Fatty Liver: Causes, Symptoms and Prevention

The liver is an important organ that performs a variety of functions in the human body. It plays a central role in the metabolism of nutrients and detoxification. However, an unhealthy lifestyle can push the liver to its limits, leading to impaired functions. A fatty liver is a common consequence of this and often affects many people without noticing. The following explains what exactly a fatty liver is, how it develops and what treatment options are available.

Table of contents

1. What is fatty liver?
2. What are the symptoms of fatty liver?
3. How can fatty liver disease be diagnosed?
4. Why does obesity often lead to fatty liver disease?
5. What measures help prevent fatty liver disease?
6. How does regular exercise affect liver health?
7. How can you reverse fatty liver disease by changing your diet?
8. How quickly can the liver recover from fatty liver disease?
9. Conclusion

What is fatty liver?

If more than 5% of fat is stored in the liver cells, this is called fatty liver (steatosis hepatis). The most common causes of fatty liver are an unhealthy lifestyle characterized by excessive calorie intake and long-term alcohol consumption (1). At the cellular level, oxidative stress occurs, the oxidation of fatty acids in the liver and damage caused by cytokines (2).

Risk factors include obesity and the presence of metabolic syndrome. In some cases, fatty liver disease can also develop in normal-weight individuals with a BMI of less than 25 kg/m². In addition, the risk of fatty liver disease is increased if type 2 diabetes mellitus, dyslipidemia or high blood pressure are already present (3).

Fatty liver disease can cause inflammation of the liver with progressive fibrosis. If left untreated, this condition can progress to liver cirrhosis, which can eventually turn into hepatocellular carcinoma (1)

What are the symptoms of fatty liver?

Most people with fatty liver disease do not experience any symptoms at first. Fatty liver disease is often discovered by chance, either due to abnormal liver values ​​or through imaging tests that can show fat accumulation in the liver.

However, some sufferers may experience symptoms that indicate liver disease, including fatigue, pain in the upper right abdomen, dark skin discoloration, and fat accumulation in the tissue (lipomatosis). In advanced stages, such as liver cirrhosis, signs of liver failure may also occur (2).

How can fatty liver disease be diagnosed?

Since fatty liver disease does not cause symptoms in many people, doctors should ideally take proactive measures to check liver health in people with the risk factors mentioned above, such as obesity and type 2 diabetes mellitus.

The diagnosis of fatty liver disease can be made using various methods. First, a detailed medical history regarding medication use and alcohol consumption should be taken and tests for chronic viral hepatitis B and C should be carried out (4).

In addition, changes in liver values ​​can be assessed using a blood test. Both direct markers such as alpha-2 macroglobulin and indirect markers such as AST, ALT, platelets and bilirubin can indicate the presence of fatty liver. If some of these values ​​are abnormal, further diagnostic measures should be considered in the next step. Liver stiffness can be measured using transient elastography. If the liver is already fibrosed, it contains more connective tissue and the tissue is stiffer (5).

When assessing elevated liver values, it is important to note that almost any medication can lead to elevated liver values. A variety of herbal remedies and drug abuse are also common causes of elevated liver values ​​(4).

But why does being overweight often lead to fatty liver disease?

Obesity is considered the main cause of non-alcoholic fatty liver disease. Overeating causes fatty tissue, particularly visceral fat, to accumulate around the organs. This promotes inflammatory processes and the development of insulin resistance. Insulin resistance disrupts fat metabolism, leading to the accumulation of fat in the liver cells and uncontrolled transport of fatty acids.

The imbalance in fat metabolism promotes the formation of harmful fatty tissue, which causes, among other things, oxidative stress in the cells. This stress factor activates inflammatory processes and can lead to the death of liver cells. This not only promotes inflammation, but also the formation of scar tissue in the liver. Inflammatory and scar-forming cells play a central role in the development of liver fibrosis (6).

What measures help prevent fatty liver disease?

The most important measures for maintaining a healthy liver include a balanced diet, regular physical activity and maintaining a healthy body weight. In addition, alcohol consumption should be reduced or ideally avoided completely. The need to take medication should also be critically questioned, as long-term use can impair liver function (7).

A balanced diet is based on an adjusted calorie intake that covers individual calorie needs without going into excess. Foods that should be avoided or reduced are saturated fatty acids and refined carbohydrates, which are mainly found in meat products, processed convenience foods and sugary drinks (2).

