New Science, New Thinking on IBS
Irritable Bowel Syndrome (IBS)
IBS is often a remitting-relapsing functional bowel disorder with no known organic cause, characterized by symptoms of abdominal pain or discomfort, often associated with disturbed defecation. IBS is often associated with bloating, urgency of bowel movement, pain during defecation, gas and excessive mucus.
The Recent Thinking in IBS
The older thinking in the healthcare community was that IBS was primarily psychosomatic. Later, this thinking evolved to the belief that the site of the disturbance in IBS was primarily in the colon. This understanding was based on the colon’s association with disrupted bowel movements and visceral sensitivity.
Recent thinking in IBS has been enabled by new tools such as confocal laser endomicroscopy,1,2 staining of immune cells,3 targeted biopsies4 and genotypic/phenotypic correlations. With the use of these new tools it has been shown that gut barrier disruption and reversible, localized, low-grade immune activation are associated with IBS.
The more recent scientific investigations reveal that the typical epicenter of the disturbance in IBS is the small intestine, while the visceral sensitivity involves the entire GI tract.5 This also involves irritated nerve endings (abdominal pain, discomfort, or cramping)6 and motility dysfunction (diarrhea, constipation, or both).7
In patients reporting bloating, it has been found that the small intestine is the region responsible for ineffective gas propulsion.8 Finally, the disruption of the microbiome in IBS patients is also known to be in the small intestine.9
The Distinctive Nutritional Requirements for People with IBS
People with IBS usually suffer from diarrhea, constipation or both. These conditions reflect the movement of food through the GI tract that is either too fast or too slow. This irregular movement can cause poor digestion, malabsorption of nutrients and loss of electrolytes. IBS is associated with growth of bad bacteria and excess mucus in the gut, which can disrupt the absorption of essential nutrients. IBS is also associated with low absorption of certain sugars, and healthcare professionals recommend restricting sugars and gradually increasing fiber in the diet, starting with 2-3 grams per day.
There is increasing evidence that impaired mucosal defense mechanisms (e.g. mast cells) are implicated in the pathogenesis of functional gastrointestinal disorders (FGIDs), allowing inappropriate immune activation.10
More recently, perturbations of GI microbiota, altered mucosal permeability and abnormal mucosal defense mechanisms have been implicated in the pathogenesis of some FGIDs.11-16 The three main IBS triggers are food, stress, and environment.2
The small intestine is the primary site for digestion and absorption of food nutrients. 90-95% of food nutrients are absorbed in this region.17 The symptoms of IBS often occur within 90 minutes of meals.18 These 90 minutes reflect the time it takes for food to reach the small intestine. In IBS populations, the gut mucosal barrier dysfunction is believed to be linked to an observation where 8 in 10 IBS patients had a vitamin D deficiency versus 1 in 4 in the general population.19,20 In another study, vitamin D supplementation didn’t separate from the control arm.21 Vitamin D has been recently singled out by nutrition assessment bodies to be a general matter of concern that may require highlighting in food labels e.g. “Nutrition Facts” effective in 2018.22 In IBS, the ability to absorb nutrients is disrupted due to bacterial overgrowth23 and its related injuries to the GI tract,24 plus formation of excessive mucus. This manifests in patients not being able to absorb fructose, other food nutrients 25,26 and bile acid. More specifically, carbohydrate maldigestion and malabsorption and the inability to absorb essential amino acids is impaired and can only be partially corrected by antibiotic therapy.27 The low serum level of essential amino acids results in a depressed rate of synthesis of proteins.28 Along with a depressed rate of protein synthesis, there is protein-losing enteropathy in subjects with bacterial overgrowth.29
The combination of protein loss and the depressed rate of protein synthesis is probably the cause of the sub-clinical protein malnutrition observed in IBS patients.30
As mentioned earlier, over 90% of nutrient digestion and absorption takes place in the small intestine.31 With IBS, this digestive and absorptive process is disrupted in several ways. The bile acid flow is disrupted as part of the IBS cascade of disruption.32 Peppermint oil (primary component: l-Menthol) helps restore secretory function such as bile flow.33 The German Commission E monograph for peppermint oil lists its use as an anti-spasmodic for bile ducts.34 This and other known activities of peppermint oil are helpful in digestion and absorption.
Dietary modification alone, as a management strategy, has had mixed success. Fiber is helpful. Exclusionary diets help in the short term but lead to nutritional imbalances and adherence issues in the long-term. Diet alone does not address the complex disruptions of the small intestine.26
To effectively manage IBS, it is important to help normalize the gut mucosal barrier dysfunction and its associated reversible, localized, low-grade inflammation and also help normalize the small intestine transit35 time. It is also important to inhibit bacterial overgrowth and to reduce the gas that disrupts absorption.
Now doctors increasingly use medical foods, such as IBgard, to help normalize the digestion and absorption of food nutrients and to help manage IBS symptoms.
IBgard is specially formulated to meet the distinctive nutritional requirements of IBS that cannot be met with dietary modification, alone. IBgard is designed to supply microspheres of peppermint oil, along with fiber and amino acids (from gelatin protein), to the small intestine. These help toward normalizing the digestion and absorption of food nutrients, and to manage the symptoms of IBS.36
By improving gut health in the first place, IBgard helps prevent nutritional problems later.
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36 Cash, Brooks, Michael Epstein, and Syed Shah. 2017. “In Patients with Irritable Bowel Syndrome-Mixed (IBS-M), a Novel Peppermint Oil Formulation Designed for Site Specific Targeting (PO-SST) in the Small Intestine Improves the 8 Symptoms That Comprise the Total IBS Symptoms Score (TISS).” In Digestive Disease Week. Chicago, IL.