Compared to calf's liver, this is a bit tougher and less delicately flavored, but it's quite good if you're careful not to overcook. It should still be pink in the middle when it's done. Substitutes: calf's liver (milder flavor, more tender) OR lamb liver (milder flavor, more tender) OR pork liver (This is more tender than beef liver, but it has a stronger, less agreeable flavor.) Source:http://www.foodsubs.com/MeatvarLiver.html liver is also a concentrated source of cholesterol. Four ounces of beef liver contain about 400 milligrams (mg) of cholesterol, exceeding the recommended daily limit set by the American Heart Association by 33 percent. With this in mind, a careful balance between the nutritional benefits and drawbacks of liver can be maintained. If you plan the amount and frequency eaten, liver can add significant quantities of important nutrients to the diet without dangerous consequences. Ounce for ounce, beef liver offers the greatest amount of protein. Four ounces of raw beef liver provides more than 22 grams of protein. Calf liver contains slightly less, while an equal amount of raw chicken liver comes in at about 20 grams. Because the protein is of animal origin, liver contains all the amino acids essential to human health. Liver has long been a part of the treatment for pernicious anemia because it is a rich source of heme iron (the organic iron in animal foods). This type of iron is five times more easily absorbed than non-heme iron. Pork liver contains the highest amount of iron, at 34 mg per 4-ounce serving. Liver is a good source of the mineral phosphorus. A diet which includes large quantities of liver also should include added calcium since high phosphorus intake can create a deficiency of calcium. One of the few natural sources of vitamin D, liver is also an excellent source of all the B vitamins (particularly B12), copper, vitamin C and trace minerals.