Fatty liver disease, risks, strategies, and its relationship with COVID-19 with an emphasis on nutrition and exercise

Document Type : Review Articles


1 Clinical Care and Health Promotion Research Center, Karaj branch, Islamic Azad University, Karaj, Iran.

2 MSc. Department of exercise physiology, faculty of physical education and sport sciences. Islamic Azad University Karaj branch. Alborz. Iran.


The COVID-19 epidemic has caused lifestyle changes in people from all walks of life and has become a global threat to the health and well-being of all countries of the world. Considering changes caused by the prevalence of the disease and quarantine conditions, the increased likelihood of the prevalence of overweight and obesity in people is among these threats. On the other hand, patients with overweight and obesity, and consequently, non-alcoholic fatty liver disease (NAFLD) have a weaker immune system than other people with ideal weight, and as a result, are more likely to develop COVID-19. As there is currently no definitive treatment for COVID-19 and NAFLD, and because people with NAFLD are more likely to develop COVID-19 based on the research in this area, paying attention to this important issue is thus necessary. Considering a regular physical activity program and having a balanced diet are among the essential strategies and may help prevent NAFLD, and consequently, COVID-19. However, given the novelty of COVID-19 pathogen and the ambiguity of the exact cause of why people get NAFLD, further research is needed to be done on the type of effective diet, as well as the type, intensity, and volume of exercise for these people. This study aimed to summarize the available evidence on the pathology and epidemiology of NAFLDs and COVID-19, as well as the effect of NAFLD on COVID-19 in people. Given the existing risks, the nutrition and exercise strategies were investigated in this regard.

What is already known on this subject?

Previous studies have separately examined the effective role of nutrition and exercise training on Covid-19 and non-alcoholic fatty liver disease, and the role of exercise has been less evaluated in these two diseases.


What this study adds?

In the present study, the controlling and preventing effective role of diet and regular physical activity on fatty liver and COVID-19 have been confirmed based on previous studies.


