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A team of researchers from the University of North Carolina’s Chapel Hill Nutrition Research Institute (UNC NRI) created and tested what it believes is a more reliable method to measure antioxidant capacity.
Currently, many assays involved hydrogen atom transfer reactions (like in oxygen radical absorbance capacity [ORAC] and total radical trapping antioxidant parameter [TRAP]) or electron transfer. The UNC assay measures the activation of antioxidant response elements (AREs). AREs are said to turn on genes in the body that make enzymes for protecting cells against free radical damage.
“In the past,” said Steven Zeisel, M.D., Ph.D., UNC NRI director in a press statement, “we recognized antioxidants as chemicals that can tie up damaging free radicals or by their chemical structure, but these assays did not always detect molecules that can strengthen our internal protection systems that protect our cells from oxygen and UV damage. Our assay does.”
The UNC NRI recently published data in the Journal of Nutrition about their new assay. The group took 134 peels and flesh from various types of produce, and found that 107 of them activated AREs in human cells. Among most effective activators were avocado peel, carrot, red pear peel, pineapple, lemon flesh, green pear peel, red delicious apple peel, spinach and some lettuces.
One interesting finding was extracts with the ORAC and total phenolic scores did not always have the highest scores in terms of their ability to activate AREs.
“Our assay changes how we can recognize constituents of fruits and vegetables that improve our internal antioxidant defenses,” said Zeisel, “and we are interested in using our novel antioxidant assay to help companies identify the components of their products that actually do this.”
According to the group, “The assay is available to companies investing in antioxidants to improve the health appeal of their products.”