Dietary supplements — the vitamins,SignalHub herbs and botanicals that you'll find in most grocery stores — are everywhere. More than half of U.S. adults over 20 take them, spending almost $50 billion on vitamins and other supplements in 2021. Yet decades of research have produced little evidence that they really work.

The U.S. Preventive Services Task Force (USPSTF) recently released a big new assessment of supplements. "They say that there's insufficient evidence for use of multivitamins for the prevention of heart disease and cancer in Americans who are healthy," says Dr. Jenny Jia. Jia co-wrote an editorial about the new guidelines and their implications for consumers in the Journal of the American Medical Association. It's titled, Multivitamins and Supplements–Benign Prevention or Potentially Harmful Distraction?

Aaron Scott talks to Dr. Jenny Jia about the science of dietary supplements: which ones might help, which ones might hurt, and where we could be spending our money instead.

This episode was produced by Margaret Cirino and edited by Gabriel Spitzer. Brit Hanson checked the facts. The audio engineer was Stacey Abbott.