Here are a few quote from the article Organic foods may not really be healthier
A "disappointingly small" number of well-designed studies have looked at whether organic foods may have health benefits beyond their conventional counterparts', according to the review, by researchers with the London School of Hygiene and Tropical Health in the UK.
Moreover, they found, what studies have been done have largely focused on short-term effects of organic eating — mainly antioxidant activity in the body — rather than longer-term health outcomes. And most of the antioxidant studies failed to find differences between organic and conventional diets.
Most of us believe that organic foods are healthier because they were made without the use of synthetic fertilizers, pesticides, hormones, etc, several studies just proved that may not be true at all.