At a Glance:
- Circadian rhythms are internal biological clocks that regulate various body processes, such as sleeping and waking.
- While external factors influence these cycles, internal factors within the gut microbiome also have a significant impact.
- By understanding this relationship, probiotic producers can formulate products that support the gut microbiome’s connection to the circadian system, potentially leading to positive health outcomes.
As the human health field expands, experts are discovering previously unexplored connections between various body functions and the gut microbiome, one of which is its relationship with the circadian system. These rhythms are typically understood to be driven by external factors, such as light and food. However, research shows that the gut microbiome can have a much more significant effect on these rhythms than previously believed. Here’s what you need to know.
What are circadian rhythms?
Circadian rhythms are driven by the circadian system, an array of internal biological clocks that regulate various body processes, such as the sleep:wake cycle.1 These rhythms can be triggered by both external and internal stimuli. Common external influences include light levels, food intake, and even temperature changes.1 However, internal factors drive circadian rhythmicity as well. Clock-controlled genes, or CCGs, are a great example. These highly specialized genes are located throughout the body and send signals to other cells that indicate it’s time to carry out a circadian process.2
How does the gut microbiome influence circadian rhythms?
Microbes in the gut help regulate circadian processes in several ways; one method is the production of specific metabolites. Gut bacteria produce a multitude of beneficial metabolites, but neurotransmitters like serotonin and GABA are thought to be particularly helpful in regulating circadian rhythms like the sleep:wake cycle.3
The gut microbiome also helps maintain circadian rhythmicity in the gut itself, even during changes in environmental conditions. For example, CCGs in the gut tend to be less sensitive to changes in light than CCGs in other areas of the body,4 allowing the gut to remain stable through these types of shifts.
This idea was further demonstrated by a study conducted on two groups of mice. One group was kept in a typical light:dark cycle, and the other group was kept in constant darkness. Throughout the observation period, researchers noted comparable rhythmicity between the two groups’ gut microbiota. This suggests that, while external stimuli certainly impact the circadian system overall, internal factors may play a bigger role in the rhythmicity of the gut.2
This same study also highlighted the significance of gut-specific CCGs in maintaining healthy gut microbiome function—which, in turn, can support a properly functioning circadian system as a whole. To show this, researchers deleted an important intestinal CCG in one group of mice and left the gene intact in another group. Mice in the group without the CCG experienced decreased rhythmicity of many gut microbes, including those that contribute to host-microbe communication along the gut-brain axis. With this communication channel impeded, the gut health of those mice declined.2
These results indicate a cyclical relationship between the circadian system and the gut microbiome: when rhythms are unstable, gut health decreases; when gut health declines, rhythms destabilize.
Where can probiotics come into play?
The impacts that the gut microbiome and circadian system have on each other is clear, and with consumers increasingly searching for sleep support solutions, probiotic companies are uniquely positioned to deliver. Many probiotic strains encourage production of neurotransmitters that play roles in the sleep:wake cycle. This angle provides a solution that supports the body’s natural functions, rather than introducing something entirely new.
Plus, a thriving gut microbiome positively impacts the circadian system, and a more stable system can lead to better sleep. Probiotics that bolster the diversity and health of gut bacteria could, therefore, indirectly assist with sleep improvements by helping the body maintain balanced circadian rhythmicity in the gut and beyond.
Become the Expert for Your Customers
Understanding the intricate connections between the gut microbiome and other body systems allows you to develop probiotics with strong differentiating functionalities. At MDG, we use our expertise in Bacillus and knowledge of the human health market to help you become an expert, too, resulting in a partnership that moves your business forward with innovation and agility. Check out our human health market page for more information.
MDG is the probiotic provider that helps you differentiate faster without the added risk of investing your own resources in the development process.
References
- Vitaterna, M. H., Takahashi, J. S., & Turek, F. W. (2001). Overview of circadian rhythms. Alcohol Research & Health, 25(2), 85–93. https://pmc.ncbi.nlm.nih.gov/articles/PMC6707128/
- Heddes, M., Altaha, B., Niu, Y., Reitmeier, S., Kleigrewe, K., Haller, D., & Kiessling, S. (2022). The intestinal clock drives the microbiome to maintain gastrointestinal homeostasis. Nature Communications, 13, Article No. 6068. https://doi.org/10.1038/s41467-022-33609-x
- Wollmuth, E., & Angert, E. (2023). Microbial circadian clocks: Host-microbe interplay in diel cycles. BMC Microbiology, 23, Article No. 124. https://doi.org/10.1186/s12866-023-02839-4
- Zhang, Y., Li, Y., Barber, A., Noya, S., Williams, J., Li, F., Daniel, S., Bittinger, K., Fang, J., & Sehgal, A. (2023). The microbiome stabilizes circadian rhythms in the gut. PNAS, 120(5), e2217532120. https://doi.org/10.1073/pnas.2217532120
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