They even look like little brains, so maybe that’s Mother Nature’s way of telling us what walnuts are good for.

Indeed, a 2009 study in the Journal of Nutrition found that diets in which nuts made up as little as 2 percent reversed signs of aging in the brains of old rats, including the ability of the brain to function and process information.

And a study presented in 2010 at the International Conference on Alzheimer’s Disease reported that mice with Alzheimer’s demonstrated improved learning, memory and motor coordination after being fed walnuts.

Walnuts contain high amounts of antioxidants, which some researchers say may combat the damage to brain cells’ DNA caused by free radicals in our bodies.