(UPDATED COVERAGE, Sept. 7) Triggering a spirited response from organic food supporters, Stanford University researchers say there is little scientific evidence that organic foods offer fewer health risks or are more nutritious than conventional food.

“There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health,” Dena Bravata, senior author of a paper study comparing the nutrition of organic and non-organic foods, said in a news release.

The report won’t likely change the dynamics of organic food demand, one retail analyst said.

“My assessment would be the sort of commitment that organic buyers have to their product is going to be more resilient than a single study and a single news article,” said Steve Lutz, executive vice president of the Nielsen Perishables Group, West Dundee, Ill.

While some consumers might be inclined to purchase less organic produce, he said most who buy organics seem pretty dedicated and are often motivated by more than pesticide residue concerns.

The news of the report was widely covered and Christine Bushway, executive director of the Brattleboro Vt.-based Organic Trade Association, said there were shifts in how the story was covered.

She said media coverage first focused on the equivalency of nutrition between organic and conventional food, which Bushway said has never been a prime motivation for organic consumers.

Bushway said she doesn’t feel the report’s conclusions  will dim demand for organic food.

“I had one editor of a print publication say to me that she felt that this would call attention to the pesticide issue, and the fact that organic food has fewer pesticides,” she said.

Bushway said the study’s conclusions about the safety of conventional and organic food were put in the context of government standards, which are not necessarily the sole factor for organic consumers.

“Our committed consumer is very aware of concerns about pesticides and aware of the President’s Cancer Panel which tells people to lower their risk of cancer by avoiding eating foods with pesticides,” she said.  

She said Stanford research confirmed that consumers can minimize exposure to pesticide residues in produce by choosing fruits and vegetables with the U.S. Department of Agriculture organic label.

Marilyn Dolan, executive director of the Watsonville, Calif.-based Alliance for Food and Farming, said the report substantiated the message that both conventional and organic produce is safe.

“The report agrees with our message,” Dolan said.

While not having a chance to review the Stanford study, Ken Mobley, general manager of Earth Source Trading Inc., Ephrata, Pa., said organic demand is not a fad and continues to show steady, consistent growth.

“It has gone to a large percentage of our company’s business, it has been a part of regular shoppers’ list of things to purchase,” he said.

The organic movement has prodded the conventional industry and growers to reduce pesticide use, Mobley said.

The research results were published in the Sept. 4 issue of Annals of Internal Medicine.
The research group, led by Bravata, a senior affiliate with Stanford’s Center for Health Policy, and Crystal Smith-Spangler, an instructor in the school’s Division of General Medical Disciplines, reviewed 17 studies with people and 223 studies of nutrient and contaminant levels in food.

The study found that the risk for contamination with detectable pesticide residues was lower among organic than conventional produce, but differences in risk for exceeding maximum allowed limits were small.

The research also found that E. coli contamination risk did not differ between organic and conventional produce.

The research did say that consumption of organic food may reduce exposure to pesticide residues.

Bravata’s patients asked repeatedly about the benefits of organic products and she didn’t know how to advise them, according to the release.

After examining the studies, researchers found “little significant difference” in health benefits between organic and conventional foods, according to the release.

The review found no consistent differences in the vitamin content of organic products, and only phosphorus was markedly higher in organic versus conventionally grown produce.

Despite what Bravata called “tons of analyses,” researchers were unable to single out particular fruits and vegetables for which organic was the consistently healthier choice, according to the release.

“Some believe that organic food is always healthier and more nutritious,” Smith-Spangler said in the release. “We were a little surprised that we didn’t find that.”

Sales of organic foods have grown from $3.6 billion in 1997 to $24.4 billion in 2011, according to the release. First-quarter 2011 data from the United Fresh Produce Association’s FreshFacts report show organic vegetables accounted for 3.3% and organic fruits tallied 1.5% of total produce sales.

Bravata said the aim of the research is to educate consumers, not discourage organic purchases.

“If you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional,” Bravata said in the release, including taste preferences and concerns about the effects of conventional farming practices on the environment.

Smith-Spangler said in the release that people should aim for healthier diets, including greater consumption of fruits and vegetables “however they are grown.”