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New Scientific Report Shoots Down EWG’s ‘Dirty Dozen’ List As Misleading And An Impediment To Public Health

The amount of “research” that is publicized today is enormous, and much of it is more designed for political rather than scientific purposes.

Just recently, we asked how Yale could tolerate propaganda being dressed up as research in a piece we titled Flawed Yale Study On Junk Food Promotes Policy Without Evidence.

Earlier we analyzed the claims by the Center for Science in the Public Interest that it had identified particularly risky foods in a piece we titled, An Opportunity Missed: ‘Ten Riskiest Foods’ List Highly Deceptive, Worse Than Useless to Consumers — CSPI’s Quest For The Headlines Means America Misses Out On a Rational Discussion About Risk.

The Environmental Working Group (EWG) has been publishing a list of 12 produce items that one should always buy the organic version of, rather than a less expensive conventionally grown item. That “Dirty Dozen” list of produce items has been much publicized by the media. The argument goes like this:

• They assert — without providing evidence — that eating exclusively USDA-certified organic produce will result in better health.

• Then they acknowledge that doing this could be a financial burden on some families.

• So they recommend always buying organic on these “Dirty Dozen” items that are the produce items most likely to cause a problem.

It is so self-evidently a problematic recommendation that one doesn’t have to be a scientist to see its flaws.

In fact, four long years ago when we heard Joy Bauer on NBC’s Today Show pushing the “Dirty Dozen,” this led us to write a column in Pundit sister publication, PRODUCE BUSINESS. Here is an excerpt:

The recent appearance on NBC’s Today show of nutritionist Joy Bauer telling viewers which organic items to buy and which conventional items not to buy because of relatively high pesticide levels illustrates part of a cultural penchant for saying things for which there is no evidence.

Ms. Bauer told viewers it pained her “as a nutritionist” to advise it, but consumers who couldn’t or didn’t get organically grown potatoes should peel potatoes before eating them. This was fascinating because the reason this advice was difficult to give “as a nutritionist” was that she was acknowledging the substantial, valuable nutrients a consumer would lose by peeling the skin. Yet Ms. Bauer was asserting the danger of pesticide residue in the potato was sufficiently large to outweigh any benefit derived from the skin.

But she doesn’t know that. Nobody knows because there has never been a peer-reviewed, randomized, double-blind, lifetime-length, human study on the issue. As she revealed her list of the “dirty dozen” produce items one should buy organically grown versions of, this representative of the science of nutrition said pesticide residue on these items “can’t be good for us.”

Real scientists, however, don’t talk that way. “Can’t be good for us” is a surmise based on nothing. We know it is based on nothing because if Ms. Bauer had evidence some particular level of pesticide wasn’t good for us, she would, presumably, tell the relevant authorities and they would change the allowed level. But that would require her to give more than an emotive grunt, to actually have a methodology, to actually have done studies, to actually know something instead of jabbering on TV to sell diet books and her nutrition services company.

Life is a series of trade-offs. My brother had heard X-rays might cause cancer so when he went to the dentist, he declined to get X-rays. One day, severe pain in a tooth required an immediate implant. When my brother asked the dentist how such a severe thing could come out of nowhere, the dentist pointed out that with X-rays, they might have been able to deal with the problem when it was small and avoid the implant.

My brother was not wrong about X-rays. Scientists universally acknowledge X-rays are dangerous; that is why they give you lead aprons, don’t let pregnant women in the room, etc. My brother, smart though he is, was not weighing the relative costs and benefits of getting regular dental X-rays versus the risks of not getting them. Maybe the acute risk of an implant procedure outweighs the risk of increased cancer. Or maybe you get cancer from having foreign substances such as implants in your body.

But my brother is allowed to make these trade-offs and judgments for himself. The reason Joy Bauer is a menace to society and a threat to public health is that she assumes the mantle of a nutritionist and then purports to tell millions of viewers what to do. This has almost nothing to do with the relative merits of buying organics. Organic consumption is booming, but key purchasing motivators are increasingly related to issues of environmental sustainability, not to health claims, for which there is just no evidence.

If an individual wants to eat organically grown fresh produce in the pursuit of better health, more power to him. There are many things in life we do not have definitive information about, but “you pay your money and you take your chances.”

If the issue were simply a penchant for saying things without scientific support, one would expect the falsehoods to break equally on all sides of the arguments. But the chatter breaks decidedly to the politically correct side instead of the science-based side.

The flaws in this “Dirty Dozen” thesis are obvious:

1) There is no evidence that eating only organic fruits and vegetables makes any difference in human health. So the premise on which the whole thing rests simply dissolves.

