Thursday, May 13, 2010

Cancer and Organic Food

In an op-ed piece called New Alarm Bells About Chemicals and Cancer, Nicholas D. Kristof, a columnist for The New York Times discusses the report released on Thursday by The President’s Cancer Panel. (Full text of The President’s Cancer Panel 2008-29009 report can be found here The report is based on research from 25 experts, and calls for increased regulation of chemicals and more action by individuals to cut the risk of cancer posed by environmental factors.

After the poorly argued debate held at Skirball Center of NYU between agricultural analyst Dennis Avery; farmer and freelance writer Blake Hurst,; former Food Standards Agency chairman John Krebs; Vogue food critic Jeffrey Steingarten; Consumer Unions director Urvashi Rangan; and former executive director of the board on agriculture of the National Academy of Sciences Charles Benbrook "Organic Food is Marketing Hype," I was very interested in reading a scientific support for organic food. I had assumed the President’s Cancer Panel would present the scientific evidence since one of the primary recommendations for individuals is to reduce their exposure to pesticides by choosing whenever possible food grown and raised without chemicals and washing conventionally grown products. So I downloaded the report.

Unfortunately, I was to be disappointed. The report states that efforts to identify, and quantify environmental exposures that raise cancer risk, including both single agents and combinations of exposures, have been compromised by a lack of effective measurement methods; inadequate computational models; and weak, flawed, or uncorroborated studies. Only a few hundred of the more than 80,000 chemicals in use in the United States have been fully tested for safety, but many of these chemicals have found their way into soil, air, water and many consumer products. Many believe there is cause for concern, but there is no easy way to test and determine. There is no proof in the report and it recommendations run counter to the principals of toxicology.

The science of toxicology is based on the principle that there is a relationship between a toxic reaction (the response) and the amount of poison received (the dose). An important assumption in this relationship is that there is almost always a dose below which no response occurs or can be measured. This assumption combined with the detection limits of the analytical work has hindered the serious investigation of low level environmental exposures. The President’s Cancer Panel states that response may be impacted by when the dose occurs, for example in utero or during childhood and there may be a cumulative impact. This is only supported by common sense, not scientific studies. The 2008-2009 report does a good job of identifying the paths of exposure for thousands of chemicals, and states: “At this time, we do not know how much environmental exposures influence cancer risk and related immune and endocrine dysfunction. Environmental contamination varies greatly by type and magnitude across the nation, and the lifetime effects of exposure to combinations of chemicals and other agents are largely unstudied. Similarly, the cancer impact of exposures during key “windows of vulnerability” such as the prenatal period, early life, and puberty are not well understood. …Environmental health, including cancer risk, has been largely excluded from overall national policy on protecting and improving the health of Americans.” I am left to make my purchasing and lifestyle decisions based on common sense, experience as an environmental engineer and beliefs, not on scientific evidence.

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