Ingesting birthwort, Aristolochia clematitis, has been linked to kidney disease and upper urinary tract cancer, according to research published in the Proceedings of the National Academy of Sciences.
This is just one example of why it’s not a good idea to blindly take herbal preparations. We just don’t know enough about all the chemicals inside the multitude of plants that are used in herbal remedies.
In the reported study 83% — a whopping majority — of the people with upper urinary tract cancer were found to have changes in their kidney DNA related to a toxin from birthwort and that are known to lead to cancer.
The researchers concluded that a primary component in birthwort, called aristolochic acid, is responsible for damage to the urinary tract and kidneys. This is one nasty chemical because it damages DNA. Our bodies can correct some DNA damage as we grow and make new cells, but the damage done by consuming birthwort accumulates and eventually spells disaster.
Unfortunately, this research is only highlighting a known problem. The U.S. FDA issued a warning over ten years ago about the dangers of ingesting products that contain aristolochic acid. The International Agency for Research on Cancer has listed herbal preparations that contain this toxin as a Group 1 carcinogen since 2006.
Birthwort and many other herbal remedies are used extensively all over the world for medicinal purposes. High incidences of upper urinary tract cancer in Taiwan, China and the Balkans have been attributed to the ingestion of birthwort.
Birthwort is a plant native to Europe, but many of its relatives shouldn’t be ingested for the same reason. Plants native to the U.S. that may contain the toxic aristolochic acid include Dutchman’s pipe, wild ginger and snakeroots of the genus Asarum.