Main Subjects

Aliniya, N., Elmieh, A., & Fadaei Chafy, M. (2020). Efficacy of Portulaca oleracea supplementation with a combination training program on the levels of some blood factors and health indicators of obese females with non- alcoholic fatty liver disease. MEDICAL SCIENCES JOURNAL, 30(3). https://doi.org/10.29252/iau.30.3.253.
Ammar, S. (2018). The Prevalence of Non-Alcoholic Fatty Liver Disease in Iranian Children and Adolescents: A Systematic Review and Meta-Analysis. Sabzevar University of Medical Sciences, Volume 25(Issue 4), 487–494.
Amrein, K., Schnedl, C., Holl, A., Riedl, R., Christopher, K. B., Pachler, C., Purkart, T. U., Waltensdorfer, A., Münch, A., Warnkross, H., Stojakovic, T., Bisping, E., Toller, W., Smolle, K. H., Berghold, A., Pieber, T. R., & Dobnig, H. (2014). Effect of high-dose vitamin D3on hospital length of stay in critically ill patients with vitamin D deficiency: The VITdAL-ICU randomized clinical trial. JAMA - Journal of the American Medical Association, 312(15). https://doi.org/10.1001/jama.2014.13204
Angelidi, A. M., Kokkinos, A., Katechaki, E., Ros, E., & Mantzoros, C. S. (2021). Mediterranean diet as a nutritional approach for COVID-19. In Metabolism: Clinical and Experimental (Vol. 114). https://doi.org/10.1016/j.metabol.2020.154407
Bai, Y., Yao, L., Wei, T., Tian, F., Jin, D. Y., Chen, L., & Wang, M. (2020). Presumed Asymptomatic Carrier Transmission of COVID-19. In JAMA - Journal of the American Medical Association (Vol. 323, Issue 14). https://doi.org/10.1001/jama.2020.2565
Barikani, A., & Pashaeypoor, S. (2019). Lifestyle in Non-alcoholic Fatty Liver: A Review. Iranian Journal of Nursing Research, 13(6), 39–47. http://ijnr.ir/article-1-2215-en.html
Chakravarthy, M. V., Siddiqui, M. S., Forsgren, M. F., & Sanyal, A. J. (2020). Harnessing Muscle–Liver Crosstalk to Treat Nonalcoholic Steatohepatitis. Frontiers in Endocrinology, 11(December), 1–15. https://doi.org/10.3389/fendo.2020.592373
Chan, J. F. W., To, K. K. W., Tse, H., Jin, D. Y., & Yuen, K. Y. (2013). Interspecies transmission and emergence of novel viruses: Lessons from bats and birds. In Trends in Microbiology (Vol. 21, Issue 10). https://doi.org/10.1016/j.tim.2013.05.005
Ding, N., Zhao, K., Lan, Y., Li, Z., Lv, X., Su, J., Lu, H., Gao, F., & He, W. (2017). Induction of atypical autophagy by porcine hemagglutinating encephalomyelitis virus contributes to viral replication. Frontiers in Cellular and Infection Microbiology, 7(FEB). https://doi.org/10.3389/fcimb.2017.00056
Dyson, J., & Day, C. (2014). Treatment of non-alcoholic fatty liver disease. Digestive Diseases, 32(5). https://doi.org/10.1159/000360511
Fabbrini, E., Sullivan, S., & Klein, S. (2010). Obesity and nonalcoholic fatty liver disease: Biochemical, metabolic, and clinical implications. In Hepatology (Vol. 51, Issue 2). https://doi.org/10.1002/hep.23280.
Filatov, A., Sharma, P., Hindi, F., & Espinosa, P. S. (2020). Neurolo-gical Complications of Coronavirus Disease (COVID-19): Encephalopathy. Cureus. https://doi.org/10.7759/cureus.7352
Galedari, M., & Kaki, A. (2017). The Effect of 12 Weeks High Intensity Interval Training and Resistance Training on Liver Fat, Liver Enzymes and Insulin Resistance in Men with Nonalcoholic Fatty Liver. Jundishapur Scientific Medical Journal, 16(5), 493–503. https://doi.org/10.22118/jsmj.2017.53990
Ganji, A., Mosayebi, G., Khaki, M., & Ghazavi, A. (2020). A Review of the 2019 Novel Coronavirus (Covid-19): Immunopathogenesis, Molecular Biology and Clinical Aspects. Journal of Arak University of Medical Sciences, 23(1), 8–21. https://doi.org/10.32598/JAMS.
Gombart, A. F., Pierre, A., & Maggini, S. (2020). A review of micronutrients and the immune system–working in harmony to reduce the risk of infection. Nutrients, 12(1). https://doi.org/10.3390/nu12010236
Grant, W. B., Baggerly, C. A., & Lahore, H. (2020). Reply: “vitamin d supplementation in influenza and covid-19 infections. comment on: Evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths nutrients 2020, 12(4), 988.” In Nutrients (Vol. 12, Issue 6). https://doi.org/10.3390/nu12061620
Haddad, C., Zakhour, M., Bou Kheir, M., Haddad, R., Al Hachach, M., Sacre, H., & Salameh, P. (2020). Association between eating behavior and quarantine/confinement stressors during the coronavirus disease 2019 outbreak. Journal of Eating Disorders, 8(1). https://doi.org/10.1186/s40337-020-00317-0
