A Functional Medicine IBS-C Protocol: Testing, Differential Diagnosis, and Treatment

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder (FGID), with a global prevalence of 12-30%. In the United States, IBS affects up to 45 million people and is responsible for 600,000 office and emergency room visits annually. Despite these high numbers, only one-third of IBS sufferers seek medical help, and of those that do, up to 84% experience minimal or no response to conventional treatment options. The need for increased awareness and improved medical intervention for the millions suffering from IBS is apparent.

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What Is Irritable Bowel Syndrome With Constipation (IBS-C)?

IBS is an FGID related to incohesive brain and gut signaling. It causes intestinal hypersensitivity and dysmotility, leading to abdominal pain associated with changes in stool frequency and appearance. IBS-C is the constipation-predominant subtype of IBS, accounting for more than one-third of diagnosed cases. 

IBS-C Signs & Symptoms

The hallmark symptoms of IBS-C are abdominal discomfort and constipation. 

Abdominal discomfort may be described as sharp pain, cramping, bloating, distension, or fullness. It is often triggered by eating or emotional stress and is better after a bowel movement. (31) 

‍Constipation can be defined as:

• Having fewer than three bowel movements per week
• Having stool that is hard, dry, lumpy, difficult, or painful to pass
• Having a feeling of incomplete evacuation after a bowel movement

Root Causes of IBS-C

Like all FGIDs, there is not a single cause of IBS-C; instead, it is understood to be related to various factors that disrupt normal immune function and gastrointestinal (GI) motility. Evidence suggests that such factors may include genetics, serotonin deficiency, infection, dysbiosis, abdominal surgeries, stress, alcohol, and smoking. These factors appear to cultivate a proinflammatory and hypersensitive intestinal environment, which causes slowed GI motility and visceral pain. (6, 23, 45) 

How to Diagnose IBS-C

Diagnosing IBS-C involves a comprehensive approach that thoroughly evaluates symptoms and medical history.

Step 1: Construct a Broad Differential Diagnosis

Recent medical guidelines dictate that IBS is no longer a diagnosis of exclusion. However, characteristic IBS symptoms overlap with many other conditions. Therefore, medical providers should undertake due diligence to rule out other conditions masquerading as IBS. 

The following blood tests are beneficial in the initial diagnostic evaluation of vague GI symptoms. These will typically result unremarkably in patients with IBS-C:

• Complete blood count (CBC)
• Comprehensive metabolic panel (CMP)
• Thyroid panel
• Celiac antibodies
• Food allergies IgE blood test

Step 2: Use the Rome IV Criteria 

The Rome IV criteria used for diagnosing IBS require that patients have recurrent abdominal pain at least one day per week during the previous three months that is associated with two or more of the following:

• Defecation
• A change in stool frequency
• A change in stool appearance

IBS is subclassified as IBS with predominant constipation when a patient reports most of their abnormal bowel movements are constipation; specifically, more than 25% are hard or lumpy, and less than 25% are loose or watery (44).  

In 2021, the Rome Foundation proposed that IBS can be diagnosed if the patient's symptoms have lasted at least eight weeks and are bothersome (i.e., interfere with daily activities, cause worry, or interfere with quality of life).

Step 3: Use Specialty Labs to Uncover the Root Causes of IBS-C

The following labs are less commonly utilized in conventional medicine algorithms but can provide valuable insight into the possible triggers contributing to IBS. 

SIBO/IMO Breath Test

It is estimated that up to 80% of patients with IBS have underlying SIBO (small intestinal bacterial overgrowth). IMO (intestinal methanogen overgrowth) is a SIBO subtype characterized by an overgrowth of methane-producing microorganisms called archaea. Methane gas has been shown to directly slow intestinal transit and cause constipation, strongly linking it to IBS-C. Per the North American Consensus guidelines, a peak methane level of at least 10 ppm at any point during a SIBO breath test is diagnostic for IMO.

Order one of the following tests to screen for IMO:

• SIBO - 3 Hour by Genova Diagnostics
• SIBO/IMO Lactulose Breath Test by Commonwealth Diagnostics International, Inc.
• trio-smart SIBO Breath Test by Gemelli Biotech

Comprehensive Stool Analysis

Subtle variations in the gut microbiome and digestion can alter the gut-brain axis and cause IBS symptoms. Dysbiosis is common in IBS patients. Dysbiotic patterns commonly observed in patients with IBS include lower levels of Lactobacillus and Bifidobacterium and an increased abundance of E. coli, Enterobacter, and Veillonella. (6) 

Each of the following comprehensive stool analyses offers a complete look at gut health by analyzing markers of digestion, nutrient absorption, immune function, and the intestines' microbial ecosystem:

• GI-MAP by Diagnostic Solutions
• GI360 by Doctor's Data
• GI Effects® Comprehensive Profile - 3 day by Genova Diagnostics

Food Sensitivity Testing

The IBS population reports a higher incidence of food sensitivities than the general population. According to one study, dairy, beans, apples, and fried foods are some of the most commonly reported trigger foods for IBS. However, food sensitivities are often difficult to identify through observation alone because the symptoms they cause are usually delayed up to 72 hours after ingestion. 

Any of the following panels can take the guesswork out of identifying food sensitivities:

• IgG Food MAP with Candida + Yeast by Mosaic Diagnostics
• 96 IgG Food Sensitivity Panel by Alletess Medical Laboratory
• foodANALYZER IgG Food Sensitivity by Access Med Labs

Stress Panel

Acute or chronic stress can trigger alterations in the gut-brain axis. This interaction influences various gut functions, including motility, secretion, and immune response. In the context of IBS, heightened stress levels can exacerbate symptoms such as abdominal pain, bloating, and irregular bowel habits. (41) 

Specialty tests designed to assess the hypothalamic-pituitary-adrenal (HPA) axis, a key component of the stress response system, can unveil abnormal cortisol levels or secretion patterns, which may disrupt the delicate balance of the gut-brain axis and, consequently, contribute to IBS symptoms.