2) Even if one posited that to be true, there is no evidence that eating only organic versions of these 12 items would have any impact on human health.

3) The ranking of the “Dirty Dozen” makes no sense because it is based on an assumption that every pesticide is precisely equal to every other pesticide in its effects. There is no attempt made to study the risk posed by any particular pesticide. It is like ranking light beer and hard whiskey each with a check off as an alcoholic beverage.

4) Without any testing or evidence, the assumption is made that the chemicals used on or naturally produced in produce grown organically poses less risk to humans than the synthetic pesticides used in conventional agriculture. Organic agriculture uses substances such as copper, and the plants may produce natural pesticides as they are stressed. The “Dirty Dozen” just assumes that organic will enhance human health.

5) Toxicologists often use the phrase: “The dose makes the poison.” Obviously everyone knows that pesticides, which are designed to kill bugs, can be dangerous. The “Dirty Dozen” assumes, without evidence, that the residues on food are significant enough to harm human health.

6) There is no attempt at cost/benefit analysis. If people get scared and won’t buy conventional items but find organic too expensive or unavailable or unappealing, then they eat Twinkies. Is this a net gain for their health? Without quantification of the claims underlying the “Dirty Dozen,” nobody can possibly know.

Although peer review is no panacea, it is notable that these claims saying health is enhanced by eating organic versions of these dozen produce items have never been subject to peer review.

We are hardly the only one to have noticed the frivolous nature of these claims. Jeff Gillman, an Associate Professor in the Department of Horticultural Science at the University of Minnesota and a prolific author and one with an inclination toward organics, had this to say about the matter:

Dirty Dozen?

Nobody in their right mind considers pesticides safe. They are, after all, poisons which we have created to kill things, be those things plants, insects, fungi, rats, or whatever. The idea that we could have foods with no pesticides on them is attractive. Now I’ve got to admit that, as a general rule, I don’t think that the levels at which most pesticides are found on foods is concerning. Our methods of detecting poisons are just too sensitive today and so we end up saying that a poison is “present” on a tomato or whatever even if it’s there at a harmless parts-per-trillion level. Still, I won’t deny that I’d prefer it if there were no synthetic pesticides on any food.

A couple of days ago, a report came out from CNN about the “dirty-dozen.” This is a list of the twelve fruits and vegetables which are most likely to have detectible levels of synthetic pesticide residues. Along with this list there is a suggestion that, when purchasing these fruits and veggies, you should select those that are organically produced whenever possible.

I don’t have a problem with this list being reported. In fact, I think it’s a good idea to give people all of the information that we can about pesticides. While I, personally, am not particularly afraid of conventionally produced fruits and veggies because of the synthetic chemicals which they may contain, I appreciate the fact that others might be. I do, however, have a major problem with the idea that organically produced fruits and veggies are necessarily safer than those produced with synthetics.

You see, organically produced food is not tested for residues of potentially damaging organic pesticides, and those same foods that are slathered by synthetic pesticides in non-organic growing systems are typically slathered by organic pesticides in organic systems, particularly if you’re dealing with foods produced using what has become known as “industrial organic production,” which fill most of our large grocery stores with USDA Certified Organic Produce nowadays.

These organic pesticides may be present at higher concentrations than synthetic pesticides and may have similar effects on humans, and even worse effects on the environment than synthetics (though it depends on the exact pesticides used and how often they are used of course).

The myth that organic foods don’t have pesticides used on them is one that really needs to die. No farmer, organic or non-organic, wants to use pesticides, and sometimes they can get away without using them. Certain crops are rarely sprayed regardless of whether they’re produced organically or not. Pesticides cost money and are dangerous, but when faced with the potential loss of a crop, producers will do what they need to do to avoid losing their crop, and if that means applying pesticides then so be it.

Organic farmers may choose to use different pesticides, and they might wait longer before they spray (although often they spray sooner because the relative efficacy of their sprays are inferior to synthetic sprays) but let’s not say that organically produced foods are free of pesticide reside. Just because we’re not testing for it doesn’t mean it isn’t there.

Alas, despite such sensible voices, the media is just a sucker for these types of lists and so every year the “Dirty Dozen” or the “Ten Riskiest Foods” get lots of headlines and lots of air play, regardless of their lack of scientific merit.

Into this wilderness of ignorance wades the Alliance for Food and Farming, a small but stalwart band dedicated to preventing the defamation of the farmer. It takes on the yeoman’s work of bringing together experts to look at widely distributed news stories to ascertain their veracity.

