Aristolochia: behind its beauty it's a very dangerous way to diet
RECENT CONCERNS about fad diets remind us of the extent to which some people will go to lose weight. While the health implications of being overweight are increasingly recognised, some approaches to weight loss are also problematic. Among the strategies available are diet pills, including natural, herb-based preparations.
Various aristolochia species appear in some herbal slimming agents, even though they have been shown to be toxic. They are banned in many countries and regulated as prescription-only substances in Ireland. In spite of this, they are readily available on the internet and the Irish Medicines Board warned in 2006 that a traditional Chinese medicinal product available in Ireland was suspected of containing aristolochia.
About 500 aristolochia species grow around the world and are known for their distinct and spectacular flowers. With all their beauty, inside lurks a hidden poison. Aristolochia species contain aristolochic acid, a known nephrotoxin, ie kidney poison and cancer-causing agent.
The Brussels tragedy
In 1991 and 1992, hospitals in Brussels noticed an unusual and sudden increase in patients requiring dialysis for kidney disease of unknown origin. Many were women with no history of kidney disease. A common link was found when several reported attending the same weight-loss clinic in Brussels and using its herbal slimming pill. By 2000, over 100 women who suffered kidney failure could trace their illness to this herbal remedy. When 39 of these patients went for surgery to remove their ruined kidneys, cancer was found throughout their surrounding tissues.
The problem started with a terrible mistake. The clinic had ordered two Chinese herbs for its remedy. The Chinese name for one of those plants is almost identical to the Chinese name for aristolochia fangchi. The suppliers sent the wrong species, and no one along the way checked its identity. Such checks are necessary, but sometimes omitted.
The medical literature that reported on the Brussels tragedy and other unexplained cases of kidney failure were examined for connections to aristolochia. Isolated cases have now been identified in the UK, France, Spain, Germany and the US. Last month, the medical team that first identified the problems in Brussels published a new report. They declared aristolochia poisoning "a worldwide problem". Irish slimmers should be alert.
One source of the problem is that aristolochia species are used in some traditional Chinese medicines. Outbreaks of kidney failure in China and India have now been traced to these traditional remedies leading to the condition being called "Chinese herb nephropathy", where nephropathy refers to kidney damage.
Another condition called "Balkan endemic nephropathy" affects thousands of people in specific regions of Bulgaria, Bosnia, Croatia, Romania and Serbia. Its origin was unknown, until clinicians noticed similarities with Chinese herb nephropathy. Then it was noted that wheat grown in the regions affected, commonly contain seeds of a weed, aristolochia clematidis. Those seeds ended up in the region's bread and were slowly poisoning people. Efforts are now under way to eliminate those weeds from the region.
Current situation
Many countries banned the sale of aristolochia species after the Belgian tragedy. One such country was the Netherlands. A report last year, however, found that of 190 traditional Chinese herbal remedies bought in the Netherlands, 25 contained aristolochic acid and another 43 possibly had traces of the poison.
The regulatory bodies in the US, Canada and the UK did not ban aristolochia, but called for its removal by herbal manufacturers. A 2003 report found over 100 herbal remedies probably containing aristolochia available for sale on the internet.
Recommendations
Aristolochia is a reminder that some herbs are extremely toxic. Natural does not necessarily mean safe.
The path to healthy body weight can be long and challenging, with many bumps and potholes. Careful consideration and well-informed advice are needed to avoid the fads and dangers that lurk along the way. Herbal slimming pills will never replace the core necessities of any attempt to lose weight: reduce calorie input, increase exercise output and find help for the journey through a friend or support group.
Dónal O'Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing at DCU