The Microbiome, Stress Hormones, & Gut Function

Over the past few decades, researchers have worked to unravel the delicate connections between the human gastrointestinal (GI) microbiota and the brain. The bidirectional communication along the gut-brain axis involves many organ systems, including the endocrine, immune, autonomic, central (CNS), and enteric nervous systems (ENS), with the intestinal microbiota influencing those interactions.^1,2 The ENS is able to operate GI function independently of the CNS; however, many of the pathways and neurotransmitters are similar between the nervous systems in the brain and the gut.³ The connections between brain and gut abound, which can be seen in the dysfunctions that often unite them. Many neurological and mood disorders often have enteric manifestations,^3,4 GI disorders may present neurological and psychiatric symptoms,^5,6 and psychological stress may adversely impact microbiome balance and GI function.^2,7

How can clinicians help patients create a healthy ecosystem within the gut to promote overall system balance, healthy immune function, and optimal wellness? In the following video, IFM educator David Rakel, MD, talks about the connection between stress and GI function:

Chronic stress and GI function: bidirectional considerations

Research suggests that stress not only alters intestinal mucosa permeability and cytokine secretion,^7,8 but stress may also significantly change the community structure and activity of the commensal microbiota in the gut.^9,10 In turn, considering the bidirectional interaction of the gut-brain axis, gut microbiota potentially influence stress-related physiologic responses.^1,10,11

Life stress has multiple physiological impacts within the human body, and may be one causal factor in dysbiosis.¹⁰

Emerging research has suggested a close interaction between the gut microbiota and the hypothalamic-pituitary-adrenal (HPA) axis, the major neuroendocrine system that regulates responses to stress, and their communication may be closely interrelated with other systems.¹²