Conventional agriculture gets a boost this week with the release of a Stanford University study that shows that the published literature "lacks strong evidence that organic foods are significantly more nutritious than conventional foods." The study, which will be touted by conventional ag groups all week, does note that consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistance bacteria, but researchers also add that no conventional foods had residues above established safety levels.
The study, which looked at 17 studies in humans and 223 studies of nutrient and contaminant levels in foods took a look at a wide range of issues. Only three of the human studies examined clinical outcomes, finding no significant differences between populations by food type for allergic reactions or symptomatic infection, such as Campylobacter.
Two studies reviewed reported lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of those levels in adults including urine, serum, breast milk and semen could find no clinical differences. The study also found no difference in the risk to exposure to E. coli contamination between conventional and organic foods, which researchers note is often unrelated to farming methods.
As for nutritional differences? They didn't find any. The one difference was higher levels of phosphorus in organic foods, though the researchers say this finding was not clinically significant.
Researchers do note that the studies used were heterogeneous and limited in number, and that publication bias may be present. There was no primary funding source listed.
One author of the study - Crystal Smith-Spangler - says some believe that organic food is always healthier and more nutritious. "We were a little surprised that we didn't find that."
One Stanford Blogger, notes that there are other reasons to buy organic, but that perceived added nutrition or safety aren't part of the argument. Expect more commentary on the study and its findings as different groups start reviewing the data and information.