USA
January 5, 2011
“Effects of Organic and Conventional Growth Systems on the Content of Flavonoids in Onions and Phenolic Acids in Carrots and Potatoes”
Journal of Agricultural and Food Chemistry
With the demand for organically produced food increasing, scientists are reporting new evidence that organically grown onions, carrots, and potatoes generally do not have higher levels of healthful antioxidants and related substances than vegetables grown with traditional fertilizers and pesticides. Their study appears in ACS’ bi-weekly Journal of Agricultural and Food Chemistry.
In the study, Pia Knuthsen and colleagues point out that there are many reasons to pay a premium for organic food products. The most important reasons for the popularity of organic food products include improved animal welfare, environmental protection, better taste, and possible health benefits. However, the health benefits of organic food consumption are still controversial and not considered scientifically well documented.
The scientists describe experiments in which they analyzed antioxidants termed “polyphenols” from onions, carrots and potatoes grown using conventional and organic methods. They found no differences in polyphenol content for organic vs. traditional methods of growth. “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 report states.
ABSTRACT
The demand for organic food products is steadily increasing partly due to the expected health benefits of organic food consumption. Polyphenols, such as flavonoids and phenolic acids, are a group of secondary plant metabolites with presumably beneficial health effects, and contents in plants are affected by, for example, plant nutrient availability, climate, pathogen infection, and pest attack. In the current study, onions, carrots, and potatoes were cultivated in two-year field trials in three different geographical locations, comprising one conventional and two organic agricultural systems. The contents of flavonoids and phenolic acids in plants were analyzed by pressurized liquid extraction and high-performance liquid chromatography−ultraviolet quantification. In onions and carrots, no statistically significant differences between growth systems were found for any of the analyzed polyphenols. 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.
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