“The Organic Center published a comprehensive survey of 97 peer-reviewed studies addressing this question. Conclusive comparative studies of vegetables are difficult — weather, soil type, the variety and harvesting practices all come into play. The review narrowed the studies to only those that had controlled for these features. They found that organic produce usually ranked higher in four antioxidant categories (total phenolics, total antioxidant capacity, quercetin, and kaempferol), vitamin C, Vitamin E, and Phosphorus.
Conventional produce often ranked higher for total protein and nitrates. (Note that nitrates are undesirable, so the authors considered higher nitrate levels to be a nutritional deficit.) Beta-carotine and potassium levels were about equal. The authors also found that the magnitude of the difference was generally much larger in favor of organics. When the organic sample had a higher nutrient level than its conventional counterpart, the magnitude of this difference was greater than 20% in 42% of the samples and greater than 30% in almost a quarter of the samples. For the same nutrients, when conventional produce ranked higher, the difference was greater than 20% in only 15% of the samples and over 30% in only 6% of the samples. Although the protein levels were higher in conventional samples in an overwhelming majority of cases, they were higher by more than 20% in only 17% of the cases. Condensing all of the data into ratios and finding the average, the authors found that the organic produce contained an average of 25% more of the nutrients included in the study than conventional produce.
For a copy of the Organic Center study click link below. www.organic-center.org/science.nutri.php?action=view&report_id=126
A quote from Are Organic Vegetables More Nutritious, published by The Organic Center:
“The nutrient density of many common foods has declined gradually over time in both the U.S. and the U.K…. Declining average nutrient levels in the U.S. food supply have been brought about by what agronomists have labeled the ‘dilution effect,’ first coined in an important review article published in 1981… The remarkable increases in per acre crop yields brought about over a half-century through advances in plant breeding, the intensity of fertilizer and pesticide use and irrigation are well known. However, few are aware that this achievement has come at a cost in terms of food nutritional quality.”
– Lizzy Koltai
Full Belly Farms is a model for healthy sustainable organic farming practices.