A new review of data and trials published between January 2012 and October 2017 found that many popular multivitamins – as well as vitamin C and D, and calcium supplements – had no real benefit to people’s health and that there’s no evidence that taking them helps to reduce the risk of cardiovascular disease, stroke, or early death.
The study, which was published in the Journal of the American College of Cardiology, was carried out by researchers from St Michael’s Hospital and the University of Toronto. Dr. David Jenkins, the lead author of the study, says that “we were surprised to find so few positive effects of the most common supplements that people consume. Our review found that if you want to use multivitamins, vitamin D, calcium, or vitamin C, it does no harm – but there’s no advantage either.”
However, there were a few apparently beneficial supplements. For example, the study found that folic acid and B vitamins may reduce the risk of cardiovascular disease and stroke.
Niacin (a type of vitamin B3) and antioxidant supplements, on the other hand, were associated with a higher risk of death by any cause, albeit a very small increase. The researchers suggest that these higher risks could be related to niacin’s adverse effects on blood-sugar levels, or that when taken in high doses, antioxidants can be harmful.
These findings suggest that we need to be conscious of the supplements that we’re taking and ensure that they’re applicable to the vitamin and mineral deficiencies that have been noted by our healthcare providers.
The vitamins that the team reviewed were A, B1, B2, B3 (niacin), B6, B9 (folic acid), C, D, and E, as well as carotene, iron, calcium, zinc, iron, selenium, and magnesium.
Research has found that some vitamins are more useful than others. For example, zinc has been linked to improving the symptoms of a cold – something that vitamin C doesn’t do, despite what people think. Vitamin D can also be hard to get from food, so if you’re deficient, supplements might also be effective.
Jenkins says that “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. So far, no research on supplements has shown us anything better than healthy servings of less processed plant foods, including fruits, vegetables, and nuts.”