Liver is a good source of protein, as well as iron and other nutrients. However, liver also has high concentrations of elements that are not good for you, such as cholesterol. People with severe deficiencies of vitamin A, iron, copper or vitamin B12 might benefit from eating liver, but this is a decision best left to a nutritionist or doctor.
Most people should eat liver no more than once a week, according to the Scientific Advisory Committee on Nutrition. Those with severe vitamin A or iron deficiencies might get the OK from their doctors to eat larger amounts.
A 3-oz serving of calf liver has 285 percent of your daily requirement of vitamin A. Vitamin A can be toxic if consumed in large amounts, because it accumulates in the body. Toxicity is more likely in children and in those who drink alcohol regularly and can cause nausea, drowsiness and fever. Severe cases can lead to bone fractures and severe anemia. People who are already taking vitamin supplements should talk to their doctors before eating liver to make sure they're not exceeding the safe recommendation for vitamin A. Pregnant women and those trying to become pregnant might need to avoid liver completely, unless their doctors give the OK. According to the National Center for Biotechnology Information, vitamin A can cause abnormal fetal development, as well as failure to thrive and kidney damage.
Liver is very high in cholesterol. The recommended maximum intake for adults is 300 mg per day. A 3-oz serving of beef liver has 330 mg, which is just over the limit. Lamb liver is higher, at 426 mg per serving, while chicken liver has 536 mg. If you already have high cholesterol, you might need to avoid it completely.
Because the liver is the organ in charge of filtering chemicals from the body, it's also the one where the hormones and chemicals injected into the animals end up. If you want to eat liver on a regular basis, buy organic. Organic meat comes from animals who haven't been injected with hormones and antibiotics. You can also choose to get vitamin A from other sources instead of liver. Try fortified milk and cheese for vitamin A. You can also get beta-carotene -- which the body then converts into vitamin A -- from plant sources, which include carrots, spinach, kale, apricots and mango.