Health Science Reviews

By Murunzi Ndivhuwo

RESEARCH QUESTION:
Can gut microbes really influence how we think, feel, behave, and even trigger neurological or psychiatric disorders?

INTRODUCTION
What if the poetic metaphor, “Always trust your gut instinct,” has a scientific basis? Recently, researchers discovered the invisible pathway connecting your gut to your brain (Microbiota gut-brain axis). Trillions of microbes in the gut are constantly communicating with the brain, influencing everything from your mood and memory to your risk of neurological disorders such as Alzheimer’s and depression. In a comprehensive review, He et al. (2014) explored how the microbiota-gut-brain axis functions.

METHODOLOGY
To investigate the microbial mind connection, researchers reviewed:

• The microbiomes of healthy and sick individuals.
• Brain scans and cognitive assessments.
• Animal studies where human microbes were transferred to mice.
• They examined neurotransmitters, the vagus nerve, immune modulation, and barrier integrity.

RESULTS
Researchers found that changes in the microbiota are linked to brain disorders.

Table 1: Changes in gut microbiota in patients with neurological disorders

Individuals with Alzheimer’s and Parkinson’s showed altered gut microbes long before brain symptoms appeared, and individuals suffering from depression have reduced Lactobacillus and Bifidobacterium. Additionally, probiotics lowered anxiety scores and prebiotic diets reduced stress markers.

DISCUSSION
Microbes don’t just sit in your intestines, they also send chemical signals such as serotonin, dopamine, and short-chain fatty acids. They activate immune responses and interact directly with the brain through the vagus nerve. They help regulate inflammation and protect the brain’s barriers. Furthermore, the gut microbiota from depressed individuals wastransferred into healthy mice, causing the mice to show depressive behaviour.

KEY TAKEAWAYS
Targeting the gut microbiome through diet, probiotics, and prebiotics could help in preventing brain disorders. It seems the brain’s future may lie in the individual’s belly.

REFERENCE
He, Y., Wang, K., Su, N., Yuan, C., Zhang, N., Hu, X., Fu, Y. and Zhao, F., 2024. Microbiota–gut–brain axis
in health and neurological disease: Interactions between gut microbiota and the nervous
system. Journal of cellular and molecular medicine, 28(18), p.e70099.