Letter to the Editor: The first Ramadan during COVID-19 pandemic: 1.8 billion Muslims should fast or not?
Authors: Saeedeh Mosaferchi, Ehsan Sharif-Paghaleh, Alireza Mortezapour, Rashid Heidarimoghadam
Journal: Metabolism (2020)

Dir Sir, With great interest we have read the recent article entitled "Fasting glucagon concentrations are associated with longitudinal decline of β-cell function in non-diabetic humans" which was published in your valuable journal [1Adams J.D. Dalla Man C. Laurenti M.C. Andrade M.D.H. Cobelli C. Rizza R.A. et al.Fasting glucagon concentrations are associated with longitudinal decline of β-cell function in non-diabetic humans.Metabolism. 2020; 105: 154175Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar]. We want to congratulate the authors for this successful article, and make a new contribution about fasting during COVID-19 pandemic. In early December 2019, a novel coronavirus emerged in China [2Prem K, Liu Y, Russell TW, Kucharski AJ, Eggo RM, Davies N, et al. The effect of control strategies to reduce social mixing on outcomes of the COVID-19 epidemic in Wuhan, China: a modelling study. Lancet Public Health.Google Scholar]. Due to high rate of transmission of the disease, officially confirmed cases have been reported in most countries around the world [3Haines A, de Barros EF, Berlin A, Heymann DL, Harris MJ. National UK programme of community health workers for COVID-19 response. LancetGoogle Scholar,4Saglietto A, D'Ascenzo F, Zoccai GB, De Ferrari GM. COVID-19 in Europe: the Italian lesson. LancetGoogle Scholar]. With the introduction of the disease as a pandemic, the importance of COVID-19 is increasing day by day [5Coronavirus Disease (COVID-19) Pandemic. 2020Google Scholar]. In addition, the confirmed cases of this disease in Muslim-majority countries are prevalent [6Takian A, Raoofi A, Kazempour-Ardebili S. COVID-19 battle during the toughest sanctions against Iran. Lancet.Google Scholar, 7Ebrahim S.H. Memish Z.A. COVID-19: preparing for superspreader potential among Umrah pilgrims to Saudi Arabia.Lancet. 2020; 395e48Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar, 8Mousavi SH, Shah J, Giang HTN, Al-Ahdal TMA, Zahid SU, Temory F, et al. The first COVID-19 case in Afghanistan acquired from Iran. Lancet Infect Dis.Google Scholar]. 1.8 billion Muslims live in more than 180 countries around the world [7Ebrahim S.H. Memish Z.A. COVID-19: preparing for superspreader potential among Umrah pilgrims to Saudi Arabia.Lancet. 2020; 395e48Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar,9World's Muslim Population More Widespread Than you Might Think. 2020Google Scholar]. One of the main activities of Muslims in less than one month later (Ramadan: the ninth month in the Islamic calendar) is fasting [10Al-Arouj M. Assaad-Khalil S. Buse J. Fahdil I. Fahmy M. Hafez S. et al.Recommendations for management of diabetes during Ramadan.Diabetes Care. 2010; 33: 1895Crossref PubMed Scopus (293) Google Scholar]. To date, various studies have been conducted on the health effects of fasting [11Talib S. van de Poll S.W.E. Brugada syndrome diagnosed after Ramadan.Lancet. 2013; 382: 100Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar,12The L. Ramadan: health effects of fasting.Lancet. 2009; 374: 588Abstract Full Text Full Text PDF Scopus (6) Google Scholar]. Majority of them, studied the impact of fasting on the lipid profile, diabetes and, body weight [13Sheikh A. Wallia S. Ramadan fasting and diabetes.BMJ. 2007; 335: 613Crossref PubMed Scopus (11) Google Scholar]. In addition, recent studies have shown the effect of fasting on the immune system [14Nagai M, Noguchi R, Takahashi D, Morikawa T, Koshida K, Komiyama S, et al. Fasting-refeeding impacts immune cell dynamics and mucosal immune responses. Cell. 2019;178:1072–87.e14.Google Scholar,15Buono R. Longo V.D. When fasting gets tough, the tough immune cells get going—or die.Cell. 2019; 178: 1038-1040Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar]. It can be concluded that the results of previous studies on the immune system have been inconsistent. With the increasing importance of COVID-19, a fundamental question needs further investigation. During the outbreak of new corona, healthy Muslims must fast in this Ramadan as in previous years? In the next section, we briefly reported some concerns. Due to suppression of immune system, patients with or recently recovered from cancer, are susceptible to COVID-19 [16Burki TK. Cancer care in the time of COVID-19. Lancet Oncol.Google Scholar,17Liang W. Guan W. Chen R. Wang W. Li J. Xu K. et al.Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China.Lancet Oncol. 2020; 21: 335-337Abstract Full Text Full Text PDF PubMed Scopus (3293) Google Scholar]. In the one hand, the effect of fasting on suppressing immune system remains unclear [14Nagai M, Noguchi R, Takahashi D, Morikawa T, Koshida K, Komiyama S, et al. Fasting-refeeding impacts immune cell dynamics and mucosal immune responses. Cell. 2019;178:1072–87.e14.Google Scholar,15Buono R. Longo V.D. When fasting gets tough, the tough immune cells get going—or die.Cell. 2019; 178: 1038-1040Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar] and on the other hand recent review study reveals the positive effect of fasting during Ramadan on treatment of cancer [18Longo Valter D. Mattson Mark P. Fasting: molecular mechanisms and clinical applications.Cell Metab. 2014; 19: 181-192Abstract Full Text Full Text PDF PubMed Scopus (907) Google Scholar]. Further confirmed protocols and guidelines must produce to clarify the status of fasting or not fasting for Muslims. Beginning of the Ramadan is considered for reducing smoking among Muslims. However, only little studies have shown the effect of smoking on increasing the chance of COVID-19 [19Olds JL, Kabbani N. Is nicotine exposure linked to cardiopulmonary vulnerability to COVID-19 in the general population? FEBS J..n/a.Google Scholar], more studies are needed in this regard. A recent study revealed that, due to the treatment protocol, patients with hypertension, or diabetes, who are treated with ACE2-increasing drugs, are at higher risk for severe COVID-19 infection [20Fang L, Karakiulakis G, Roth M. Are patients with hypertension and diabetes mellitus at increased risk for COVID-19 infection? Lancet Respir. Med.Google Scholar]. Due to the effect of fasting on Diabetes, Blood fat and Hypertension, rigorous studies are needed to find the effect of fasting on reducing/increasing the chance of a healthy person to becoming ill. None declared.