Thursday, May 8, 2008


I was reading through Robert Weinberg's the Biology of Cancer tonight when I came across something a bit surprising:

"Do Man-made xenobiotic mutagens ever cause cancer?
The heated debate about the man-made carcinogens in the air and food chain-specifically the products of synthetic organic chemistry- has continued unabated for half a century. Much of this debate has been focused on trace contaminants in the food chain, notably pesticides, and on the possibility that they become metabolically activated into potent mutagens and thus carcinogens once they have entered our bodies. Bruce Ames, of the Ames test, has estimated that, by eating naturally occurring foodstuffs humans are exposed on a daily basis to between 5000 and 10,000 distinct natural chemical compounds and their metabolic breakdown components. Included among these are about 2000 miligrams (mg) of burnt material (the products of cooking various foodstuffs at high temperatures) and 1500 mg of naturally occuring pesticides (used by plants to protect themselves against insect predators). In contrast, the average daily exposure to all synthetic pesticide residues contaminating the food chain is about 0.1 mg. About half of the naturally occurring plant pesticides are found to be carcinogenic when tested in laboratory rodents using standard testing protocols. Since (1) synthetic pesticides are as likely to register as carcinogens in rodent tests as are randomly chosen compounds of natural (i.e., plant) origin; since (2) plant-derived compounds, such as those in the vegetables we eat, are generally presumed to be save; and since(3) concentrations of synthetic pollutants in the food chain are many orders of magnitude below the natural (and equivalently carcinogenic) plant compounds, this raises the question of whether synthetic pesticides are ever responsible for significant numbers of human cancers is Western populations. It may be that the role of synthetic chemical species in creating human cancers (with the exception of tobacco combustion products and the products of cooking food at high temperature) is limited to those chemicals that are encountered repeatedly and at very high concentrations in certain occupations, such as agriculture workers who handle large quantities of pesticides routinely"

Sounds to me like it probably isn't worth changing your behavior to prevent cancer beyond not smoking, and some preventative testing and vaccines.

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