The complex relationship between stress and irritable bowel syndrome (IBS) has long been a subject of scientific investigation and clinical interest. IBS is a condition that affects 5-10% of the worldwide population.

While the exact cause of IBS remains elusive, it is increasingly evident that stress plays a significant role in its onset, exacerbation, and overall management. This interplay between stress and IBS encompasses a bi-directional relationship, where stress can trigger IBS symptoms and, in turn, the symptoms themselves can contribute to increased stress levels. 

Understanding the intricate mechanisms by which stress influences, IBS can provide valuable insights into developing effective therapeutic strategies and lead to an improved quality of life for individuals living with this condition.

This article will highlight the relationship between stress and IBS. We’ll discuss functional medicine testing that can help to evaluate this connection, as well as complementary and integrative therapies that can be beneficial. 

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Understanding Irritable Bowel Syndrome (IBS)

IBS is a gastrointestinal disorder with unknown etiology. To be diagnosed with IBS, a person must have had abdominal pain at least one day per week for the past three months, in addition to two or more of the following symptoms: abdominal pain in relation to changes in bowel movement frequency; abdominal pain accompanied by bowel movements; abdominal pain with consistency changes in the stool. 

There are four subtypes of IBS, including unclassified IBS (IBS-U), mixed IBS (IBS-M), constipation-predominant IBS (IBS-C), and diarrhea-predominant IBS (IBS-D). IBS-D is the most common type of IBS. 

Symptoms of IBS

Symptoms of IBS can vary and may include:

• Diarrhea
• Constipation
• Indigestion
• Nausea
• Incomplete passing of stools (feels like you still have to go but cannot)
• Excess amounts of flatulence (gas)
• Urgency with bowel movements
• Abdominal cramping
• Abdominal pain
• Anxiety
• Depression

The Relationship Between Stress and IBS

In order to understand how stress affects the body, we must discuss the body’s stress response. The stress response is induced by the hypothalamic pituitary adrenal (HPA) axis. When the body undergoes stress, whether physical, mental, emotional, or perceived, a center in the brain called the hypothalamus senses this stress and releases a hormone. This hormone will travel to another center in the brain, the pituitary gland, and alerts the gland that stress is occurring. The pituitary gland, in response, releases its own hormone, which will alter the adrenal glands of the stress. The adrenal glands respond by releasing a variety of hormones, the primary one being cortisol. Cortisol has many effects on the body, including increasing blood pressure and blood sugar, but it also induces gastrointestinal (GI) changes. Delayed gastric (stomach) emptying, increased transit and contractions of the muscles of the colon leading to diarrhea, and increased sensitivity in the GI leading to heartburn symptoms with standard stomach acid, are all results of an increase in cortisol. 

Our stress response was never meant to be long-term or chronic; however, in today’s society, many people do experience chronic stress. This can result in symptoms such as indigestion, diarrhea, and heartburn. One source of chronic stress may be the gastrointestinal symptoms themselves, leading to a vicious cycle: gastrointestinal symptoms cause stress, stress-induced gastrointestinal symptoms, and the bidirectional cause and effect continues. 

Physiological Mechanisms of IBS

The gut-brain axis may also play a significant role in the etiology of IBS. Within our large intestine lives the gut microbiome: a collective group of bacteria, viruses, fungi, and parasites. The gut microbiome is essential to our health, as they affect digestion, absorption, synthesis of vitamins, and hormone metabolism. Additionally, these microbes make neurotransmitters and neurotransmitter precursors. These molecules have the ability to cross the blood-brain barrier, where the brain will then respond by modulating the nervous system, inflammatory, and other processes in the body. 

5-HT is a precursor to serotonin, known as the “happy neurotransmitter.” 5-HT can be made in the brain and in the gut, with 95% of 5-HT actually made and stored in the gut, mostly by cells called enterochromaffin cells (EC). It’s important to note that when 5-HT is made by the gut, it does not cross the blood-brain barrier, and thus, its effects are outside the central nervous system. 5-HT induces an array of effects in the gut in relation to IBS. Gut 5-HT can activate neurons inside the intestinal wall to affect intestinal movement, inducing peristalsis or movement in the GI tract, secretion of other intestinal glands, and intestinal sensations. 5-HT will also activate other neurons outside the intestinal wall that can induce nausea, vomiting, abdominal pain, and discomfort, all symptoms of IBS. 

