Background and Methodology
The study surveyed existing literature and compared nutrient content of organic and conventional crops using statistical methods to identify significant differences and trends in the data. For each organic-to-conventional comparison, a percentage was calculated with the formula (organic-conventional)/conventional x 100. The Wilcoxon signed-rank test was used to identify significant differences in nutrient content as represented by the percent difference.
The findings showed that organic crops contained significantly more vitamin C, iron, magnesium and phosphorus and significantly less nitrates than conventional crops. There were no significant trends showing less protein, but of a better quality and higher content of nutritionally significant minerals with lower amounts of some heavy metals in organic crops compared to conventional crops. The study concluded that there appears to be genuine differences in the nutrient content of organic and conventional crops.
Worthington, V. (2001). Nutritional quality of organic versus conventional fruits, vegetables and grains. Journal of Alternative and Complementary Medicine 7(2):161-173.