Steve Savage: “A Rational Analysis of the USDA Pesticide Residue Data”

A guest post by agricultural scientist Steve Savage,
proprietor of Applied Mythology.
(Updated 1/6/16 to reconnect missing illustrations. This post first appeared on Sustainablog 6/15/11)

When the Environmental Working Group (EWG) makes its annual “Dirty Dozen List” of fruits and vegetables with pesticide residues, it does so without paying any attention to which chemicals were found or what level was detected. This is why it is so misleading.  To do the analysis properly does take a lot more “work” – it took me much of the last two days to do it.

First I had to download the raw data which comes as a 5.5 MB ZIP File that expands to a 83 MB text file.  My son wrote a little Ruby On Rails script that sifts through the millions of rows of data to find the 30,000 actual “detections” of pesticide residues that the USDA reported for 2009.  That list has the identity of the pesticide and its concentration in parts per million, billion or sometimes trillion.  Next, I searched for anMSDS for each of the 300 or so different chemicals to get the specific acute toxicity (this is usually in section eleven of each document).  The acute toxicity is expressed as an LD50 – the milligrams of chemical it would take per kilogram of body weight to kill 1/2 of the rats in a feeding study (Oral LD50).  These are publicly available documents which are usually easy to find except for old, discontinued pesticides and some of the metabolites.  Dividing the LD50 by the detected amount gives you the multiple of its own body weight that the rat would have to eat to reach a toxic dose.

An Example You Can Blame on McDonald’s

As an example, an old, extremely toxic pesticide, aldicarb (Temik) has an LD50 of 1 mg/kg.  This is exactly what you imagine when you hear the word, “pesticide.”  In one sample of fresh potatoes, the USDA scientists detected 0.01 mg/kg of aldicarb sulfoxide – a metabolite which is just as toxic as the aldicarb.  For the rats to die from eating such potatoes would require that they rapidly consume 90 times their own weight of those particular potatoes.   The most toxic potato sample had 1.5mg/kg of the aldicarb sulfoxide which means that the rates could die by eating just one times their own body weight.  A rat might be able to do that.

The EWG essentially treats every one of the 30,000 detections as equal in risk to these worst-case potato values.  Because most pesticides are far, far less toxic than aldicarb, the average residue found by the USDA on potatoes has a safety margin of 595,163.   The only reason that aldicarb is still used on potatoes (and it will be phased out soon), is that for purely brand protection reasons, MacDonald’s asked it’s fry suppliers not to give them any more GMO potatoes (they had been using them for several years, and they still cook them in GMO soybean oil and serve up GMO sodas with corn sweetener).  Still, McDonalds killed the Bt-potato.  That is why potato growers plant their potatoes into a furrow with granular aldicarb so that the roots pick up the insecticide for ~60 days, protecting them from the Colorado Potato Beetle.  Still, potatoes are in about the middle of the pack in terms of average safety margin.  Oranges have a safety factor of nearly 1.5 million.

Sweet corn, which makes the “Clean Fifteen” list for EWG is actually the crop with the lowest average safety margin (8,909).  This demonstrates the meaninglessness of the Dirty Dozen list.

Beyond Averages

Of course, averages can be misleading.  It is more instructive to look at the full distribution of results.  The graph below summarizes all the sample results for fruit crops.  For this graph, values on the right side of the graph represent extremely low risk while those to the left represent relatively higher risk.  As you can see, even though these crops had many pesticide residues, they almost all were present at vanishingly levels meaning extremely minor risk.  People just don’t eat one hundred, one thousand or several million times their body weight of one food in a sitting!

The same is true for vegetables.  The few residues detected on lettuce have safety margins in the million-fold range and the non-Organic lettuce was actually a little better than the Organic lettuce.  By this methodology potatoes and spinach come out the worst with some safety margins in the thousand range.  Still, the message from the real data is completely different than what one gets from the EWG’s “analysis.”

When the EWG list is reported by the unsophisticated media, they say things about it which are completely false.  For instance thirdage.com said, “The “dirty dozen” list of the twelve fruits and vegetables with the highest amount of pesticide residue was released Monday by the Environmental Working Group (EWG).”  That would be impossible because the EWG did not access the raw data which would be necessary to identify how “high” the residues actually were.  They say that cherries “dropped off the list” without mentioning that cherries were not even one of the crops tested in 2009.

So, what does the USDA data actually tell us?  That we should feel confident that the fruits and vegetables available in our markets are perfectly safe, and we should be consuming them in ever greater quantities to take advantage of all the cancer- and other disease-fighting chemicals they naturally contain.  It also tells us that the EWG should be ashamed of their list, print a full retraction, and refund their ill-gotten financial gains.

If anyone would like a copy of the processed data or graphs I would be happy to email it from savage.sd@gmail.com.  Also if anyone would like to improve on my collection of LD50 values that would be much appreciated.  My website is Applied Mythology.

Crop dusting image from wikimedia

sustainablog (http://s.tt/18H4H)

Mary Magnan on the NEJM Fail — the Benbrook & Landrigan Non-Disclosures

Dear Reader, if you are a subscriber to The New England Journal of Medicine then I hope you will take the time to carefully read the preceding guest post by Dr. Mary Magnan. I anticipate that you will come to the same conclusion I did – that NEJM must, at the very least, publish a correction to the Benbrook & Landrigan article. And on the NEJM website the article should be prepended with a full disclosure of the blatant conflicts of interest that were not disclosed by the authors. I also hope that subscribers to NEJM will take the trouble to explain their strong feelings to the editors.

In the media there is clearly a “double standard” applied to discussions on genetic engineering – particularly in agriculture. The tacit assumption of the reporting journalist or editor is that the person taking the anti-GMO position is the innocent “good guy environmentalist”, who is just trying to inform the public of the dangers of this technology. Conversely, the person who discusses GMO risk v. benefits is presumed to be beholden to corporate interests. The code word “Monsanto” is usually considered sufficient to terminate rational discussion.

This specific case of the NEJM publication is an example of an article carefully crafted to appear to be a scientific reference for contrary-to-fact claims that herbicide-resistant crops are increasing the negative impact of pesticides. The trick the authors use is to tabulate only the time series total mass of the herbicide glyphosate. Not discussed are the important benefits of glyphosate – that in recommended application regimes glyphosate is one of the least toxic herbicides, that glyphosate is replacing significantly more toxic chemicals, resulting in much-increased conversion of acreage to environmentally beneficial “no-till farming”.

So the conclusions of the Benbrook & Landrigan article are exactly backwards from the perspective of a scientist objectively evaluating the before-after the introduction of the glyphosate-resistance trait.

What would motivate Benbrook & Landrigan to publish such nonsense? Well, particularly in the case of Benbrook – that is his job – to provide the “scientific references” to counter the conclusions of all the worlds major scientific institutions that GMO crops are as safe as non-GMO alternatives, and good for the environment and good for the farmers.

I appreciate Dr. Magnan’s significant effort invested to carefully document what Benbrook & Landrigan should have disclosed to NEJM. My reading of the evidence is that NEJM would have declined to publish this piece.

For an overview of the evidence on pesticides before/after GMO introduction, please Dr. Steve Savage: When Increased Pesticide Use Is A Good Thing which concludes with this:

To reiterate, pesticide use or its increase are not automatically undesirable things.  It depends on what is the alternative and what is the nature of the particular pesticide in question.  Plant biotechnology is just one important tool in the bigger tool box of agriculture.  Sometimes it allows farmers to use a more attractive pesticide option (Bt Sweet Corn would the be best example of this).  Sometimes it helps them with the adoption of sustainable practices that depend on relatively low risk herbicides.  For farmers, biotechnology and pesticides are not an either/or.  They are often partners.

Dr. Savage has published many articles on the complex subject of agricultural pests, IPM (Integrated Pest Management) and pesticides. Another useful perspective is The Muddled Debate About Pesticide Use And GM Crops:

Bottom line, a biotechnology trait may decrease or increases the need for a pesticide.  There will also be many cases where the biotech trait has nothing to do with pesticide use.  There is no necessary good or bad linkage between these two categories of agricultural technology – both can serve to make crop production better.  Both are options that should be available to those who farm.

Jimmy Botella: Waiter, there is a gene in my soup!

Our second nomination today for Best Biotech Talks is Jimmy Botella, Professor of Plant Biotechnology, School of Agriculture and Food Sciences at the University of Queensland. Jimmy has no pretensions, he just arrows right into the kernels of mum-fear that are exploited so profitably by the Natural Organic Foods industry:

Have you ever seen the real banana? Do you know how strawberries come about? It might come as a shock to you, but what you regard as ‘natural food’ might not be natural at all, and perhaps genetically modified (GM) food is not as bad as you think. At TEDxUQ, Jimmy Botella busted some of the fallacies we have regarding the food we eat every day, and gave us a sneak peak of what GM food actually is, and where it sits in our current society.

We think you’ll agree “This is a keeper”.

Big Organic mounts Asymmetric Warfare attack on public scientist Kevin Folta

There are misrepresentations in this PLOS BIOLOGUE guest post that need to be promptly corrected. Dr. Folta has written a brief analysis of these issues at Science20 Transparency Weaponized Against Scientists.

“Weaponized FOIA” is an appropriate term for the harassment tactic devised by Gary Ruskin and his organic industry backers. Very simply this is “Asymmetric Warfare” against forty public scientists. The attackers have whatever resources they may need – including funding for public relations firms and lawyers. Dr. Folta has only his own personal resources to defend his reputation. He doesn’t have the option to just turn over his defense to a team of professionals.

I am especially outraged at this harassment for alleged lack of transparency. I have been reading Dr. Folta since at least 2012. Why? Because when I undertook to understand the risks and benefits of modern agriculture my first task was to identify scientists that I could trust. My doctorate is Computer Science – with no training in molecular biology or horticulture. But I know how to find expertise in other fields. I find some candidate scientists that look to be credible, then put some hours into Google Scholar looking for papers and citations. It’s not rocket science to discover the researchers who have the respect of their colleagues. Then over time it’s a matter of looking at the quality and logical consistency of arguments.

For example, early on I found Penn State molecular biologist Nina Federoff. Looking at her work and CV I noted that she was a recipient of the U.S. National Medal of Science. Perhaps she is a pretty good choice for a scientist to trust. By following her citations to the work of other scientists a web of references develops. That’s how I came across prof. Kevin Folta.

Dr. Folta is very unusual in the research community because he invests a quite remarkable amount of unpaid effort into science communications. RSS is your friend for harvesting information generated by scientists like Dr. Folta who publish frequently on a personal blog, give public lectures, record podcasts, etc. All of the writing and presenting that I found – you can find too. If you do that you will quickly confirm my finding that Dr. Folta is objective and transparent to a level that sets a standard for the rest of us to live up to.

From my experience it is very clear why special interests promoting an anti-science agenda will want to discredit Dr. Folta. Hence the Asymmetric Warfare on his reputation. You can verify my claim by reading his blog Illumination and listening to his new podcast Talking Biotech. If you do that you will see that this man is not a shill for any special interest. He is exactly the sort of objective scientist that you are looking for.

Organic marketing: Not truthful, often misleading

I am supportive of those who choose to grow organic food and those who choose to buy it. However, I do not accept the organic industry’s attack on new tech agriculture. It is entirely without justification.

If the roles were reversed and conventional agriculture engaged in similar “black marketing” against organics, the regulatory authorities and consumer groups would come down like a ton of bricks.

One wonders why, then, this multibillion-dollar industry gets a free ride to propagate negative and false advertising denigrating the livelihood of the vast majority of America’s farmers.

It’s time for it to stop.

JOHN R. BLOCK was U.S. secretary of agriculture from 1981 to 1986. On the Academic Review report John begins with this 

As someone who has dedicated his career to agriculture, I’ve often wondered what drives the now double-digit growth in the $35 billion U.S. organic products industry. Why are so many people willing to pay premiums up to 100 percent or more for items that carry an organic label, and do they really understand what that label means and — even more important — what it doesn’t mean?

Many of these questions have now been answered in a blockbuster report by the scientific-integrity watchdog Academics Review. The report examines the last 25 years of academic and organic industry market research, public statements and often questionable marketing practices.

What they have found should be raising red flags for all of us.

The organic industry likes to project a friendly image of small farmers and contented cows. But as this report extensively documents, the behavior of this multibillion-dollar industry is considerably less benign.

Among the other findings is the extent to which the large organic food corporations engage in what it describes as deceptive advertising linked to scientifically baseless scares about conventional food.

Worse, this “black marketing” takes place with the implied approval of the U.S. Department of Agriculture’s Organic Seal and the silent acquiescence of the regulatory authorities charged with ensuring that all labeling and advertising be “truthful and non-misleading.”

As a leading consultant warned the organic industry in the 1990s, “If the threats posed by cheaper, conventionally produced products are removed, then the potential to develop organic foods will be limited.” Since then we’ve witnessed a remorseless campaign based on junk science or no-science attacking food grown with modern fertilizers, pesticides, GMOs and other technologies.

Advertising and promotional material — including “educational” materials developed for schools — suggest non-organic food is linked to almost every disease under the sun, including “developmental and learning problems such as ADHD,” “high blood pressure, type 2 diabetes, depression and cancer.”

Tens of millions of organic marketing dollars flow annually to activist organizations such as the Environmental Working Group which spread misinformation and fear. Unsupported, provably counter factual claims are so habitual to the industry that they are even included in official statements: “Not only is organic safer, healthier and more nutritious,” claims the Organic Consumer Association in testimony to USDA, but buying organic will “reduce food-borne illness and diet-related diseases.”

The Organic Seal does not and cannot signify any health or safety criteria whatsoever. It merely certifies that products were produced using less modern inputs.

Source…

Why Consumers Pay More for Organic Foods? Fear Sells and Marketers Know it.

You have probably noticed how much of the anti-GMO and organic industry advertising is based on fear-mongering. For a deep dive into how this works, I suggest the 2014 Academic Review report:

Why Consumers Pay More for Organic Foods? Fear Sells and Marketers Know it.

An academic review of more than 25 years of market research, marketing tactics and government programs driving sales in the organic and natural product industries

(April 8, 2014 Priest River, ID) An extensive review of more than 200 published academic, industry and government research reports into why consumers adopt organic product purchasing behaviors was conducted by Academics Review – a non-profit led by independent academic experts in agriculture and food sciences. This review was then supplemented with an assessment of more than 1,000 news reports, 500 website and social media account evaluations and reviews of hundreds of other marketing materials, advertisements, analyst presentations, speeches and advocacy reports generated between 1988 and 2014. Our findings were reviewed and endorsed by an international panel of independent agricultural science, food science, economic and legal experts from respected international institutions with extensive experience in academic food and agriculture research and publishing.

Our report finds consumers have spent hundreds of billion dollars purchasing premium-priced organic food products based on false or misleading perceptions about comparative product food safety, nutrition and health attributes. The research found extensive evidence that widespread, collaborative and pervasive industry marketing activities are a primary cause for these misperceptions. This suggests a widespread organic and natural products industry pattern of research-informed and intentionally-deceptive marketing and paid advocacy. Further, this deceptive marketing is enabled and conducted with the implied use and approval of the U.S. government endorsed and managed U.S. Department of Agriculture (USDA) Organic Seal and corresponding National Organic Standards Program (NOSP) in direct conflict with the USDA’s NOSP stated intent and purpose.

“It is our hope that responsible members of the organic food industry and government officials will use these findings to address consumer misperceptions about important issues of food safety and nutrition,” said Professor Bruce Chassy, professor emeritus University of Illinois, Department of Food Science & Human Nutrition. “Accurate food safety, nutrition and health information combined with consumer pocket book protections should be a threshold standard for any U.S. government program that cannot be coopted by special interest marketing groups.”

Dietary pesticides (99.99% all natural)

Plants are not just food for animals… The world is not green. It is colored lectin, tannin, cyanide, aflatoxin, and canavanine [Janzen (16)].

A false claim keeps crossing my desk: that organic foods are safer; and especially safer due to the prohibition of synthetic pesticides. This is false. In fact the motivation for development of many of the synthetic pesticides in use today is to reduce toxicity for both consumers and agricultural workers. This effort has been successful, but due to the vested interests in the “organic” marketing designation the prohibition against synthetic pesticides prevails.

John R. Block was U.S. secretary of agriculture from 1981 to 1986, so he is a good source for a concise summary of what “organic” really means:

The Organic Seal does not and cannot signify any health or safety criteria whatsoever. It merely certifies that products were produced using less modern inputs.

“Let me be clear about one thing,” said USDA Secretary Dan Glickman when organic certification was being considered. “The organic label is a marketing tool. It is not a statement about food safety. Nor is ‘organic’ a value judgment about nutrition or quality.”

Yet USDA’s own research shows consumers buy higher priced organic products because they mistakenly believe them safer and more nutritious.

The science is clear on this point: As numerous studies, USDA monitoring, and a massive “meta-analysis” recently conducted at Stanford University confirm, organic foods are no more nutritious, nor do they carry any fewer health risks, than conventional foods. In fact, a good case could be made that conventional food may be considerably safer.

