D: It's time to go again to the mailbag. A listener writes:

Dear A Moment of Science,

I've heard a lot about how antioxidants can help prevent disease. Does that mean that I should eat as many antioxidant-rich foods as possible?

Y: A good and timely question. First, to set the stage a bit, antioxidants are molecules that protect cells from damage and are believed to lower the risk for many diseases, including cancer, heart disease, and memory loss. And so it may seem wise to eat many anti-oxidant packed foods, including coffee, tea, alcohol, and fruits and vegetables.

D: But there's evidence that not all antioxidants provide equal benefits. For example, a study by scientists at Harvard found that people who consumed more antioxidants overall, mostly from tea and coffee, did not lower their risk for stroke and dementia as they aged. But people who ate lots of antioxidants in the form of vitamin E-rich foods, such as nuts, seeds, and green leafy vegetables, had a lower risk of dementia. People who ate lots of vitamin C-rich foods, like oranges, had a lower risk of stroke.

Y: Now, this does not mean that antioxidants in tea and coffee provide no benefit. In fact, other studies suggest that antioxidants in tea and coffee may help lower the risk for some types of cancer, Parkinson's disease, and type 2 diabetes. So it does seem wise to eat a variety of antioxidant-rich foods.

D: But it's also important to understand that not all antioxidants are alike, and that types found in different foods provide particular benefits.