In an extensive literature review, Stanford University doctors have concluded there is no evidence to suggest that organic foods are more nutritious than conventional alternatives.

They said, however, organic foods may contain fewer pesticides and antibiotic-resistant bacteria.

The doctors reviewed 17 studies in humans and 223 studies of nutrient and contaminant levels in foods.

Two studies reported significantly lower urinary pesticide levels among children consuming organic vs. conventional diets. However, studies did not identify clinically meaningful differences.

The risk for contamination with detectable pesticide residues was lower among organic than conventional produce – but differences in actual risk were small, the Stanford doctors said.

Escherichia coli contamination risk did not differ between organic and conventional produce.

Bacterial contamination of chicken and pork products at retail was common but unrelated to farming method.

However, the risk for isolating bacteria resistant to three or more antibiotics was higher in conventional than in organic chicken and pork.

Overall, the medical researchers concluded that the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

To read the full 22-page report in the Annals of Internal Medicine, go to