What is gut-brain axis?
Gut-brain axis refers to the bidirectional signalling pathways of the brain and gut through multiple physically and biochemically connection, including vagus nerve, neurotransmitters, peptides and so on. It regulates and connects gut functions with emotional and cognitive centers in the brain by influencing various mechanisms such as immune activation, intestinal permeability, enteric reflex, and endocrine signalling.
How does the gut-brain axis affect our overall health?
- Gut Health and Mental Well-being: Gut health is closely related to mental health because some of the “feel-good” neurotransmitter that regulates mood and mental health such as serotonin, dopamine and GABA (gamma-aminobutyric acid) are produced by gut microbiota. Imbalances in gut bacteria can disrupt the production and regulation of these neurotransmitters, potentially contributing to mood disorders such as depression and anxiety. The studies also found the connection between gut microbiota and the incidence of depression.
- Inflammation and Brain Function: Imbalanced gut bacteria can trigger inflammation in the GI tract. Inflammation can worsen conditions such as irritable bowel syndrome (IBS) by increasing gut permeability and activating pain pathways. Chronic inflammation has also been associated with the development of diabetes and cardiovascular diseases.
- The Impact of Stress on Gut: Stress can disrupt the balance of the gut microbiota and the gut-brain axis, resulting in gut dysbiosis (imbalanced gut bacteria) and increased gut permeability, often referred to as "leaky gut." This allows bacteria from the gut to enter the bloodstream and trigger an inflammatory response. Research suggests that dysbiosis can increase the risk of infections and autoimmune diseases.
- Stress promotes Unhealthy Food Choices: Stress stimulates the release of cortisol, which can lead to increased appetite and cravings for high-calorie, palatable foods. These foods provide temporary relief from stress and stimulate the release of "feel-good" neurotransmitters. Additionally, stress can alter an individual's metabolic responses to food, such as lower fat oxidation, higher insulin secretion, and decreased resting energy expenditure. These changes can have implications for the gut microbiota.
How can we optimize our gut-brain axis then? Here are some practical tips:
- Prioritize a Plant-Rich Diet: Include a variety of fruits, vegetables, whole grains, legumes, and nuts in your daily meals. These foods high in fiber that can promote the growth of beneficial gut bacteria and reduce stress hormone of the individuals. The research showed high-fiber diet is also good for grain. It can delay age-related brain inflammation in order to lower the risk of Alzheimer’s disease and dementia in old age.
- Probiotics and Fermented Foods: Incorporate probiotic-rich foods like yogurt, kefir, kombucha and kimchi into your diet. These foods introduce beneficial bacteria into the gut, supporting a healthy microbiome. Besides, fermented foods are the good source of tryptophan which is a key amino acid to produce serotonin (“feel good” neurotransmitter) to improve mood and reduce stress.
- Mindful Eating: Slow down and pay attention to your body's hunger and fullness cues. Mindful eating practices promote a relaxed state for body and mind; enhance digestion and absorption of nutrients, fostering a healthier gut environment.
- Reduce Processed Foods: Minimize your intake of highly processed and sugary foods, as they can negatively impact gut health and promote inflammation.
- Stress Management: Incorporate stress-reducing activities such as yoga, meditation, regular exercise, and quality sleep into your routine to promote a healthy gut-brain.
This article is written by Lim Yi Han (Nutritionist) for Green Image Organic Enterprise Sdn Bhd
References:
- Madison, A., & Kiecolt-Glaser, J. K. (2019). Stress, depression, diet, and the gut microbiota: human-bacteria interactions at the core of psychoneuroimmunology and nutrition. Current opinion in behavioral sciences, 28, 105–110. https://doi.org/10.1016/j.cobeha.2019.01.011
- Microbiology Society (2023). Kombucha to kimchi: Which fermented foods are best for your brain? https://microbiologysociety.org/news/press-releases/kombucha-to-kimchi-which-fermented-foods-are-best-for-your-brain.html#:~:text=Fermented%20foods%20are%20a%20source,neurotransmitters)%20in%20their%20raw%20form.
- Strandwitz P. (2018). Neurotransmitter modulation by the gut microbiota. Brain research, 1693(Pt B), 128–133. https://doi.org/10.1016/j.brainres.2018.03.015
- Zhu, F., Tu, H., & Chen, T. (2022). The Microbiota-Gut-Brain Axis in Depression: The Potential Pathophysiological Mechanisms and Microbiota Combined Antidepression Effect. Nutrients, 14(10), 2081. https://doi.org/10.3390/nu14102081