The gut-brain axis (courtesy Dr. Andy McLean)

It’s all in your head. Or maybe your gut.

Common idioms relate to the association between the gastrointestinal (GI) tract and emotions: “Trust your gut” (instinct); “That made me sick to my stomach” (disgust); “I have butterflies in my stomach” (anxiety); “Show some guts” (courage).

There has been significant interest of late in research on the gut-brain axis – including among UND researchers. This bidirectional system of communication links the GI tract, the endocrine system, immune system, and the brain. The vagus nerve is a direct link from the stomach to the brain, and, in fact, vagus nerve stimulation is an FDA approved treatment for chronic or treatment resistant depression.

Most of us have heard about the association between the neurotransmitter serotonin and mood. While we associate neurotransmitters with the brain, over 90% of the body’s serotonin is derived from cells in the gut, and from here does not cross the blood-brain barrier. However, such chemical messengers, including dopamine, GABA, and glutamate, may affect signaling between the gut and brain even when they do not directly enter the central nervous system.

One of the most exciting areas of research impacting overall health, including mental health, has to do with the gut microbiome. Non-industrialized populations retain a much more diverse gut biome than their industrialized counterparts, and in general do not have high rates of chronic diseases like obesity, type 2 diabetes, and certain autoimmune diseases as those in industrialized countries. (As an aside, I lived for a year on a developing island in the Caribbean, where there was ample fresh fruit, fish, and nuts for consumption.  However, with “westernization,” the population gradually took on the “Western” diet and subsequently developed significant issues related to metabolic syndrome and cardiovascular disease, despite not being considered “industrialized.”)

What to do? While probiotics (strain-specific) might be helpful for some individuals (condition-specific), there is not ample evidence to recommend them for the general population. While researchers continue to work on the riddle of the gut-brain access, the health intervention that continues to be most robust has to do with lifestyle. A healthy diet, exercise, sleep, and stress reduction affect both your gut and, subsequently, your mood.

Last pearl for the day: Dietitian is spelled with “two ts.”

Reminder, if you would like to share inspirational quotes, stories, or ideas which might be helpful to others, please feel free to email Dr. Melissa Naslund at melissa.naslund@UND.edu.