Irritable Bowel Syndrome (IBS) accounts for half of all gastrointestinal (GI) doctor visits, and IBS-D is a type of IBS that includes frequent diarrhea as a common symptom. This GI condition can be troublesome, typically affects people under 50, and can cause disruptions at work and social activities. Surprisingly, many people suffer silently as less than half of people with IBS symptoms address these issues through a healthcare provider. 

If you are one of those people, this article will shed some light on this condition and provide options so you no longer have to struggle. With comprehensive care, the negative impacts of this condition can be significantly reduced. Functional labs are a powerful tool used as part of comprehensive care that can provide answers and empower you in managing this condition.

 [signup]

What is IBS-D?

IBS-D is a subcategory of IBS, a GI condition that causes varying digestive issues. Patients with IBS-D have loose or watery stools in greater than 25% of their bowel movements. This subcategory of IBS makes up 40% of IBS patients. What's interesting about IBS is that it's considered a Functional Gastrointestinal Disorder (FGID) or Functional Bowel Disorder (FBD) in which it's associated with gut function alterations without causing changes in bowel tissue, may not affect lab values, and does not increase the risk of colorectal cancer. However, IBS patients still have chronic GI issues.

What Causes IBS-D? 

The exact causes of IBS and IBS-D are still undetermined. However, many factors play a role in the development of IBS-D. Some of these factors include muscle contractions in the intestine, nervous system issues, stress, infections, gut microbiome disruptions, and food reactions. Muscle contractions in the intestines can lead to IBS-D because they can be stronger than usual, leading to gas, bloating, and diarrhea.

Regarding the nervous system, when signals between the brain and the intestines are poorly coordinated, the body may overreact to normal digestive changes. This overreaction can lead to abdominal pain or diarrhea. Gastroenteritis, diarrhea caused by an infection such as food poisoning, has also been associated with bacterial overgrowth in the intestines resulting in IBS-D.

Stress is a common trigger of this disorder and can worsen symptoms or become more recurring. Another trigger is food reactions. Many people with IBS will have more severe symptoms after consuming foods such as wheat, dairy, citrus, beans, cabbage, and other foods, which suggests sensitivity or intolerance-induced IBS. Studies are also revealing different overgrowth of microbes in the microbiome can impact the type of IBS, such as hydrogen-predominant SIBO (small intestinal bacteria overgrowth) in IBS-D patients. Evidence also suggests that the disruption of the gut microbiota plays a role in both the development and persistence of irritable bowel syndrome.

These causes and triggers should not cause alarm; they provide a positive outlook as these underlying causes can be effectively managed through functional medicine approaches.

IBS-D Symptoms

The hallmark symptoms of IBS-D are abdominal pain and chronic diarrhea that occurs at least once per week and has happened for at least three months to fit the ROME IV diagnostic criteria. Patients with IBS-D rarely experience constipation.

Other presentations of IBS-D include:

●  Bloating

●  Increased satiety

●  Indigestion

●  Nausea

●  Gas

●  Bowel urgency that feels incomplete

●  Mucous in the stool

What Are The Benefits of Regular Lab Testing For Patients With IBS-D?

Regular testing is vital in IBS-D because functional treatment plans may take time to show substantial changes in gastrointestinal health. Reordering functional medicine labs is usually recommended after 3-12 months of starting a plan, but some labs, like thyroid hormones, may need reassessment sooner. The frequency of retesting depends on each individual's case and lab results. Functional medicine labs help identify imbalances and underlying factors related to IBS-D symptoms, requiring ongoing monitoring to track progress.

Generally, labs should be retested every 3 to 9 months to ensure the treatment plan is effective. IBS-D is a diagnosis of exclusion. Ruling out other conditions with similar symptoms is crucial. Many conditions can cause similar digestive symptoms, such as SIBO or other forms of dysbiosis. Accurate diagnosis and effective management of IBS-D require ruling out these other conditions with similar symptoms.

Top Labs To Run Bi-Annually On Patients With IBS-D

To diagnose IBS-D, the ROME IV criteria are used, and other conditions with similar symptoms are ruled out. Although standard labs and imaging like CBC, CMP, and colonoscopy help rule out GI issues, they often show normal results in IBS-D cases. Functional medicine labs can offer a detailed evaluation of IBS-D's underlying causes. The following are some top labs practitioners use to help their IBS-D patients:

Neurotransmitter Panel

The GI tract is influenced by the enteric nervous system (ENS). Neurotransmitters like serotonin regulate functions such as GI motility, secretion, and sensation. Disruptions in these neurotransmitters can cause issues with these GI functions, increasing the risk of IBS-D or triggering a flare in patients. Thus, regular testing of these neurotransmitters can help prevent and manage any associated symptoms of IBS-D triggered by imbalances in neurotransmitters. 

The neurotransmitter panel is a urine test that can be easily completed at home. It examines more than 30 molecules related to neurotransmitters, including amines, amino acids, and organic acids. The test provides a detailed report with quantitative results and reference ranges for all urine neurotransmitters analyzed, which can guide practitioners on treatment protocols or adjustments that need to be made to current protocols to help IBS-D with an underlying cause of neurotransmitter imbalances.

Microbiome Analysis

Evidence shows that imbalances in the gut microbiome can contribute to symptoms of IBS-D. It has a role in the pathophysiology of this chronic disorder. Healthy gut microbiota regulates several body systems, including metabolic, immune, and neuroendocrine. Disruptions to the microbiome can lead to issues with the brain-gut connection, which then contributes to digestive problems such as IBS.

A comprehensive stool test can analyze the health of the gut microbiome by assessing for overgrowth, diversity, and inflammatory processes. This test examines over 300 microorganisms, including bacteria associated with SIBO providing some insight into a primary factor contributing to IBS. This test can also show any infections, such as food poisoning, that can cause IBS-D. The results of this test can provide practitioners with a thorough examination of any underlying causes of IBS due to disruptions in gut health, allowing for individualized approaches to manage IBS-D.

Food Sensitivity Panel

Food sensitivities or intolerances are believed to be a potential trigger of IBS-D. Some individuals with IBS-D may have intolerances to certain foods, such as gluten or lactose. Consuming these foods can lead to IBS-D symptoms like diarrhea, bloating, and abdominal pain. Evidence shows that patients with IBS who eliminate foods they are sensitive to can have a 10-25% decrease in symptoms. Therefore, food sensitivity testing should be a priority for these patients. Analysis of these immunoglobulin markers of food reactions can help personalize nutritional plans specific to the results enabling targeted elimination to improve the impact of IBS-D. This panel is achieved by a blood sample and can be completed at home or in the clinic.

Adrenal Stress Test

People with IBS have been shown to respond differently to stress than those without IBS. Stress hormones may trigger symptoms in the colonic tissue of IBS patients but not in individuals without IBS. Moreover, people with IBS tend to produce higher levels of cortisol, a stress hormone, when facing stressors than those without IBS. Thus, regulating stress hormones such as cortisol can help to reduce  IBS symptoms linked to stress. Regular testing can help practitioners monitor these levels and suggest appropriate recommendations based on the results to help manage stress response and IBS. The adrenal stress test is a salivary test in which saliva samples are taken at four different times within a day to assess cortisol levels throughout the day, giving a more comprehensive look into the stress response.

Additional Labs to Check 

Additional tests to check involve ruling out other similar digestive disorders, such as IBD. Colonoscopy, CT, and MRI are used to diagnose IBD and other digestive issues. These tests can help rule out those conditions by giving an in-depth view of the intestinal tract.

[signup]

Summary

IBS-D can be a long-term gastrointestinal condition characterized by symptoms like abdominal pain and diarrhea. Diagnosing IBS-D involves ruling out other conditions, as there is no specific test for it which can make managing and treating this condition challenging. If left untreated, IBS-D can impact a person's daily activities and quality of life. Fortunately, functional medicine tests like a microbiome analysis or a food sensitivity panel can be used to identify the underlying factors that trigger IBS-D. Practitioners can utilize these tests regularly to assess each patient's specific determinants of this condition so they can create personalized treatment plans to manage this digestive issue effectively.