Fatty liver disease cannot be transmitted from person to person. Unlike viral hepatitis, which spreads through blood or bodily fluids, fatty liver develops due to metabolic factors within an individual's own body. The two main types—non-alcoholic fatty liver disease (NAFLD) and alcohol-related fatty liver disease (ARLD)—arise from excess fat accumulation in the liver caused by insulin resistance, obesity, or chronic alcohol consumption. Whilst the condition itself is not contagious, family members may share genetic predispositions or lifestyle habits that increase risk. Understanding that fatty liver is a metabolic rather than infectious condition helps focus attention on modifiable risk factors and preventive strategies.

Can Fatty Liver Be Transmitted Between People?

Fatty liver disease cannot be transmitted from person to person. It is not an infectious or contagious condition. There is no risk of spreading it through physical contact, sharing food, drinks or utensils, or any other form of close interaction. Unlike viral hepatitis (such as hepatitis B or C), which can be transmitted through blood or bodily fluids, fatty liver disease develops due to metabolic factors within an individual's own body.

The two main types of fatty liver disease are non-alcoholic fatty liver disease (NAFLD) and alcohol-related fatty liver disease (ARLD). NAFLD occurs when excess fat accumulates in the liver of people who drink little to no alcohol, whilst ARLD develops in those who consume alcohol excessively over time. Neither condition involves a pathogen or infectious agent that could be passed between individuals.

Whilst fatty liver itself is not transmissible, certain risk factors may run in families due to shared genetic predispositions or lifestyle habits. For example, family members may share dietary patterns, physical activity levels, or genetic variants that influence metabolism and fat storage. However, this familial clustering reflects inherited susceptibility rather than direct transmission of the disease.

It is important to distinguish fatty liver disease from viral hepatitis, which can be infectious. If you have concerns about liver health or have been diagnosed with fatty liver disease, your GP can provide appropriate guidance and, if necessary, arrange tests to rule out other liver conditions such as viral hepatitis. Understanding that fatty liver is a metabolic rather than infectious condition can help reduce unnecessary anxiety about transmission whilst focusing attention on modifiable risk factors and preventive strategies.

What Causes Fatty Liver Disease?

Fatty liver disease develops when the liver accumulates excessive amounts of fat. Medically, steatosis is defined as fat accumulation in 5% or more of liver cells (hepatocytes), which can be detected on imaging or confirmed by liver biopsy. This accumulation occurs due to an imbalance in how the body processes and stores lipids. The underlying mechanisms differ between the two main types of fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is closely linked to metabolic dysfunction. When the body becomes resistant to insulin—a hormone that regulates blood sugar—the liver responds by producing and storing more fat. This process is often associated with obesity, particularly excess abdominal fat, which releases inflammatory substances and free fatty acids into the bloodstream. The liver then takes up these fatty acids and converts them into triglycerides, leading to fat accumulation. In some individuals, NAFLD can progress to non-alcoholic steatohepatitis (NASH), where inflammation and liver cell damage occur alongside fat accumulation.

Alcohol-related fatty liver disease (ARLD) develops through a different pathway. When alcohol is metabolised in the liver, it produces toxic byproducts that interfere with normal fat metabolism. Chronic alcohol consumption disrupts the liver's ability to break down and export fats, causing them to accumulate within liver cells. The amount and duration of alcohol intake directly influence the severity of fat accumulation.

Other, less common causes of fatty liver include certain medications. Examples include corticosteroids, tamoxifen, amiodarone, methotrexate, valproate and some antiretroviral drugs. If you are taking any prescribed medication, do not stop or change your treatment without consulting your doctor or pharmacist. Other causes include rapid weight loss, malnutrition, and rare genetic conditions affecting fat metabolism. Some medical conditions, including hepatitis C infection and Wilson's disease, can also contribute to hepatic steatosis. Identifying the underlying cause is essential for appropriate management and preventing disease progression.

Reporting side effects: If you suspect a medicine is causing liver problems or any other side effect, you can report it via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or by downloading the Yellow Card app.

Risk Factors for Developing Fatty Liver

Multiple risk factors contribute to the development of fatty liver disease, with many being modifiable through lifestyle changes. Understanding these factors can help individuals assess their risk and take preventive action.