Recently, we ran a piece, Analysis of CDC Database On Foodbourne Illness: Most Outbreaks Not Associated With Produce; Foodservice/At-Home Mishandling Is Chief Cause Of Produce-Related Outbreaks that discussed how the Alliance had undertaken to study the degree to which food safety problems were caused at farm level.

Now the Alliance has undertaken to support a study on this whole “Dirty Dozen” concept:


An expert panel of toxicologists, risk assessors and nutritionists has concluded that a report concerning pesticide residues and produce, known as the Dirty Dozen List, is misleading to consumers, is an impediment to public health because it discourages consumption of fresh fruits and vegetables and that there is no scientific evidence that pesticide levels found on produce pose any risk. Based upon these findings, there is no reason why a consumer should use this list to guide their purchasing decisions for fruits and vegetables.

More information behind these findings will be revealed July 15, when an independent report commissioned by the Alliance for Food and Farming will be made available to the media and the public. This report and corresponding efforts to provide consumers with better information regarding pesticide residues on produce was the subject of a free webinar held today for produce industry members.

“The Alliance for Food and Farming exists to provide farmers with a voice to communicate their commitment to food safety and care for the land,” said Matt McInerney, Executive Vice President for Western Growers and current chairman of the Alliance for Food and Farming. “Findings from this new report and the outreach tools surrounding its release will go a long way in helping farmers demonstrate they produce the safest food in the world and that the real danger to public health is that people are not eating enough fruits and vegetables.”

Along with the release of the report, the Alliance for Food and Farming will launch a new website devoted solely to the issue of pesticide residues on fresh produce and in assuring consumers of the safety of these healthful products. These items will also be the subject of a media webinar where reporters will be presented with findings from the independent expert panel review.

Participating in today’s industry webinar is Dr. Rick Reiss, of Exponent, Inc., who was the facilitator of the Alliance for Food and Farming’s Expert Panel Report. Dr. Reiss is an experienced environmental health scientist with expertise in risk assessment. He is currently President of the Society for Risk Analysis. Dr. Reiss and one of the report’s expert panel members, Dr. Carl Keene, Professor of Nutrition and Internal Medicine at University of California, Davis, will be on hand to present their findings to reporters during the July 15 press conference.

In addition, the Alliance for Food and Farming has turned to Elizabeth Pivonka, President and CEO, of the Produce for Better Health Foundation, to explain to reporters the challenges her organization faces in its work to increase consumption of fresh fruits and vegetables — a difficult task without obstacles such as those promoted in the Dirty Dozen report.

“Today’s webinar, the July 15 report release and launch of the new website are just the beginnings of a renewed effort to help farmers tell the story of the care they take in growing a safe, healthy product,” said Mark Murai, President of the California Strawberry Commission and Vice Chairman of the Alliance for Food and Farming Management Board. “The website and the information we present will become a great resource for the media, consumers, retailers and the entire produce industry. “

Murai explained that the Alliance for Food and Farming is a non-profit organization which operates on voluntary contributions. Its membership includes approximately 50 agriculture associations, commodity groups and individual grower/shippers who represent farms of all sizes and includes conventional as well as organic farmers. He noted that all funding for this effort has come from farmers or groups representing farmers.

Bob Whitaker, Chief Science and Technology Officer for the Produce Marketing Association, expressed his organization’s support for the efforts of the Alliance for Food and Farming to help provide consumers with facts and information on this important issue. PMA is a member of the Alliance for Food and Farming and provided funding for the development of the new website.

We wanted to understand better what this report is all about, so we asked Pundit Investigator and Special Projects Editor Mira Slott to find out more. Mira first contacted Dr. Carl Keen, MARS Chair in Developmental Nutrition, Professor of Nutrition & Internal Medicine, and a Nutritionist in the Agricultural Experiment Station at University of California, Davis.

Q: The “Dirty Dozen” starts with the premise that organic is healthier than conventional. Isn’t that a big leap? Is there any evidence that supports this?

A: You really have hit a major point. Effectively we need to address two different themes. We must start with the premise that organic is healthier than conventional. And yes, it is a big leap.

There is no data to show any additional health benefits. In fact, there have been two very large studies done on this recently, where data showed organically grown produce did not produce a superior health profile than conventional. One study, Winter and Davis in 2006, concluded it couldn’t find any real differences in the nutritional value of organic and conventionally grown.

And the same conclusion was reached in the Dangour study in 2009. No one has really demonstrated differences in health benefits, which doesn’t necessarily mean there aren’t any. Certainly you could create a scenario where food grown with pesticides might not be healthy, but that would be exceeding what anyone would sell in the marketplace.