• HPA Profile by Sanesco 
• Adrenocortex Stress Profile by Genova Diagnostics

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Treatment Plan for IBS-C

Using a step-by-step approach, doctors can help patients palliate IBS symptoms while correcting the underlying imbalances leading to GI dysfunction.

Step 1: Palliate Symptoms

Here's Why This Is Important:

Alleviating symptoms like constipation and abdominal pain improves patient comfort and quality of life, allowing them to engage in daily activities without disruption.

How Do You Do This?

Given the prevalence of food sensitivities in the IBS population, dietary modifications should almost always be considered in patients with IBS. Foundational nutritional habits that do not include restriction can go a long way in supporting GI health. These include eating slowly, chewing food thoroughly before swallowing, and listening to hunger and satiety signals. (5) 

Adding fiber to the diet also supports healthy bowel movements by nourishing beneficial Lactobacillus and Bifidobacterium gut bacteria and improving stool consistency. Bacterial fermentation of fiber produces short-chain fatty acids (SCFAs), which can interact with the nervous system to decrease pain signals. Non-fermentable fibers, such as psyllium, oats, and partially hydrolyzed guar gum, are usually best tolerated by those with IBS.

For some patients, a therapeutic 6-8 week elimination diet may be warranted to reduce exposure to triggering foods stimulating overactive immune responses and causing digestive symptoms. The low FODMAP diet, for example, has been shown to reduce IBS symptoms in 75% of IBS patients. Patients should be instructed to rechallenge foods back into the diet to test their tolerance; foods that do not trigger symptoms can be safely reintroduced into their regular diet.

Medications and natural supplements can also be used to encourage regular bowel movements and alleviate abdominal pain. According to the American Gastroenterological Association (AGA), the following agents should be considered for the symptomatic management of IBS-C:

• Osmotic laxatives: polyethylene glycol (PEG)
• Antispasmodics: hyoscyamine, dicyclomine, peppermint oil
• Secretagogues: linaclotide, lubiprostone, plecanatide, tenapanor
• Tricyclic antidepressants: amitriptyline

Step 2: Reestablish a Healthy Gut Microbiome

Why Is This Important?

Restoring microbial balance in the gut can help regulate bowel function and reduce IBS symptoms over the long term.

How Do You Do This?

Address intestinal dysbiotic patterns by using a combination of antimicrobials and probiotics. 

• Prescription antibiotics, such as rifaximin and metronidazole, are commonly prescribed in two week-courses to treat IMO. 
• Herbal antimicrobials, including allicin, berberine, neem, and oregano oil, can be used as natural alternatives that are just as effective as antibiotics in treating IMO (8). 
• Multi-strain probiotics containing Lactobacillus and Bifidobacterium species reinoculate the gut with beneficial bacteria to maintain microbial balance. Evidence suggests that probiotic supplements improve IBS symptoms. (48, 51)

Patients should also be advised against excessively consuming alcohol, processed foods, and antibiotics, as these can negatively impact microbiome diversity and lead to dysbiosis.

Step 3: Address the Gut-Brain Axis

Why Is This Important? 

The gut-brain connection plays a significant role in IBS. Research has exposed that the gut microbiome influences the brain by producing neuroactive metabolites and neurotransmitters, activating the immune system, and stimulating the vagus nerve. Imbalances in the gut-brain axis exacerbate IBS symptoms. (32) 

How Do You Do This?

Once a healthy microbiome has been reestablished, it should be maintained by eating an anti-inflammatory diet rich in fiber, prebiotics, and antioxidants. The Mediterranean diet has improved microbial diversity and abundance of beneficial bacterial species within the gut microbiota. 

Stress negatively impacts the gut-brain axis through its effects on the endocrine and immune systems. Mind-body therapies counteract the adverse effects of stress by stimulating the parasympathetic ("rest and digest") division of the nervous system. Evidence supports the use of the following therapies to reduce global IBS symptoms:

• Heart rate variability (HRV) biofeedback
• Mindfulness meditation
• Acupuncture
• Deep breathing
• Yoga

Research has also spotlighted the role of aerobic exercise in increasing the diversity and abundance of beneficial microbes in the gut microbiota, suggesting a potential mechanism for why exercise is related to improved gut and brain health. Engaging in any type of physical activity correlates with improved IBS symptoms, ranging from simply increasing your daily step count by walking to scheduling specific exercise sessions at least three times weekly.

The Risks of Untreated IBS-C

Chronic constipation can increase the risk of developing hemorrhoids.

IBS commonly co-occurs with:

• Migraines
• Sleep disturbances
• Fibromyalgia
• Chronic pelvic pain
• Depression
• Anxiety

Many people with IBS report poorer quality of life and reduced productivity (30). 

IBS-C Case Study

To learn more about effective IBS-C treatment protocols, read a case study here:

How One Patient Fixed Her Chronic Constipation In 2 Weeks

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Key Takeaways:

• IBS-C is a functional GI disorder characterized by the hallmark symptoms of abdominal pain and constipation. Symptoms can be debilitating and significantly impact the quality of life, and, unfortunately, allopathic treatment protocols don't always elicit desired patient outcomes. 
• For the effective management of IBS-C, a holistic evaluation and an appreciation of the interconnectedness of the GI, immune, and nervous systems that play into its etiology are required. A personalized treatment plan that goes beyond symptom management can correct underlying imbalances to encourage the restoration of optimal GI functioning and the resolution of bothersome symptoms.