How safe and effective are herbal dietary supplements?

Millions of people are taking herbs and other plant-based dietary supplements to improve their health, but they have precious little information on the actual effectiveness or potential ill effects of these products. That's the topic of an article in the current issue of Chemical & Engineering News (C&EN), ACS' weekly newsmagazine.

C&EN Senior Editor Celia Henry Arnaud suggests that consumers are taking a gamble when it comes to the safety and effectiveness of hundreds of pills and potions cluttering store shelves. Such products include black cohosh and red clover, used by menopausal women to reduce hot flashes, and kava, which is used to treat anxiety and insomnia.

Scientists are concerned that some supplements may contain high levels of toxic metals, such as lead and mercury, or pesticides. There's also the possibility that the plant itself might be toxic or that a supplement can cause harm by reacting with conventional drugs.

The U.S. Food & Drug Administration, which regulates supplements as foods rather than drugs, recently took a step toward improving the situation by requiring all supplement manufacturers to test their products for contaminants. But scientists still know little about the ingredients in many supplements and what effect they might have on the body. Ongoing research is providing new information that will help address these concerns in the future, including the long-term safety of these products for consumers, the article indicates.