Jun 25, 2007
Ptaquiloside Redux
Almost ten years ago, I wrote a feature article on the cancer risk associated with the bracken toxins known as ptaquiloside for ChemWeb. The article was updated and mirrored on Paul May’s Molecule of the Month website at Bristol University, and quite bizarrely still draws a few readers to the Sciencebase site via my byline on the article. I suppose the reason it is still popular is that it makes it to page on in Google should you search for the word bracken.
Anyway, this article occasionally triggers some rather interesting correspondence with readers. Most recently, John Nayler emailed me to ask whether or not toxic chemicals from bracken might leach into groundwater beneath bracken-infested areas. I had to admit I did not know, but a paper published recently in the journal Chemosphere (2007, 67, 202-209) discusses the microbial degradation and impact of ptaquiloside on soil microbes themselves, which sheds some light on the potential impact of this carcinogenic toxin.
Another of Nayler’s concerns regards whether or not bracken is
not
simply an
unpleasant weedbracken is not simply an unpleasant weed with a cancer risk associated with eating the “fiddle heads” (a delicacy in Japan), but whether or not landowners, whose land is infested with bracken might be liable for public health lawsuits should those with a right to roam on their land be exposed to bracken spores. The risk may be small but that never stopped an ambulance-chasing lawyer in the past.
Cancer Research UK has a FAQ on the cancer potential of bracken. Despite isolated ptaquiloside coming up positive in carcinogenicity tests a decade ago, the latest research, according to Cancer UK is that there is no risk of cancer associated with eating bracken fiddlehead greens. So, what about those spores. Studies have shown bracken spores to cause cancer in mice, but those mice were given a lot of spores and to extrapolate to human cancer risk is (death)wishful thinking. A walk among the bracken is more likely to trigger a sneezing fit if the spores are high than anything else, and as CRUK points out, diet and smoking are far greater risk factors than bracken for cancer.
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David Nolan said,
October 2, 2007 at 2:57 pm
Funny that I should come across this article after Google searching Ptaquiloside. I am trying to learn more about the compound and the bracken associated with it. My niece has developed stomach cancer at 31. It has metastasized and she has just begun chemotherapy. I believe that it is genetic since there is a family history but I did not want to make an assumption. She tested negative for H. pylori and is a nonsmoker/drinker. We both grew up in a dairy region of mid-Michigan and ate plenty of local beef and deer and drank lots of milk. I see lots of info on Venezuela, New Zealand and Japan about their cattle and bracken connection but so far, nothing about bracken in the US. I am going to do some more searching around but I would appreciate any information on Ptaquiloside, bracken and stomach cancer here in the States, specifically the Midwest, that anyone might have. Thanks for the update on the article and the research.
David Bradley said,
October 2, 2007 at 3:21 pm
David, so sorry to hear about your niece. I take it you saw my earlier article, which is rather out of date now - http://www.chm.bris.ac.uk/motm/ptq/ptqh.htm
I don’t have any additional information on the connection between bracken, ptaquiloside and cancer, but the latest research papers that mention both ptaquiloside and cancer can be found here
db
Kiyoyuki Yamada said,
November 15, 2007 at 9:07 am
Via email:
Dr. David Bradley, Science Writer
Nearly ten years ago, you wrote an article on bracken toxin ptaquiloside, and at that time you were in communication with me by e-mail about this problem. During the past several years, there appeared reports as to veterinary medicine and ecology on ptaquiloside. Recently (August 2007) we published a review article including the above mentioned results: Nat. Prod. Rep., 2007, 24, 798-813. I am informing you of the appearance of our review, which may be helpful for your work.
Best wishes,
Kiyoyuki Yamada, Nagoya University