STANFORD, Calif.—Doctors at Stanford University revisited previous research comparing organic and conventionally raised foods and concluded that there is little evidence that organic is healthier.

Eating organic fruits and vegetables can lower exposure to pesticides, but the amounts measured in conventionally grown produce was within safety limits, researchers reported. And organic foods did not prove more nutritious either.

“I was absolutely surprised,” said Dr. Dena Bravata, a senior research affiliate at Stanford and longtime internist who began the analysis because many of her patients asked if it would be healthier to eat organic foods.

Bravata and her team sifted through thousands of studies and identified 237 of the most relevant to analyze. They include 17 studies of populations consuming organic and conventional diets and 223 that compared either the nutrient levels or the bacterial, fungal or pesticide content of various products grown organically and conventionally.

Individuals might choose organic over conventional because of taste preferences or environmental concerns, Bravata said, but when it comes to the healthfulness of foods “there isn’t much difference.”

People often mistakenly think organic foods are healthier for them because they are free of pesticides and bacterial contamination, or have greater nutritional value, said Tony Banks, a commodity marketing specialist for the Virginia Farm Bureau Federation. “It is very important that consumers have accurate information about their food choices, regardless of whether they prefer organic or conventionally grown foods.

“This Stanford study is the latest of many to dispel myths about organic and conventional foods,” Banks said. “We’ve known all along that farmers produce healthy food for American consumers, whether it is grown conventionally or organically.”

Organic foods account for 4.2 percent of retail food sales, according to the U.S. Department of Agriculture. The USDA certifies products as organic if they meet specific requirements, including being produced without synthetic pesticides or fertilizers or routine use of antibiotics or hormones.

Consumers can spend more for some organic products, but demand is rising. The sale of organic products grew by 9.5 percent in 2011 and reached $31.5 billion in sales, according to findings from an Organic Trade Association survey.

Contact Banks at 804-290-1114.