In a nutshell researchers say that eating 1½ ounces of tree nuts daily can reduce your risk of heart disease and diabetes. Walnuts are rich in omega-3s.
Hazelnuts contain arginine, an amino acid that may lower blood pressure. An ounce of almonds has as many heart-healthy polyphenols as a cup of green tea and 1/2 cup of steamed broccoli combined; they may help lower LDL cholesterol as well.
The key is moderation, since nuts are high in calories.
Keep a jar of chopped nuts in your fridge, and sprinkle a tablespoon on cereal, salads, stir-fries, or yogurt. Or have an ounce as a snack most days of the week.