Are the vitamin and mineral supplements you take of much benefit to your health? A study led by researchers at St Michael's Hospital (Canada) and the University of Toronto and published in the Journal of the American College of Cardiology, shows that supplements provide neither consistent health benefit nor do any harm. The study was a systematic review of existing data and single randomised control trials done between January 2012 and October 2017. It found that multivitamins, vitamin D, calcium and vitamin C, which are the most common supplements, showed no benefit in the prevention of cardiovascular disease, heart attack, stroke or premature death.
"We were surprised to find so few positive effects of the most common supplements that people consume," Dr David Jenkins, the study's lead author, was quoted as saying. "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." His team reviewed A, B1, B2, B3 (niacin), B6, B9 (folic acid), C, D and E, and beta-carotene, calcium, iron, zinc, magnesium and selenium. The term 'multivitamin', in this review, was used to describe supplements that include most vitamins and minerals, rather than a select few.
Vitamin and mineral supplements are taken to add to nutrients that are found in food but lack in the body due to poor absorption. The study found that only folic acid and B-vitamins with folic acid may reduce cardiovascular disease and stroke.
In a randomised study, researchers from the Physicians' Health Study II (NEJM JW Gen Med Nov 15 2012
) examined the effects of multivitamin supplementation on cognitive function later in life. Male physicians (age, ≥65) took daily multivitamin or placebo supplements for a mean of 8.5 years; no difference was noted in cognitive function as measured by five different cognition tests.
Earlier, in 2012, an analysis for the US preventive services task force concluded that a systematic review of studies that involved vitamin and mineral supplements for primary prevention of cardiovascular disease, cancer, or all-cause mortality among healthy individuals, showed no evidence of benefit from supplements.
"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," Dr Jenkins said. "So far, no research on supplements has shown us anything better than healthy servings of less processed plant foods including vegetables, fruits and nuts."