Steatosis is an accumulation of fat in tissues. It most commonly affects the liver. Fat accumulation in the liver can lead to liver conditions.

A healthy liver contains some fat, but if fat accounts for more than 5–10% of the liver’s weight, doctors call this a fatty liver, or steatosis. It can mark the beginning of nonalcoholic fatty liver disease (NAFLD).

NAFLD includes a range of liver conditions that occur in people who consume little or no alcohol. The more severe form is nonalcoholic steatohepatitis (NASH). NASH can cause the liver to swell and become damaged.

Doctors associate NAFLD with metabolic syndrome, obesity, diabetes, and hyperlipidemia. NAFLD occurs in nearly 8 in 10 people who have metabolic syndrome.

This article discusses steatosis, including its causes and symptoms and how doctors treat someone with this condition.

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Design by MNT: Photography by Studio Firma/Stocksy & Nephron, CC BY-SA 3.0, via Wikimedia Commons

Steatosis is an accumulation of fat in the liver cells. Doctors may also refer to it as hepatic steatosis.

NAFLD

NAFLD has several stages:

  1. simple steatosis
  2. steatohepatitis
  3. fibrosis
  4. cirrhosis or scarring of the liver
  5. hepatocellular carcinoma (in some cases)

Doctors refer to the disease as “silent” because it initially has no symptoms. The only way to determine the presence of steatosis is to look at liver cells under a microscope.

NAFLD is very common. At the fatty liver stage, it is not serious.

Alcohol-induced steatosis

Steatosis may also be present if a person has alcoholic fatty liver disease.

The main cause of this type of steatosis is heavy alcohol consumption. It can be reversible if doctors diagnose it early and the person stops consuming alcohol.

Otherwise, progression can lead to alcoholic steatohepatitis and, ultimately, cirrhosis. The outlook for cirrhosis is typically poor.

Learn more about alcoholic liver disease.

There are two forms of steatosis:

  • Macrovesicular: Large or small droplets of fat, or lipid, occur in the liver cells and displace the nuclei, which contain the cells’ DNA. This is the more common type.
  • Microvesicular: Numerous fat droplets occur within the liver cells but do not displace the nuclei. This type is much rarer.

Learn more about body cells.

Doctors do not fully understand the causes of steatosis. Fat may accumulate in the liver for many reasons.

Steatosis may have a link to insulin resistance.

Insulin resistance can cause an increase in free fatty acids (FFAs) in the liver. This happens because insulin fails to suppress an enzyme called lipase, which breaks down triglycerides in fat cells.

The liver then tries to break down the FFAs, but it is overwhelmed and unable to do so. The FFAs begin to accumulate in the liver cells, causing steatosis.

Doctors think that obesity is the main risk factor for fat accumulation in the liver. Around two-thirds of adults with obesity have fatty liver.

NAFLD and steatosis are part of metabolic syndrome. Therefore, the other risk factors for steatosis are those associated with insulin resistance, such as type 2 diabetes and polycystic ovary syndrome.

Other factors that might increase a person’s risk include:

  • elevated levels of blood lipids such as cholesterol and triglycerides
  • high blood pressure
  • use of certain medications, such as tamoxifen (Nolvadex)
  • alcohol consumption

Simple steatosis does not have any symptoms. However, as the condition progresses, a person may experience:

A doctor may suspect steatosis based on a person’s risk factors. They will then order tests to help them diagnose the condition. They may order blood tests to measure:

  • liver function
  • blood lipid levels
  • blood sugar, or glucose, levels

Hepatitis panel tests, which measure the amount of viral hepatitis in the blood, may also be beneficial in some cases.

Imaging tests may show fatty liver disease. Doctors may use the following techniques to take an image of the liver:

  • ultrasound
  • computed tomography (CT)
  • magnetic resonance imaging (MRI)

However, these tests cannot diagnose steatosis specifically.

A liver biopsy is the only way to confirm a diagnosis of steatosis. During this procedure, a doctor removes a small sample of liver tissue using a needle. A healthcare professional then examines the tissue under a microscope to look for fat accumulation.

Simple steatosis does not require treatment, and it is a reversible condition. However, a person should focus on making lifestyle changes to improve their overall health and reduce the risk of developing other liver diseases.

If a person has NASH, there is no specific cure. Treatment focuses on managing symptoms and preventing further damage to the liver.

In some cases, a liver transplant may be necessary.

People can reduce their risk of steatosis by reaching or maintaining a moderate weight and following a balanced diet. It is also important to exercise regularly and avoid drinking too much alcohol.

People with diabetes or other conditions that increase the risk of steatosis should work closely with their doctor to manage their condition.

Diet

People with steatosis should try to consume whole or minimally processed foods containing complex carbohydrates, fiber, and protein. Foods should provide a range of nutrients, vitamins, and minerals to help the body function properly.

The Mediterranean diet is a good choice for liver health because it minimizes the consumption of processed foods, added sugar, and saturated fat.

A doctor may refer people to a dietitian to help them plan meals that support liver health.

Learn more about what to eat to heal a fatty liver.

Steatosis is a condition in which fat accumulates in the liver cells. Obesity is a major risk factor for developing steatosis.

Steatosis is the beginning stage of nonalcoholic fatty liver disease (NAFLD), which can progress to a more serious condition called nonalcoholic steatohepatitis (NASH). NASH can lead to cirrhosis, liver failure, and death.

However, if doctors diagnose steatosis early, a person can reverse the condition by reaching or maintaining a moderate weight, following a balanced diet, and stopping alcohol consumption, if applicable.