Antioxidants reduce inflammation and stress on cells to help prevent or slow the process of cellular aging, CBS News medical correspondent Dr. Jennifer Ashton explained on "The Early Show" Wednesday.
Ashton said, "Antioxidants were known to be in fruits and vegetables, green tea and red wine, but this is the first time researchers have measured the antioxidant content in these foods, finding they're full of them."
The University of Scranton (Pa.) study by Joe Vinson, a professor of chemistry, found almost all whole-grain breakfast cereals and many common, grain-based snacks contain substantial amounts of polyphenols, a form of antioxidants that is thought to have major health benefits. Ashton said antioxidants are linked to benefits for many health issues, from heart disease to cancer.
Ashton explained some cereals with raisins, in addition to the whole-grain content, were the highest in antioxidants. The researchers also found that cereals with added cinnamon or cocoa also had high rates of antioxidants due to the polyphenols in cinnamon and cocoa.
Ashton added, "You want to make sure that you choose cereals that don't have a lot of extra sugar, and artificial ingredients that will counteract the good of the antioxidants."
As for snacks, popcorn had the highest antioxidants, followed by whole grain crackers.
Ashton said popcorn -- as long as it's not loaded with butter -- is a good source, Ashton said.
But can these foods and snacks replace fruits and vegetables?
Ashton said "no," adding the key is a balanced, well-rounded diet.
"Though this research found that whole grain products have comparable antioxidants per gram to fruits and veggies, they are often different kinds and you should eat a wide variety of healthy foods," Ashton told CBS News. "Sorry, you still need to eat your vegetables."