Melatonin-Microbiome Axis: The Immune System, and the Biochemistry and Pharmacology of Cognition and Learning

Abstract

The interplay between melatonin, the microbiome, the immune system, and cognitive function is gaining recognition for its multifaceted influence on human health. Melatonin, traditionally known for regulating circadian rhythms, has emerged as a critical modulator of immune responses, oxidative stress, and gut microbiota. This review examines the symbiotic relationship between melatonin and the microbiome, particularly its impact on the gut-brain axis, neurogenesis, and synaptic plasticity-core processes that underpin cognition and learning.

We conducted an observational study across six age groups, ranging from children to the elderly, examining participants with and without dysbiosis. In individuals without dysbiosis, normal melatonin levels were observed, alongside the presence of melatonin receptors on 15–17% of the microbiome components—a novel finding. Participants across all age groups displayed equal cognitive ability in learning foreign languages, suggesting melatonin’s crucial role in enhancing cognitive function, regardless of age.

Melatonin’s neuroprotective effects, including its antioxidant, anti-inflammatory, and neurogenic properties, were shown to mitigate oxidative stress and modulate neurotransmitter systems like serotonin, dopamine, and GABA, promoting cognitive performance. Furthermore, melatonin’s ability to influence immune function, particularly through the regulation of pro-inflammatory cytokines, underscores its potential as a therapeutic agent for cognitive enhancement and neuroprotection.

The study’s findings highlight the complex biochemical and pharmacological interactions between melatonin, the microbiome, and the immune system, offering novel insights into their collective role in cognition and learning. Understanding these mechanisms could open new avenues for addressing cognitive decline, learning disorders, and neurodegenerative diseases.