 My quick summary is organic labeled products are limited to pre-scientific agriculture.

Are natural pesticides better? Definitely, not – though, because natural pesticides are not regulated,  we know much less about their toxicity. Bruce Ames is one of the heroes of environmentalism, so NY Times science writer John Tierney turned to the Ames et al 1999 paper to document his column Synthetic v. Natural Pesticides: the captioned Dietary pesticides (99.99% all natural). This paper is open access, free PDF here, by B N Ames, M Profet, and L S Gold: Division of Biochemistry and Molecular Biology, University of California, Berkeley.

When a toxicologist says “99.99%, by weight, of the pesticides we eat are natural” she is probably referring to this paper. I like the way John Tierney characterizes the Ames work

Dr. Ames was one of the early heroes of environmentalism. He invented the widely used Ames Test, which is a quick way to screen for potential carcinogens by seeing if a chemical causes mutations in bacteria. After he discovered that Tris, a flame-retardant in children’s pajamas, caused mutations in the Ames Test, he helped environmentalists three decades ago in their successful campaign to ban Tris — one of the early victories against synthetic chemicals.

But Dr. Ames began rethinking this war against synthetic chemicals after thousands of chemicals had been subjected to his test. He noticed that plenty of natural chemicals flunked the Ames test. He and Dr. Gold took a systematic look at the chemicals that had been tested on rodents. They found that about half of natural chemicals tested positive for carcinogencity, the same proportion as the synthetic chemicals. Fruits, vegetables, herbs and spices contained their own pesticides that caused cancer in rodents. The toxins were found in apples, bananas, beets, Brussel sprouts, collard greens, grapes, melons, oranges, parsley, peaches — the list went on and on.

Then Dr. Ames and Dr. Gold estimated the prevalence of these natural pesticides in the typical diet. In a paper published in 2000 in Mutation Research, they conclude:

About 99.9 percent of the chemicals humans ingest are natural. The amounts of synthetic pesticide residues in plant food are insignificant compared to the amount of natural pesticides produced by plants themselves. Of all dietary pesticides that humans eat, 99.99 percent are natural: they are chemicals produced by plants to defend themselves against fungi, insects, and other animal predators.

We have estimated that on average Americans ingest roughly 5,000 to 10,000 different natural pesticides and their breakdown products. Americans eat about 1,500 mg of natural pesticides per person per day, which is about 10,000 times more than the 0.09 mg they consume of synthetic pesticide residues.

Even though these natural chemicals are as likely to be carcinogenic as synthetic ones, it doesn’t follow that they’re killing us. Just because natural pesticides make up 99.99 percent of the pesticides in our diet, it doesn’t follow that they’re causing human cancer — or that the .01 percent of of synthetic pesticides are causing cancer either. Dr. Ames and Dr. Gold believe most of these carcinogenic pesticides, natural or synthetic, don’t present problems because the human exposures are low and because the high doses given to rodents may not be relevant to humans.

“Everything you eat in the supermarket is absolutely chock full of carcinogens,” Dr. Ames told me. “But most cancers are not due to parts per billion of pesticides. They’re due to causes like smoking, bad diets and, obesity.”

He and Dr. Gold note that “many ordinary foods would not pass the regulatory criteria used for synthetic chemicals,” but they’re not advocating banning broccoli or avoiding natural pesticides in foods that cause cancer in rodents. Rather, they suggest that Americans stop worrying so much about synthetic chemicals:

Regulatory efforts to reduce low-level human exposures to synthetic chemicals because they are rodent carcinogens are expensive; they aim to eliminate minuscule concentrations that now can be measured with improved techniques. These efforts are distractions from the major task of improving public health through increasing scientific understanding about how to prevent cancer (e.g., what aspects of diet are important), increasing public understanding of how lifestyle influences health, and improving our ability to help individuals alter their lifestyles.

You can read a detailed account of their work in the Handbook of Pesticide Toxicology.

The Panic Virus: A True Story of Medicine, Science, and Fear

In Why the ‘Prius Driving, Composting’ Set Fears Vaccines Greg Miller interviews author Seth Mnookin on his new book. Here’s a fragment of the Q&A:

Q: There’s a perception that vaccine refusal is especially common among affluent, well-educated, politically liberal parents—is there any truth to that?

