A person cannot survive without a liver, but the liver can regrow itself. In other words, people can live with part of a liver or a liver that is not functioning properly.

The liver is a vital organ that regulates waste products in the blood, eliminates toxins, and stores excess energy in the form of glycogen.

For the same reason, if a person needs a liver transplant, a living donor only needs to donate part of this organ. The remaining portions of the liver then regrow in both the donor and the recipient.

Various injuries and diseases — such as cirrhosis and hepatitis — can cause liver problems. Although dialysis can support a failing liver, a person usually needs a transplant.

Keep reading to learn about the liver’s various functions, the diseases that can affect it, and more.

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It is not possible to live without a liver.

However, people can often live with a liver that is not functioning properly. The length of time a person can survive will depend on the severity of the damage, its cause, and the individual’s overall health.

According to a 2017 study, non-alcohol-related fatty liver disease — a common yet less severe form of liver disease — reduces life expectancy by an average of 4 years.

In contrast, cirrhosis, which is a more severe type of liver disease, can significantly shorten life expectancy.

Having a damaged liver does not mean that a person has liver failure. People with liver failure, which is when the liver completely shuts down, can usually only live a day or two without treatment.

In some cases, liver dialysis can support a failing liver by removing toxins from the blood. However, it is not effective for all forms of liver failure.

The liver is a large, dark red organ located mainly in the upper right portion of the abdomen.

It plays an important role in digesting food and absorbing nutrients. The body relies on the liver to carry out a range of functions, which include:

  • Producing bile: Bile is a substance that helps the body absorb and break down nutrients, especially fats. It also helps the body get rid of harmful substances.
  • Storing and metabolizing vitamins: The liver helps metabolize and store fat-soluble nutrients such as vitamin E and vitamin A.
  • Detoxification: The liver eliminates toxic substances from the body and helps break down alcohol, medications, and drugs.
  • Metabolizing bilirubin: The liver converts heme, a substance in red blood cells, to a greenish compound called biliverdin and then a yellowish-red compound called bilirubin. It then processes the bilirubin, most of which leaves the body as part of bile in the feces, although some passes through the kidneys into the urine. In liver failure and liver disease, excess bilirubin accumulates, which can cause a yellowing of the skin known as jaundice.
  • Maintaining other body functions: The liver also affects several other bodily functions, including the breakdown of red blood cells, protein synthesis in the blood plasma, and the removal of iodine from the thyroid hormones.

When the liver does not work properly, toxic substances can accumulate in the blood. This buildup can damage the body’s other organs.

When a person has liver disease, the body may struggle to digest and absorb certain nutrients. Additionally, harmful levels of bilirubin can accumulate in the bloodstream. The symptoms of liver disease include:

  • gastrointestinal issues, such as vomiting and nausea
  • jaundice
  • low energy
  • dehydration
  • pain in the upper right abdomen

Liver disease can be acute, which means that signs and symptoms appear within 4 weeks of onset, or it can become chronic, meaning a long-term illness.

Acute liver disease presents more suddenly, usually due to an injury such as poisoning or an infection such as viral hepatitis. Chronic liver disease means that symptoms appear more gradually, often over months or years.

Both types of disease can cause liver failure.

Chronic liver disease often responds well to treatment or lifestyle changes, especially in the early stages when people have minimal symptoms.

Some examples of liver disease include:

Non-alcohol-related fatty liver disease

Non-alcohol-related fatty liver disease is one of the most common liver diseases. It causes a buildup of fat in the liver, but, in many cases, it produces no symptoms. However, more severe cases can lead to inflammation that damages the liver, resulting in serious liver disease and, sometimes, liver failure.

Acute fatty liver of pregnancy

Similar to fatty liver disease, acute fatty liver of pregnancy causes a fat buildup in the liver during pregnancy. However, acute fatty liver in pregnancy appears more suddenly. It can cause serious and life threatening complications.

Hepatitis

Hepatitis means liver inflammation. Viruses cause most forms of hepatitis, including hepatitis A, B, and C. However, autoimmune hepatitis is a chronic disease that causes the body’s immune system to attack the liver. Alcohol misuse is also a possible cause of hepatitis.

Cirrhosis

Cirrhosis means scarring of the liver. It can happen as a result of chronic diseases or be due to exposure to toxic substances. Alcohol misuse is a common cause.

Poisoning

Poisoning with certain substances, such as an overdose of the drug acetaminophen, can cause acute liver failure.

Biliary atresia

Biliary atresia is a congenital abnormality in which the bile duct is missing or malformed. The symptoms usually appear in the first weeks to months of an infant’s life.

The liver is the only organ that can regenerate itself. In fact, the liver can regrow even when up to 90% of the liver is absent.

This means that it is possible to grow a whole liver from just a small piece of another liver. A living donor can, therefore, give part of their liver to a person with liver failure.

During a liver transplant, a surgeon removes a person’s diseased or failing liver. They replace it with either a whole liver from a deceased donor or a partial liver from a living donor. Both the recipient’s and the living donor’s partial liver will regrow to become full livers.

The livers of donors can regrow within a few weeks to months.

According to a 2021 article, a liver transplant can prolong life expectancy by about 15 years in individuals with acute and chronic end stage liver disease.

Without a transplant, liver failure is usually fatal.

The liver is a vital organ that is critical to sustaining life. It eliminates toxins, breaks down nutrients, and stores vitamins and energy.

It is not possible to live without a functioning liver. This means that although people can live with liver disease, those with liver failure need a transplant.

As the liver can regrow itself, a living donor can give a person part of their liver.