Effects of physical activity and nutrition on fibroblast growth factor 21 and irisin in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver diseases. At the present time, the most important treatment of NAFLD is the lifestyle changes, which include diet and physical activity. The purpose of this study is to determine the effects of diet compatible with NAFLD and physical activity on serum irisin and FGF21 levels and some biochemical and anthropometric parameters in non-alcoholic fatty liver disease. A total of 33 subjects (16 males and 17 females) participated in the present study, which were diagnosed with NAFLD. General information, nutrition habits, physical activity status and 24-hour dietary recall were collected through questionnaire and a diet compatible with NAFLD was presciribed individually. A total of 17 subjects (9 males and 8 females) completed the 4 weeks medical nutrition therapy (MNT). At the beginning and at the end of 4 weeks, anthropometric measurements and blood samples were taken from the individuals. In the collected blood samples, serum irisin and FGF21 levels were quantified with commercial ELISA kits. Physical activity records and 2-day food records were collected for 4 weeks. As a result of 4 weeks MNT, body weight, body mass index, waist circumference, neck circumference, body fat ratio, body fat mass, ALT, AST and GGT of males and body weight, body mass index, body fat mass, ALT and AST of females were significantly decreased. At the beginning, FGF21 level was 166,6±91,95 pg/mL in males and 328,6±226,72 pg/mL in females, while serum irisin level was 6,3±2,10 ng/mL in males and 4,3±0,77ng/mL in females. At the end of 4 weeks, serum FGF21 level was 214,7±107,33 pg/mL in males and 244,1±131,21 pg/mL in females, while serum irisin level was 5,2±0,57 ng/mL in males and 4,3±0,77 ng/mL in females. Irisin and FGF21 levels of subjects did not change according to MNT or physical activity status. Further studies are needed to understand the association of irisin and FGF21 with NAFLD.