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By Annie Hauser

Tomatoes grown on organic farms contain more vitamin C and antioxidants than those grown on conventional farms, Brazilian researchers report in the journal PLOS ONE.

Organic tomatoes are exposed to more environmental stress than conventional fruits, perhaps prompting the plants to fortify themselves against the environment through higher sugar levels, vitamin C, and antioxidants, researchers say. Conventional tomatoes experience little environmental stress, thanks to pesticides and fertilizers.


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"When plants are grown more the way they are in nature and grown in good heavy soils, it doesn't surprise me that they’re going to be of more robust quality and be more able to fend off diseases and pests," says Michael Hansen, PhD, a senior scientist with Consumer Reports who specializes in food safety issues and did not work on the study.

Hansen points to other studies of organic milk and organic meat that have found similar results, due to more natural farming practices. "When cows, for example, eat only grass, no grains, the quality of their milk and meat is superior," he says. "There are much higher omega-3 levels in the milk and meat because omega-3s come from the chlorophyll in grass."

Organic vs. Conventional Fruit

In the study, researchers from the Federal University of Ceara in Ceara, Brazil, found that organic tomatoes were about 40 percent smaller than conventional tomatoes. Organic tomatoes that were ripe and ready for commercial sale had 55 percent more vitamin C than conventional tomatoes. The total phenolic content, a measure of flavanoid, antioxidant, and flavor intensity, was 139 percent higher in the organic fruit.

"Our work clearly demonstrates that tomato fruits from organic farming have indeed a smaller size and mass than fruits from conventional growing systems, but also a substantially better quality in terms of concentrations in soluble solids and phytochemicals, such as vitamin C," researchers wrote in the study.

This means that if farmers did not try to reduce plants' environmental stress through pesticides and fertilizers, it could improve certain aspects of tomato quality, researchers wrote.

The new study is only the latest to find a higher nutrient density in organic tomatoes. A recent comparative study published in the journal Food Chemistry showed that organic tomato juice has a higher phenolic content and higher antioxidant levels than conventional tomato juice.

But this information does run contrary to a controversial Stanford University meta-analysis published in the Annals of Internal Medicine last year, which found that eating organic produces little to no nutritional benefit and only a 30 percent lower risk of pesticide exposure.

Hansen says the Stanford analysis was flawed and "drastically manipulated the data" to show less of a difference between organic and conventional foods. The bottom line, Hansen says, is that organic food can be more nutritious than conventional foods, but it's not always a guarantee.

"Can you extrapolate this new study to all organic tomatoes sold anywhere in the U.S.? No. But it does show that, when grown properly, organic fruits and vegetables can have a higher nutrient density," Hansen says. "Consumers can make decisions based on how much these things cost in their local areas."

"Study: Organic Tomatoes Pack a Greater Nutritional Punch" originally appeared on Everyday Health.

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