5. WALNUTS

What it has:     unlike other nuts, walnuts are high in omega-3 fatty acids, the kind associated with fish like salmon and sardines.

Why you should eat more:    Omega -3 fatty acids have been shown to reduce the risks of heart disease and stroke, prevent blood clots, protect against irregular heartbeat, decrease blood pressure and enhance the immune system.

How to up your intake:     Walnuts are extremely high in calories, so use moderation; sprinkle on a salad or toss into a trail mix with dried fruit or just eat about 5 a day on their own.