Keywords
Nonalcoholic Fatty Liver Disease Diet Exercise Training Resistance Aerobic
Dear Editor,
We read with great interest the article entitled “The Effects of Aerobic and Resistance Exercise Training on Liver Enzymes and Hepatic Fat in Iranian Men With Nonalcoholic Fatty Liver Disease” (1) the authors reported that both the aerobic (AT) and resistance (RT) exercise training significantly reduced the hepatic fat content, alanine amino transferase (ALT), and aspartate amino transferase (AST) levels in patients with nonalcoholic fatty liver disease (NAFLD). However, these results have been shown in previous studies (2-9), and we believe that the current study provides an important contribution to the literature. Therefore, we needed to point out some issues.
NAFLD is a disease that is directly related to lifestyle, so its prevalence is a consequence of the rising incidence of obesity, diabetes, and other metabolic syndrome components (10). On the other hand, it seems that lifestyle modifications and changes in the composition of the diet also play a key role in the treatment of NAFLD (10). Eating fat, saturated/trans, unsaturated fat with an emphasis on omega-3, simple sugars, fiber, processed meats and fast food play a pivotal role in prevention, improvement or worsening of this multifactorial disease. Therefore, it is important to assess the diet of patients because of its potential role in NAFLD. Changes in diet would be considered confounding factors in this study; however, the dietary intakes of the participants in this study have not been evaluated. At the same time, patients with NAFLD should receive dietary advice regarding the most acceptable therapy for their disease (10).
Moreover, it is not clear in this study whether the subjects represented new cases of NAFLD, if they had previously received any therapy, or how long they had been diagnosed with the disease.
Furthermore, according to the aim of this study, the amount of physical activity at baseline was not determined, and it is not clear if there were any differences between the three groups of patients in terms of their initial total physical activity.
Finally, we suggest that this study be revised once more so that readers of this journal can clearly understand how the effects of daily exercise improve NAFLD.
References
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1.
Shamsoddini A, Sobhani V, Ghamar Chehreh ME, Alavian SM, Zaree A. Effect of Aerobic and Resistance Exercise Training on Liver Enzymes and Hepatic Fat in Iranian Men With Nonalcoholic Fatty Liver Disease. Hepat Mon. 2015;15(10). ee31434. [PubMed ID: 26587039]. https://doi.org/10.5812/hepatmon.31434.
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2.
Cuthbertson DJ, Shojaee-Moradie F, Sprung VS, Jones H, Pugh CJ, Richardson P, et al. Dissociation between exercise-induced reduction in liver fat and changes in hepatic and peripheral glucose homoeostasis in obese patients with non-alcoholic fatty liver disease. Clin Sci (Lond). 2016;130(2):93-104. [PubMed ID: 26424731]. https://doi.org/10.1042/CS20150447.
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3.
Guo R, Liong EC, So KF, Fung ML, Tipoe GL. Beneficial mechanisms of aerobic exercise on hepatic lipid metabolism in non-alcoholic fatty liver disease. Hepatobiliary Pancreat Dis Int. 2015;14(2):139-44. [PubMed ID: 25865685].
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Keating SE, George J, Johnson NA. The benefits of exercise for patients with non-alcoholic fatty liver disease. Expert Rev Gastroenterol Hepatol. 2015;9(10):1247-50. [PubMed ID: 26289101]. https://doi.org/10.1586/17474124.2015.1075392.
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Loomba R, Cortez-Pinto H. Exercise and improvement of NAFLD: Practical recommendations. J Hepatol. 2015;63(1):10-2. [PubMed ID: 25863525]. https://doi.org/10.1016/j.jhep.2015.03.009.
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Martins C, Aires L, Junior IF, Silva G, Silva A, Lemos L, et al. Physical Activity is Related to Fatty Liver Marker in Obese Youth, Independently of Central Obesity or Cardiorespiratory Fitness. J Sports Sci Med. 2015;14(1):103-9. [PubMed ID: 25729297].
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Ordonez R, Carbajo-Pescador S, Mauriz JL, Gonzalez-Gallego J. Understanding nutritional interventions and physical exercise in non-alcoholic fatty liver disease. Curr Mol Med. 2015;15(1):3-26. [PubMed ID: 25601465].
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8.
Takahashi A, Abe K, Usami K, Imaizumi H, Hayashi M, Okai K, et al. Simple Resistance Exercise helps Patients with Non-alcoholic Fatty Liver Disease. Int J Sports Med. 2015;36(10):848-52. [PubMed ID: 26090879]. https://doi.org/10.1055/s-0035-1549853.
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9.
Whitsett M, VanWagner LB. Physical activity as a treatment of non-alcoholic fatty liver disease: A systematic review. World J Hepatol. 2015;7(16):2041-52. [PubMed ID: 26261693]. https://doi.org/10.4254/wjh.v7.i16.2041.
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10.
Ghaemi A, Taleban FA, Hekmatdoost A, Rafiei A, Hosseini V, Amiri Z, et al. How Much Weight Loss is Effective on Nonalcoholic Fatty Liver Disease? Hepat Mon. 2013;13(12). ee15227. [PubMed ID: 24358045]. https://doi.org/10.5812/hepatmon.15227.