One-fifth of Indian herbal medicines available over the internet contain heavy metals such as lead, mercury and arsenic, according to researchers who analysed 193 products obtained online.
The scientists called for tighter regulation of so-called Ayurvedic medicines.
The team randomly selected 193 products from internet sites selling Ayurvedic remedies and analysed their content.
They detected lead, mercury or arsenic in 20,7% of products. If taken in high enough quantities these can lead to acute poisoning.
“Our first priority must be the safety of the public,” said Dr Robert Saper at Boston University school of medicine. “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.”
Ayurvedic healing has been practised for over two millennia in India and is becoming popular in Europe and the United States. It has two strands — herbal-only medicines and remedies that combine herbs with metals, minerals and gems.
About 80 cases of lead poisoning associated with Ayurvedic medicine have been reported worldwide and previous studies have found a problem with high levels of heavy metals in the herbal remedies.
“It is a real issue,” said Professor Edzard Ernst, an expert in complementary medicine at the Perimeter medical school in Exeter, south-west England, who was not involved in the study.
“A thousand years ago it was thought that through heating [lead] was made non-toxic, which is clearly not the case.
“These traditions live on and they carry on endangering our health.”
He said there was weak evidence that Ayurvedic medicine could be effective in some circumstances, but none of the products investigated by the researchers had been proved to work. —