How Gut Health Affects Mental Health

Introduction:

Gut Health is characterized as the overall state of your digestive system and the community of

microorganisms/gut microbiome that live within it. While there are many misconceptions

about how to maintain its health, its primary functions involve breaking down food, absorbing

nutrients, balancing bacteria, and eliminating waste. It’s crucial in overall

health, and has various effects in both mental and physical health.

What does it mean to have good gut health?

Achieving good gut health involves having a properly balanced and diverse gut microbiome,

where the beneficial bacteria outweigh the harmful ones, leading to the proper function of the GI

tract, the absence of digestive symptoms (such as diarrhea, constipation, and gas), and an overall

healthier contribution to immune function and energy levels.

How does gut health affect mental health?

Our gut health affects mental health in many ways, however it’s greatly associated with the

gut-brain axis; a two way communication system that essentially links the central nervous

system and gastrointestinal system through many signals,  producing neurotransmitters

like serotonin (which more directly affects the mood) and GABA (gabba-aminobutyric acid), and

triggering an immune response that can affect the body as a whole.

Effects on mental health also primarily consist of effects on mood regulation, stress and anxiety,

and brain function.

Mood Regulation: While a healthy gut can promote better moods, an imbalanced gut (also

known as dysbiosis) has been shown to contribute to anxiety, depression, and stress by producing

neurotransmitters like serotonin and dopamine, which influence happiness, pleasure, and

motivation.

Stress and Anxiety: Inflammation in the gut microbiome can lead to the release of cytokines

(such as TNF-α, IL-Iβ, and INF-α) that can increase the permeability of the blood-brain barrier,

leading to molecules entering the brain and influencing (to a certain extent) its function, leading

to anxiety and depression.

Brain Function: Gut health is largely linked to the brain through the gut-brain axis, showing

associations with communication pathways,  microbial influence, and the immune system. A

dysregulated gut plays a crucial role in the development of chronic inflammation, microglia, and

metabolites, which can go on to affect our cognitive performance, mood disorders, and our stress

response (for example, cortisol levels).

Additionally, the vagus nerve plays a crucial role in mood regulation associated with gut health,

acting as a direct highway for communication that occurs between the gut and the brain.

Furthermore, an unhealthy gut can often trigger the HPA (hypothalamic-pituitary-adrenal) axis,

which is the body’s central stress response system, leading to inflammation and the release of

stress hormones.

Conclusion:

Mental health isn’t just imaginary; it can oftentimes have a basis in real bodily functions or

conditions. While there isn’t a one-size-fits-all way of maintaining our mental health, a good

place to start is by maintaining our physical health through healthy diets, remaining hydrated,

prioritizing sleep, and exercising regularly.

References:

• ​Champion, C. (2023, October 23). You are what you eat: Diet may affect your mood and brain function. Www.uclahealth.org. https://www.uclahealth.org/news/article/you-are-what-you-eat-diet-may-affect-your-mood-and-brain

• Harvard Health Publishing. (2023, July 18). The gut-brain connection. Harvard Health; Harvard Health. https://www.health.harvard.edu/diseases-and-conditions/the-gut-brain-connection

• Hill, J. (2024, November 26). What is the gut-brain connection? HelpGuide.org. https://www.helpguide.org/wellness/nutrition/gut-brain-connection

• O’Riordan, K. J., Moloney, G. M., Keane, L., Clarke, G., & Cryan, J. F. (2025). The gut microbiota-immune-brain axis: Therapeutic implications. Cell Reports Medicine, 6(3), 101982. https://doi.org/10.1016/j.xcrm.2025.101982

• Warner, L. (2025, February 20). 5 simple ways to improve gut health - Harvard Health. Harvard Health. https://www.health.harvard.edu/staying-healthy/5-simple-ways-to-improve-gut-health