S.M.: It’s dangerous to make broad generalizations about a group, but anecdotally and from the overall data that’s been collected it seems to be people who are very actively involved in every possible decision regarding their children’s lives. I think it relates to a desire to take u ncertainty out of the equation. And autism represents such an unknown. We still don’t know what causes it and we still don’t have good answers for how to treat it. So I think that fear really resonates.

Also I think there’s a fair amount of entitlement. Not vaccinating your child is basically saying I deserve to rely on the herd immunity that exists in a population. At the most basic level it’s saying I believe vaccines are potentially harmful, and I want other people to vaccinate so I don’t have to. And for people to hide under this and say, “Oh, it’s just a personal decision,” it’s being dishonest. It’s a personal decision in the way drunk driving is a personal decision. It has the potential to affect everyone around you.

Q: But why liberals?

S.M.: I think it taps into the organic natural movement in a lot of ways.

I talked to a public health official and asked him what’s the best way to anticipate where there might be higher than normal rates of vaccine noncompliance, and he said take a map and put a pin wherever there’s a Whole Foods. I sort of laughed, and he said, “No, really, I’m not joking.” It’s those communities with the Prius driving, composting, organic food-eating people.

 

Steven Novella: No Health Benefits from Organic Food

The recent review of organic vs conventional produce agrees with previous systematic reviews that there is insufficient evidence to conclude that organic produce is healthier or more nutritious that conventional produce. Despite the scientific evidence, the alleged health benefits of organic produce is the number one reason given by consumers for buying organic. This likely represents the triumph of marketing over scientific reality.

At Science-Based Medicine neuro-scientist Steven Novella recently took another skeptical look at organic benefits, including the Crystal Smith-Spangler meta-review. I was pleased to see Steve start off by flagging the naturalistic fallacy.

A recent review of 240 studies has concluded that:

 The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

Organic produce has become increasingly popular in recent years. There are several reasons that consumers might prefer organic produce, including the belief that organic farming is better for the environment and more sustainable. I am going to focus in this article about the health effects of organic produce. Environmental claims for organic farming are complex and controversial – I will just say that such claims largely fall prey to the naturalistic and false dichotomy fallacies. In my opinion, farming practices should be evaluated on their own merits individually, based on evidence rather than philosophy. Sustainable and environmentally friendly farming are certainly laudable goals and I support farming practices promote them, however they are labeled.

(…)

Steve Savage: Do You Really Need to Buy Organic Foods To Avoid Pesticide Residues?

What I found disappointing about the Stanford study was the weakness of its analysis of differences in pesticide residues. 

I was delighted to find that Steve Savage had posted a well-researched critique  Do You Really Need to Buy Organic Foods To Avoid Pesticide Residues? of the meta-analysis “Are Organic Foods Safer or Healthier Than Conventional Alternatives?” The main-stream media didn’t get much further than the “Conclusion” paragraph of the press release

Conclusion: The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

Every media reference I’ve encountered emphasizes the “…may reduce exposure to pesticide residues”. Does that mean “reduce exposure” from safe-and-totally-insignificant to…? Perhaps – but that really isn’t the focus of the Stanford paper – which is the nutritional vector. Steve’s introduction gets right to the implied pesticide risk that concerns me:

Last week, a meta-analysis from a highly credible, academic source (Stanford University, its medical school and nearby institutions), raised serious questions about the often-touted, nutritional advantage of organic food. They digested the contents of 237 peer reviewed articles comparing organic and conventional foods and diets. They concluded that “the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods.” This drew a great deal of attention and organic advocate defense. Because even though Stanford is affectionately known by alums such as me as “the farm,” it is certainly no ag-school promoting the status quo. Instead, it enjoys a very strong reputation for research excellence. It isn’t easy to dismiss these findings.

Many commentators, confronted with the highly credible de-mythification of the nutritional advantage of organic, jumped to the paper’s slight evidence supporting a 30% reduction in exposure to pesticide residues as a way to justify paying extra for organic. Does the science really support that claim? No.

Please read Steve’s commentary with an open mind. If you are not completely persuaded, then for further reading may I suggest the B N Ames, M Profet, and L S Gold paper Dietary pesticides, which is an edited version of a chapter titled ‘Cancer Prevention and the Environmental Chemical Distraction‘, in the 2003 book Politicizing Science: the Alchemy of Policymaking. The Kindle edition is only $9.99, and a very good investment it is.