Abstract: The authors identified all peer-reviewed studies published in the scientific literature appearing since 1980 comparing the nutrient levels in organic and conventional foods and screened them in two ways for scientific validity. They identified 236 “matched pairs” of measurements that include an organic and conventional sample of food. The organic foods within these matched pairs were nutritionally superior in 145 pairs, or 61% of the cases, while the conventional foods were more nutrient dense in 87 matched pairs, or 37%. There were no differences in 2% of the matched pairs. Organic samples contained higher concentrations of polyphenols and antioxidants in about three-quarters of the 59 matched pairs representing those four phytonutrients. Conventional samples contained higher levels of potassium, phosphorus and total protein levels in over three-quarters of the 87 cases representing those nutrients. The magnitude of the differences in nutrient levels strongly favored the organic samples. One-quarter of the matched pairs in which the organic food contained higher levels of nutrients exceeded the level in the conventional sample by 31% or more. Only 6% of the matched pairs in which the conventional sample was more nutrient dense exceeded the levels in the organic samples by 31% or more.
Reference: Benbrook, Charles M., Xin Zhao, Jaime Yanez, Neal Davies and Preston Andrews. (2008). New evidence confirms the nutritional superiority of plant-based organic foods. 53 p. The Organic Center. Available online at: http://www.organic-center.org/reportfiles/NutrientContentReport.pdf