Hall, J. E. (2016). Guyton and Hall: Textbook of Medical Physiology Thirteenth edition. Elsevier, 13(1).
Hallsworth, K., & Adams, L. A. (2019). Lifestyle modification in NAFLD/NASH: Facts and figures. JHEP Reports, 1(6). https://doi.org/10.1016/j.jhepr.2019.10.008
Hamidi Hesari, M., & Bani torfi, M. (2019). -Probiotics and therapeutic applications-. Laboratory & Diagnosis, 10(42), 61–66. http://labdiagnosis.ir/article-1-322-en.html
Hammami, A., Harrabi, B., Mohr, M., & Krustrup, P. (2020). Physical activity and coronavirus disease 2019 (COVID-19): specific recommendations for home-based physical training. In Managing Sport and Leisure. https://doi.org/10.1080/23750472.2020.1757494
Hanson, A., Wilhelmsen, D., & DiStefano, J. K. (2018). The role of long non-coding RNAs (lncRNAs) in the development and progression of fibrosis associated with nonalcoholic fatty liver disease (NAFLD). Non-Coding RNA, 4(3). https://doi.org/10.3390/ncrna4030018
He, J., Tao, H., Yan, Y., Huang, S. Y., & Xiao, Y. (2020). Molecular mechanism of evolution and human infection with the novel coronavirus (2019-nCoV). In bioRxiv. https://doi.org/10.1101/2020.02.17.952903
Jamali, R., & Jamali, a. (2010). Non-alcoholic fatty liver disease Non-alcoholic fatty liver disease is among the prevalent causes of chronic hepatitis and cirrhosis. Here, we discuss the best diagnostic and therapeutic approaches for metabolic syndrome. Liver. 14(2), 169–181.
Jones, A. W., & Davison, G. (2018). Exercise, Immunity, and Illness. In Muscle and Exercise Physiology. https://doi.org/10.1016/B978-0-12-814593-7.00015-3
Kazemi, N., KOrdi, M. R., Noori, R., & Kasraeian, M. (2017). Effect of Aerobic and Resistance Training on Resistin & Insulin Levels in Women with Gestational Diabetes. Sport Physiology, 9(33), 101–114. https://doi.org/10.22089/spj.2017.1929.1246
Keymasi, Z., Sadeghi, A., & Pourrazi, H. (2017). Effect of Pilates Training on Hepatic Fat Content and Liver Enzymes in Men with Nonalcoholic Fatty Liver Disease. Journal of Applied Health Studies in Sport Physiology, 4(2), 49–56. https://doi.org/10.22049/jassp.2019.26576.1241
Khanizadeh, A.-M., Ejlali, M., & Karimzadeh, F. (2020). The Effect of SARS-COV-2 Viruses on the Function of Different Organs, Especially the Nervous System. The Neuroscience Journal of Shefaye Khatam, 8(3), 111–121. https://doi.org/10.29252/shefa.8.3.111
Kwak, M. S., & Kim, D. (2018). Non-alcoholic fatty liver disease and lifestyle modifications, focusing on physical activity. In Korean Journal of Internal Medicine (Vol. 33, Issue 1). https://doi.org/10.3904/kjim.2017.343
Lange, K. W., & Nakamura, Y. (2020). Lifestyle factors in the prevention of COVID-19. Global Health Journal, 4(4). https://doi.org/10.1016/j.glohj.2020.11.002
Mahdian, H., Farzanegi, P., & farzaneh hesari, A. (2018). Effect of combined therapy with resveratrol, continuous and interval exercises on oxidative stress and inflammation in cardiac tissue of male rats with non-alcoholic fatty liver. Journal of Neyshabur University Of Medical Sciences, 6(3). http://journal.nums.ac.ir/article-1-560-en.html
Marhl, M., Grubelnik, V., & Markovi, R. (2020). Diabetes & Metabolic Syndrome: Clinical Research & Reviews Diabetes and metabolic syndrome as risk factors for COVID-19. Diabetes & Metabolic Syndrome, 14.
Morgan, A. (2016). Effect of aerobic training with diet control program on cases of nonalcoholic fatty liver. International Journal of Therapies and Rehabilitation Research, 5(4). https://doi.org/10.5455/ijtrr.000000152
Nabizadeh Haghighi. (2016). Comparing Effects of Medication Therapy and Exercise Training with Diet on Liver Enzyme Levels and Liver Sonography in Patients with Non-Alcoholic Fatty Liver Disease (NAFLD). Journal of Fasa University of Medical Sciences, 5(4).
Nseir, W., Hellou, E., & Assy, N. (2014). Role of diet and lifestyle changes in nonalcoholic fatty liver disease. In World Journal of Gastroenterology (Vol. 20, Issue 28). https://doi.org/10.3748/wjg.v20.i28.9338
Organization, W. H., & (UNICEF), U. N. C. F. (2020). Water, sanitation, hygiene, and waste management for the COVID-19 virus: interim guidance, 23 April 2020. World Health Organization.
