Circadian Rhythms in Gastroenterology: The Biological Clock's Impact on Gut Health.

1. Gastroenterology. 2025 Dec;169(7):1380-1396. doi: 10.1053/j.gastro.2025.06.017. Epub 2025 Jun 28. Circadian Rhythms in Gastroenterology: The Biological Clock's Impact on Gut Health. Bishehsari F(1), Post Z(2), Swanson GR(3), Keshavarzian A(4). Author information: (1)Gastroenterology Research Center (GRC), Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas; MD Anderson Cancer Center-UTHealth Houston Graduate School of Biomedical Sciences, Houston, Texas; Rush Center for Integrated Microbiome and Chronobiology Research (CIMCR), Rush University Medical Center, Chicago, Illinois; Rush University, Department of Anatomy & Cell Biology, Chicago, Illinois. Electronic address: Faraz.bishehsari@uth.tmc.edu. (2)Rush University Medical Center, Department of Internal Medicine, Division of Digestive Diseases and Nutrition, Chicago, Illinois. (3)Rush Center for Integrated Microbiome and Chronobiology Research (CIMCR), Rush University Medical Center, Chicago, Illinois; Rush University, Department of Anatomy & Cell Biology, Chicago, Illinois; Medical University of South Carolina, Division of Gastroenterology and Hepatology, Charleston, South Carolina. (4)Rush Center for Integrated Microbiome and Chronobiology Research (CIMCR), Rush University Medical Center, Chicago, Illinois; Rush University, Department of Anatomy & Cell Biology, Chicago, Illinois; Rush University Medical Center, Department of Internal Medicine, Division of Digestive Diseases and Nutrition, Chicago, Illinois; Rush University, Department of Physiology, Chicago, Illinois. Chronic gastrointestinal (GI) diseases, including functional, inflammatory, and neoplastic conditions, are increasing globally, partly due to modern lifestyles. The circadian rhythm, regulated by the central clock in the hypothalamus and synchronized with peripheral clocks in the GI organs, orchestrates GI functions in response to environmental cycles. This clock is influenced by cues such as light, sleep, and eating times. The circadian machinery prepares the host to cope with environmental conditions to adjust cellular and organ function accordingly. Modern behaviors-like night-time light exposure, travel across time zones, shift work, mistimed eating, and social jet lag-disrupt the circadian clock, affecting GI processes such as digestion, absorption, motility, intestinal barrier function, immune function, and the microbiome, promoting not only GI pathology, but also systemic inflammatory and metabolic disorders. This review summarizes the circadian rhythm's role in normal GI function, examines the consequences of circadian disruption in the GI tract, and discusses circadian-based therapeutic interventions. These interventions aim to realign the circadian clock with external cues or optimize medication timing according to biological rhythms. Understanding the role of the circadian clock in GI conditions can provide preventive and therapeutic opportunities to reduce the burden of GI diseases. Copyright © 2025 AGA Institute. Published by Elsevier Inc. All rights reserved. DOI: 10.1053/j.gastro.2025.06.017 PMID: 40588189 [Indexed for MEDLINE]