Non-GMO labels, like this one at Whole Foods, may strengthen consumer perceptions that genetically modified foods may carry risks to health. Ordon Chibroski/Portland Press Herald/Getty Images hide caption

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Ordon Chibroski/Portland Press Herald/Getty Images

An assortment of organic vegetables is seen on display. A growing body of evidence documents how farming methods can influence the nutritional content of foods. Justin Sullivan/Getty Images hide caption

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Justin Sullivan/Getty Images