Coffee contains antioxidants that help control cell damage that contribute to the development of disease. It's also a source of chlorogenic acid, which has been shown in animal experiments to reduce glucose concentrations.

Several compounds in coffee may contribute to its antioxidant capacity, including phenols, volatile aromatic compounds, and oxazoles that are efficiently absorbed. Researchers found that a typical serving of coffee contains more antioxidants than typical servings of grape juice, blueberries, raspberries and oranges. Four to six cups of coffee are fine, but after six the gains start to diminish.

“We were surprised to learn that coffee quantitatively is the major contributor of antioxidants in the diet both in Norway and in the US,” said Rune Blomhoff, professor of nutrition at University of Olso.