When muscle testing for gut brain axis health, do you focus on issues and therapies related to the gut first? Do you have any advice for assessing that feedback loop quickly?

The gut brain axis is one of the most fascinating health topics, in part because it's hard to grasp the vastness of the microbiome and influence that it has upon our health and wellness, let alone the bidirectional communication between the microbiota and the brain (i.e., the gut brain axis (GBA)); we are learning more every day, yet our understanding is still in its infancy.

The gastrointestinal system contains its own nervous system known as the enteric nervous system, along which, hormones and immune signals are exchanged. Communication works both ways – brain to gut and gut to brain, therefore any disturbance in the brain is expressed in the gut and vice versa. As the age-old Hippocratic saying goes, "All disease begins in the gut”; thus, addressing GI health is essential to global health of the individual, and always a good place to start. Regarding the GBA, two molecules have been shown to play an important role - serotonin and zonulin.

Well-known for its mood-modulating capacity, serotonin, your "feel-good" hormone, is made both in the digestive tract and the brain, though the vast majority (95%) is made in your intestines. Research has demonstrated that particular spore-forming bacterial species within the gut microbiome stimulate gut endocrine cells to produce serotonin; thus, a healthy microbiome is essential for serotonin production. Zonulin, a protein that is released during inflammatory gut conditions, disrupts intestinal tight junctions and allow for bacterial endotoxins and products of digestion to circulate throughout your body, causing immune system upregulation, and subsequent inflammation. Zonulin that has traveled from the gut can bind to zonulin receptors on the tight junctions of the blood brain barrier, causing them to open and allow stressors (e.g., pathogens, toxins, inflammatory markers, etc.) to enter the brain. Chronic neuro-inflammation has been associated with many conditions including mood disorders and is an important contributor to GBA axis.

I am not aware of any method to assess the feedback look quickly. The vagus nerve plays an important role in the GBA, but there are a host of other signaling molecules that facilitate the bidirectional flow of information including hormones, cytokines, etc. This is an interesting article that describes the communication network, and may support you in directing your assessment. 

This question was answered by Leah Linder, ND.