ORAC, or Oxygen Radical Absorbance Capacity, is a method of measuring antioxidant capacities of different foods.

ORAC was developed by scientists at the National Institute on Aging in the National Institutes of Health (NIH) in Baltimore, Maryland, and in 2007, scientists with the United States Department of Agriculture published an updated list of ORAC values for 277 foods commonly consumed by the U.S. population (fruits, vegetables, nuts, seeds, spices, grains, etc.).

Of the foods tested, varieties of berries, spices and legumes are those that rank the most highly in their ability to neutralize free radicals. Here is a list of the most antioxidant-rich foods, listed from highest to lowest.

References

Cao G, Alessio H, Cutler R (1993). "Oxygen-radical absorbance capacity assay for antioxidants". Free Radic Biol Med 14 (3): 303-11. PMID 8458588. Ou B, Hampsch-Woodill M, Prior R (2001). "Development and validation of an improved oxygen radical absorbance capacity assay using fluorescein as the fluorescent probe". J Agric Food Chem 49 (10): 4619-26. PMID 11599998. Oxygen Radical Absorbance Capacity of Selected Foods - 2007; Nutrient Data Laboratory, Agricultural Research Service, United States Department of Agriculture, November 2007. Huang D, Ou B, Prior R (2005). "The chemistry behind antioxidant capacity assays". J. Agric. Food Chem. 53 (6): 1841-56. PMID 15769103.Nutrient Data Laboratory, Agriculture Research Service, US Department of Agriculture, Oxygen radical absorbance capacity (ORAC) of Selected Foods - 2007.