Nearly 21% of traditional Ayurvedic medicines sold over the Internet contained toxic levels of lead, mercury or arsenic, according to a study published in the Aug. 27 issue of the Journal of the American Medical Association (JAMA).

Robert Saper, MD, MPH, of Boston University School of Medicine, and co-authors of the study called on FDA to set and enforce daily dose limits for toxic metals in all dietary supplements, and suggested Ayurvedic manufacturers be required to offer their products for independent third-party testing.

Overall, 20.7% of the 193 products tested contained amounts of lead, mercury or arsenic that exceeded one or more acceptable standards for daily intake. Tests evaluated both rasa shastra and non-rasa shastra Ayurvedic medicines manufactured in the U.S. and India.

Researchers noted that to produce rasa shastra products, herbs are intentionally mixed with metals like mercury, lead, iron, zinc and other materials like mica and pearl to produce a therapeutic effect.

Rasa shastra medicines tested were twice as likely to contain metals than their counterparts. Of Ayurvedic products manufactured in the U.S., 21% contained lead, 3% contained mercury and 3% had arsenic. Among the Indian-made medicines, 17% contained lead, 7% had mercury and none contained arsenic.

The study notes that Ayurvedic medicine products made by American Herbal Products Association (AHPA) members are significantly “less likely to contain metals,” or nearly four times less likely, according to an AHPA statement.

“A company’s decision to become a member of AHPA represents an investment in quality and a sustained interest in improving standards at the company and industry level,” said Michael McGuffin, AHPA president. “The area of trace elements in dietary supplements is one the association has dedicated time and attention to, and, through the work of our committees, we will continue to assist AHPA companies in reaching their quality standards.”

Mr. McGuffin said the suggestion that FDA mandate and enforce limits for heavy metals in dietary supplements, “should be seriously considered, not just for dietary supplements but also for conventional foods.”

Since 1978, more than 80 cases of lead poisoning associated with Ayurvedic medicine have been reported, according to the study.

Researchers used five different Internet search engines to select 25 sites selling Ayurvedic medicines. Of the 673 products identified they randomly chose 230 to purchase in 2005. After receiving 193 orders, researchers sent products to the New England Regional EPA for testing using x-ray fluorescence spectroscopy.

The traditional Indian practice of Ayurveda takes a holistic approach to wellness, involving herbal medicine, meditation and exercise. It exists alongside modern medicine in India, with its own network of clinics, hospitals and colleges. In recent years its popularity has grown in the U.S. and other western cultures.