Antioxidant Levels Not Higher in Organic Vegetables

Polyphenol Content Similar in Conventionally Grown and Organically Grown Veggies, Study Finds

Reviewed by Laura J. Martin, MD on November 05, 2010
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Nov. 5, 2010 -- Organically grown crops are widely perceived as being healthier than conventionally grown crops. But a new study finds that some vegetables that are grown in conventional ways using fertilizers and pesticides have antioxidant levels similar to their organic counterparts.

Pia Knuthsen, PhD, senior research scientist at Denmark’s National Food Institute, and colleagues analyzed antioxidants called polyphenols in onions, carrots, and potatoes grown organically and also in the same veggies cultivated conventionally.

They found no differences in polyphenol content.

Polyphenol Levels Similar

“On the basis of the present study carried out under well-controlled conditions, it cannot be concluded that organically grown onions, carrots, and potatoes generally have higher contents of health-promoting secondary metabolites in comparison with the conventionally cultivated ones,” the Danish researchers report in a news release.

The finding could have impact because the demand for organically produced food has been increasing “due to the expected health benefits of organic food consumption,” the researchers say. And organically grown food is generally more expensive than conventionally produced crops.


Organically produced foods also are considered to have better texture and taste, which also explains why they have become more popular in recent years, the researchers say.

The scientists cultivated onions, carrots, and potatoes in two-year field trials in three different locations. The vegetables were grown in conventional ways in one of the three, and organically in the other two.

“In onions and carrots, no statistically significant differences between growth systems were found for any of the analyzed polyphenols,” the authors write. Thus, it appears that the polyphenols found in organically grown foods that have been shown to help fight dementia, heart disease, and cancer are found in similar quantities in vegetables grown using fertilizer and pesticides.

The study is published in the Journal of Agricultural and Food Chemistry, a publication of the American Chemical Society.

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News release, Journal of Agricultural and Food Chemistry.

Soltoft, M. Journal of Agricultural and Food Chemistry, November 2010.

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