How used coffee grounds could make some food more healthful

María-Paz de Peña and colleagues note that coffee -- one of the most popular drinks in the world -- is a rich source of a group of antioxidants called dietary phenolic compounds. Spent grounds, however, often end up in the trash. But recently, scientists have discovered that antioxidants aren't just in the brewed coffee; they're also in the used grounds. De Peña wanted to figure out the total phenolic content in extracts from these leftovers.

The researchers used three different methods to release antioxidants from spent grounds and found high levels of phenols in the extracts -- sometimes at higher levels than in brewed coffee. Thus, they have the potential to serve as additives to enhance the potential health effects of other food products, the scientists conclude.