This snack is rich in selenium, which helps protect your body from tiny, damaging particles called free radicals. One study found that young people who didn’t have enough of this nutrient in their diets were more likely to be depressed. The researchers couldn’t say that low selenium caused depression, though. Just one Brazil nut has almost half your daily requirement of the mineral so be careful to limit how many you eat. Other foods with this mineral include brown rice, lean beef, sunflower seeds, and seafood.