US health body launches online resources to curb confusion on dietary supplements

25 Jan 2018 --- The Office of Dietary Supplements (ODS) at the National Institutes of Health – the US’ medical research agency – has two new resources to help people understand what is known about the effectiveness and safety of many ingredients in dietary supplements promoted for fitness and weight loss. Both fact sheets are available online in a health professional version that is detailed and fully referenced, as well as consumer versions in both English and Spanish.

The first fact sheet, Dietary Supplements for Exercise and Athletic Performance, covers products – sometimes called ergogenic aids – that aim to improve strength or endurance, increase exercise efficiency, achieve a performance goal more quickly and increase tolerance for more intense training.

“Dietary supplements marketed for exercise and athletic performance can’t take the place of a healthy diet, but some might have value for certain types of activity,” says Paul M. Coates, Ph.D., Director of ODS. “Others don’t seem to work, and some might even be harmful.”

This fact sheet covers more than 20 ingredients commonly found in fitness supplements, including antioxidants, beetroot, tart cherry, branched-chain amino acids, caffeine, creatine and protein. Creatine, for example, might help with short bursts of high-intensity activity like sprinting or weight lifting, but not for endurance efforts like distance running or swimming. Antioxidants such as vitamins C and E don’t seem to improve any physical activity, though they're needed in small amounts for overall health.

More than two-thirds of adults in the US are overweight or obese, and many are trying to lose those extra pounds. The fact sheet Dietary Supplements for Weight Loss guides readers through the confusing set of options in the marketplace.

“Americans spend over US$2 billion a year on dietary supplements promoted for weight loss, but there’s little evidence they actually work,” says Anne L. Thurn, Ph.D., Director of the ODS Communications Program. “And people may not know that many manufacturers of weight-loss supplements don’t conduct studies in humans to find out whether their product works and is safe.”

This fact sheet covers 24 ingredients found in these products, including African mango, beta-glucans, chromium, garcinia, green tea, hoodia and raspberry ketones. Chromium, for example, might help you lose a very small amount of weight and body fat, and is safe, but raspberry ketones haven’t been studied enough to know whether they're safe or effective. And while drinking green tea is safe, taking green-tea extract pills has been linked to liver damage in some people, NIH comments.

“We encourage people to talk with their healthcare providers to get advice about dietary supplements and to visit the ODS website to learn valuable information about these products,” says Coates. “People can also sign up for the ODS listserv to be notified when we add new information to our website.”