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A new international study suggests that organic foods contain higher levels of antioxidants than conventionally grown versions.

The research, led by Newcastle University and published last week in the British Journal of Nutrition, found concentrations of antioxidants such as polyphenolics that were 18- to 69-percent higher in organic food.

“Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies,” the study reads.

The researchers suggest that switching to eating organic fruit, vegetables and cereals provide consumers 20- to 40-percent more antioxidants, which would be equivalent to eating between one to two extra servings of fruit and vegetables a day.

The team also found that pesticide residues were four times more likely to be found in conventional crops than organic ones and that levels of the toxic heavy metal cadmium are nearly twice as high for conventionally grown foods.

However, the U.S. Department of Agriculture’s Pesticide Data Program (PDP) tests conventional fruits and vegetables each year and finds that “U.S. food does not pose a safety concern based upon pesticide residues.” As for cadmium, the study itself notes that “the exact health benefits associated with reducing [cadmium] intake levels via a switch to organic food consumption are difficult to estimate.”

The paper is a meta-analysis of more than 340 studies of the compositional differences between organic and conventional crops.

“There are a lot more high-quality studies comparing the nutritional quality and safety of organic versus conventional foods and this larger, higher-quality database supports some conclusions that were not reached in some of the earlier studies,” said one of the authors, Professor Charles Benbrook of Washington State University.

While fewer pesticides on organic foods may not have come as a big surprise, Benbrook said the cadmium findings were certainly interesting.

“None of the earlier reviews picked that up and reported significant differences in cadmium levels, but our meta-analysis was much more sophisticated,” he said. It takes into account the sample size and variance of each study included in the analysis, in addition to the mean level of nutrients.

The findings contradict a 2009 study commissioned by the UK Food Standards Agency, which found there were no substantial differences or significant nutritional benefits from organic food.

Critics of this latest study suggest that it overstates the public health significance of the findings. While the findings on increased antioxidants may be news, nutritionists have a hard time saying exactly how beneficial they are.