{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T20:49:13Z","timestamp":1778273353359,"version":"3.51.4"},"reference-count":56,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,8,29]],"date-time":"2021-08-29T00:00:00Z","timestamp":1630195200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background: The human gut microbiota is defined as the microorganisms that collectively inhabit the intestinal tract. Its composition is relatively stable; however, an imbalance can be precipitated by various factors and is known to be associated with various diseases. Humans are daily exposed to ionizing radiation from ambient and medical procedures, and gastrointestinal side effects are not rare. Methods: A systematic search of PubMed, EMBASE, and Cochrane Library databases was conducted. Primary outcomes were changes in composition, richness, and diversity of the gut microbiota after ionizing radiation exposure. Standard methodological procedures expected by Cochrane were used. Results: A total of 2929 nonduplicated records were identified, and based on the inclusion criteria, 11 studies were considered. Studies were heterogeneous, with differences in population and outcomes. Overall, we found evidence for an association between ionizing radiation exposure and dysbiosis: reduction in microbiota diversity and richness, increase in pathogenic bacteria abundance (Proteobacteria and Fusobacteria), and decrease in beneficial bacteria (Faecalibacterium and Bifidobacterium). Conclusions: This review highlights the importance of considering the influence of ionizing radiation exposure on gut microbiota, especially when considering the side effects of abdominal and pelvic radiotherapy. Better knowledge of these effects, with larger population studies, is needed.<\/jats:p>","DOI":"10.3390\/nu13093025","type":"journal-article","created":{"date-parts":[[2021,8,31]],"date-time":"2021-08-31T04:07:28Z","timestamp":1630382848000},"page":"3025","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":55,"title":["The Effects of Ionizing Radiation on Gut Microbiota, a Systematic Review"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5489-8050","authenticated-orcid":false,"given":"Ana","family":"Fernandes","sequence":"first","affiliation":[{"name":"Department of Nuclear Medicine, Centro Hospitalar Universit\u00e1rio de S\u00e3o Jo\u00e3o, E.P.E., 4200-319 Porto, Portugal"}]},{"given":"Ana","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Department of Nuclear Medicine, Centro Hospitalar Universit\u00e1rio de S\u00e3o Jo\u00e3o, E.P.E., 4200-319 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9157-5541","authenticated-orcid":false,"given":"Raquel","family":"Soares","sequence":"additional","affiliation":[{"name":"Department of Biomedicine, Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal"},{"name":"i3S, Instituto de Investiga\u00e7\u00e3o e Inova\u00e7\u00e3o em Sa\u00fade, Universidade do Porto, 4200-135 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4537-5450","authenticated-orcid":false,"given":"Pedro","family":"Barata","sequence":"additional","affiliation":[{"name":"i3S, Instituto de Investiga\u00e7\u00e3o e Inova\u00e7\u00e3o em Sa\u00fade, Universidade do Porto, 4200-135 Porto, Portugal"},{"name":"Department of Pharmaceutical Science, Faculdade de Ci\u00eancias da Sa\u00fade da Universidade Fernando Pessoa, 4249-004 Porto, Portugal"},{"name":"Department of Pathology, Centro Hospitalar Universit\u00e1rio do Porto, 4099-001 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kumagai, T., Rahman, F., and Smith, A.M. 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