In a random sample of commercially prepared Ayurvedic medicines purchased via the Internet, we found that nearly 21% contained detectable levels of lead, mercury, and/or arsenic, and the prevalence of these potentially toxic metals did not differ by country of manufacture; ie, United States vs India. Rasa shastra medicines were more than twice as likely as non–rasa shastra products to contain detectable metals. All metal-containing products exceeded 1 or more standards for acceptable daily metal intake. Several Indian-manufactured rasa shastra medicines could result in lead and/or mercury ingestions 100 to 10 000 times greater than acceptable limits.
Metals identified in our sample of Ayurvedic medicines are likely a result of the practice of rasa shastra or contamination. Many rasa shastra medicines are made with bhasmas
, which are elaborately prepared with various forms of metals including cinnabar (mercuric sulfide), galena (lead sulfide), realgar (arsenic sulfide), and white arsenic (arsenic trioxide).4,5
Ekangvir Ras is an example of a rasa shastra medicine made with naga
(lead) bhasma and parada
(mercury). Ayurveda experts in India believe that if bhasmas are properly prepared according to ancient protocols, the metals undergo shodhana
(“purification”), rendering them nontoxic and therapeutic. Case reports in the literature, however, have documented significant toxicity with the use of some of these products.2,3
The prevalence of metals in non–rasa shastra medicines was still substantial (17%) and could be a consequence of environmental contamination of the herbs18
or incidental contamination during manufacturing.
Our finding that close to 21% of Ayurvedic medicines manufactured and distributed by US and Indian companies via the Internet contain lead, mercury, or arsenic is consistent with our previous report that 20% of Indian-manufactured Ayurvedic medicines purchased in South Asian ethnic markets in Boston contain these metals.6
However, the Ayurvedic medicines analyzed in the Boston study had higher median metal concentrations (lead, 40 μg/g; mercury, 20 225 μg/g; and arsenic, 430 μg/g) and were more often recommended for pediatric use (50% vs 5%) than the medicines analyzed in our Internet sample. Studies of Ayurvedic medicines purchased from stores in New York,7
have also reported similar findings, and lead has been found in non-Ayurvedic herbal and vitamin supplements manufactured in the United States19,20
as well as in traditional medicines from other cultures.21,22
The public health impact of metals in rasa shastra and contaminated herbal medicines in India is unknown and controversial.23
Ayurveda advocates in India maintain that rasa shastra medicines have been used effectively and safely for millennia.4,5,23
They ascribe case reports of metal toxicity to improper commercial manufacturing practices or lack of supervision from a practitioner skilled in rasa shastra.23
However, many Ayurvedic medicine users believed to be unaffected may actually have unrecognized, misdiagnosed, or subclinical metal intoxications. Patients with Ayurvedic medicine–associated lead poisoning commonly undergo endoscopy for abdominal symptoms or bone marrow biopsy for anemia before they receive a correct diagnosis.24
Given widespread use of Ayurvedic medicines in India and throughout the world, observational studies assessing whether rasa shastra and non–rasa shastra medicine use are independent risk factors for increased lead burden are urgently needed.
Limitations of our study include potential misclassification of the product’s country of manufacture and rasa shastra status. Information provided by the Web site, label, and/or manufacturer was occasionally contradictory or ambiguous. However, this limitation does not affect the overall prevalence of metals in the sampled medicines, and any misclassification would have been nondifferential. Unobtainable products were not random and may have had a higher or lower likelihood of containing metals, thus potentially affecting the overall sample prevalence. We did not assess batch-to-batch variability in metal concentrations. However, this would likely not significantly alter overall prevalence estimates. Wide variation among published standards for acceptable limits of daily metal ingestion makes it difficult to assess the magnitude of potential toxicity for different products. Finally, we did not ascertain the specific physical form or chemical species of the metals. To the best of our knowledge, the physico-chemical form of metals in rasa shastra medicines and their bioavailability have not been fully characterized or reported. We are unaware of rigorous evidence supporting claims that bhasmas made using lead, mercury, and arsenic are nontoxic, and documented case reports of poisonings2,3
contradict these theories.
Regarding generalizability, products in our study can be purchased via the Internet without consultation from an Ayurvedic practitioner. Thus, our results may not reflect products recommended or provided by individual Ayurvedic practitioners to patients in the context of a patient-practitioner consultation.25
Compared with Ayurvedic practitioners in India, US practitioners are reportedly less likely to use rasa shastra medicines.25
Rasa shastra is not included in the scope of practice being developed by the US-based National Ayurvedic Medical Association, a professional organization for US-and Indian-trained Ayurvedic practitioners (Jennifer Rioux, PhD, personal communication, 2008). Internet products may also not be similar to those sold over the counter in mainstream US pharmacies and health food stores.
Despite these limitations, our data likely provide a relatively accurate snapshot of the prevalence of metal-containing Ayurvedic medicines sold via the Internet in 2005. A 2005 Institute of Medicine report concluded that “the regulatory mechanisms for monitoring the safety of dietary supplements... [should] be revised. The constraints imposed on FDA [US Food and Drug Administration] with regard to ensuring the absence of unreasonable risk associated with the use of dietary supplements make it difficult for the health of the American public to be adequately protected.”26
A 2006 National Institutes of Health state-of-the-science conference similarly stated that “public assurance of the safety and quality of [dietary supplements] is inadequate.”27
Our data demonstrating elevated levels of lead, mercury, and arsenic in publicly available Ayurvedic medicines and prior studies finding toxic metals in non-Ayurvedic supplements19–22
support these conclusions. New FDA regulations28,29
and current Indian policies23,30
do not specify any maximum acceptable concentrations or daily dose limits for metals in dietary supplements for domestic use. 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.