The federal department has identified twelve products sold in Canada that analysis has shown to contain high levels of lead, mercury or arsenic. The products come under the Karela, Safi, Maha Sudarshan Churna, Yograj Guggul, Sudarshan or Shilajit brands.
As a precaution, consumers are advised not to take any supplements made by these companies unless they bear an eight-digit Drug Identification Number, Natural Product Number or a Homeopathic Drug Number, indicating that they have been assessed for safety, efficacy and quality.
Health Canada has issued a statement saying that it is currently working with importers and distributors of the products in question to remove them from the market.
Ayurvedic medicine makes use of the purported therapeutic properties of heavy metals but according to Health Canada improper manufacturing processes can lead to "dangerously high levels of heavy metals remaining in the final product".
Analysis of heavy metal content of products available in Canada was prompted by an article published in the Journal of the American Medical Association in December 2004, which found that 14 Ayurvedic products sold in the Boston area contained potentially harmful levels of heavy metals.
The Karela, Safi, Maha Sudarshan Churna and Shilajit brands were also implicated in the JAMA study.
An initial advisory issued in March 2004, prior to full investigation of the availability of products in Canada, reported that a Safi product had been found to contain 40 times the maximum concentration of arsenic allowed in drugs.
Heavy metals can accumulate in the vital organs, and children are the most at risk from their toxic effects. Symptoms of arsenic poisoning are listed as nausea, abdominal pain, vomiting, muscle cramps, heart abnormalities, liver damage, anaemia and reduced motor nerve function.
Lead poisoning can cause weight loss, insomnia, dizziness, swelling of the brain and paralysis, and Mercury poisoning can cause tremors, insomnia, memory loss, slowed sensory and motor nerve function, and reduced mental function.