Recently I wrote a column on hot dogs that are advertised as having no synthetic preservatives. The reference is to nitrites that are used to prevent botulism. I pointed out that these “natural” hot dogs actually use celery juice as a preservative because of its high nitrite content. The fact is that whether nitrite comes from a lab or a plant is irrelevant. In the column I also objected to a billboard funded by the Physicians Committee for Responsible Medicine that equated eating hot dogs to smoking cigarettes. My comments elicited a letter to the editor from Susan Levin, M.S., R.D., director of nutrition education at the Physicians Committee for Responsible Medicine. This organization identifies itself as a “Washington, D.C.-based nonprofit organization dedicated to promoting preventive medicine, especially better nutrition, and higher standards in research.” I disagree with that description. I consider PCRM to be a fanatical animal rights group with a clear cut agenda of promoting a vegan lifestyle and eliminating all animal experimentation. Her letter is reproduced below, followed by my response to Ms. Levin.
Susan Levin’s letter to the editor:
“As a dietitian with the non-profit organization that put up the Indianapolis billboard that writer Joe Schwarcz refers to, highlighting the link between hot dogs and colorectal cancer, I want to set the record straight about our public education efforts.
Contrary to Schwarcz's insinuations, our billboard is based on a recent landmark report from the American Institute for Cancer Research and the World Cancer Research Fund.
After reviewing all existing data on nutrition and cancer risk, including more than 58 published studies, nine teams of scientists from around the world concluded in 2007 that processed meats increase one's risk of colorectal cancer, on average, by 21 per cent for every 50 grams of processed meat consumed daily. That's about the size of a typical hot dog. Just this year, the same prestigious organizations updated that report - the most comprehensive ever conducted on colorectalcancer risk. Scientists concluded that 45 per cent of all colorectal-cancer cases could be prevented if we ate more plant foods and less meat and made other lifestyle changes. Based on these findings, the report suggests that people completely cut processed meats out of their diets.
More than 400 Canadians a week are diagnosed with colorectal cancer, according to the Colorectal Cancer Association of Canada. Avoiding hot dogs, bacon, pepperoni and other processed meats could help reduce that tragic toll.”
My response to Ms. Levin follows. (You’ll note that I make reference to Bastyr University, her alma mater. This is not exactly Harvard. Bastyr is a school of naturopathy that teaches homeopathy, reiki, and various other “alternative” modalities.)
“I would like to offer a few comments pertaining to your letter. First, let me mention that I have been following PCRM since its inception and am very familiar with its agenda and antics. I probably know more about the organization than you do, so please spare me arguments about it being science-based and a champion for public health. We both know what the actual agenda is.
Second, if you read any of my books, especially my “An Apple A Day,” or “Foods That Harm, Foods That Heal,” although I suspect they are not on the reading list at Bastyr University, you’ll know that I am very much an advocate of a plant based diet, but I see no problem with moderate meat consumption. I have no argument against a vegan diet, but I do not think it is necessary, and neither does the evidence suggest that it is. I have an issue with any kind of extremism, and PCRM is certainly an extremist organization. And I consider the billboard I referred to, the one that equates hot dogs to cigarettes not only to be extreme, but scientifically unsupportable.
I agree that there is sufficient evidence to suggest a link between cured meat consumption and colorectal cancer, although the association is weak, with an RR (relative risk) consistently less than 2. Indeed the most recent analysis, a review in the European Journal of Cancer Prevention, concludes that "currently available epidemiological evidence is not sufficient to support a clear and unequivocal independent positive association between processed meat consumption and colorectal cancer."
But let’s take the WCRF (World Cancer Research Fund) data, in spite of the weakness inherent in any such observational studies, and accept the 20% increase in risk with a hot dog a day. Since the colorectal cancer risk is about 7%, a 20% increase would mean roughly one extra case per one hundred people who eat a hot dog or its equivalent every day. And not many eat a hot dog every day. Anyway, I certainly do not push hot dogs, and as I clearly stated in my column, cured meats should be limited, but comparison to cigarettes is totally unjustified. The increase in cancer risk by smoking is 2000%! Alcohol is a greater risk in colorectal cancer than cured meats.
My main complaint against PCRM is that it masquerades as a just scientific body. Cherry-picking data, a common PCRM practice, does not mesh with the scientific method. Should a study come out demonstrating some benefit from consuming dairy products, or absolving meat of some accusation, would PCRM publish that on its website? We both know the answer to that question. That’s the difference between an operation like yours and my Office. We go where the data lead, we don’t lead the data. Having a preconceived agenda leads down a treacherous road. You might want to take a look in the closet of the organization that you are working for. You’ll find more than the occasional skeleton. Extremism in the pursuit of an agenda is almost always a vice, while moderation is a virtue. That is true even when the agenda has some valid points.”