Organic products have no significant nutritional advantage over conventional foods, even though consumers can pay more for them, a new study finds.
The four-year study began when two doctors wondered what advice they should give their families and patients about whether to buy organic or conventional foods.
"It became much larger than we expected," says Crystal Smith-Spangler, a primary care doctor at Stanford University and lead author on the study out today in the Annals of Internal Medicine.
Eventually, researchers looked at 240 studies conducted from 1966 to 2011 covering nutrient and contaminant levels. Among the findings:
There were no significant differences in the vitamin content of organic and conventional fruits and vegetables.
Detectable pesticide residue was found in 7% of organic produce and 38% of conventional produce. However, only three studies found pesticide residue that exceeded maximum allowed limits.
As to how pesticides could be in an organic product that must be grown without them by law, Smith-Spangler said it could either be long-lasting, now-banned pesticides in the soil or drift from nearby fields.
Both organic and conventional foods were at similar risk for bacterial contamination.
Organic produce often costs more, but the differential varies. In 2009, it generally cost at least 25% more in Boston and San Francisco wholesale markets, according to the U.S. Department of Agriculture. In rare cases, the organic food was equal or even a smidge lower in price.
Yet there wasn't much difference, "if you're an adult and making a decision based solely on your health," said Dena Bravata, senior author of the paper and a physician at Stanford's Center for Health Policy.
A statement from the Organic Trade Association said the new findings confirm that organics reduce consumers' exposure to pesticides and that overuse of antibiotics can lead to higher levels of bacteria resistant to antibiotics in meat.
"Is it healthier to have less pesticides in your body, especially if you're a kid? Absolutely," says Urvashi Rangan of Consumers Union, publisher of Consumer Reports magazine.
Smith-Spangler says consumers should know that eating produce improves health -- so whatever you choose, load up on fruits and veggies.
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