"Vitamins and minerals in plant foods provide protective antioxidants" says James Joseph, who heads the Neuroscience Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston. "But fruits, vegetables, nuts, seeds, and grains contain thousands of other types of compounds that contribute significantly to the overall dietary intake of antioxidants." However, not all fruits and vegetables are created equal. To help pick the best with respect to antioxidant activity, Guohua Cao and Richard Cutler developed a procedure called the oxygen radical absorbance capacity (ORAC) assay. ORAC can serve as a guide for which foods to include in your diet. The ORAC rankings show blueberries with the highest rating followed by black plums, blackberries, raspberries, strawberries, sweet cherries, avocado, navel oranges, and red grapes to name a few.