Pecans also provide the highest number of antioxidants of all nuts tested, including almond and walnuts, according to the USDA.
A one ounce serving of pecans contains 196 calories, 3 grams of dietary fiber and over 19 vitamins and minerals, including vitamin A and E, calcium, potassium and zinc.
Pecans are also a good source of oleic acid, the same type of fatty acid found in olive oil. Researchers from North Western University in Chicago recently found in lab tests that oleic acid has the ability to suppress the activity of gene cells thought to trigger breast cancer. While this research is still in its early stages, researchers say it could eventually translate into the recommendation to eat more foods rich in oleic acid, like pecans and olive oil. A one ounce serving of pecans provides 25% more oleic acid that 1 tablespoon serving of olive oil.