Co-authored by Henry I. Miller
"Many of the 'healthiest foods' we eat may not be as healthy as we think" was the lede of a recent Channel 11 news story out of Pittsburgh. It was based on the Environmental Working Group's just released 2013 "Dirty Dozen" report on pesticide residues on produce, which is trotted out every year by the NGO. These misleading pseudo-analyses frighten consumers and actually discourage them from buying healthy fruits and vegetables.
The news story continues, "Pesticides are meant to kill pests, but the residue isn't meant to be eaten, and it could be harmful to your health." Actually, the only truth in that statement is that "pesticides are meant to kill pests." The rest of it is false, according to the United States Department of Agriculture, which unambiguously states that "U.S. food does not pose a safety concern based upon pesticide residues."
The Channel 11 news story is typical of the insidious reporting that results from the EWG list. (We refuse to call it a study.) In fact, such news stories are the very reason EWG releases the report each year -- to generate coverage that inhibits people from eating produce that isn't organic. Unless of course, the produce is on the relatively new list, "The Clean Fifteen," which contain the lowest level of pesticides, according to EWG.
EWG tries to make their "Shopper's Guide" appear legitimate by relying on samples taken and tested by the USDA and FDA. According to an article in The Huffington Post, "The EWG looked at six measures of pesticide contamination, gave each measurement a score from one to 100 and compiled the results.
But what was their methodology, if you could call it that? "In government tests analyzed by the Environmental Working Group, detectable pesticide residues were found on 67 percent of food samples after they had been washed or peeled. We found striking differences between the number of pesticides and amount of residues detected on Dirty Dozen Plus™ and Clean Fifteen™ foods." (Yes, they've trademarked the names.)
In essence their approach is (in our words), "Some produce had more residue and some had less. We put the ones with most on a list and called them 'dirty' and the ones with least and made a different list and called them 'clean.'"
This type of gimmick should result in an "F" in a 4th grade science fair, not adoring coverage in major media.
Federal agencies agree that pesticide residues, even from those topping the dirty dozen list, are not in the least harmful at the levels they occur. If you think the government agencies are in cahoots with "big agriculture" and you shouldn't believe them, consider that even the first lady in her "Let's Move" campaign advocates consumption of more fruits and vegetables, and hasn't insisted they be organic.
Yet the Dirty Dozen is resurrected each year, and each time -- like Charlie Brown fooled by Lucy pulling away the football at the last second -- the media buy into it.
The EWG's crying "Wolf!" about this non-issue began in 1995, when, backed by such eminent scientific entities as the Barbra Streisand Foundation (we are not making this up), the organization published its first "Dirty Dozen" -- a list of produce that supposedly contained the highest levels of chemical pesticides. The annual list, which this year includes some of the most nutritious and delicious components of our diet - such as apples, tomatoes, potatoes, cucumbers, peaches, strawberries and grapes - is accompanied by an admonition to limit consumption of those kinds of fresh produce and to avoid conventionally grown varieties in favor of the more costly organic options.
However, a study published in 2011 in the Journal of Toxicology by Dr. Carl Winter and Josh Katz of UC-Davis showed that 90% of the cases "exposed" in EWG's 2010 list involved levels of pesticides 1,000 times lower than the chronic reference dose (the level of daily exposure likely to be without an appreciable risk of deleterious effects during a lifetime of chronic exposure). They concluded, "The potential consumer risks from exposure to the most frequently detected pesticides on the 'Dirty Dozen' list of foods are negligible and cast doubts as to how consumers avoiding conventional forms of such produce items are improving their health status."
Moreover, as Dr. Winter wrote in a separate commentary for the International Food Information Council, "Three-quarters of the pesticide/commodity combinations [identified by the EWG] showed consumer exposure estimates more than one million times lower than doses given to laboratory animals continuously over their entire lifetimes that do not show adverse effects."
These are critical observations because, as has been known from antiquity, "the dose makes the poison"; in other words, a substance is toxic only if the dose and length of exposure are sufficient to cause damage - a fundamental principle of toxicology seemingly alien to the EWG (which relies heavily on the percentage of samples with pesticide, rather than on potentially toxic levels). Moreover, the EWG's main recommendation - to "buy organic" - is belied by the fact that many organically grown versions of the "dirty" products are also "contaminated." As Winter and Katz pointed out, the same data from the Department of Agriculture Pesticide Data Program used by the EWG indicate that there are pesticide residues in nearly a quarter of organic food samples.
But there's an even more persuasive point to be made about our consumption of pesticides. The vast majority of pesticidal substances that we consume occur in our diets "naturally," and they are present in organic foods as well as conventional ones. In a landmark research article published in the Proceedings of the National Academy of Sciences, University of California, Berkeley, biochemist Bruce Ames and his colleagues found that "99.99 percent (by weight) of the pesticides in the American diet are chemicals that plants produce to defend themselves. Only 52 natural pesticides have been tested in high-dose animal cancer tests, and about half (27) are rodent carcinogens; these 27 are shown to be present in many common foods."
The bottom line of Ames' experiments: "Natural and synthetic chemicals are equally likely to be positive in animal cancer tests. We also conclude that at the low doses of most human exposures the comparative hazards of synthetic pesticide residues are insignificant." In other words, consumers who buy overpriced organic foods in order to avoid pesticide exposure are focusing their attention on 0.01 percent of the pesticides that they consume.
The "Dirty Dozen" list is always a headline grabber for EWG, so it is no wonder that the media-hungry activist group keeps updating the same worthless analysis each year. The report informs -- or more aptly, misinforms -- the public conversation about the alleged dangers of pesticides on food. EWG cleverly publishes the report in the spring, just as Americans are getting excited about the prospect of summer produce.
The media have failed dismally to do their homework. Reporters consistently fail to ask pertinent questions about dose, exposure, likelihood of actual harm or compliance with federal regulations. Had they done so, they would have discovered that the pesticide tolerances in food established by the EPA are extraordinarily conservative -- that is, highly risk averse -- and that even these stringent limits are exceeded less than one percent of the time. But reporters and editors regurgitate the same old story, touting the Dirty Dozen's supposed dangers while ignoring the science that belies the warnings
Although the minuscule amounts of synthetic pesticides in our foods pose negligible health risks, some activists actually advise consumers not to eat fruits and vegetables at all if they can't afford organic varieties -- in spite of decades of evidence that those who eat the most conventionally grown fruits and vegetables have half the cancer rates for practically every type of cancer and live longer than those who eat less.
We will never convince the intransigent ideologues of the error of their ways, but the media can -- and must -- do better at presenting accurate and complete information.
Jeff Stier is a senior fellow at the National Center for Public Policy Research and directs its Risk Analysis Division. Henry I. Miller, a physician and molecular biologist, is the Robert Wesson Fellow in Scientific Philosophy and Public Policy at the Hoover Institution. He was the founding director of the Office of Biotechnology at the FDA.