Pia Knuthsen of the National Food Institute at the Technical University of Denmark in Soborg, Denmark, and colleagues analyzed antioxidants termed "polyphenols" from onions, carrots and potatoes grown using conventional and organic methods and found no differences in polyphenol content for organic vs. traditional growing methods using chemical fertilizers and pesticides.
"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 researchers say in a statement.
Knuthsen and colleagues point out that there are many reasons to pay a premium for organic food products, including environmental protection, better taste, no exposure to chemical fertilizers and pesticides, less use of fossil fuels use to make chemical fertilizers and pesticides and possible health benefits.
"However, the health benefits of organic food consumption are still controversial and not considered scientifically well documented," the researchers say.
The findings are published in the Journal of Agricultural and Food Chemistry.