Researchers found that one-fifth of the herbal medicines tested contained metals such as lead, mercury and arsenic at levels that could be toxic, says a study published today in 15 December issue of JAMA (2004; 292: 2868-2873).
The scientists noted that approximately 80 percent of India's one billion population uses Ayurveda, a medical system that originated in India more than 2000 years ago and greatly relies on herbal medicine products (HMPs). In the west Ayurvedic HMPs are marketed as dietary supplements.
Robert Saper and colleagues from the Boston University School of Medicine examined Ayurvedic HMPs manufactured in South Asia and sold in Asian grocery stores in and around Boston to examine their heavy metal content. From April to October 2003, the researchers purchased 70 different Ayurvedic HMPs and measured concentrations of lead, mercury and arsenic in the samples.
The researchers found that 14 (20 percent) of the 70 HMPs - manufactured by 11 different companies - contained lead, mercury and/or arsenic, and that if taken as recommended by the manufacturer, each of these could result in heavy metal intake above the published regulatory standards. Lead was found in 13 HMPs, mercury in six and arsenic in six.
"Our findings support calls for reform of DSHEA that would require mandatory testing of all imported dietary supplements for toxic heavy metals," concluded the researchers.
However according to the American Herbal Products Association (AHPA), the authors fail to clarify that many of these products - in addition to naturally occuring metals - contain non-herbal ingredients, such as sulfide of mercury, "which no doubt accounts for the high levels of heavy metals detected in these imported products".
The AHPA points out, for example, that: "one product was found to contain more than 10 percent mercury and four others were noted to exceed one percent of total heavy metals".
In other words, the stores selling these products are selling adulterated supplements that are unlawful under DSHEA. The AHPA said it was therefore unclear why the researchers were calling for the "reform of DSHEA" to prohibit such products being sold when in fact they are already unlawful as they contain an unnatural amount of heavy metals.
"No change in the law is required, though manufacturers, importers and retailers need to assure that the products they manufacture, import and sell are free of adulteration. AHPA encourages its members to test products for heavy metals," said the AHPA in a statement.
Michael McGuffin, president of the AHPA, told NutraIngredientsUSA.com that the scientists "did a fine job" in terms of research, but "these products should not be sold under US law", suggesting the problem of these supplements lies not with Ayurvedic herbal medicines, but with the importing of these particular products.