In addition, industrially produced fructose, which is also contained in many ready-made products, should be avoided. It can have a harmful effect on health by disrupting the balance of the intestinal flora, increasing the permeability of the intestinal wall and ultimately leading to liver inflammation and insulin resistance (8). Fructose from natural foods such as fruit and vegetables, on the other hand, has a health-promoting effect due to its nutrient composition and strengthens a healthy intestinal flora. This was measured in a study by Korean scientists with over 50,000 subjects. Subjects who consumed higher amounts of fruit and vegetables had a significantly lower risk of non-alcoholic fatty liver disease (9).

There are currently no drugs specifically approved for the treatment of fatty liver disease. However, adjunctive cardiovascular therapy can help lower cholesterol levels and high blood pressure, or improve glucose utilization in type 2 diabetes mellitus (6, 7).

How does regular exercise affect liver health?

Regular physical activity has a positive effect on health through various mechanisms. Among other things, more muscle mass is associated with higher glucose consumption and thus prevents insulin resistance (7).

In a study, Hallsworth et al. came to the conclusion that regular exercise can have a positive effect on liver values ​​even in a short period of eight weeks, even if no significant weight loss was recorded in the test subjects during this period. They carried out a set strength training session three times a week. After this period, a reduction of 13% in fat cells in the liver was measured. Fat oxidation and insulin resistance were also reduced.

The researchers of this study explain that physical activity increases the production of the transport protein GLUT4. This promotes the uptake of fatty acids and glucose from the blood into the muscles more efficiently. Once these nutrients are absorbed into the muscle cells, they are used primarily for energy production, which has a positive effect on the overall metabolic state. In addition, inflammatory processes associated with insulin resistance are suppressed (10).

Another study found similar effects from four weeks of endurance training. This led to a significant reduction in free fatty acids in the blood. Free fatty acids can be specifically transported from the subcutaneous fat tissue to the active muscles during physical activity. In addition, the process of lipolysis, in which fats are converted into fatty acids, is optimized. This allows the body to use its fat reserves more efficiently and improve the energy supply to the muscles (11).

How can you reverse fatty liver disease by changing your diet?

In addition to physical activity, diet plays a crucial role in health. Changing eating habits in people with fatty liver disease promotes weight loss, among other things. In 2022, Spanish researchers found that the type of diet does not initially play a significant role as long as the total amount of calories is reduced. In other words, people who focus primarily on eating less overall lose weight more efficiently than those who deliberately avoid certain foods. The researchers emphasize that the change in diet automatically increased the intake of high-quality foods and reduced low-quality foods such as convenience foods and sugary drinks, which had a positive effect on liver values ​​(12).

One diet that has been shown to be particularly beneficial for health is the Mediterranean diet. It promotes a plant-based nutritional approach rich in whole grains, vegetables, fruits, legumes and nuts. It also includes a high consumption of fish, moderate consumption of eggs, poultry and dairy products (mainly yogurt and cheese) and a low consumption of red meat, processed meats and sweets. In addition, this diet is characterized by the use of olive oil as the main source of fat. Overall, it provides many nutrients and bioactive compounds that are associated with the prevention or mitigation of fatty liver disease as well as general health.

The anti-inflammatory and antifibrotic properties of the Mediterranean diet are due, among other things, to the consumption of monounsaturated and polyunsaturated fatty acids and high amounts of fiber. These food components help to support healthy intestinal flora and normal insulin levels. They also promote fat burning and fat breakdown in liver cells (13).

How quickly can the liver recover from fatty liver disease?

Fatty liver disease can be recovered if those affected lose at least 5% of their body weight. However, if the liver disease is already at an advanced stage, greater weight reductions can have a greater impact. In the case of liver fibrosis in particular, a weight reduction of at least 10% has been shown to be particularly effective. In one study, this goal was achieved after just 16 weeks through an adapted diet and an individual training plan.

Research shows that weight loss can achieve recovery rates of up to 90%. However, despite known and effective measures, only about 10% of patients in clinical practice achieve these goals, as many sufferers find it difficult to remain regularly active and to adjust their diet and especially alcohol consumption (1, 7).

Conclusion

Fatty liver is a pathological condition of the liver in which more than 5% of the liver cells are fatty. In most cases, it does not cause any symptoms, but over time it can lead to fibrosis of the liver tissue, liver cirrhosis and even liver cancer. People at higher risk of developing fatty liver disease are overweight people and patients with type 2 diabetes mellitus and arterial hypertension. There are currently no drug treatments that can cure fatty liver disease. The most effective method of combating this disease is therefore lifestyle changes, including a healthy and balanced diet and regular physical activity. These measures have been proven to have a positive effect on liver values ​​and help maintain health.

literature

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