عنوان مقاله [English]
Background and Purpose: Estrogen deficiency during menopause is one of the causes of fatty liver and metabolic syndrome and its progression in postmenopausal women. Due to the importance of estrogen reduction during menopause and its relationship with non-alcoholic fatty liver disease, as well as the effect of exercise and calorie restriction on improving the risk factors for this disease, in this study the effect of aerobic training and calorie restriction on lipid profile, liver steatosis and hormonal changes in Postmenopausal Women with Non-Alcoholic Fatty-Liver Disease (NAFLD) was evaluated.
Methodology: Twenty-four women with type 1 non-alcoholic fatty volunteered to participate in this study. The Subjects were randomly divided into 3 groups: aerobic training, calorie restriction and calorie restriction with aerobic training. In the calorie restriction group, 25% of each subject’s daily energy requirement was reduced for 12 weeks. In the aerobic training group, 25% increase in energy expenditure through aerobic exercise was considered. Aerobic training was running on a treadmill based on MET=6 (65% to 80% of the subject’s heart rate reserve) 4 days a week for 12 weeks. Also in the combined group, 12.5% increase in energy expenditure through aerobic exercise and 12.5% calorie restriction through low calorie diet were considered. Plasma levels of estrogen, lipid profile, fasting insulin and glucose 48 hours before and after the training period were measured. Liver fat was measured using abdominal elastography.
Results: After 12 weeks, plasma estrogen and serum insulin levels in the calorie restriction group (-7.91-%, -19.23%, respectively) and combined (-7.03%, -25.65%, respectively) decreased significantly compared to the pretest (p<0.05), But no significant change was observed in the aerobic training group. Only in the combined group, the levels of cholesterol (-7.94%) and triglycerides (-9.58 %) showed a significant decrease compared to the pretest (p<0.05). There was no significant change in HDL levels in any of the groups after 12 weeks. All three groups, aerobic exercise, calorie restriction and combination compared to the pre-test, significantly reduced the LDL levels (-2.41%, -1.54%, -2.27%, respectively), fasting glucose (-1.99%, -5.65, -6.99%, respectively), insulin resistance index (-11.32%, -23.38%, -30.96%, respectively), and hepatic steatosis (-14.50%, -6.22%, -5.90%, respectively) (p <0.05).
Conclusion: In general, considering the improvement of LDL, fasting glucose, insulin resistance index and liver steatosis in all three groups in the present study, it can be concluded that 12 weeks of negative energy balance protocol is an effective process in improving the factors associated with non-alcoholic fatty liver disease in postmenopausal women. However, aerobic exercise combined with calorie restriction can lead to more effective changes in improving body composition, lipid profile, and metabolic control, and aerobic exercise is more effective in maintaining estrogen levels and improving hepatic steatosis. Therefore, according to the background of research and the importance of estrogen reduction during menopause and its relationship with non-alcoholic fatty liver disease and due to the decrease in estrogen levels as a result of negative balance due to calorie restriction, to improve the risk factors for this disease, it is recommended to use a combination of aerobic exercise along with calorie restriction in the treatment process.