"It" is the most common fatty liver. Are you affected?

Author: Wang Meng, Ph.D., attending physician, Xuanwu Hospital, Capital Medical University

Reviewer: Wang Changyuan, Chief Physician, Xuanwu Hospital, Capital Medical University

When it comes to "fatty liver", most people may have heard of it, and even know that it is a liver disease caused by excessive fat accumulation in liver cells. However, most people may not know much about the most common type of fatty liver, which is non-alcoholic fatty liver disease.

"Fatty liver" is the common name for fatty liver disease, which can be divided into alcoholic fatty liver disease, non-alcoholic fatty liver disease, and fatty liver caused by other reasons such as acute fatty liver of pregnancy. Among them, non-alcoholic fatty liver disease is the most common. Non-alcoholic fatty liver disease refers to fatty liver caused by factors other than alcohol and other factors that are clearly harmful to the liver.

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1. What are the dangers of non-alcoholic fatty liver disease?

At present, fatty liver has been identified as a type of chronic liver disease. In my country, the prevalence of fatty liver is increasing, with the adult prevalence rate as high as 29%, which seriously threatens people's health. Fatty liver can not only lead to liver diseases such as hepatitis, cirrhosis, and hepatocellular carcinoma, but is also closely related to diabetes, digestive tract tumors, coronary heart disease, cerebrovascular disease, etc. If you find that you have fatty liver, even if it is the most common non-alcoholic fatty liver disease, you should not take it lightly.

Non-alcoholic fatty liver disease includes simple fatty liver, non-alcoholic fatty liver hepatitis and its related cirrhosis. Studies have shown that when patients with non-alcoholic fatty liver disease are over 50 years old and suffer from hypertension, type 2 diabetes or metabolic syndrome, their risk of cirrhosis will increase significantly. Researchers followed up patients with non-alcoholic fatty liver disease for 5 to 10 years and found that the risk of cardiovascular events in such patients increased by 1.64 times, the risk of type 2 diabetes increased by 1.86 times, and the risk of metabolic syndrome increased by 3.22 times. The results are shocking! And the problem does not stop there. These diseases will further lead to a significant increase in the incidence of hypertension and stroke. In addition, non-alcoholic fatty liver disease can also aggravate colon cancer, breast cancer, bone loosening, chronic kidney disease, etc.

Therefore, when ultrasound examination results show the presence of fatty liver or fatty infiltration of the liver, we must not take it lightly, but pay enough attention to it and conduct further screening and evaluation.

2. How to diagnose non-alcoholic fatty liver disease?

The diagnosis of nonalcoholic fatty liver disease can be divided into two steps.

The first step is to rule out other causes of fatty liver, such as alcohol abuse. In other words, the doctor carefully asks the patient about his living habits, especially his drinking habits, to make sure that the patient's fatty liver is not caused by alcohol abuse, the use of certain drugs, or genetic diseases.

Step 2: There needs to be imaging or histological evidence for diffuse hepatic fatty degeneration. In other words, a confirmed diagnosis of non-alcoholic fatty liver disease also requires "evidence" from medical examinations, including imaging and histological examinations.

(1) Imaging diagnostic basis

B-ultrasound is an effective imaging diagnostic method that can accurately identify fatty liver. Although its sensitivity and specificity are low, it is low-cost, radiation-free, and convenient to examine. Transient elastography (TE) is a non-invasive technique that uses ultrasound to measure liver stiffness value (LSM) to assess the degree of liver fibrosis, and can be used as a supplementary examination for fatty degeneration and fibrosis of the liver. In addition, imaging diagnosis also includes magnetic resonance imaging (MRI) and computed tomography (CT), but these two examination methods are mainly used for the diagnosis of liver space-occupying lesions and focal fatty liver. The accuracy of the diagnosis of simple fatty liver is not higher than that of B-ultrasound, and there is electromagnetic radiation, and the cost is relatively high. Therefore, the two methods are less popular in the diagnosis of simple fatty liver.

(2) Histological diagnosis basis

Liver biopsy can more accurately identify fatty degeneration, cell damage and inflammatory response, making it the "gold standard" for diagnosing fatty liver.

