Health Risk of Eating Pesticide-Treated Fruits and Vegetables

San Antonio Express News
Sunday, December 18, 2005

By Dr. Jerry Parsons

With the festive (eating everything in sight!) holiday season upon us, I thought I would take this opportunity to put your mind to rest about the safety of the food you will be enjoying. I read an article which indicates that “an overwhelming number of Texans, 87 percent, think the use of pesticides on fruits and vegetables presents a health risk, but less than one quarter regularly eat organically grown produce.” This information is from a Texas poll conducted quarterly for Harte Hanks Communications Inc. by the Public Policy Resources Laboratory at Texas A&M University. Only 9 percent of those polled think eating fruits and vegetables treated with pesticides creates no health risk while 4 percent are uncertain. The intelligent, informed persons of our society are represented by this small 13 percent of people who are smart enough and educated enough not to be stampeded into hysteria by chemicals are killing scare-mongers. Possibly a bit of truth thrust into the center of this sea of confusion and chemical mania will support the 13 percent rational group and convert some of the confused 87 percent.

In the 1970’s, Dr. Bruce Ames, chairman of the department of biochemistry at the University of California, Berkeley, developed a method that uses bacteria instead of animals to determine if a chemical causes mutations or potentially carcinogenic substances. His method became known as the “Ames Test” and was used extensively by the environmental movement for many years.

Dr. Ames indicates that more recent use of the Ames Test resulted in a change in his own thinking. The test uncovered mutagenic or potentially carcinogenic substances “everywhere” he said in a “20/20” interview, citing such examples of coffee, fried hamburgers and bread crusts. The more the Ames Test revealed, especially in conjunction with parts per billion chemical analysis, the more evident it became that practically all foods have carcinogens in them.

Furthermore, he finds no scientific evidence that most synthetic chemicals, such as pesticides, are more carcinogenic than what occur as part of the background level in nature. He told John Stossel of 20/20, “There’s a whole movement of people who are committed to the idea that man made chemicals are causing a lot of cancer. It’s just that I don’t think there’s much science behind it. In fact, the science is all going the other way.”

Dr. Ames went on to say that pesticide free or “organic” produce is not necessarily better than that grown with pesticides “because the amount of pesticide residues, manmade pesticide residues, people are eating is absolutely trivial in very, very tiny amounts. You get more carcinogens in a cup of coffee than in all the pesticide residues you eat in a day.”

He made his comparison on the basis of a ranking system that he and his colleagues developed, and that was the subject of an article they published last year in Science. The team ranked various substances- both natural and man made for their potential to cause human cancer based on a combination of carcinogenicity and typical daily human exposures to the substances. As noted by John Stossel, in his interviews, pesticides, such as DDT and EDB, came out much lower (in the ranking for cancer-causing potential) than herb tea and peanut butter. Alcohol was higher on the list. And so were mushrooms.

Ames explained that “vegetables are good food” but have developed “nature’s pesticides” of their own in order to try to ward off attackers, such as insects, fungal and bacterial diseases. Many naturally occurring substances are more carcinogenic than many synthetic chemicals, “Dr. Ames emphasized.

At this point, you may begin to believe that eating any fresh fruit or vegetable, whether “organically” grown or not, would cause you cancer, but that is, of course, not the case. According to the American Council on Science and Health (ACSH), a national consumer education association, the best way to minimize the potential hazard is to eat a wide variety of foods. This would lessen the chance that any single carcinogen would be eaten in quantities that would overwhelm the body’s natural ability to handle low amounts of hazardous substances with relative safety.

Mr. Stossel, in developing the “20/20” story, contacted the American Cancer Society and American Medical Association for their views on Dr. Ames and his work and found that they largely agree with him.

So it seems that those who want carcinogen free food will soon become extinct. The Texas A&M Poll indicates that young and middle aged Texans appear to be the most concerned about using pesticides on fruit and vegetable crops. Eighty nine percent of those 18 to 29 years old and 92 percent of those 30 to 44 believe using pesticides may create a health risk. Of those ages 45 to 61, 83 percent believe there is some risk, and of those older than 62, 79 percent say there’s a risk. I guess the old saying, “older is wiser,” is also applicable when considering the need for the common sense use of pesticides by commercial agricultural producers in order to efficiently and effectively feed the peoples of the world. Possibly some of the older Texans remember what it feels like to be hungry and never want to enjoy the experience again!

Dr. Jerry Parsons is a Professor for Texas A&M University and a Texas Cooperative Extension Horticulturist for over 30 years in South Central Texas. For more information on this or other horticulture topics, go to and our County Extension website at

Comments are closed.