August 28, 2008
Study Finds Harmful Metals In Some Ayurvedic Medicines
Researchers said on Tuesday that one in five Ayurvedic medicines commonly used by followers of the ancient Indian health philosophy were found to contain the metallic poisons lead, mercury or arsenic.
The ancient Ayurveda system includes medicines, meditation, exercise and dietary guidelines practiced by millions of adherents on the Indian subcontinent and increasingly in the West.
Dr. Robert Saper and colleagues reported that nearly 21 percent of 193 Ayurvedic medicines analyzed had detectable levels of one or more of the metals, and at least half of those exceeded established standards for unhealthy exposure levels.
The findings raise concerns about the ingredients found in the lightly regulated dietary supplement market that includes vitamins and traditional Chinese medicines, Saper said.
The U.S. Food and Drug Administration rely on manufacturers to report ingredients accurately and then investigate complaints.
Saper wrote: "We suggest strictly enforced, government-mandated daily dose limits for toxic metals in all dietary supplements and requirements that all manufacturers demonstrate compliance through independent third-party testing."
Saper said some studies show that some herbs have a very promising anti-diabetic effect, anti-high blood pressure effect and a cholesterol-lowering effect.
"In Ayurveda and all those traditional systems there certainly are some promising wisdom and heritage that we need to harvest. But the key thing is we need to separate out what's helpful and ... what needs to be looked at and perhaps set aside."
The team's study followed up a published report in the same journal in 2004 when they purchased Ayurvedic medicines produced in South Asia from Boston-area stores and found similar contaminants.
Saper said it was unclear how the metals get into the medicines. He agreed with Wynn Werner of the Ayurvedic Institute in Albuquerque, New Mexico, that there could be several sources.
Some metals occur naturally in soil, and plants and herbs used to make Ayurvedic medicines may concentrate the contaminants. The metals may come from human-made pollutants and industrial sources, particularly in India where lead pollution is widespread.
Some metals may be introduced, accidentally or intentionally, during the manufacturing process.
Rasa Shastra, a specific class of Ayurvedic medicines, contained very high levels of lead or mercury, as well as precious metals and processed gemstones.
Indian practitioners say extensive preparation of the metals elicits the benefits while rendering them harmless, but Saper called this doubtful.
He warned against the use of rasa shastra medicines until more research can be done and said few if any manufacturers outside of India produce them.
About half the Ayurvedic medicines in the study found to be contaminated with lead would exceed the daily dose limit of 20 micrograms set by the American National Standards Institute. But ingestion of even small amounts of lead may harm the brain and the kidneys and could raise blood pressure, Saper said.
On the Net:
- Boston University School of Medicine
- Boston Medical Center
- Journal of the American Medical Association