(HealthDay News) – Based on the published literature, there is a lack of evidence for the health benefits of organic food, according to a review published in the Sept 4 issue of the Annals of Internal Medicine.

Crystal Smith-Spangler, MD, of the Veterans Affairs Palo Alto Health Care System in California, and colleagues conducted a systematic review of 17 human studies and 223 studies of the nutrient and contaminant levels in foods to examine the evidence comparing the health effects of organic and conventional foods.

The researchers observed considerable heterogeneity in estimates of differences in nutrient and contaminant levels, except for phosphorus levels, which were higher in organic produce, although the difference was not significant. Organic foods were 30% less likely to be contaminated with pesticides, but there was a small difference in risk for exceeding maximum allowed limits. There was no difference in the risk of Escherichia coli contamination between organic and conventional produce. In conventional versus organic chicken and pork, the risk for isolating bacteria resistant to three or more antibiotics was 33% higher.

“The evidence does not suggest marked health benefits from consuming organic vs. conventional foods, although organic produce may reduce exposure to pesticide residues and organic chicken and pork may reduce exposure to antibiotic-resistant bacteria,” the authors write.

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