMJ.

SWNS reporter Tom Campbell contributed to this report.