Love your backyard organic tomatoes? Here's a reason to love them even more. A new study published in the journal PLoS One has found that organic tomatoes are healthier and contain higher levels of nutrients than those doused in pesticides.
Brazilian researchers analyzed the nutrient contents of organic and conventionally grown tomatoes grown on two farms less than a mile apart. Although the organic tomatoes in their study grew to be about 40 percent smaller than the conventional tomatoes, they contained 139 percent more healthy polyphenols and 55 percent more vitamin C than their pesticide-treated counterparts. The most likely reasons the organic tomatoes were healthier, the authors suspected, were that organic tomatoes have to work harder to ward off pests with natural defense mechanisms and to extract nutrients from the soil. Both things boost nutrient levels, but those jobs are made easier for conventional tomatoes because pesticides and synthetic fertilizers take care of those things.
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And the organic tomatoes had higher sugar levels, which improve their flavor.
"Our observations suggest that, at least for fruit and vegetable production, growers should not systematically try to reduce stress to maximize yield and fruit size," the authors wrote, "but should accept a certain level of stress as that imposed by organic farming with the objective of improving certain aspects of product quality."
Last year, scientists from Stanford University published an analysis of these sorts of nutritional comparisons between organic and conventional produce and concluded that there is no difference between the two. That's because the nutrient quality of any produce, organic or not, can be influenced by soil quality, microclimate, transportation, and even storage conditions of the produce. Many studies used in the Stanford analysis were criticized for not factoring those things in. But even the Stanford researchers noted that, according to multiple studies, organic fruits and vegetables have higher levels of polyphenols and vitamin C, just as this study showed.
Nutritional quality aside, the Pesticide Action Network's "What's On My Food?" website notes that the USDA has detected 35 different pesticide residues on tomatoes, among them chemicals known to cause cancer, suspected endocrine disruptors, and pesticides that kill honeybees.
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Of course, the best-tasting tomatoes are the ones grown in season, and since tomato season is still months away, buy organic tomatoes sold in glass jars.
Then donate a few dollars to help the Rodale Institute, the oldest research institution in the country devoted to organic farming. The Institute is crowd-funding a study that will compare the nutrient density of a number of conventional and organic crops, not just study the differences on a crop-by-crop basis, as has been done in the past. The institute has already been doing similar research for 30 years, looking at corn and soy that have been managed organically and conventionally on neighboring research fields, and this new study will be able to address the issues of growing methods, soil quality, harvesting, and processing. Help the institute reach its $25,000 fundraising goal at crowdrise.com.