# Nutritional Support for Liver Diseases
## 2 Nutritional Support for Liver Diseases
### Cirrhosis  
Cirrhosis is characterized by severe fibrosis of the liver due to various factors, such as viral infection, drugs, and alcohol, as well as the end stage of chronic liver disease [4; 92]. As a result of liver cirrhosis, absorption, and its functions, for example, metabolic, are impaired, such as the transformation of proteins, fat, carbohydrates, or toxic compounds, and as a result, cirrhosis becomes a systemic disease [4; 93]. In addition, hypermetabolism is observed in 15-30% of patients with cirrhosis, and their resting energy expenditure is \(>\)120%, which adversely affects nutritional status [94; 95; 96]. During the progression to cirrhosis, the risk of malnutrition and sarcopenia increases--Figure 2[97; 2]. Sarcopenia is characterized by a decrease in skeletal muscle mass or strength and/or physical performance [98]. It is found in as many as 40-70% of patients with chronic liver diseases [99], and its etiology is usually multifactorial and includes chronic inflammation, insulin resistance, nutritional deficiencies, and endocrine disorders [100]. Loss of muscle mass may be a factor worsening the prognosis of patients with diseases of the hepatobilinary system. In the case of cirrhosis, there is talk of reduced survival and an increased risk of severe infection [99; 101]. The loss of muscle mass in patients with cirrhosis is also associated with the development of hepatic encephalopathy odds ratio (OR) of 2.74 (95% CI, 1.87-4.01; \(l^{2}=54.97\%\); \(p=0.049\)) when compared to a population of patients with cirrhosis who do not have sarcopenia [102]. It is likely that muscle tissue provides an alternative pathway for ammonia detoxification (converts circulating ammonia to glutamine) [103]. When hepatic metabolism is impaired in advanced liver disease, ammonia accumulates in the serum. By penetrating the blood-brain barrier, it causes astrocyte edema, vasoconstriction, cerebral edema, and brain hypoperfusion [104]. In the case of the co-existence of sarcopenia with obesity, low muscle mass may be masked by excessive body weight, which increases the risk of cirrhosis decompensation and death in this group of patients [105; 106]. The overall incidence of sarcopenia among patients with cirrhosis is 37.5% (95% CI 32.4-42.8%, \(n=6.403\)), with a higher incidence among men than women (41.9%, 95% CI 35.8-48.2%, \(n=3.141\) vs. 28.7%, 95% CI 20.5-37.8%, \(n=1.590,p=0.012\)), patients with alo  
Figure 2: Causes and effects of malnutrition and sarcopenia in a patient with cirrhosis. (Created with BioRender.com). holic liver disease when compared to non-alcoholic liver disease (49.6%, 95% CI 42.9-56.3%, \(n=1.219\) vs. 33.4%, 95% CI 27.4-39.6%, \(n=2.166\), \(p<0.001\)), and greater severity of cirrhosis (Child-Pugh C) (46.7%, 95% CI 39.0-54.5%, \(n=585\)). For comparison, patients with Child-Pugh class A saw 28.3%, 95% CI 20.5-36.8%, \(n=1.143\) (\(p=0.007\)) [107]. Interestingly, patients with sarcopenia, compared to patients without sarcopenia, have an approximately 1.5-fold higher risk of NAFLD (OR 1.54 (95% CI, 1.05-2.26), with high heterogeneity between studies I\({}^{2}=83\%\), \(p<0.0001\)) [108]. Sarcoma is often associated with malnutrition [109]. In the population with cirrhosis, malnutrition is most often defined as a loss of skeletal muscle mass and/or strength and a decrease in subcutaneous and visceral adipose tissue mass. A common cause of these structural changes is a reduction in protein and energy intake [110]. In order to avoid underdiagnosis, malnutrition should be routinely screened in patients with cirrhosis. However, the interpretation of such a study may be biased by the effects of fluid retention, ascites, and peripheral edema [111]. Malnutrition can also be seen as a complication of cirrhosis as it has a negative impact on disease progression and outcome. Hospitalization and mortality rate are doubled in malnourished patients compared to adequately nonwished patients, and malnutrition is an independent predictor of prognosis [112; 113; 114].