Walnuts are high in alpha-linolenic acid (ALA), a type of omega-3 fat — one of the healthy types of fat. Research shows that eating foods rich in ALA can have an impressive impact on your heart disease risk. For each gram of ALA you eat per day, you lower your risk of dying from heart disease by 10%. Walnuts contain about 2.5 grams of ALA per 1-ounce serving. Walnuts seem to benefit everyone’s heart, but people with Type 2 diabetes especially should take note. Those who eat five servings of tree nuts per week have a lower risk of heart disease. A serving is about 12 to 14 walnut halves or 1/4 cup. If you want to eyeball it, it’s about the amount that fits in the palm of your hand.