In the early stages of non-alcoholic fatty liver disease, patients may not have any special symptoms or feel any physical changes. When we find elevated serum aminotransferase during a physical examination or ultrasound indicates diffuse fatty liver, we need to be alert that non-alcoholic fatty liver disease may be at work. At this time, it is particularly important to seek medical attention in a timely manner and conduct further examinations.

3. How to prevent and treat non-alcoholic fatty liver disease?

For patients with non-alcoholic fatty liver disease, if it is just a simple fatty liver state, it will not affect other organs. However, if metabolic syndrome or obesity exists at the same time, it may further affect the liver. Therefore, losing weight, improving insulin resistance, preventing and treating metabolic syndrome and type 2 diabetes and its related complications are the first priorities for treating non-alcoholic fatty liver disease. Secondly, efforts should be made to reduce the deposition of fat in the liver, especially for patients with non-alcoholic fatty liver hepatitis. For patients with non-alcoholic fatty liver hepatitis and fatty liver fibrosis, effective measures should also be taken to prevent further deterioration of the disease and reduce the occurrence of cirrhosis and other complications.

(1) Improve your lifestyle

Reducing body weight and waist circumference is an important measure to prevent and treat nonalcoholic fatty liver disease and its complications.

Healthy diet: Overweight or obese patients should control their calorie intake. It is recommended to reduce the intake by an average of 500 to 1000 kcal (about 2092 to 4184 kJ) per day on the basis of the target intake, reduce the intake of sugary drinks, saturated fatty acids (animal fat and palm oil, etc.) and trans fatty acids (fried foods), eat more whole grains, foods rich in omega-3 fatty acids and dietary fiber, and strictly control dinner calories and eating behavior after dinner.

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Strengthen physical exercise: avoid sitting for long periods of time and do moderate aerobic exercise (such as cycling, brisk walking, swimming, dancing, etc.) more than 4 times a week, with a cumulative time of 150 to 250 minutes. In addition, do light to heavy resistance muscle training (lifting dumbbells, push-ups, elastic bands, etc.) 2 to 3 times a week.

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Liver fibrosis can only be reversed if the body weight drops by more than 10% and is maintained for 1 year. If the body weight does not drop by more than 5% after 6 to 12 months of lifestyle changes, it is recommended to use drugs such as orlistat and metformin under the guidance of a physician for assistance.

(2) Treatment of metabolic syndrome

Non-alcoholic fatty liver disease and metabolic syndrome are mutually causal. Metabolic disorders are not only closely related to the high incidence of type 2 diabetes and cardiovascular diseases, but also participate in the occurrence and development of fatty liver disease. Therefore, one or more drugs are generally used clinically to treat obesity, hypertension, type 2 diabetes, dyslipidemia, gout and other diseases. Unless there is liver failure and decompensated cirrhosis, patients can be treated with angiotensin II receptor antagonists, ω-3 polyunsaturated fatty acids, statins, metformin, pioglitazone, etc.

(3) Drug treatment of liver damage

The auxiliary treatment of liver protection and anti-inflammatory drugs is mainly used for: ① Patients with fatty hepatitis confirmed by biopsy; ② Clinically suggested the presence of fatty hepatitis or progressive liver fibrosis; ③ Elevated aminotransferase during the use of related drugs to treat metabolic syndrome; ④ Combined with drug-induced liver injury, autoimmune hepatitis, chronic viral hepatitis, etc. Commonly used liver protection and anti-inflammatory drugs include polyene phosphatidylcholine, silymarin, bicyclol, ursodeoxycholic acid, glycyrrhizic acid diamine, etc. However, it should be noted that these drugs are not recommended for combined use.

(4) Others

Liver transplantation is an option for patients with end-stage liver disease and hepatocellular carcinoma.

4. Tips (for non-alcoholic fatty liver disease)

(1) Avoid extremely low-calorie diets to lose weight!

(2) Avoid using Chinese and Western medicines that may be hepatotoxic, and use health supplements with caution!

(3) Limit your drinking or avoid excessive drinking!