Most popular vitamin and mineral supplements have no effect
Meta-analysis finds popular tablets do neither good or harm. Andrew Masterson reports.
A review of the most commonly consumed vitamin and mineral supplements has found that most neither heighten nor lower the risk of cardiovascular disease, heart attack, stroke or premature death.
In a paper published in the Journal of the American College of Cardiology, researchers from St. Michael's Hospital and the University of Toronto, Canada, analysed data from studies including randomised control trials published between 2012 and 2017.
The results show that the four most commonly consumed supplements – multivitamins, vitamins D and C, and calcium – had no effect on rates of major cardiovascular events.
The review, led by David Jenkins from the hospital’s Clinical Nutrition and Risk Factor Modification Centre, found that only two popular supplements – folate, and folate combined with B vitamins – reduced the risk of cardiovascular disease or strokes, and even those results were unclear.
Two other supplements – niacin (vitamin B3) and antioxidants – were associated with a very small increase in the chances of death from any cause.
“We were surprised to find so few positive effects of the most common supplements that people consume,” says Jenkins.
“Our review found that if you want to use multivitamins, vitamin D, calcium or vitamin C, it does no harm – but there is no apparent advantage either.”
The global dietary supplements market is huge, and growing rapidly. Research published in early 2018 found that total revenue for the sector in 2015 was $US50 billion, and is projected to increase to $US278 billion by 2024.
An Australian survey, released in May this year, found that just under 43% of Australians had taken vitamins or supplements during 2017.
The review by Jenkins and colleagues looked at English studies covering A, B1, B2, B3, B6, B9 (folic acid), C, D and E, as well as beta-carotene, calcium, iron, zinc, magnesium, and selenium.
Jenkins says the results indicate that people should seek advice from a healthcare provider before opting to take any vitamin or mineral supplement.
“In the absence of significant positive data – apart from folic acid’s potential reduction in the risk of stroke and heart disease – it’s most beneficial to rely on a healthy diet to get your fill of vitamins and minerals,” he explains.
“So far, no research on supplements has shown us anything better than healthy servings of less processed plant foods including vegetables, fruits and nuts.”