A new study published in the latest issue of the Society of Chemical Industry’s (SCI) Journal of the Science of Food and Agriculture claims that there is no evidence to support the argument that organic food is better than food grown with the use of pesticides and chemicals. However, The Organic Center’s Chief Scientist Chuck Benbrook, Ph.D., has the following to say about the study.

A study just out in the Journal of the Science of Food and Agriculture is entitled “Effect of plant cultivation methods on content of major and trace elements in foodstuffs and retention in rats.” The Danish research team compared the retention of nutrients in rats fed a diet composed of organic and conventional dried fruits and vegetables. Only trace mineral levels were compared; no results were reported on vitamins, polyphenols, and antioxidants (nutrients that routinely are present at higher concentrations in organic food).

No differences were found in nutrient levels, leading the authors to suggest that such findings might dampen consumer demand for organic food. Some media outlets have picked up this finding, and have dramatically broadened it to support headlines and statements like “Organic food no more nutritious than conventional.” A review of the study’s experimental design, however, raises serious questions about whether this study’s results actually support the more narrow conclusions stated by the authors.

The team grew the fruits and vegetables in both the “conventional” and organic plots on soils that were previously managed organically. Accordingly, the conventional crops enjoyed all the nutrient-enhancing and plant-health benefits of heightened soil quality from prior organic soil management. Given the series of studies published in the U.S. in the last three years pointing to soil quality enhancement in organic systems as the major cause, or explanation of observed differences in nutritional quality, it is not surprising that this Danish study found no statistically significant difference in mineral levels in the organic and “conventional” crops that were harvested and fed to the rats.

In addition, the organic plots were grown under limited nitrogen, whereas the conventional crop was not. On the basis of the criteria the Center developed to judge the scientific validity of comparison studies, and used in completing our March 2008 report on the nutrient content of organic food, this Danish study is clearly “invalid” for purposes of comparing the nutrient content of conventional and organic foods.  

The study was carefully conducted and valid for testing the impacts of the production conditions embedded in its experimental design, but by virtue of this design, little weight should be placed on its findings in terms of the differences in conventional and organic management on crop nutritional quality. 

Source: Mette Kristensen, Lars Ostengaard, Ulrich Halekoh, Henry Jorgensen, Charlotte Lauridsen, Kirsten Brandt, and Suzanne Bugel. “Effect of plant cultivation methods on content of major and trace elements in foodstuffs and retention in rats,” Journal of the Science of Food and Agriculture, 2008