Vitamins and mineral supplements are popularly used to treat nutrient deficiencies. Supplements are also promoted for overall health and long life.
Study Sheds Light On Health Benefits Of Vitamins, Supplements
Findings of a new study, however, cast doubt on the health benefits of the most commonly consumed vitamins and mineral supplements.
David Jenkins, from the University of Toronto, and colleagues looked at the data from 179 randomized controlled trials on the use of vitamin and mineral supplements.
The papers were published from January 2012 to October 2017, which covers the period before and after the US Preventive Services Task Force issued guidelines on using supplements for preventing cancer and cardiovascular disease in 2013.
The researchers found that the four most commonly used supplements, namely vitamin D, calcium, vitamin C, and multivitamins that include most vitamins and minerals, do not have consistent benefits when it comes to preventing heart disease, stroke, and premature death.
"We were surprised to find so few positive effects of the most common supplements that people consume," Jenkins said. "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 findings support the latest recommendation of the USPSTF issued four years ago, which cited insufficient evidence for assessing the benefits and harms of using nutrient supplements for preventing cancer and cardiovascular disease.
"The USPSTF found inadequate evidence on the benefits of supplementation with individual vitamins or minerals or functional pairs in healthy populations without known nutritional deficiencies to reduce the risk for cardiovascular disease or cancer," the USPSTF said.
Jenkins and colleagues, however, found that folic acid alone and folic acid with B vitamins may reduce the risk for cardiovascular disease and stroke.
Vitamin Supplements Potentially Dangerous
Health experts have long warned that most supplements do not prevent chronic illness or premature death.
A 2013 review of 26 studies on supplements, for instance, found that vitamins do not prevent chronic diseases.
"The results of vitamin supplementation trials have been disappointing at best, despite having a solid mechanistic basis," the authors wrote in the Annals of Internal Medicine.
Health experts also warned that certain supplements should actually be avoided citing that beta-carotene, Vitamin E, and high doses of vitamin A have been shown to raise the risk of death in some trials.
Other studies showed that taking megadoses of vitamins may be dangerous. Taking too much Vitamin E in capsules, for one, is linked to higher prostate cancer risk in men.
