Read All About It: Organic Food Is Not Healthier

Read All About It: Organic Food Is Not Healthier

By Joseph D. Rosen, Ph.D.
etween March 27 and April 3, four articles appeared in the mainstream British press that only served to further confuse readers about the alleged nutritional superiority of organic food.

“Organic IS healthier, say food scientists” was the headline of a March 27 article written by the Telegraph’s science correspondent, Nic Fleming. According to the story, scientists at the University of California reported that organically-grown kiwis exhibited small but statistically significant increases in vitamin C and in polyphenol content compared to conventionally-grown kiwis. (Many polyphenols found in food are chemical antioxidants that are thought to be protective against free radical processes that may, in part, be responsible for chronic illnesses such as cancer and coronary heart disease.) Mr. Fleming, however, made no mention of the fact that studies such as this one have been reported many times in recent years and results have been inconsistent. Sometimes the organic produce is higher in antioxidants, and sometimes the conventional produce is higher.

My own (as yet unpublished) review of the scientific literature demonstrates that the agricultural production method is not as important as the variety (cultivar) of the fruit or vegetable, the year that the produce was grown, geographic location, soil conditions, and amount of sunlight the crops received. To Mr. Fleming’s credit, he does mention that another University of California professor questioned whether the small increases in antioxidant activity would have any real impact on human health. But then he concludes his article by writing that others had shown that organic milk “has 68% more omega-3 fatty acids — important for normal brain functioning than other milk.” Milk is very low in omega-3 fatty acids to begin with and 68% more of a very tiny quantity is still a very tiny quantity. Furthermore, nutritionists recommend that adults drink low-fat or nonfat milk because of the high saturated fat content of whole milk. There is nothing magical about omega-3 fats — when the saturated fats are removed, so are the omega-3 fats.

Antioxidant Anticlimax

There was more news to follow. On April 2, the Daily Mail ran a story titled, “Proof at last that organic apples can be better for you.” The next day The Independent carried an article written by Ian Herbert titled, “It’s not just a fad — organic food is better for you, say scientists.”

Both news stories were about three organic food lectures presented at a conference held at the University of Hohenheim in Germany between March 20 and 23. According to the The Independent, scientists from Britain, France, and Poland presented evidence that “organic carrots, apples, peaches, and potatoes…have greater concentrations of vitamin C, beta-carotene, and chemicals that protect against cancer and heart disease than conventional produce.” (Nowhere in the published proceedings of the conference are there any presentations comparing the nutritional content of organic carrots and potatoes to their conventional counterparts; maybe Mr. Herbert got potatoes and tomatoes mixed up.)

The Daily Mail story was a bit more accurate, correctly matching up the Polish researchers with the apple and tomato studies and the French investigators with the peach study. According to the Daily Mail, researchers at Warsaw Agriculture University found “organic tomatoes had more vitamin C, beta-carotene, and flavonoids than conventional ones.” (Flavonoids are antioxidants and are a subclass of polyphenols.) The article also noted that the organic tomatoes contained less lycopene than the conventional tomatoes but failed to mention that lycopene is a much more effective antioxidant than beta-carotene and is one of the few antioxidants for which there is at least some epidemiological evidence of efficacy in preventing prostate cancer. Apparently the reporter for the Daily Mail never read the article the researchers submitted for publication.

If the reporter had done so, it would have been evident that there was a distance of 60 km between the organic and the conventional farms from which samples were taken, a distance much too far to make meaningful scientific comparisons in studies of this type. As for the increased levels of flavonoids in the tomatoes, a reading of the article revealed that the only flavonoid measured was quercitin. Quercitin is just one of the many flavonoids found in tomatoes, and finding an increased concentration of only one flavonoid is meaningless. Even more meaningless is attaching significance to results obtained from only one growing season. Research published in 2006 by Alyson Mitchell’s group at the University of California demonstrated that there were increased quercitin levels in organic tomatoes grown in 2003, but no differences were found in the 2004 and 2005 growing seasons.

A second presentation by the Polish scientists compared organic and conventional apple purees. According to both newspaper articles, the organic apple puree was higher in phenols, flavonoids, and vitamin C. A reading of the published proceedings told a different story, however. Although the organic purees had significantly higher levels of vitamin C and flavonoids than the conventional purees, the differences (and health advantage, if any) disappeared after the purees were pasteurized. In fact, the conventional apples had levels of flavonoids about three times higher than the organic apples after pasteurization. Total polyphenol content, a much better indication of antioxidant content than flavonoid content, was not significantly different between the two farming methods, either before or after pasteurization. The data showed, once again, how polyphenol content is influenced by fruit variety. For example, the conventionally-grown Boskoop cultivar had 80% more total polyphenol content than the organically-grown Lobo cultivar.

According to the Independent, the French researchers found that organic peaches “had a higher polyphenol content at harvest.” True, if you only look at their 2004 results. In the 2005 harvest, there were no differences whatsoever in polyphenol content between organic and conventional peaches, illustrating once again the importance of carrying out these types of experiments over several years before any valid conclusions can be made.

Opinion, Built on Partial Information, Built on Weak Data

The newspaper accounts of these events did not tell the complete story because the reporters did not read what the Polish and French investigators wrote; nor is there any evidence that they spoke to them about their actual data. Instead, they apparently obtained their information from the recollections of one or more persons who had recently returned from the conference.

Partially based on the misinformation published in the Independent and the Daily Mail, Peter Melchett wrote an opinion piece (“Organic Farming Bearing Fruit”) in The Guardian on April 3. Lord Melchett is the proprietor of an organic farm and is the Policy Director of the Soil Association, an organization whose income is derived, in part, from certifying organic farms. Melchett uses the studies reported on in the newspaper stories I have discussed above as a springboard to urge the UK’s Food Standards Agency (FSA) declaration that organic food is more nutritious than conventional food.

I doubt, however, that the FSA will be convinced by the papers presented in Germany that organic food is any healthier. After all, the papers were not peer-reviewed by other scientists and did not appear in respected scientific journals. Moreover, they essentially confirmed the findings of other researchers, i.e., antioxidant content of a food is determined by factors more important than whether or not food is grown organically or conventionally (cultivar and year to year variation, for two). Melchett appears to be living in a world of his own, claiming that the scientific evidence that organic food is better for you is growing, when in fact it is not. Actually, the scientific case for the nutritional superiority of organic food is so poor that Melchett was recently reduced to arguing on a BBC broadcast that “science doesn’t tell us the answers, so some of it we have to go on feelings.”

Finally, Melchett complains about last year’s refusal by the FSA to declare organic milk more nutritious even though it contained more alpha-linoleic acid (ALA), an omega-3 fatty acid, than conventional milk. Melchett is either unaware of or is ignoring a 2004 peer-reviewed publication written jointly by scientists from the U.S. National Cancer Institute, Harvard University, Harvard Medical School, and the Karolinska Institute in Stockholm warning that “increased dietary intakes of ALA may increase the risk of advanced prostate cancer.” Certainly, a proponent of the precautionary principle, like Melchett, should not urge people to drink organic milk until there is definitive proof ALA does not increase the risk of so lethal a disease.

Joseph D. Rosen, Ph.D., is an Emeritus Professor of Food Toxicology at Rutgers University and an ACSH Advisor.

Article Courtesy of: http://www.acsh.org/