Effect of Ramadan fasting on gastrointestinal tract: A review

In the present systematic review, we aimed at reviewing the peer review articles investigating the effect of Ramadan fasting on gastrointestinal disease.

We searched databases of Pubmed, Embase, google scholar, Cochrane library, SID, and Magiran from 1960 to June 2019. Only original research published in peer-reviewed scientific journals, which evaluated the effect of Ramadan fasting on gastrointestinal symptoms and diseases were included.

Using our systematic search, 37 articles met our predefined inclusion criteria.Studies showed that the upper gastrointestinal (UGI) bleeding and peptic and duodenal ulcers perfusion in Ramadan were higher compared with the month before and a month after Ramadan. Moreover, studies showed that anthropometric indices, inflammatory cytokines, liver enzymes level, and hepatic steatosis were improved in the fasting group compared with the non-fasting group in patients with non-alcoholic fatty liver disease. In cirrhotic patients, some studies showed that although Ramadan fasting had no effect on liver function or even improve liver enzymes in patients with disease severity of child class A & B, it was associated with higher risk UGI bleeding in cirrhotic patients. One study investigated the effect of Ramadan Fasting in inflammatory bowel disease patients and showed that in patients with ulcerative colitis (UC), the mean score of disease activity decreased after Ramadan and this decrement was significant in male UC patients.In addition, studies indicated that Ramadan fasting does not have an effect on liver function or frequency and severity of gastrointestinal symptoms except for constipation in healthy subjects.  

According to the results, Ramadan fasting does not associate with any adverse effect in the healthy population. However, in some gastrointestinal diseases such as peptic ulcers, it may be associated with complications.