The Organic Center is described as a not for profit advocacy group by their supporters in the popular press, which makes them appear to be a bunch of good guys who are interested in promoting good health through organic food. The Organic Center, however, is supported by tax-deductible contributions mainly from organic food companies and their officers, and the main interest of those companies is shareholder profits (as it has to be in our capitalist society), not improved consumer health.
One of the prime messages from The Organic Center in recent years is that organic food is more nutritious, a claim not supported by scientific fact nor by the FDA, USDA, or the UK's Food Standards Agency. Last March, The Organic Center published a fifty-two-page report claiming that organic fruits and vegetables contained 25% more nutrients than conventionally-grown crops. This conclusion was based on their "rigorous methodology" which examined 236 paired comparisons between organic and conventional foods under identical or similar growing conditions. Although this number sounds impressive, Harold McGee of the New York Times wrote that because the report ranged across eleven nutrients and more than a dozen crops, it "hardly seems to justify" the report's conclusions.
I examined the report a bit more carefully and found numerous errors throughout. Correcting for these errors, I calculated in an ACSH report published in July that the 25% figure had no basis in fact and that there were essentially no differences in nutritional content between organically and conventionally grown crops (actually, conventional came out slightly better).
My report generated a response from The Organic Center's chief chemist, Charles Benbrook, and his colleagues (Preston Andrews, Neal Davies, Jaime Yanez, and Xin Zhao), critical of my analysis.
•First, they accuse me of accusing them of "cherry-picking" (their quotation marks) results, but I never used that term nor the term "bias." I did, however, point out that they omitted, in full or in part, several publications with information favorable to conventional food (References 11, 13, 14, 27, and 40 in the ACSH report). References 11 and 40 were published in late 2007 and early 2008, respectively, well within the time period that Benbrook and his colleagues claim to have included in their literature search.
•Second, they find fault with my criticism that people don't eat kiwi skins (the organic kiwi skins, where a large amount of antioxidants are admittedly found, were significantly thicker than the conventional skins), claiming that whole kiwis are consumed in several dishes. A Google search for unpeeled kiwi (and related search terms) found some recipes, mainly for juicer aficionados. People who juice have more than enough antioxidants in their diet, though. They also make a truly remarkable statement, accusing me of imposing a new criterion, i.e., "valid studies are those that report results for just the edible portion of a crop." I plead guilty as charged! (But then, if I pay as much as 300% more for organic fruits and veggies, I don't want to throw any part away.)
•Third, I am faulted for arguing that "any study reporting a difference of 20% or less is not meaningful." I never wrote that and I really wish that Benbrook and his colleagues would check their facts more carefully (a recurring problem).
•Fourth, I am accused of "knocking out 2/3 of [all] the matched pairs" of organic-conventional objects of comparison. Absolutely not true, as there were 232 matched pairs in their report. I did knock out about 2/3 (twenty-six of thirty-eight) in their "Magnitude of Differences" category — for scientifically legitimate reasons that are detailed in the footnotes to Table III of the ACSH report.
•Fifth, the Organic Center designation of nitrate as an undesirable nutrient is incorrect. While I, myself, would have agreed with this designation about fifteen years ago, new research shows that fear of dietary nitrate is unfounded and nitrate may actually be a desirable dietary nutrient. I have in the past provided several scientific references attesting to this as well as a report from the European Food Safety Authority that the benefits of dietary nitrate outweighed any risks. Benbrook and his colleagues did not provide one reference for designating dietary nitrate "undesirable" and have never explained why they consider it so.
•Sixth, I am accused of writing that vitamin C and ascorbic acid data should be disregarded. In fact, I was surprised to learn that the difference between organic and conventional matched pairs for this nutrient was only 10%. I suggested a ten-cent multivitamin for those who thought they were getting inadequate vitamin C from conventional food. According to the Harvard School of Public Health, a daily intake of 200 to 300 milligrams vitamin C appears to be a good target, which they suggest can be reached "with a good diet and a standard multivitamin."
•Seventh, I don't think Benbrook and his colleagues understand that the change I made concerning kaempferol was in their favor, raising the organic/conventional ratio from 1.05 to 1.15 for this antioxidant and their claim of 25% nutritionally superior to 26%, as explained in Table IV of the ACSH report. I also improved their beta-carotene ratios (they made an error in arithmetic) for organic food, and I hope I don't get criticized for that.
The most outrageous criticism of all faults me for questioning the validity of a matched pair in which the organic farmer used the pesticide chitosan but the conventional farmer did not. Chitosan induces the crops to produce large amounts of antioxidant chemicals, and this was reflected in the results (as much as 395% more antioxidant in organic Chinese cabbage compared to conventional). Yet comparing the organic vegetables treated with chitosan to conventional vegetables grown without chitosan is the same as comparing the accomplishments of athletes who use steroids to those who do not — it reminds us of chitosan's properties but tells us nothing about underlying qualities inherent to organic vs. conventional produce.
I think it is time for the Organic Center as well as Benbrook and his colleagues to admit that their report actually demonstrated that organic food is not any more nutritious than conventional food.
Joseph D. Rosen, Ph.D., is an Emeritus Professor of Food Toxicology at Rutgers University and an ACSH Advisor. Read his full report on the organic exaggerations described above, Claims of Organic Food's Nutritional Superiority: A Critical Review.
See also: Rosen's recent article on organic milk exaggerations.