What confuses people is that if asked whether there are any differences in nutrient composition of foods grown organically and those grown conventionally, the answer is you may see differences.

If insects are munching away at a plant and stressing that plant, one response is a higher concentration of defensive compounds [that the plant produces]. In that way, one can show chemical differences. It’s the next leap that’s missing. There are no studies showing the difference in polyphenolics translates into a measurable improved health profile. I’m not denying it’s possible, but I take the show-the-data approach.

Is there any scientific logic that it’s healthier, assuming there is something in the food inherently different, other than the absence of a toxin. The EWG never really makes the distinction. It is one thing to say there is a change in composition and another to conclude that somehow that profile is better.

A completely different argument is that organics are less toxic. Less toxic agents are hard to define, because you need to consider the increased risk for contaminants. It’s like saying that using non-pasteurized dairy product is safer, when there is an increased risk of contamination. The typical response is that it’s safer if you’re careful and you do it right, but that doesn’t change the fact that there’s still an increased risk. What frustrates me is that these groups don’t get into risk-benefit analysis.

Q: How valid are tests for determining pesticide residue levels? Perhaps more important, is the difference in pesticide residue levels significant enough that people should be concerned?

A: We’ve become absolutely smashing when doing analytics. We can measure molecules, where there is no risk associated with it. The trouble now is with people making assumptions that if this amount is bad, any amount is bad. People have deficits of certain vitamins in their diets, which could result in serious health problems, although consuming too much represents a risk. It’s fallacious to say any amount is bad.

Trying to prove a negative is kind of worrisome; there are people who will argue, why take a chance on consuming any pesticides? How do you know if you did a bigger study it would show a particular environmental agent caused harm? Essentially, you can do that forever. We can’t let fear of the unknown paralyze us.

Assume you have pesticide residues, if you peel a banana the more important number is what amount is in the food when consumed. Even if you ask if one item has more pesticide residues than another, it’s not necessarily a relevant question if the amount of residue is not significant enough to cause risk.

The EWG doesn’t have perspective. I want to throw my hands up when the underpinning issue is not addressed. Yes, if I peel the item, I’m exposed to less residue, just like if I wash the item I’m exposed to less residue, but what’s the difference if it’s not enough to matter either way.

Q: Even if there are studies done that show higher residue levels, how does that translate to human health, whether eating these 12 items as organic will do anything good, or in fact create an impediment to consumers who might otherwise eat the conventional produce?

A: I don’t think good comprehensive studies have been done to prove that it scares consumers away. But what we do know is that increased consumption of fruits and vegetables lowers risks of diseases. No matter how we look at it, at best, fruits and vegetables have been hovering around a few servings a day for 20 years, and produce consumption may have even declined recently, and this is well recognized as a public health issue. If I was a consumer and didn’t have a lot of information but heard these plants have a lot of problems, even if I knew there was a list of 12, I wouldn’t memorize that list, so I’d just be panicked about all of them.

People just hear a message that something is bad. I find the “Dirty Dozen” terminology troublesome; the implication not really stated is that the government is not doing its job. We would be outraged if all these foods in the grocery store were unsafe. Once that idea gets seeded, it’s very scary.

Is there really harm in propagating this un-scientific information? Think of vaccines. Tens of thousands of parents stopped immunizing their kids because of a very questionable report now taken back by the journal, with the author quietly retreating. A lot of damage can happen with erroneous reports. People are extremely well intentioned, but consumers often over respond and don’t weigh unintended consequences.

In theory, the “Dirty Dozen” list hits lower economic groups the greatest because organic usually is more expensive. Rules around what is organic are complicated, oftentimes arcane. Just because it’s natural doesn’t necessarily imply it is better or safer. Some of the deadliest compounds are natural compounds. That’s not the bright light; that’s not the right debate.

The EPA is constantly evaluating the efficacy of pesticides, and has taken some off the market when there are scientific concerns. There are differences in pesticides and herbicides. If you have a pesticide with emerging scientific evidence to present risk, then focus on it but you still need to look at the amount of exposure.

In my mind, there needs to be rational decision-making in place. I’m sure the folks behind these lists are well intentioned, but they are unable to present reasonable data and evidence of why there is a risk factor.

I can show some people will die with seat belts on, but we know that the overall effect of wearing seat belts saves thousands of lives. We have no data that pesticides at these levels have shown any damage. Our society has become so adverse to risk, we’ve lost perspective of cost-benefit ratios. I do developmental research, and we study these produce compounds, which are protective for the cardiovascular system. Any impediment put in the way of consuming fresh fruits and vegetables is detrimental to consumers’ health. We need to find ways to increase consumption.

