Some foreign herbal products found containing toxic metals

One in five herbal products used in so-called Ayurvedic medicine and sold over the Internet contain harmful levels of toxic metals, a study found.

Herbal pills, powders and liquids are the foundation of Ayurvedic medicine, an ancient system of health care that originated in India. It has become more popular in the U.S. as interest in yoga and alternative medicine has grown.

Almost 21 percent of 193 Ayurvedic products purchased online contained amounts of lead, mercury or arsenic that exceeded one or more U.S. safety standards, according to the research published in the Journal of the American Medical Association. In a finding that surprised the researchers, products manufactured in the U.S. were slightly more likely to contain contaminants than those made in India.

"The take-home message here is that current regulations in our country governing dietary supplements, in general, are inadequate to protect the consumer," said Robert B. Saper of Boston University School of Medicine, the study's lead author.

The highest concentrations of metals were found in a type of Ayurvedic product known as "rasa shastra," in which mercury, lead, zinc and other metals are deliberately combined with herbs to produce a therapeutic effect, Saper said. Rasa shastra products, primarily made in India, were more than twice as likely to contain lead and mercury, the researchers found.