By Andrea McBeth
As darkness creeps earlier into the evenings across the Pacific Northwest, we're reminded of the natural cycles that govern not just the world around us but also within us. The human microbiome, much like a forest responding to seasonal shifts, exhibits a profound connection with our sleep patterns. During these shorter days and the stress-filled holiday season, understanding this connection becomes crucial for our well-being.
Sleep, often undervalued in our fast-paced culture, is a time of significant biological activity, particularly for our gut microbiota. It parallels the brain's glymphatic system, a recently discovered macroscopic waste clearance system, which operates predominantly during sleep. This system facilitates the removal of soluble proteins and metabolites from the central nervous system, while distributing compounds like glucose, lipids, amino acids, and neurotransmitters. Similarly, our gut microbiome undergoes a detoxification and rejuvenation process overnight. This nocturnal activity suggests a potential correlation between our microbiome and the body's broader lymphatic system, an area ripe for exploration, particularly regarding the intersection of neuroimmune and gut microbial interactions.(1) A recent longitudinal study has unveiled a crucial link between chronic insomnia and cardiometabolic diseases (CMD), mediated by the gut microbiota-bile acid axis. Specifically, genera like Ruminococcaceae UCG-002 and Ruminococcaceae UCG-003 have been pinpointed as key players in this association, suggesting that targeting the microbiota-bile acid axis could be a novel approach to mitigating the impact of chronic insomnia on cardiometabolic health.(2)
Circadian Rhythms and Microbial Metabolism
The intricate relationship between our circadian rhythms and the gut microbiome is a burgeoning field of study. The human circadian system regulates various physiological processes, including sleep-wake cycles, feeding behavior, hormone release, and body temperature.(3) Our gut microbiota exhibits its own circadian rhythm, influenced by our dietary habits and feeding times. Disruptions in these rhythms, such as irregular sleep patterns or late-night eating, can lead to a misalignment known as circadian rhythm disruption, which impacts gut microbial composition and function.(4)
This alignment is evident in the gut's nightly 'motility wave,' a phase of increased peristaltic activity that clears undigested food and bacterial populations, resetting the intestinal environment. Experimental studies, like those conducted on Vibrio fischeri in the Hawaiian bobtail squid, illuminate how microbial metabolic activity synchronizes with the host's circadian rhythms. These studies reveal that the microbial metabolic response is intricately tied to the host’s circadian biology, impacting nutrient absorption, immune function, and overall gut health.(5) Another fascinating dimension of this interaction is the way gut microbial metabolites influence central and hepatic clock gene expression and sleep duration, regulating body composition through circadian transcription factors. These insights highlight the bidirectional relationship between sleep and gut health, where sleep fragmentation and short duration can lead to gut dysbiosis, potentially mediated through the HPA-axis.(6,7) This understanding underscores why late-night eating disrupts not just our digestive process but also the microbial activities geared toward resetting and preparing for the next day.
Jet Lag, Time Zones, and Microbiome Adjustment
The holiday season often entails travel across time zones, leading to circadian misalignment or jet lag, which not only affects our sleep-wake cycle but also our gut microbiome. The disruption in the host's circadian rhythm can desynchronize the microbial circadian rhythm, leading to dysbiosis, which can affect digestion, immune function, and even mood.(8)
Emerging research suggests that specific probiotic strains, dietary fibers, and postbiotics may play a role in realigning our circadian rhythms during travel. These interventions could potentially help in quicker adjustment to new time zones by supporting the synchronization of the gut microbiome with the shifted external environment. This area of research is particularly promising for developing dietary strategies to mitigate the effects of circadian disruptions during travel.(9)
Conclusion: Embracing Sleep for Microbial Harmony
As we embrace the fall season, let us acknowledge the profound role of sleep in maintaining microbial balance. Just as a diverse and balanced microbiome is crucial for our health, so too is a consistent and restorative sleep pattern. By understanding and respecting our body's natural rhythms and the intricate dance between our sleep and microbiome, we can better equip ourselves to handle the stress and demands of the holiday season. Let's prioritize a consistent sleep routine, complemented by appropriate dietary and supplement choices, as a cornerstone of our holistic approach to health this autumn.
- Solari, E., Marcozzi, C., Negrini, D., & Moriondo, A. (2021). Interplay between Gut Lymphatic Vessels and Microbiota. Cells, 10(10). https://doi.org/10.3390/cells10102584
- Jiang, Z., Zhuo, L.-B., He, Y., Fu, Y., Shen, L., Xu, F., Gou, W., Miao, Z., Shuai, M., Liang, Y., Xiao, C., Liang, X., Tian, Y., Wang, J., Tang, J., Deng, K., Zhou, H., Chen, Y.-M., & Zheng, J.-S. (2022). The gut microbiota-bile acid axis links the positive association between chronic insomnia and cardiometabolic diseases. Nature Communications, 13(1), 3002.
- Matenchuk, B. A., Mandhane, P. J., & Kozyrskyj, A. L. (2020). Sleep, circadian rhythm, and gut microbiota. Sleep Medicine Reviews, 53, 101340.
- Frazier, K., & Chang, E. B. (2020). Intersection of the Gut Microbiome and Circadian Rhythms in Metabolism. Trends in Endocrinology and Metabolism: TEM, 31(1), 25–36.
- Heath-Heckman, E. A. C., Peyer, S. M., Whistler, C. A., Apicella, M. A., Goldman, W. E., & McFall-Ngai, M. J. (2013). Bacterial bioluminescence regulates expression of a host cryptochrome gene in the squid-Vibrio symbiosis. mBio, 4(2). https://doi.org/10.1128/mBio.00167-13
- Sen, P., Molinero-Perez, A., O’Riordan, K. J., McCafferty, C. P., O’Halloran, K. D., & Cryan, J. F. (2021). Microbiota and sleep: awakening the gut feeling. Trends in Molecular Medicine, 27(10), 935–945.
- Frazier, K., Frith, M., Harris, D., & Leone, V. A. (2020). Mediators of Host-Microbe Circadian Rhythms in Immunity and Metabolism. Biology, 9(12). https://doi.org/10.3390/biology9120417
- Wang, X., Wang, Z., Cao, J., Dong, Y., & Chen, Y. (2023). Gut microbiota-derived metabolites mediate the neuroprotective effect of melatonin in cognitive impairment induced by sleep deprivation. Microbiome, 11(1), 17.
- Codoñer-Franch, P., Gombert, M., Martínez-Raga, J., & Cenit, M. C. (2023). Circadian Disruption and Mental Health: The Chronotherapeutic Potential of Microbiome-Based and Dietary Strategies. International Journal of Molecular Sciences, 24(8). https://doi.org/10.3390/ijms24087579