Some people are no doubt relieved by the news last week from the editorial in the American Cancer Society Journal, Cancer, reacting to the findings of the "Ad Hoc Panel on Pesticides and Cancer" convened by the National Cancer Istitute of Canada, trivializing the cancer risk posed by pesticides in the diet. The message is clever and reassuring, but it is also misleading, unscientific and contrary to what the general public needs to understand to promote health through personal actions and public policies.
Most people familiar with the relationship of diet and health, and basic information on pesticide toxicity and epidemiology, would agree with the editorial that it would be crazy and damaging for Americans to stop eating fruits and vegetables in an effort to avoid pesticide residues.
Most experts also agree with the ACS conclusion that pesticide residues in the diet pose very modest risk to the average person. By "average" the editorial no doubt means a grown person, in reasonably good health, that eats a reasonably average diet, and that has no genetic, health or environmental predisposition or unusual risk factors that heighten vulnerability to disease. The editorial's definition of "average" covers about two-thirds of the population.
For the other third, to varying degrees from modest to significantly, pesticide residues in the diet raise the risks at multiple stages in life of various health problems. Rarely does exposure to one or several pesticides directly and unilaterally "cause cancer" in a human being. Even tobacco does not do that; if it did closer to 100% of people who smoke would get cancer. The only cancer source which seems to be almost perfectly predictable is radiation; i.e., the dose-disease incidence relationship is close to linear.
The weight of scientific evidence is clear that if people were not exposed to pesticides through the diet, water, in their homes and buildings, the incidence and severity of several cancers, several birth defects, and a host of neurological problems would be lower and/or lessened across the U.S. population. "Average" Americans will continue to be spared the reproductive problems, disease and other problems for which pesticide exposure is one of many risk factors. But for some "unaverage" people their loses and suffering will be none the less real, as are the costs to families and society. In many cases, indeed perhaps most, people's exposure to pesticides are easily avoided, which is why the public health debate over pesticides will not end because of this latest report from the ACS.
Prudent public health policy has to increasingly focus on health promotion and prevention of exposure to factors increasing risk of ill-helath. Clearly, exposure to chemicals and other damaging microbiological, bacteria, and mineral substances contribute to health problems in America. Does this mean lifestyle factors and changes should be de-emphasized, like eating more fruits and vegetables? NO!!
It means that progress in health promotion requires a multifacteted, life-long, cradle-to-grave persistence. At the policy level, it requires the courage to act decisively when information and science shows reason to do so, despite the unavoidable uncertainties in establishing iron-clad cause and effect relationships. At the personal level it requires willingness to learn about good health and how to attain it, and the self-discipline to avoid things we all know, at some level, are probably not good for us, our families, or kids.
The scientific and public health community has yet to find its voice in convincing people of the need for such a multifacted, all-angles approach to promoting health and preventing ill-health. Reports that play off one cause of health, or ill-health against another send a message that reflects sloppy thinking and bad science, and which moreover instills in people false hope that good health will be theirs if they avoid just those few things that are most surely risky, according to the experts.
11/15/97