More than half of U.S. adults take dietary supplements . I don’t, but some of my family members do. But does popping all of these vitamins, minerals, and other substances really lead to a longer, healthier life? A new nationwide study suggests it doesn’t.
Based on an analysis of survey data gathered from more than 27,000 people over a six-year period, the NIH-funded study found that individuals who reported taking dietary supplements had about the same risk of dying as those who got their nutrients through food. What’s more, the mortality benefits associated with adequate intake of vitamin A, vitamin K, magnesium, zinc, and copper were limited to food consumption.
The study, published in the Annals of Internal Medicine, also uncovered some evidence suggesting that certain supplements might even be harmful to health when taken in excess . For instance, people who took more than 1,000 milligrams of supplemental calcium per day were more likely to die of cancer than those who didn’t.
The researchers, led by Fang Fang Zhang, Tufts University, Boston, were intrigued that so many people take dietary supplements, despite questions about their health benefits. While the overall evidence had suggested no benefits or harms, results of a limited number of studies had suggested that high doses of certain supplements could be harmful in some cases.
To take a broader look, Zhang’s team took advantage of survey data from tens of thousands of U.S. adults, age 20 or older, who had participated in six annual cycles of the National Health and Nutrition Examination Survey (NHANES) between 1999-2000 and 2009-2010. NHANES participants were asked whether they’d used any dietary supplements in the previous 30 days. Those who answered yes were then asked to provide further details on the specific product(s) and how long and often they’d taken them.