Stress Soup with a Side of IBS: Gut Health, The Microbiome, and the Effects of Chronic Stress

Written by Dr. Laura Jones

Over the past 10-20 years, research has revealed that there is a strong connection between the human gut, the bacteria that inhabit it, and the biochemistry of the brain.  We call the bidirectional highway between the gut and the brain the gut-brain axis.  This communication roadway involves many systems of the body, including the endocrine, immune, and nervous systems and is influenced greatly by the beneficial bacteria that inhabit the gut. The gut and the brain share many similar pathways and neurotransmitters and the connections between brain and gut are demonstrated in the dysfunctions that commonly unite them. There is a growing body of evidence that suggests several neurological and mood disorders originate in the gut. In fact, gastrointestinal disorders may manifest as neurological and psychiatric symptoms.  From a functional medicine perspective, we see a clear connection between psychological stress, microbiome balance (this is another term for the balance of bacteria in your gut) and gastrointestinal health.

As functional medicine practitioners working with patients with gastrointestinal symptoms, one of our main goals is to create a healthy ecosystem within the gut to promote overall system balance. This, in turn, affects immune function, and significantly impacts the risk of chronic disease and ability to maintain wellness. Research demonstrates that stress alters intestinal mucosa permeability (leading to leaky gut) and cytokine secretion, which creates systemic inflammation. Research also demonstrates that stress may significantly change the microbiome, and the activity of the bacteria in the gut. 

Considering the bidirectional highway that is the gut-brain axis, gut microbiota can then influence stress-related brain responses including vulnerability to anxiety, depression, and insomnia at the very least. Stress alone has been shown to be responsible for the manifestation of imbalances in gut microflora, called gut dysbiosis. In addition, new research also reveals a connection between the hypothalamic-pituitary-adrenal (HPA) axis, the gut microbiota, and the neuroendocrine system responsible for managing the stress response.  

Many neurotransmitters, including serotonin, norepinephrine, epinephrine, and dopamine are active in the gastrointestinal tract as well as the brain.  For example, it is estimated that 80-90% of the body’s serotonin production is along the gut wall.  These neurotransmitters influence gut motility, absorption of nutrients, the gut’s immune system, and the microbiome.  Stress-related changes, like an increase in stimulatory epinephrine or norepinephrine, may shift the types and amounts of the microflora in the gut leading to phycological changes, including vulnerability to mental/emotional health concerns.

One defining character of functional medicine is the personalized treatment plans that identify and address the root causes of disease.  For many, addressing stress level is one of the lifestyle factors that is most critical. Identifying predisposing factors that may have reduced good flora in the gut such as antibiotics in childhood, the use of steroid hormones, a poor diet, or genetic vulnerabilities is also part of the detective work used to put the pieces of each patient’s story together.  Managing stress and modifying the body’s response to stress may lead to more positive health outcomes.  Research suggests that some stress reducing techniques have the potential to improve immune function, improving our resilience to stress and infection.

An evaluation of the effectiveness of stress management in inflammatory bowel disease (IBD), found that the stress management techniques, including meditation, relaxation training, guided imagery, and exercise, not only reduced anxiety but also reduced inflammation and improved quality of life in patients with bowel disease. Some small, human studies have investigated the effect of supplemental prebiotic and probiotic therapy on stress-related conditions. Results revealed that daily consumption of probiotics preserved gut bacteria diversity and relieved stress-associated abdominal dysfunction. Probiotic have been shown to be a potential treatment for anxiety, ameliorate depression symptoms, and decrease the cortisol response triggered by emotional stress.

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