Metabolic and lifestyle factors play a central role in NAFLD development:

• Obesity and overweight status, particularly central (abdominal) obesity, significantly increase risk

• Type 2 diabetes and insulin resistance create metabolic conditions favouring fat accumulation

• High cholesterol and triglycerides (dyslipidaemia) reflect broader metabolic dysfunction

• Metabolic syndrome—a cluster of conditions including high blood pressure, elevated blood sugar, excess abdominal fat, and abnormal cholesterol levels—substantially raises NAFLD risk

• Sedentary lifestyle and lack of regular physical activity contribute to weight gain and insulin resistance

• Poor dietary habits, including high intake of refined carbohydrates, sugary beverages, and saturated fats

Alcohol consumption is the primary risk factor for ARLD. The UK Chief Medical Officers recommend that to keep health risks from alcohol low, it is safest not to drink more than 14 units of alcohol per week on a regular basis. If you do drink as much as 14 units per week, it is best to spread this evenly over three or more days. However, individual susceptibility varies, and some people may develop liver damage at lower levels of consumption.

Demographic and genetic factors also influence risk:

• Age: Risk increases with age, particularly after 50 years

• Gender: Men are at higher risk for ARLD, whilst NAFLD affects both sexes

• Ethnicity: People of South Asian background show increased NAFLD susceptibility in the UK. Evidence for other ethnic groups is less clear, and individual metabolic risk factors remain the most important consideration

• Family history: Genetic variants affecting fat metabolism and insulin sensitivity can be inherited

Medical conditions and medications that may contribute include polycystic ovary syndrome (PCOS), hypothyroidism, sleep apnoea, and certain drugs such as corticosteroids and some chemotherapy agents. If you have multiple risk factors or abnormal liver blood tests, discuss your individual risk with your GP. There is no routine screening programme for fatty liver disease, but your GP can assess whether further investigation is appropriate based on your clinical circumstances.

Prevention and Management of Fatty Liver

Preventing and managing fatty liver disease centres on addressing modifiable risk factors through lifestyle modifications and, when necessary, medical interventions. NICE guidance (NG49) emphasises a holistic approach tailored to individual circumstances.

Lifestyle modifications form the cornerstone of both prevention and treatment:

• Weight management: For those who are overweight or obese, gradual weight loss of 7–10% of body weight can significantly reduce liver fat and inflammation. Aim for steady weight loss of 0.5–1 kg per week through sustainable dietary changes rather than crash dieting

• Dietary improvements: Adopt a balanced diet rich in vegetables, fruits, whole grains, and lean proteins. Reduce intake of refined carbohydrates, sugary foods and beverages, and saturated fats. The Mediterranean diet pattern has shown particular benefit for liver health

• Regular physical activity: Aim for at least 150 minutes of moderate-intensity aerobic exercise weekly, such as brisk walking, cycling, or swimming. Muscle-strengthening activities on at least two days a week are also recommended

• Alcohol reduction or abstinence: For ARLD, complete abstinence from alcohol is essential. For anyone with cirrhosis from any cause, complete abstinence is advised. For NAFLD without cirrhosis, staying within the UK Chief Medical Officers' low-risk guidelines (not regularly drinking more than 14 units weekly, spread over three or more days) is advisable

Medical assessment and monitoring may include:

• Optimising control of associated conditions such as diabetes, hypertension, and high cholesterol through appropriate medications

• Fibrosis risk assessment: If NAFLD is suspected or confirmed, your GP may arrange an Enhanced Liver Fibrosis (ELF) blood test to assess whether you have advanced scarring (fibrosis). NICE recommends considering repeat ELF testing every three years in adults with NAFLD. An ELF score of 10.51 or above suggests advanced fibrosis and usually prompts referral to a liver specialist

• Imaging: Ultrasound scans can detect fat in the liver (steatosis). Specialised scans such as FibroScan (transient elastography) can help assess the degree of liver scarring

• Blood tests: Liver function tests (LFTs) may be performed, but it is important to know that these can be normal even when NAFLD is present. LFTs do not reliably indicate the severity of liver scarring, which is why additional tests such as the ELF score are used

When to seek medical advice:

• Routine concerns: Contact your GP if you experience unexplained persistent fatigue, discomfort in the upper right abdomen, or unexplained weight loss

• Urgent symptoms: Seek same-day or urgent medical attention if you develop: – Vomiting blood or passing black, tarry stools – Yellowing of the skin or whites of the eyes (jaundice) – Swelling of the abdomen (ascites) – Drowsiness, confusion, or altered behaviour (signs of hepatic encephalopathy)

There is no routine screening programme for fatty liver disease in the UK. However, if you have risk factors or if steatosis is found incidentally on a scan, your GP can assess your individual risk and arrange appropriate tests. Early intervention can prevent progression to more serious liver conditions, including cirrhosis and liver failure. Your healthcare team can provide personalised guidance and support to help you make sustainable lifestyle changes that protect your liver health long-term.

Frequently Asked Questions