Melatonin, best known as the “sleep hormone,” is critical for regulating circadian rhythms.
Yet, recent research has revealed an unexpected but fascinating role of melatonin in maintaining gut microbiota balance and protecting neurological health.
The gut-brain axis, a bidirectional communication system linking the gut and the central nervous system, is at the heart of this relationship.
Emerging evidence suggests that melatonin can modulate gut bacteria, reduce gut permeability, and mitigate inflammation – all of which are crucial for brain health.
The gut is not just a passive organ for digestion; it is a dynamic ecosystem influenced by various factors, including melatonin.
Melatonin levels are naturally higher in the gastrointestinal tract than in the pineal gland, where it is primarily produced (Chen et al., 2011). This hormone acts as a powerful antioxidant, scavenging free radicals and reducing oxidative stress.
Ahmadi et al. (2024) highlight melatonin’s ability to positively alter gut microbiota composition. The study found that melatonin supplementation promotes the growth of beneficial bacteria, such as Lactobacillus and Bifidobacterium, while suppressing harmful pathogens.
This rebalancing of gut bacteria improves intestinal barrier function, reducing gut permeability – a condition commonly associated with neuroinflammation and systemic disease.
The connection between gut health and brain function is well-established, with gut dysbiosis being linked to numerous neurological disorders, including Alzheimer’s disease, Parkinson’s disease, depression, and anxiety (Rogers et al.,2016).
Dysbiosis triggers systemic inflammation and oxidative stress, which can exacerbate these conditions.
Melatonin acts as a neuroprotective agent by modulating the gut-brain axis.
It reduces inflammation by downregulating pro-inflammatory cytokines and strengthens the gut lining, preventing harmful molecules from entering the bloodstream.
Furthermore, melatonin’s antioxidant properties protect neurons from damage caused by oxidative stress, a major contributor to neurodegeneration (Alghamdi, 2018).
These findings open the door to novel therapeutic strategies for managing neurological diseases.
Melatonin, in combination with prebiotics and probiotics, could be a game-changer in restoring gut-brain balance.
However, clinical trials are needed to establish effective doses and evaluate long-term safety.
Since most scientific papers conduct research on rats which are nocturnal animals, to confidently extrapolate results to humans, it is essential to conduct causal studies on diurnal animal models.
Melatonin’s dual role in regulating sleep and gut microbiota offers exciting opportunities for improving both gut and brain health.
As we continue to uncover its therapeutic potential, melatonin may emerge as a cornerstone in the management of complex neurological and gastrointestinal disorders.
References:
Ahmadi, S., Taghizadieh, M., Mehdizadehfar, E., Hasani, A., Khalili Fard, J., Feizi, H., Hamishehkar, H., Ansarin, M., Yekani, M., & Memar, M. Y. (2024). Gut microbiota in neurological diseases: Melatonin plays an important regulatory role. Biomedicine & Pharmacotherapy, 174, 116487. https://doi.org/10.1016/j.biopha.2024.116487
Alghamdi B. S. (2018). The neuroprotective role of melatonin in neurological disorders. Journal of neuroscience research, 96(7), 1136–1149. https://doi.org/10.1002/jnr.24220
Chen, C. Q., Fichna, J., Bashashati, M., Li, Y. Y., & Storr, M. (2011). Distribution, function and physiological role of melatonin in the lower gut. World journal of gastroenterology, 17(34), 3888–3898. https://doi.org/10.3748/wjg.v17.i34.3888
Rogers, G. B., Keating, D. J., Young, R. L., Wong, M. L., Licinio, J., & Wesselingh, S. (2016). From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Molecular psychiatry, 21(6), 738–748. https://doi.org/10.1038/mp.2016.50