The Boulder, Colo.-based research group The Organic Center says a new report it released last week shows that organic fruits, vegetables and grains are 25 percent more nutritious than conventionally grown plant-based food.
The report, published as a "State of Science Review" by the Organic Center, is titled "New Evidence Confirms the Nutritional Superiority of Plant-based Organic Foods." The report is an analysis of 97 published studies showing that "organic plant-based foods are 25 percent more nutrient-dense than conventional foods, and include significantly higher concentrations of polyphenols and antioxidants," according to a center release.
The center said nutrient levels were studied in 236 matched pairs of foods with results on the levels of 10 nutrients as well as nitrates. A matched pair, for example, would contain an apple crop grown organically and another apple crop from a nearby conventional farm with similar soil, climate, plant genetics and irrigation systems, nitrogen levels and harvest practices.
Researchers compared 191 matched pairs for 10 nutrients that included antioxidants; vitamins A, C and E; phosphorous and potassium; nitrates; and protein. The organic food was more nutrient-dense in 119 of the pairs, or 62 percent, compared to 36 percent of the conventional matched pairs, according to the center.
The organic food was more nutrient dense in 75 percent of the matched pairs comparing "antioxidants, polyphenols and the flavonoids quercetin and kaempferol," the center said.
The typical American diet contains barely half of these nutrients, "a major reason why the federal government recommended such a significant increase in the number of daily servings of fruits and vegetables as part of the new USDA dietary guidelines," said Dr. Charles Benbrook, the center's chief scientist and a co-author of the report.
Dr. Neal Davies, a professor in the School of Pharmacology at Washington State University and another co-author, said, "We have carried out many careful comparisons of both nutrient levels and biological activity of antioxidant polyphenols in organic and conventional foods over the last five years. Not only are we seeing a general trend in favor of the nutrient density of organic food, but also evidence that nutrients are often present in organic foods in a more biologically active form."
But Dr. Christine Bruhn, director of the Center for Consumer Research at the University of California, Davis, questioned what she called the "scientific validity" of the report, saying the authors have not published their findings in a peer-reviewed scientific journal. "The authors comment on the difference in specific antioxidants, however I am not aware of a recommendation for the level of these antioxidants needed for optimal health," Bruhn said in an email reply. "Researchers at UC Davis have found a difference in some nutrients based upon the amount of nitrogen fertilizer used. Their work indicates any difference isn't related to the total organic approach, but rather to the use of nitrogen. Conventional farmers can easily modify their production practices should the difference be of nutritional significance to the human diet."