Are organics more nutritious than conventional foods? A comprehensive systematic review

Some consumers prefer organic foods based on the belief that they are safer, healthier, and more nutritious than conventional ones. However, this assumption is still a controversial issue. The present study aims to synthesize scientific evidence confirming or refuting the nutritional superiority of organic foods over conventional foods. We accessed scientific databases and surveyed studies analyzing and comparing nutritional and residual values in organic and conventional foods. We collected 147 scientific articles containing 656 comparative analyses based on 1779 samples of 68 vegetable, fruit, and other (cereals, pulses, etc.) foods, 22 nutritional properties, and nine residues. Results show that in 191 (29.1%) comparisons, there were significant differences between organic and conventional foods. In a similar quantity of cases (190; 29.0%), there were divergences in the results since some studies reported significant differences while others did not. Finally, most of the comparative analyses (275; 41.9%) showed no significant difference between organic and conventional foods. Therefore, the results herein show no generalizable superiority of organic over conventional foods. Claims for nutritious advantages would eventually be applied to specific comparisons, depending on the food type and nutritional parameter.