Research from the Harvard Nurses' Study indicates that eating a quarter cup of walnuts five times a week may reduce the risk of heart disease by as much as 35 percent. These effects have been linked to the anti-clotting and cholesterol-lowering properties of the omega-3 fatty acids contained in walnuts. Walnuts contain other nutrients such as zinc, iron, folate, calcium, vitamins A, E, and C. They are also a good source of vegetable protein and easily fit into the Meat & Alternates category in the Canadian Food Guide to Healthy Eating. Caution - while most of the fat is the heart-healthy unsaturated type, walnuts are high in overall fat and calories. One ounce or the equivalent of 14 walnut halves provides approximately 185 calories and 18.5 grams of fat.