Just one Brazil nut provides more than a day's worth of selenium, which may help slash your risk of certain cancers, including prostate. Men with high selenium levels have also been shown to have better blood-sugar control, which can help prevent diabetes. The biggest commonly consumed nut, Brazils are rich and creamy in taste, partly owing to their high fat content, and they contain all nine essential amino acids. They're particularly high in glutamic acid, an amino acid that may help boost memory. 

How to eat them: Make chocolate-dipped nuts: Microwave 6 ounces dark chocolate with a little chili powder. Stir in 1 cup Brazil nuts until coated. Transfer to wax paper, and refrigerate.