Nutrition & Metabolism
Authors:
Pooneh Angoorani, Hanieh-Sadat Ejtahed, Shirin Hasani-Ranjbar, Seyed Davar Siadat, Ahmad Reza Soroush & Bagher Larijani
Background: Intermittent fasting has been reported to have positive effects on obesity, diabetes, cardiovascular diseases,
hypertension, and several neurodegenerative diseases through different mechanisms such as alteration in the
gut microbiota. This systematic review was conducted with the aim of providing an overview of the existing animal
and human literature regarding the gut microbiota alterations in various fasting regimens.
Method: A systematic literature search was conducted on PubMed, Scopus and Web of Science databases up to May
2021 to find all relevant studies examining the gut microbiota alteration during the fasting. Original researches on
animal models or human patients were included in this study.
Results: The search fulfilled 3072 documents from which 31 studies (20 animal and 11 human studies) were
included. Upon fasting, abundance of several beneficial bacteria including Lactobacillus and Bifidobacterium shifted
significantly. Moreover, some taxa, including Odoribacter which negatively associated with blood pressure bloomed
during fasting. Ramadan fasting, as a kind of intermittent fasting, improves health parameters through positive
changes in gut microbiota including upregulation of A. muciniphila, B. fragilis, Bacteroides and butyric acid–producing
Lachnospiraceae.
Conclusion: The findings suggest that different fasting regimens including alternate-day fasting, calorie- and
time-restricted fasting programs and Ramadan fasting could promote health maybe through the modulation of gut
microbiome. However, further studies are needed to explore properly the connection between gut microbiota and
meal frequency and timing.