Dopamine is another neurotransmitter made in the gut and is associated with feelings of reward, attention, and memory. Problems in the dopaminergic system have been linked to depression, anxiety, and dysbiosis of the microbiome, and there is research supporting the idea that dopamine plays a role in IBS, although researchers are still uncertain of the exact mechanism.

Gamma-aminobutyric acid (GABA) is another neurotransmitter made in the GI tract. GABA can influence the release of gastric acid, gastric emptying, motility of the GI tract, and pain perception in the gut. Studies have shown irregularities in the GABA system in those with IBS and thus have concluded that GABA may play a role in this condition. 

Histamine is another neurotransmitter involved in immune responses and is also made in the gut. Histamine affects the permeability and motility of the intestinal tract. Many studies have shown an increase level of histamine in the colon of those with IBS, suggesting histamine plays a role in the etiology of IBS.

Psychological Factors and Stress

Psychological stress plays a significant role in IBS; some even refer to IBS as a combination of “irritable bowel” and “irritable brain.” Psychological stress can alter intestinal sensitivity, permeability, motility, and secretion of various substances. Additionally, stress activates the gut-brain axis, which in turn results in IBS symptom flares. Psychological stress also induces changes in the microbiome of the gut, which can induce IBS symptoms and may play a role in the development of this disorder. 

Functional Medicine Labs to Test for Root Cause of Stress and IBS

Functional medicine labs for stress and IBS can include the following:

Comprehensive Stool Test

A comprehensive stool test evaluates markers of digestion, absorption, immune function, and inflammation and also takes a deep dive into the microbial composition of the gut microbiome. As discussed above, digestion, absorption, immune function, and inflammation may all be altered and may induce symptoms of IBS. Additionally, the microbiome plays an important role and can influence the development and severity of IBS. Thus, a comprehensive stool test, such as Doctors Data GI360, can be of significant importance for those with IBS and can help to isolate which mechanisms of gastrointestinal functioning are affected. 

Neurotransmitter Testing

Since neurotransmitters are made in the gut and have a significant connection to the etiology of IBS, neurotransmitter testing is warranted.

Stress Testings 

Stress can be tested by evaluating the level of cortisol. Cortisol, our body’s primary stress hormone, also controls our circadian cycle or sleep-wake cycle. Thus, cortisol should be released throughout the day in what we refer to as a cortisol curve. When significant stress is present, this can cause our cortisol curve to be irregular. ZRT Diurnal Cortisol test is a great option, as it shows levels of cortisol throughout the day. 

Importance Of Individualized Treatment Plans for Addressing Both Stress And IBS Symptoms

Since stress and IBS are tightly intertwined, a treatment plan for IBS must include the treatment and management of stress. This can benefit the patient in two ways. First, a treatment plan documented on improving physiological factors that contribute to their disease, as in the case of stress and IBS, will improve their condition. Second, many IBS sufferers are unsatisfied with conventional treatment options. Educating patients on the connection between stress and IBS and implementing therapies can help give the patient additional options for treatments and help them to feel that there is hope for their condition. 

Stress Management Strategies for IBS

Many stress management techniques can be implemented for those with IBS. Cognitive-behavioral therapies (CBTs) revolve around the idea that negative thoughts influence how we feel, and these feelings change the way we behave. Deep breathing exercises, guided imagery, and muscular relaxation are all techniques that fall under the umbrella of CBT. Research shows that ⅓ IBS patients see improvements in symptoms with the utilization of CBT. Relaxation techniques can also be effective in the treatment of IBS. Mindfulness-based stress reduction (MBSR) is a type of meditation that was created in the 1970s and has since been utilized for a variety of health conditions, including anxiety, depression, pain, hypertension, immune and skin disorders, and more. In a study done on IBS patients and MBSR, patients saw a 71% improvement in GI symptoms.