Pakzad, B., & Owlia, M. B. (2020). Corona Pandemic, Earth Restart Button. Journal of Shahid Sadoughi University of Medical Sciences, 28(1), 2229–2234. https://doi.org/10.18502/ssu.v28i1.3126
Portincasa, P., Krawczyk, M., Smyk, W., Lammert, F., & Di Ciaula, A. (2020). COVID-19 and non-alcoholic fatty liver disease: Two intersecting pandemics. In European Journal of Clinical Investigation (Vol. 50, Issue 10). https://doi.org/10.1111/eci.13338
Romero-Gómez, M., Zelber-Sagi, S., & Trenell, M. (2017). Treatment of NAFLD with diet, physical activity and exercise. In Journal of Hepatology (Vol. 67, Issue 4). https://doi.org/10.1016/j.jhep.2017.05.016
Saeidi, M., Kalantari, M., Dordizadeh Basirabad, E., & Entezari, M. (2020). ACE-2; an Entry Receptor for SARS-CoV-2. Journal of Marine Medicine, 2(1), 33–40. https://doi.org/10.30491/2.1.13.
Segars, J., Katler, Q., McQueen, D. B., Kotlyar, A., Glenn, T., Knight, Z., Feinberg, E. C., Taylor, H. S., Toner, J. P., & Kawwass, J. F. (2020). Prior and novel coronaviruses, Coronavirus Disease 2019 (COVID-19), and human reproduction: what is known? Fertility and Sterility, 113(6). https://doi.org/10.1016/j.fertnstert.2020.04.025
Shakoor, H., Feehan, J., Al Dhaheri, A. S., Ali, H. I., Platat, C., Ismail, L. C., Apostolopoulos, V., & Stojanovska, L. (2021). Immune-boosting role of vitamins D, C, E, zinc, selenium and omega-3 fatty acids: Could they help against COVID-19? In Maturitas (Vol. 143). https://doi.org/10.1016/j.maturitas.2020.08.003.
Shirvani, H., & Rostamkhani, F. (2020). Exercise considerations during coronavirus disease 2019 (COVID-19) Outbreak: A narrative review. In Journal of Military Medicine (Vol. 22, Issue 2). https://doi.org/10.30491/JMM.22.2.161
Shirvani, H., Soleimani, M., Sanayinasab, H., & Rahmati-Ahmadabad, S. (2018). A Review on the Effect of Exercise on Obesity by Modulating the Immune System and Toll-Like Receptors.  Journal of Military Medicine, 20(5). http://militarymedj.ir/article-1-1808-en.html
Somi, M. H., Boostani, K., Azadbakht, S., Alizadeh, M., & Eftekharsadat, A. T. (2017). Original Article Determine effect of weight loss on serum level of inflammatory cytokines IL- 1β, IL -6 , CRP andTNF- α in obese patients with fatty liver disease, 39 (3): 61-69. https://mj.tbzmed.ac.ir/Article/19433
Tavakoli, H. R., Rahmati-Najarkolaei, F., Malkami, A., & Dizavi, A. (2018). The Relation between Fast Food Consumption and Non-Alcoholic Fatty Liver: A Case-control Study. Iranian Journal of Endocrinology and Metabolism, 20(1). http://ijem.sbmu.ac.ir/article-1-2364-en.html
Wang, J., Wang, J., He, W., He, W., Tsai, P. J., Chen, P. H., Ye, M., Guo, J., & Su, Z. (2020). Mutual interaction between endoplasmic reticulum and mitochondria in nonalcoholic fatty liver disease. Lipids in Health and Disease, 19(1), 1–20. https://doi.org/10.1186/s12944-020-01210-0
Wang, L., Wang, Y., Ye, D., & Liu, Q. (2020). Review of the 2019 novel coronavirus (SARS-CoV-2) based on current evidence. International Journal of Antimicrobial Agents, 55(6). https://doi.org/10.1016/j.ijantimicag.2020.105948
Xu, X., Chen, P., Wang, J., Feng, J., Zhou, H., Li, X., Zhong, W., & Hao, P. (2020). Evolution of the novel coronavirus from the ongoing Wuhan outbreak and modeling of its spike protein for risk of human transmission. In Science China Life Sciences (Vol. 63, Issue 3). https://doi.org/10.1007/s11427-020-1637-5
Yang, Y., Lu, Q. Bin, Liu, M. J., Wang, Y. X., Zhang, A. R., Jalali, N., Dean, N. E., Longini, I., Elizabeth Halloran, M., Xu, B., Zhang, X. A., Wang, L. P., Liu, W., & Fang, L. Q. (2020). Epidemiological and clinical features of the 2019 novel coronavirus outbreak in China. In medRxiv. https://doi.org/10.1101/2020.02.10.20021675
Ye, M., Ren, Y., & Lv, T. (2020). Encephalitis as a clinical manifestation of COVID-19. In Brain, Behavior, and Immunity (Vol. 88). https://doi.org/10.1016/j.bbi.2020.04.017
Zhou, P., Yang, X. Lou, Wang, X. G., Hu, B., Zhang, L., Zhang, W., Si, H. R., Zhu, Y., Li, B., Huang, C. L., Chen, H. D., Chen, J., Luo, Y., Guo, H., Jiang, R. Di, Liu, M. Q., Chen, Y., Shen, X. R., Wang, X., … Shi, Z. L. (2020). Erratum: Addendum: A pneumonia outbreak associated with a new coronavirus of probable bat origin (Nature (1988) 81 11 (18-19)). In Nature (Vol. 588, Issue 7836). https://doi.org/10.1038/s41586-020-2951-z