Supplements and Safety

A new documentary, “Supplements and Safety,” pulls back the curtain on some of America’s most popular supplements, and it suggests that many people who buy them may not be getting what they are paying for. The program, airing on the PBS investigative series “Frontline” on Tuesday night, is a collaboration between “Frontline,” The New York Times and The Canadian Broadcasting Corporation.

The program examines the widespread use of potent vitamins, herbs, fish oil and fat-burning supplements. Millions of Americans use these products safely every year. But researchers have found that in many cases they can cause unexpected side effects. And because dietary supplements are largely unregulated by the federal government, adulteration and contamination are common, experts say.