Are Organic Foods Safer or Healthier than Conventional?
Discussions and questions about the value of organic foods vs. conventionally-raised food products were rekindled by a new study by researchers at Stanford University who concluded, “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-resistance bacteria.”
The research team reviewed literature published between 1966 and 2011. The team identified 5,908 peer-reviewed articles that reported a comparative evaluation of either populations consuming diets of food grown organically and conventionally, or a comparative evaluation of nutrient, microbial, or pesticide levels of fruits, vegetables, grains, meats, poultry, milk or eggs grown organically or conventionally. From these published studies, 240 were included in a meta-analysis. Of these, 17 studies involved humans and 223 were studies of nutrient or contaminant levels.
Of the three human studies that made clinical comparisons, the consumption of organic food did not significantly reduce instances of an allergic response in patients studied nor were rates of symptomatic infection with the Campylobacter bacteria affected. Two of the human studies found that children who consumed organic foods had lower urinary pesticide levels than children with conventional diets, but there were no “clinically meaningful differences” in these and other biochemical measures in adults. For nutrients, phosphorus was higher in organic produce – a difference that has no clear advantage and organic milk and chicken tended to be higher in beneficial omega-3 fatty acids. Plant foods had lower risk of contamination with detectable pesticide residues if they were organic, but both types of food were highly likely to be within the maximum governmental limits.
Overall, this study found very little difference in the nutritional value of organic vs. conventional produce, meats and dairy foods. There was a difference in risk for detectable levels of pesticides, but whether the difference is important from a health standpoint is not clear.
Source: Susan Nitzke, UW-Extension Nutrition Specialist and UW-Madison Professor Emeritus