In a warning that is bound to cause a fresh row over the quality of Asian herbal medicines, British scientists were due to announce on Tuesday that millions of people in Asia — specially in India and China — might be exposed to the risk of kidney failure and bladder cancer from taking herbal medicines widely available in the continent.
Scientists from King's College London have found that many herbal medicines used for a wide range of conditions — including slimming, asthma and arthritis — are derived from a botanical compound containing aristolochic acids. These products are now banned in the US and many European countries, but herbs containing these toxic acids can still be bought in China and other countries in Asia, and are also available worldwide over the internet.
The scientists reviewed worldwide cases of aristolochic acid nephropathy (AAN), a type of kidney failure caused by the intake of these acids. They suggest there may be many thousands of cases across Asia that are undiagnosed or misdiagnosed. With the outcome of their study, the researchers hope to raise awareness of the risks of aristolochic acids and reduce the global disease burden from this severe condition.
"We do know that preparations containing aristolochic acid (AA) are widely used in India and that this is associated with chronic kidney disease and kidney cancer if a sufficient dose is taken," lead author Professor Graham Lord told TOI. "Ethnopharmacological analyses suggest that aristolochia is widely used in India. India must start better monitoring of medicines containing herbal remedies and also assessment of patients with chronic kidney disease and kidney cancer for the presence of AA."
Lord said at the moment they did not how widespread the problem was in India. "We have found evidence that many millions of people continue to be exposed to significant health risk due to these herbal medicines, widely used in China and India," he said. "There is also a striking lack of good quality evidence that might help guide the diagnosis and management of AAN."
Their paper, published in "Annals of Internal Medicine", indicates that the regulatory measures that have been adopted by national and international agencies so far may be inadequate in preventing harmful exposure to aristolochic acids.
The compound is linked to many cases of kidney diseases and urothelial cancer, a form of cancer of which bladder cancer is the most known variant.
The authors reviewed the latest data on the epidemiology of AAN. They used several search engines to include all publications that are about or refer to aristolochic acids and Chinese herbal nephropathy, and identified 42 different case studies and one trial relating to the management of the disease.
While explaining the origin and development of the disease, they propose a protocol that should make it easier to diagnose AAN. In addition, they suggest a new disease classification to help international clinicians better identify AAN patients and draft guidelines for the treatment of these patients.
The research team consisted of an international collaboration of scientists from Belgium, Czech Republic, Germany and the UK. "This research is a great demonstration of how international scientific collaboration is vital in helping to describe how a toxin used in widely available products can lead to cancer," said Dr Refik Gokmen, co-author from King's College London.
