Walnuts provide calcium and antioxidant vitamins A, C and E. The vitamin E fraction in walnuts is particularly high in gamma-tocopherol, a powerful antioxidant. They also contain B-complex vitamins and minerals such as magnesium, zinc, iron, phosphorus and copper for energy metabolism. They are also a good source of energy as nearly half of the carbohydrate in walnuts is fiber while seventy five percent of the carbohydrates are complex. They are also a rich source of arginine and contain the branched chain amino acids isoleucine, leucine and valine.
Walnuts contain essential fats, and no cholesterol or trans fats and its consumption has shown to lower total cholesterol levels as well as LDL cholesterol levels. They are one of the few good plant sources of omega-3 fatty acids (alpha linolenic acid) which has been shown to lower the risk of cardiovascular disease. Most people consume diets that are high in omega 6 fatty acids, which are common in most vegetable oils, but have low intakes of omega-3 fatty acids, especially if they do not consume fish. While it is important to reduce the total amount of fat in the diet, the type of fat is equally important. In recent years, omega-3 polyunsaturated fatty acids (PUFA) have been identified for their protective functions in improving serum cholesterol profiles, reducing risk of heart attack, reducing inflammation from autoimmune disease, improving insulin sensitivity in diabetics and enhancing the immune response.
Consumption of about 40 to 50 gms of walnuts a day would be sufficient. It can be eaten by anyone and causes no problems.