To get further perspective, Mira contacted Dr. Richard Reiss, Sc.D., Principal Scientist, Chemical Regulation and Food Safety, Exponent, Alexandria, Virginia.

Q: What is your assessment of the “Dirty Dozen” list?

A: The list is based on findings of residue, but it doesn’t take into account toxicity of levels found. There are well-accepted and routinely applied methodologies to assessing risk associated with chemicals. EWG made no effort to connect the residue levels to a health risk on accepted methodology. The reason they haven’t done this is that EPA has already done it. EPA heavily regulates pesticide residues. It is the most stringent of any risk assessment process in this country and probably the world.

From someone who studies this, I can tell you that for every pesticide, EPA requires an extensive battery of toxicity tests, and EPA uses those results to restrict application rates; whether certain pesticides can be used on a certain fruit, the rates that can be applied, intervals and ways to apply.

Q: Doesn’t there also need to be a risk assessment in terms of what alternatives are used? For example, couldn’t certain organic growing methods increase risks?

A: The jury is still out on using manure for fertilizer, but it may be more important to focus on the quality control system of a farm. Plants have there own defense mechanism of chemicals they use to deal with a pest. Organically grown foods are stressed and the plants produce more natural pesticides to combat pests, so it’s not so straight-forward. Our conclusion is there is no difference in health benefits between organic and conventional.

The risk of not eating fruits and vegetables, however, is an obvious risk. There can be no clearer evidence when talking about diet and epidemiology that produce is good for you. Studies have shown for 20 or 30 years that those people that eat diets rich in fruits and vegetables are healthier. And if you make the correlation that those people who consumed all those fruits and vegetables were exposed to more residue levels, it is obvious the risk associated with not eating them is vastly higher than the risk of residue levels you might consume. That is a point that people miss.

Q: What is your involvement with this report?

A: As the principal scientist at Exponent, I helped put together the panel of scientific experts and served as an organizer to facilitate the study.

Q: What would you say to those who discredit the report by saying that its sponsor, the Alliance for Food & Farming, is biased?

A: Science is an objective process that speaks for itself. Attacking the messenger, in my view, is an admission they don’t have scientifically based arguments in response.

First the Alliance did a webinar for the trade, you can see the slides here. Then the Alliance released the study entitled A Review of the Science on the Potential Health Effects of Pesticide Residues on Food and related Statements Made by Interest Groups, you can see that here.

The basic conclusions of the study panel:

• The EWG’s list may reflect a relatively accurate ordering of the listing of the 47 commodities from the “highest” to “lowest” levels/numbers of pesticide residues. However, the list is misleading to consumers in that it is based only upon exposure data while remaining silent about available information on the assessment of the toxicity of pesticides presented in the diet, and, as such, does not provide a basis to assess risk. There also is no acknowledgment of the fact that the data show that the residue levels detected are, with very rare exception, below or, more likely, well below, the legal limits established only after calculating the potential total nonoccupational exposure that an individual might experience to a pesticide approved for use on an agricultural commodity. Furthermore, it is disconcerting that EWG does not describe its methodology in sufficient detail so that others can duplicate their analysis and independently judge its credibility, particularly given the widespread press coverage that its Shopper’s Guide to Pesticides has received.

• The Panel does not agree with EWG’s assertion that there is a “growing consensus among scientists” that the amount of pesticide residues currently found on food constitutes a significant public health issue. While there will always be some uncertainty associated with evaluating the possibility of small health risks, the available scientific data do not indicate that this source constitutes a significant risk.

• The U.S. EPA’s current process for evaluating the potential risks of pesticides on food is rigorous, and health-protective. The EPA’s testing requirements for pesticides used on food are more extensive than for chemicals in any other use category, and include testing targeted specifically to assess the potential risks to fetuses, infants, and children.

• The currently-available scientific data do not provide a convincing argument to conclude that there is a significant difference between the nutritional quality of organically grown food and food grown with conventional agricultural methods.

That the Alliance is doing good work by supporting this type of study is without doubt. We can hope that by providing fair-minded assessments of things such as the “Dirty Dozen,” the media will become less likely to give credence to such claims.

At very least, we can hope that the media sees another side to the story and that it will try to incorporate the scientific viewpoint into their articles and reports.

It is not an easy task and the road will doubtless be long, but The Alliance for Food and Farming is walking in the path of righteousness as it begins down this road.

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