"There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health," Bravata, was quoted as saying in a report on the Stanford University website.
The research paper had been published in the Annals of Internal Medicine on September 2012.
They had not found strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives, though consumption of organic foods can reduce the risk of exposure to pesticides.
The Stanford study has been triggered by repeated questions from patients about the health benefits or organic food. Bravata had not known how to advise them.
Organic foods had become popular in the United States with sales estimated to grow from 3.6 billion US dollars to 24.4 billion US dollars in 2011. They could be twice as expensive as conventional foods.The researchers had analyzed 237 studies which 17 related to the consumption of conventional and organic food and 223 studies that compared the nutritional values of organically grown and conventionally grown foods.
The duration of the studies ranged from two days to two years and there were no long term studies.
No consistent differences were seen in the vitamin content of organic products, and only one nutrient - phosphorus - was significantly higher in organic produce. Phosphorus deficiency however was not a common health problem in the US.
"There was also no difference in protein or fat content between organic and conventional milk, though evidence from a limited number of studies suggested that organic milk may contain significantly higher levels of omega-3 fatty acids," the report said.
"Some believe that organic food is always healthier and more nutritious," the report quoted Smith-Spangler, who is also an instructor of medicine at the School of Medicine as saying.
"We were a little surprised that we didn’t find that."
Organic produce had a 30 percent lower risk of pesticide contamination than conventional fruits and vegetables but organic foods are not necessarily 100 percent free of pesticides.
But the pesticide levels of all foods generally fell within the allowable safety limits.
Two studies of children consuming organic and conventional diets did find lower levels of pesticide residues in the urine of children on organic diets, though the significance of these findings on child health were not clear yet.
Organic chicken and pork appeared to reduce exposure to antibiotic-resistant bacteria, but the clinical significance of this was also not clear.
The researchers have said that it is not their intention to discourage people from buying organic foods.
Bravata had said there were reasons beyond health benefits that for consuming organic food, including taste, environmental concerns and animal welfare.
The researchers have said that many Americans do not consume enough fruits and vegetables either conventional or oganic.
