Ayurvedic medicine has become highly popular in Western countries; it originates, of course, from India, and is considered to be one of the world’s oldest health care systems. Its adherents claim to create harmony between the body, mind, and spirit, maintaining that this balance prevents illness, treats acute conditions, and contributes to a long and healthy life. In India Ayurveda is mainstream and more than 90% of the population are said to use it. Outside India, Ayurveda is usually classified as an alternative therapy.
Ayurvedic treatments can consist of a range of modalities, including herbal remedies taken by mouth. These preparations have often been reported to be contaminated with toxic metals. Despite several case reports of poisoning from such contamination, the epidemiological evidence is still limited. A new paper on this important topic is therefore welcome. It reports on a cluster of lead and mercury toxicity cases which occurred 2011 among a community of users of Ayurvedic remedies in the US.
Following the identification of the index case, adherents of Ayurveda were offered heavy metals screening. The results showed that 46 of 115 participants (40%) had elevated blood lead levels (BLLs) of 10 μg/dl or above, with 9.6% of BLLs at or above 50 μg/dl.
The authors issued the following warning: this is the largest cluster of lead and mercury toxicity following use of Ayurvedic supplements described in the literature in the US. Contamination of herbal products is a public health issue of global significance. There are few regulations addressing contamination of “natural” products or supplements.
Rasa shastra, the practice of adding metals, minerals or gems to herbal preparations, is a well-documented part of Ayurveda. Adverse reactions to herbs are described in traditional Ayurvedic texts, but practitioners tend to be reluctant to admit that their remedies could be toxic and that reliable information on their risks is not readily available.
Already in 1990, a study on Ayurvedic medicines in India found that 41% of the products tested contained arsenic, and that 64% contained lead and mercury. A 2004 study found toxic levels of heavy metals in 20% of Ayurvedic preparations sold in the Boston area. A 2008 study of more than 230 products found that approximately 20% of remedies (and 40% of rasa shastra medicines) purchased over the Internet from U.S. and Indian suppliers contained lead, mercury or arsenic.
My 2002 systematic review summarised all the available evidence and concluded that heavy metals, particularly lead, have been a regular constituent of traditional Indian remedies. This has repeatedly caused serious harm to patients taking such remedies. The incidence of heavy metal contamination is not known, but one study shows that 64% of samples collected in India contained significant amounts of lead (64% mercury, 41% arsenic and 9% cadmium). These findings should alert us to the possibility of heavy metal content in traditional Indian remedies and motivate us to consider means of protecting consumers from such risks.
Despite these concerns, Ayurveda-fans continue to believe that the toxicity of these remedies is reduced through the purification processes of Ayurvedic remedy preparation. Bizarrely, they may involve prayers as well as physical pharmacy techniques.
The Indian government ruled that Ayurvedic products must be labelled with their metallic content. However, one Indian expert, has been quoted claiming that “the absence of post-market surveillance and the paucity of test laboratory facilities [in India] make the quality control of Ayurvedic medicines exceedingly difficult at this time”. In the US, most Ayurvedic products are marketed without having been approved by the FDA. Since 2007, the FDA has placed an import alert on some Ayurvedic products in order to prevent them from entering the US.
Protecting consumers from heavy metal poisoning by Ayurvedic remedies is certainly not easy – but, in the interest of public health, it is a task that we must tackle with some ungency.