Health Science Reviews

by Jana Van Der Westhuizen

Have you ever had a gut feeling about something or felt butterflies in your stomach? You are most probably receiving communication from your “second brain”, called the enteric nervous system (ENS).

The ENS consist of two thin layers of nerves that line the gastrointestinal tract all the way from the oesophagus to the rectum. Unlike your central nervous system, the ENS cannot do maths or construct sentences, but is rather involved in controlling digestion.

Scientists call this communication between the gut and the brain, the gut-brain axis (GBA). The communication is bidirectional, linking cognitive and emotional brain centres to intestinal function, implying that your brain will affect the health of your gut and your gut will affect the health of your brain.

In addition to the nervous connection, the gut and brain are also connected by chemical signalling, that scientists refer to as neurotransmitters. The happy hormone, Serotonin, is not just produced in your brain, but is interestingly produced in large amounts by the gut and its microbes. Another neurotransmitter, gamma-aminobutyric acid (GABA), responsible for controlling fear and anxiety is also produced by the gut microbes.

This revolutionized understanding of the GBA paths the way for new treatment options or bowel-disorders, such as irritable bowl syndrome (IBS). Because our two “brains” communicate with one another, therapies that help one may help the other. Antidepressants may be prescribed for IBS patients, not for their mental health but rather because the medication calms nerves in the gut. The use of probiotics and diet has also proved to restore the microbe habitat of the gut. This in turn, have an effect on anxiety, depression and memory function by influencing brain neurochemistry.

In conclusion, the connection between the gut and brain gives us insight on the relation between our physical well-being and mental health. An apple a day may not just keep the doctor away, but your psychiatrist too!

Reference:

Carabotti, M., Scirocco, A., Antonietta Maselli, M., and Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems.