The Link Between Stress and IBS, Part 1

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For any person who has suffered prolonged or severe digestive complaints, with or without a diagnosis of Irritable Bowel Syndrome (IBS), understanding how to get back to wellness can feel confusing and daunting. But in your journey towards better health, you may be missing one very important question that could make all the difference: Can stress management and rebalancing the gut microbiota improve IBS symptoms? This three-part article series will help answer that question, shed some light on a complicated disorder and provide knowledge, guidance and hope to those suffering from IBS.

Irritable Bowel Syndrome (IBS) has been defined as a functional disorder of the gastrointestinal (GI) tract with typical symptoms of abdominal pain and altered bowel habits. As a functional disorder there is no special testing to confirm IBS, unlike inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn’s disease. Although IBD conditions have diagnosable inflammation and damage, this does not mean inflammation doesn’t also play a role in IBS. In fact, low-grade inflammation has been considered one of the contributing factors of IBS.

There are six possible contributing factors to the symptoms of IBS:

• Low-grade inflammation
• Abnormal gut motility (constipation and diarrhea)
• Visceral hypersensitivity (abdominal pain)
• Altered brain-gut function
• Intestinal permeability (aka leaky gut)
• Psychosocial factors

IBS is the most prevalent functional bowel disorder worldwide, affecting 10-25% of the population in developed countries and accounting for approximately 50% of doctor visits for GI complaints. So, if you suffer from IBS, you certainly are not alone! IBS is becoming as common as living a fast-paced, stressful life. This is not a coincidence, considering the role stress plays in the disorder. Specifically, anxiety and depression are common conditions shared among IBS patients; an altered stress response has been found in IBS sufferers; and stressful life events have been shown to increase risk of developing or causing relapse of IBS.

In Part One of this three-part article series, you will learn more about the connection between stress and IBS. Part Two, coming up in the next ELM Maine issue, will dive deeper into the link between stress and microbiota dysbiosis (imbalance of the bug community living in your digestive tract) as well as how dysbiosis leads to IBS symptoms. Finally, you’ll want to keep reading because Part Three, the last in the series, will discuss nutrition and lifestyle changes you can make to manage stress, rebalance your gut microbiota and improve IBS symptoms.

How the Human Body Responds to Stress
Stress has been a normal part of human life since Homo sapiens existed. Although the stressors have changed, the body’s response has not. When you are exposed to a stressor – extreme heat or cold, illness, physical trauma, loss of a loved one, traffic, work deadline, a cruel co-worker or even the thought of something stressful – your body responds physiologically. This response is called the General Adaptation Syndrome.

General Adaptation Syndrome
Hans Selye, the “Father of Stress Research,” proposed the now widely accepted three-phase progressive stress model called the General Adaptation Syndrome. This model describes three phases:

1. Alarm Phase. This is the body’s initial response to a stressor.
2. Resistance Phase. This phase begins when the body starts to adapt to the stressor.
3. Exhaustion Phase. If the stress is continued and prolonged, that stressor can negatively affect health, wearing down the body’s resistance to stress.

During the alarm phase, a stress or threat is perceived and the body kicks into action – as if you are Cro-Magnon man running from a cave bear. This reaction occurs for any perceived stress – literally running from a bear, fighting with a loved one, getting into an accident, public speaking, even negative self-talk. After the perceived threat is gone, the body is still processing it during the resistance phase. This helps the mind and body continue to handle emotional crises, fight infections or perform strenuous tasks. If the threat dissipates, eventually the body returns back to baseline – feeling healthy and having energy. However, if the stressor becomes frequent or prolonged, the body cannot get back to baseline and the exhaustion phase is reached.

Understanding how to manage stress is going to be critical for anyone suffering from IBS, especially considering that IBS patients often report more stress and anxiety than the general population. The exhaustion phase is not inevitable, however. Learning in what ways the body regulates its stress response and how each stressor is perceived is an important step towards reducing stress on the body.

Regulating the Stress Response – The H-P-A Axis
Selye’s General Adaptation Syndrome is a simplified version of the body’s stress response. In reality, there are many complicated, highly coordinated processes going on in the body. As soon as a stress or threat is perceived, the brain activates the body’s sympathetic nervous system which stimulates the release of epinephrine and norepinephrine from the adrenal glands. This reaction is typically known as the “fight or flight response” and coincides with the alarm phase. During this response heart rate, blood pressure, breathing rate, alertness and metabolic rate all increase while digestion and urine output decrease.

At the same time, the hypothalamus, pituitary and adrenal glands all work in concert to continue regulating the body’s stress response. This intimate relationship is called the Hypothalamus-Pituitary-Adrenal (HPA) Axis and is responsible for regulating the body’s long-term stress response. In response to stress, there is a trickle-down effect in the HPA axis – the hypothalamus releases corticosterone releasing factor (CRF) which stimulates the pituitary to release adrenocorticotrophic hormone (ACTH) which stimulates the adrenal glands to release cortisol.

The more frequent and prolonged a stressor is, the more CRF, ACTH and cortisol the body produces and the higher the risk of dysfunction in the HPA axis. Additionally, the body’s chain reaction to CRF production can lead to intestinal permeability, a contributing factor in IBS. This intestinal permeability then creates additional stress on the body through increased inflammation, another contributing factor in IBS, stimulating the HPA axis. The end result is a vicious snowball effect of more intestinal permeability, more inflammation and a prolonged stress response. These types of physical stressors, however, may be mitigated through better regulation of non-physical stressors including how the brain perceives stress.

Perceived Stress – How the Brain and Gut Communicate
There are many physical stressors that may activate the stress response – illness, extreme hot or cold, physical trauma, sleep disturbances, obesity, insulin resistance, low physical activity or over-training, and inflammatory conditions including arthritis, allergies and intestinal permeability. Although most of these may be under the power and control of the individual, one category of stressors may feel even more overwhelming than the physical: perceived stress.

Each person handles stress differently. Some people can let things roll like water off a duck’s back. Others may feel paralyzed by each perceived threat. This perception of each threat encountered is what truly dictates the individual’s stress load. Stress from relationships, finances, work, self-loathing, lack of control, and general anxiety can sometimes feel harder to manage. Yet, these emotional stressors may be what is causing the most harm in IBS sufferers because of the gut-brain connection.

The digestive system has its own separate nervous system running through it, called the Enteric Nervous System (ENS). This nervous system has hundreds of millions of neurons that create a direct link between the gut and brain. Through this neuronal communication highway, the gut provides feedback to the brain and the brain provides feedback to the gut. This communication regulates gut motility, sensory perceptions such as pain, and the production of secretions in the digestive tract like stomach acid and hormones. Activity in the digestive tract is controlled by this communication as well as the parasympathetic, or “rest and digest,” nervous system. This part of your autonomic nervous system helps calm you and promotes all aspects of the digestive process.

The issue arises when the “rest and digest” nervous system cannot be activated due to stress. This is because the sympathetic nervous system works in opposition of the parasympathetic nervous system. If the body is in “fight or flight” mode, it cannot also be in “rest and digest.” Chronic stress influences this gut-brain communication which greatly impacts many aspects of digestive health including gut motility, visceral pain perception and intestinal permeability – all contributing factors in IBS. Because the gut-brain communication pathway is highly influenced by perceived stressors, it becomes apparent that stress can play a significant role in the development or recurrence of IBS.

The Role of Stress in Irritable Bowel Syndrome
There is a substantial amount of research indicating stress has an enormous impact on whether an individual will suffer from IBS symptoms. Research has shown:

• Emotional stressors of anxiety and depression are common among IBS patients
• Stressful life events have been shown to increase the risk of developing IBS
• There is a high occurrence of early life stress in IBS patients
• IBS is more prevalent among caregivers bearing the stress of caring for a seriously ill patient
• Mood disorders are predictive of developing functional gastrointestinal disorders such as IBS.

The authors of the article “The microbiome: A key regulator of stress and neuroinflammation” stated it more succinctly: “Stress is…one of the most significant risk factors for irritable bowel syndrome.” In fact, the six contributing factors in IBS can each be linked as effects related to the stress response.

Linking the Stress Response to the Six Contributing Factors of IBS
Although the etiology, or underlying cause, of Irritable Bowel Syndrome is still not completely defined or understood, there are six factors that are considered to contribute to the condition: altered brain-gut function, abnormal gut motility, intestinal permeability, low-grade inflammation, visceral hypersensitivity, and psychosocial factors. There is also an intimate interplay between these factors, adding another layer of complexity to IBS symptoms.

1. Altered brain-gut function. As mentioned previously, the enteric nervous system is the line of communication between the brain and gut. This communication influences the functioning of the digestive tract, including motility, sensory perception and digestive secretions. Chronic stress will blunt “rest and digest” activity, changing the messages between the brain and gut. When this communication is altered it can lead to abnormal gut motility and visceral hypersensitivity, other contributing factors in IBS.
2. Abnormal gut motility. Irritable bowel syndrome is commonly subtyped based on the bowel habits, or gut motility traits, of the patient – IBS-C for constipation dominant, IBS-D for diarrhea dominant and IBS-M for mixed or alternating bowel habits. Altered brain-gut function can change the speed of movement through the digestive tract, leading to constipation, diarrhea, or a mix of both. Another driving factor of healthy gut motility is production of serotonin, or 5-HT. The neurotransmitter serotonin also helps regulate the HPA axis indicating stress may affect serotonin production. This creates two potential pathways leading to IBS – altered gut-brain function and a complicated relationship between serotonin and gut motility.
3. Intestinal permeability. The lumen, or hollow interior, of the intestines is lined with a very thin layer of cells called epithelial cells. This layer creates a barrier to keep harmful substances out while selectively allowing nutrients and fluid into the body. Excessive stress has been shown to damage the epithelial layer, compromising this line of defense and causing intestinal permeability. The impaired protective barrier now allows larger substances through, such as undigested food particles and pathogens, triggering immune and inflammatory responses and creating more stress on the body. Studies have not only shown increased intestinal permeability in IBS patients, but also indicated a positive correlation between intestinal permeability and symptom severity for IBS sufferers.
4. Low-grade inflammation. When there is damage to the intestinal lining, such as intestinal permeability, the immune system responds by releasing a type of immune cell called mucosal mast cells which may contribute to the progression of IBS symptoms. Studies of IBS patients have indicated a positive correlation between the number of mucosal mast cells, the degree of intestinal permeability, the amount of psychological stress and the severity of IBS symptoms. Additionally, these mast cells then trigger the release of pro-inflammatory substances called cytokines, which include interleukin-6 (IL-6), Interleukin-1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α). Chronic stress has been shown to increase pro-inflammatory cytokines which, in turn, activate the HPA axis and prolong the body’s stress response. This now potentially carves a path of increased damage, additional mast cells, more inflammation and intensified IBS symptoms. In fact, studies have shown this to be the case – increased concentrations of both inflammatory and immune cells have been found in the intestinal tissue of IBS patients.
5. Visceral hypersensitivity. Visceral hypersensitivity is a term used to indicate pain in the abdominal region, a common complaint in IBS patients. The stress response has been shown to contribute to this factor through the intimate interplay with the body’s inflammatory response. Stress creates inflammation by increasing proinflammatory cytokines throughout the body. Stress has also been shown to activate the production of mucosal mast cells, further increasing pro-inflammatory cytokines. This excessive inflammatory response creates a chain reaction that eventually signals the gut via the enteric nervous system. Both the inflammatory gut signaling and stress-induced mast cells can then lead to increased visceral hypersensitivity and other IBS symptoms according to some studies. Additionally, serotonin also comes into play here. Serotonin not only regulates the HPA axis and gut motility, it normalizes emotions and visceral perception as well. This may indicate there is a relationship between serotonin production, stress and gut motility that could influence abdominal pain perception in IBS patients.
6. Psychosocial factors. As mentioned earlier, mood disorders can predict the development of IBS. In fact, previous anxiety and depression is a risk factor for developing IBS following an intestinal infection. Additionally, many observations – from epidemiology, empirical data and clinical observations – associate stressful life events with the onset, severity and persistence of IBS in certain subtypes, further endorsing the role stress plays in IBS sufferers.

   This is not meant to overwhelm you with a lot of anatomy/physiology and statistical information! In short, just remember there are several studies linking stress to each and every contributing factor of IBS symptoms. So, if you suffer from IBS or IBS-like symptoms, understanding your stress load will be a key step on your journey to better health.

   Another key step is asking a question that still remains to be answered – does stress also affect the gut microbiota? Please stay tuned and pick up the next issue of ELM Maine to find out!

   Stephanie Walsh, CPT, CNTP, CEPC is a Certified Nutrition Therapy Practitioner, Certified Eating Psychology Coach and Certified Personal Trainer. Contact Stephanie at (207) 730-2208 or email her: swalsh@theholistichealthapproach.com. www.theholistichealthapproach.com.

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