Another Dubious Link Between Pesticides And Cancer
January 18, 1999
by Dennis T. Avery
CHURCHVILLE, Va.—A new Danish study reports that women with high levels of a pesticide named Dieldrin in their fatty tissues have a higher incidence of breast cancer than other women.
The study was published in the Dec. 5 issue of the British medical journal Lancet and was quickly turned into an alarmist story on the NBC "Nightly News."
The Dec. 3 segment by NBC science correspondent Robert Bazell featured as a guest Mary Wolff of the Mount Sinai Medical Research Center in New York. She claimed, "We're able to see that measured exposure to a pesticide 20 years earlier appears to be related to an elevation of cancer risk."
Yet NBC failed to inform its viewers of Wolff's dubious 1993 study "proving" women with higher levels of DDT in their tissues had a higher breast cancer risk. A more comprehensive study by the Kaiser Foundation Research Institute in 1994, which included more women with even higher levels of DDT in their fatty tissues, found no linkage.
AS BRIAN MACMAHON of the Harvard School of Public Health commented in the Journal of the National Cancer Institute, the conflicting studies were "another reminder of the caution with which the results of a single epidemiological study...should be regarded."
The world has been looking for a link between pesticides and cancer for 37 years, ever since a former high school biology teacher named Rachel Carson told us in her brilliantly flawed book "Silent Spring" that pesticides were causing cancer in humans.
However, billions of research dollars have failed to find a credible link between pesticides and human cancer. According to a National Research Council report, the conventionally grown food we eat occasionally contains traces of pesticides, but it is unlikely to pose an appreciable cancer risk.
AS THE DANISH study found a smoking cancer gun? Probably not. Dieldrin has been banned from farm use since 1974 and banned even for use in termite control since 1987. Organo-chlorine pesticides like Dieldrin and DDT were widely used in Asia, and breast cancer rates in Asia are much lower than those of America or Europe.
Bazell also interviewed breast cancer survivor Nancy Evans, who said, "I think we need to get the pesticides out of the nation's food supply."
Unfortunately, if her wish were granted, it would mean more cancer. The American Institute for Cancer Research says eating five fruits and vegetables per day prevents 20 percent of cancer incidence.
If we eliminate pesticides, our fruits and vegetables will cost more and suffer more damage from insects and diseases. A 1991 National Cancer Institute study found only 23 percent of adults eat five or more servings of fruits and vegetables a day.
HOW MANY MORE people would get cancer if the produce, instead of being relatively cheap and attractive, were instead expensive and worm-eaten?
Organic foods are hardly free of hazards. Data from the Centers for Disease Control show people who eat organic and "natural" foods are more than eight times as likely to be attacked by the virulent new strain of E. coli bacteria. Organic farmers rely on animal manure as their main source of fertilizer, and animal manure is the primary reservoir of this deadly bacterium.
The NBC story also warned that organo-chloride pesticides like Dieldrin might mimic human estrogen, disrupting our hormone systems, which could cause infertility and other health problems.
HOWEVER, the main evidence for this sort of endocrine disruption is a June 1996 Tulane University study. Four laboratories tried but failed to replicate the Tulane findings. In July 1997, the Tulane researchers retracted their study, admitting in a letter to Science magazine they had "not been able to replicate our initial results."
But don't expect the NBC "Nightly News" to tell you if the Danish study is found flawed and cast onto the scientific scrap heap. NBC's record indicates the network is more interested in frightening viewers than in giving them the full story on pesticides and cancer.
Dennis T. Avery is based in Churchville, VA, and is director of the Hudson Institute's Center for Global Food Issues.