A Stanford study finding little evidence of health benefits from organic foods provoked international attention last week, prompting dozens of reports in U.S. and international publications. On NPR, the study attracted coverage on both flagship shows, Morning Edition and All Things Considered.
In Seattle though, most dedicated buyers of healthy foods seem to have shrugged. And scientists at Washington State University, home of the nation’s first organic agriculture major, have calmly pushed back at the study and some of the conclusions being drawn from it.
The Stanford researchers conducted a review of other scientific literature to carry out a meta-analysis of what the overall research on organic foods and health might show. In their study, published in the Annals of Internal Medicine, they came to two basic conclusions: “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-resistant bacteria.”
According to Washington State University Regents Professor John Reganold, a leader in scientifically studying organics and farming, there have actually been a dozen such nutrition meta-analysis studies since 2000, with nine finding evidence in favor of organics and three, including Stanford’s, finding little to no evidence.
As a well-nuanced New York Times report on the Stanford study noted rather pointedly, the Stanford study actually overlooked one of those nine — a highly regarded study Reganold led. It found markedly higher nutrition levels for organically grown strawberries — including for Vitamin C and antioxidants – and healthier soils on the organic strawberry farms.
Still, Reganold praised the study for provoking discussion. but also pointing to a widely circulated response by one of his colleagues, research Professor Chuck Benbrook, who took careful but restrained issue with many aspects of the Stanford study.
Others were less charitable. The headline on a Huffington Post commentary by Frances Moore Lappe called the work "shockingly reckless," which wasn't too far beyond the strong critique from Lappe, whose work has helped guide the city of Seattle's official thinking on food issues.
A Stanford news writer attributed the big reaction to two factors: “Many people have strong feelings about organic foods, and I suspect many more – reporters included – want to know if buying organic is worth their money.”
Stanford clearly did its part to gain attention for the study. The Stanford press office and the researchers provided good quotes for making the story a rather easy media takedown of anyone’s assumptions of wide-ranging health benefits from organics. In Stanford’s own press release, one of the study authors said, “Some believe that organic food is always healthier and more nutritious. We were a little surprised that we didn’t find that.” The study author spoke of organics being a “ripe area” for meta-analysis.
In fact, as many shoppers who follow organics closely realize, the science has really only begun to develop evidence on any nutritional differences between organically and conventionally produced foods. That said, the scientific evidence, including the Stanford study, is clear on organic foods having less pesticide residues.
Trudy Bialic, public affairs director for PCC Natural Markets in the Seattle area, said in an email, “I’ve not had one call, not one email. I think one of our nine store directors had one question from a customer. So the response from organic shoppers, pretty much zip, they expect attacks on organic and they also are aware of the research showing benefits.”
Experts generally agree that consumers in all income categories base their organic shopping decisions on a variety of factors. Many of these were noted by the Stanford researchers in their interviews, including health risks, whether the food is for children or adults, benefits to the environment, the treatment of animals, and, in many cases, the knowledge that pesticide residues are heavy on some specific types of produce and minimal on others, even with conventional farming.
WSU'S Benbrook, a former executive director of the National Academy of Sciences’ agriculture board, wrote 12 pages of “initial reflections” on the Stanford study. He faulted the study for a highly unusual manner of expressing statistical differences that tended to downplay the likelihood, for instance, the differences in pesticide exposure on conventional and organic produce. Benbrook said that, because of his professional interest, he had actually read more than two-thirds of the roughly 300 papers cited in the Stanford research.
Benbrook found the researchers’ conclusions about health benefits tepid and tending toward understatement. And he seemed to suggest that such caution is not likely to hold up over the long run:
Over time, I believe that unbiased analysis compiled with modern-day science is likely to show with increasing clarity that growing and consuming organic food, especially in conjunction with healthy diets rich in fresh, whole foods, is one of the best health-promotion investments we can make today as individuals, families, and a society.
For his part, Reganold notes a number of ways in which the findings could have been presented differently to give a fuller appreciation of what organic agriculture means for individual health and the environment. He points, for instance, to the study’s findings of a higher presence of antibiotic resistant bacteria in conventionally produced chicken and pork as an important matter. And Reganold, a soil scientist and agricultural ecologist, stressed that the evidence in favor of organics for environmental sustainability, including “creating healthy soils to pass on to future generations,” is clear.
While scientific discussion about organics can help people, Reganold said, “The organic movement is driven by consumers and it appears that with the continuing growth in the organic food market, they want more organic food.”
Reganold sees an important role for the organic movement as a change agent in agricultural practices. While organic farming has grown significantly, much more acreage is also now managed through integrated farming practices, which use both methods drawn from organics and some conventional practices, such as limited use of agrochemicals. In Washington state, he said, that has meant significant change in many apple orchards that now use less synthetic pesticides.
As for his own shopping decisions, Reganold said he eats a lot of organics, especially of crops like berries and apples where pesticide residue tends to be high. Much of his motivation is simply to protect the environment and support farmers using organic practices: “I think, well, they are going the extra step.” While his diet is heavy on fruits, vegetables, whole grains, and beans for health reasons, the limited meat he buys is usually range fed, which he said has largely the same benefits of organic meats.
The organic movement has also had another important effect, helping to move the larger conversation toward sustainability. He noted that a farm “can be organic without being sustainable.” But he said, “Results of studies comparing a host of environmental and economic sustainability indicators of organic and conventional farming systems really favor organic."