“Something is pulling us toward those organic veggies that are grown without synthetic pesticides or fertilizers,” blog NPR’s Allison Aubrey and Dan Charles this morning. But a new metastudy out of Stanford University suggests that whatever it is, it’s not based on scientific proof that organic produce –- a flourishing $12.4 billion slice of the food marketing industry –- is any more nutritious than conventionally grown crops.
The researchers did find that there was less pesticide residue on organic foods –- an average of 7% vs. 38% -- and that consuming them may reduce exposure to antibiotic-resistant bacteria. The analysis of four decades of research, which is published today in the Annals of Internal Medicine but released to the press in advance, examined 237 studies over a four-year period.
“When we began this project, we thought that there would likely be some findings that would support the superiority of organics over conventional food,” Dr. Dena Bravata, a senior affiliate with Stanford’s Center for Health Policy and an author of the paper, tells the New York Times’ Kenneth Chang. “I think we were definitely surprised.”
The researchers “concluded that fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Nor were they any less likely to be contaminated by dangerous bacteria like E. coli,” Chang reports.
A smaller study done in 2009 by Alan Dangour at the London School of Hygiene and Tropical Medicine with a European emphasis reached similar conclusions, Elizabeth Weise reports in USA Today. But Consumers Union scientist Urvashi Rangan reminds Weise that organic farming started as a movement designed to be better for the environment and for farmers.
"The health benefits really ended up being almost inadvertent, a nice fringe benefit" of farming in a sustainable way,” she says. "Is it in some ways healthier to have less pesticides in your body, especially if you're a kid? Absolutely," she maintains.
But the study also concluded that “the vast majority of conventionally grown food did not exceed allowable limits of pesticide residue set by federal regulations,” NPR’s Aubrey and Charles point out. As for why there is any pesticide residue on organic foods at all, “sometimes chemicals drift over from nearby crops, or produce is handled in the same warehouse as organic produce,” Sonya Lunder, a senior analyst at the Environmental Working Group, tells CNN’s William Hudson.
“Specialists long have said that, organic or not, the chances of bacterial contamination of food are the same, and Monday's analysis agreed,” writes the AP’s Lauran Neergaard. “But when bacteria did lurk in chicken or pork, germs in the non-organic meats had a 33% higher risk of being resistant to multiple antibiotics,” according to the researchers.
Farmers say feeding animals antibiotics is “necessary to meet demand for cheap meat,” observes Neergaard. “Public health advocates say it's one contributor to the nation's growing problem with increasingly hard-to-treat germs.”
Meat is a comparatively small portion of the organic market -- $538 million in 2011, according to the Organic Trade Association, but it is also the fastest-growing sector, up 13% last year.
NPR’s Aubrey and Charles also suggest that, somewhere down the road, vegetables might be marketed based on their nutritional content, including “signs in the supermarket that advertise, for instance, iron-rich beans. Maybe they'd be organic, or maybe not.”
The Stanford study is making news across the globe this morning, but the debate is not likely to put it to rest. “Critics say the work is inconclusive and call for more studies,” reports the BBC. The Soil Association in the U.K., for example, says "studies that treat crop trials as if they were clinical trials of medicines, like this one, exaggerate the variation between studies, and drown out the real differences." It points to a U.K. review paper that “found that most of the differences in nutrient levels between organic and non-organic fruit and vegetables seen in this U.S. study are actually highly significant."
In any event, anti-produce zealots are not being given permission to wave the findings in your face, demanding more hot dogs and potato chips in place of tomatoes, bean sprouts and Anjou pears. Crystal Smith-Spangler, a primary care doctor at Stanford University and lead author on the study, tells USA Today’s Weise, “There is overwhelming evidence that eating produce improves health -- so whatever you choose to buy, load up on fruits and veggies.”