Liver is an important organ and a popular food in many cultures. Pork, bovine, lamb and chicken livers are perhaps the most common for the table. Cooked similarly to other cuts of meat, you can eat liver as main dish, either plain or smothered in onions, or in combination with other meats. Liver is an important part of some traditional recipes, such as Scotland’s haggis and India’s mutton liver fry. Some spreads, such as liver pate' and liverwurst also add liver to your daily diet.
Protein and Fat
Liver is an excellent source of protein. According to LIVESTRONG.COM'S MyPlate, 1 oz. of calf liver contains 6.2 g of protein. This represents about 12 percent of the daily value. Protein is an important macronutrient for the maintenance and building of body tissues including muscle, hair and nails. Protein is also an important component of enzymes and hormones. While many think that liver has excessively high fat and calories, this is not so. In fact, 1 oz. of calf liver contains just 2.4 g of fat, or 3 percent of the daily value, and 49 calories. Chicken liver contains fewer calories and fat than beef and calf liver; however, it also has less protein.
Liver is a very concentrated source of vitamins. “McCance and Widdowson’s the Composition of Foods” states that 1 oz. of calf liver delivers over 100 percent of the daily value of vitamin B-12 and vitamin A. It is also a good source of folate and riboflavin. Vitamin B-12 is important for red blood cell production and nervous system function. Vitamin A plays a key role in eye, hair and skin health. Folate is important in digestion and red blood cell health, and the body uses riboflavin to produce energy from foods.
Calves livers in particular is an excellent source of iron, supplying 11 mg per 3-oz serving, or 61 percent of the daily value of iron, which is 18 mg, according to the Office of Dietary Supplements. Beef liver contain less iron, about 5.2 mg per serving. One oz. of calf liver delivers over 100 percent of the daily value of copper and about 25 percent of the daily value for selenium and zinc. Like vitamin B-12 and folate, copper is important for proper red blood cell function and helps with iron metabolism. Selenium, considered an antioxidant, is involved in a number of enzymes and is important for male fertility. Zinc aids wound healing and maintains a healthy immune system.
While moderate consumption of liver can be beneficial owing to its nutrient profile, excessive consumption can be harmful due to its cholesterol content. Doctors advise pregnant women to avoid liver and liver products because a high vitamin A intake can harm the unborn baby. Liver and offal are also high in purines, which can aggravate gout and kidney stones. If you have exotic tastes, eating polar bear liver can cause very high levels of vitamin A, which leads to dizziness, nausea, headaches, joint pain and, in severe cases, death.