Despite higher prices, organic foods haven't proven to be any more nutritious than more conventional foods, according to a new study from Stanford University. The study also played down the greater risks of pesticides in conventional foods.
"There isn't much difference between organic and conventional foods, if you're an adult and making a decision based solely on your health," said Dena Bravata, MD, MS, the senior author of the paper, in a university statement. The research was published in the Annals of Internal Medicine.
For the study, 237 published studies comparing organics to conventional foods were examined. Among the findings:
- No consistent differences were seen between organic and conventional produce in vitamin content, and only one nutrient — phosphorus — was significantly higher in organic versus conventionally grown produce. Researchers also noted that few people have phosphorous deficiency.
- No difference in protein or fat content was found between organic and conventional milk, though evidence from a limited number of studies suggested that organic milk may contain significantly higher levels of omega-3 fatty acids.
- Organic produce had a 30 percent lower risk of pesticide contamination than conventional produce, although organic foods are not necessarily 100 percent free of pesticides. Moreover, researchers found that the pesticide levels of all foods generally fell within the allowable safety limits. Two studies showed children on organic diets had lower levels of pesticide residues and organic chicken and pork appeared to reduce exposure to antibiotic-resistant bacteria, but researchers indicated the significance of these findings in both cases is unclear.
Researchers, who received no outside funding, noted that taste preferences and concerns about the effects of conventional farming practices on the environment and animal welfare are among other reasons to choose organic. The study's goal was to help consumer's make more informed decisions.
Not surprisingly, organic advocates are up in arms. Many say nutrition isn't the reason people buy organic foods but taste and safety are the main drivers.
"This study confirms that choosing organic foods reduces consumers' exposure to pesticide residues, and that the overuse of antibiotics in non-organic production leads to higher level of bacteria resistant to antibiotics in meat," Laura Batcha, EVP of the Organic Trade Association, told Bloomberg News. "Studies have increasingly shown the importance of minimizing young children's exposure to even low levels of chemical pesticides."
Critics noted that the paper couldn't delve into the long-term effects of pesticide exposure since none of the studies lasted longer than two years, with many lasting only a few days. The current limits for pesticides set for the EPA was also assumed to be correct. The examined studies also analyzed general "produce" or "meat" categories and didn't offer head-to-head comparisons for specific food items.
- Are Organic Foods Safer or Healthier Than Conventional Alternatives?: A Systematic Review - Anals of Internal Medicine
- Little evidence of health benefits from organic foods, Stanford study finds - Stanford School of Medicine
- Stanford Scientists Cast Doubt on Advantages of Organic Meat and Produce - New York Times
- Organic food adds no vitamins for extra cost, research finds - Bloomberg New/Washington Post
- 'Organic' a waste of money? Depends on your reason for buying it - Los Angeles Times
- Going organic could lead to a letdown, researchers find - Kansas City Star/Associated Press
- Organic no better than conventional? Baloney - Atlantic Magazine