Lifestyle modifications, including exercise and sleep, can affect IBS symptoms. A study done on 102 people with IBS showed exercise significantly reduced symptoms, so much so that the authors concluded, “Physical activity should be used as a primary treatment modality in IBS.” Sleep is another important lifestyle factor that cannot be ignored, as 40% of people with IBS report distorted sleep. There is research suggesting that poor sleep is correlated with the following day's IBS symptoms, including abdominal pain, anxiety, and fatigue. Creating a good bedtime routine, including avoiding bright lights and stimulants before bed, getting exercise, and ample sunlight during the day, can all help with sleep.

Patient Education and Support for Stress and IBS Management

Many people who suffer from IBS feel frustrated with the healthcare system and their treatment options. Additionally, IBS sufferers tend to feel alone, isolated, and frustrated with their condition. Thus, it's important to provide those with IBS the proper education about their condition, especially revolving around the connection between stress and IBS. Patients with IBS should be encouraged to place emphasis on self-care and stress management strategies, as these are strategies that they can control and implement at home. Support groups and counseling resources should also be provided, such as the IBS Patient Support Group and the IBS Network. For those who may be more introverted, phone or tablet apps may be more appropriate. There are various apps that can help IBS patients utilize stress-relieving therapies from the comfort of their own homes. 

Supplements and Herbs for Stress Management

There are many supplements and herb options for stress management. Let’s take a look at some of the most well-researched supplements:

Probiotics for Stress Management

Probiotics are supplements that contain strains of various beneficial bacteria, viruses, and fungi. Because of the gut-brain axis, probiotics may be beneficial for stress reduction. A study done on Japanese students showed probiotic supplementation effectively reduced both cortisol levels and gastrointestinal symptoms when compared to controls. 

Dose: The dose of probiotics should be customized based on comprehensive stool results for optimal treatment.

Duration: Duration of use should be determined by symptom relief and/or testing improvements

Ashwagandha for Stress Management 

Ashwagandha is an herb that is categorized as an “adaptogen.” As the name implies, adaptogens help the body adapt to stress. In addition to lowering inflammation, Ashwagandha has been shown to lower cortisol levels, making it a fantastic choice for those with IBS.

Dose: 300 mg- 12,000 mg daily 

Duration: Until symptoms and/or biomarkers improve

Vitamin B6 for Stress Management 

Vitamin B6 is a water-soluble vitamin required for over 4% of reactions in the body. Vitamin B6 is important, especially for the nervous system, and may be beneficial as part of a stress management treatment plan since it is required for the creation of the neurotransmitters GABA, serotonin, histamine, and dopamine. All of which are neurotransmitters that influence mood and may have a connection to IBS, as discussed above. Additionally, low vitamin B6 levels have been associated with the development of IBS. 

Dose: 100 mg daily 

Duration:  35 days 

Supplements and Herbs for IBS Flares

Many supplements and herbs can be helpful in the treatment of IBS. Let’s take a look at the most evidence-based options: 

Peppermint Oil for IBS 

Peppermint oil has been shown to decrease abdominal cramping and pain and relax muscles of the GI tract. A meta-analysis assessed peppermint oil effects on IBS in 12 trials with over 800 patients. Results showed peppermint oil to be effective at reducing IBS symptoms while also being a safe therapy.

Dose: 0.2 to 0.4 mL 3x/day in enteric-coated capsules per day 

Duration: Until symptoms resolve and/or biomarkers improve

Fiber for IBS 

Fiber, a gelatinous substance found in many fruits and vegetables, has been recommended for years by physicians for IBS as it can affect gut motility, secretions, and the microbiome. Fifteen randomized control trials showed fiber to be effective at reducing IBS symptoms. However, the type of fiber does matter. Psyllium and ispaghula, two types of soluble fiber, were shown to be the best types of fiber for IBS. Conversely, bran, an insoluble fiber, was shown to be ineffective at reducing symptoms of IBS. 

Dose: 20-25 g. soluble fiber daily 

Duration: Indefinitely 

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Summary

IBS is a condition that plagues many people. Knowing the connection between stress and IBS can help both the practitioner, as they can emphasize the importance of stress management to the patient, and the patient, as they can understand what's happening in their body. Functional medicine testing can help practitioners investigate the stress-IBS connection in their patients so they can formulate an all-encompassing treatment plan with the goal of symptom resolution and disease stabilization.