The potency of an antioxidant is typically measured in terms of its “oxygen radical absorbance capacity,” or ORAC. The U.S. Department of Agriculture reports ORAC values per 100 grams of food and recommends about 5,000 ORAC units per day. Most people average around 1,000. According to the USDA, blueberries have an ORAC rating of 6,552 while strawberries rate 3,577.