Have you ever thought about using the low FODMAP diet to manage IBS symptoms?
Digestive distress is your body’s signal that there’s an imbalance in your digestive system. In many cases, chronic digestive issues are actually quite common. The symptoms may range from everyday “irritations” to full-blown debilitation. And they often include symptoms such as gas, bloating, diarrhea, constipation, and abdominal dissension associated with irritable bowel syndrome (IBS). Identifying, understanding, and addressing the underlying cause can help you restore gut balance and customize a food and lifestyle plan to achieve optimal wellness.
Certain foods can intensify the symptoms of IBS. Research indicates that an effective approach for managing IBS symptoms is the low FODMAP diet; improving symptoms such as bloating, abdominal pain and distension, flatulence, constipation and diarrhea.1-3 And practice guidelines from Japan4 and the United Kingdom5 include the low FODMAP diet as a dietary intervention to manage IBS. Nonetheless, a low FODMAP diet does not cure IBS, but rather helps control symptoms and it’s one possible intervention, among others.
WHO’S AT RISK FOR FODMAP INTOLERANCE?
IBS is a chronic functional gastrointestinal disorder (FGID) that is characterized by a constellation of symptoms, including gas and bloating.6,7 In individuals with this most common FGID, the muscles of the large intestine are impaired—either moving food through the gastrointestinal tract too quickly (IBS with diarrhea, IBS-D) or too slowly (IBS with constipation, IBS-C) due to intense or weak contractions, respectively. Two other subtypes are Mixed IBS (IBS-M) and Unsubtyped IBS (IBS-U).8-10
The abnormal contractions cause abdominal pain and/or cramping, diarrhea, constipation, episodes of alternating diarrhea and constipation, incomplete elimination, mucous in stools, gas, and bloating.6,11,12 Individuals with IBS are particularly susceptible to FODMAPs because they may exacerbate the symptoms of IBS. Knowing the amounts and types of FODMAPs tolerated is essential to better understanding the cause of and managing IBS symptoms.13,9
WHAT ARE FODMAPs?
Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPs) are easily fermentable short-chain carbohydrates and sugar alcohols that are found in many of the foods we consume. Some people have difficulty absorbing FODMAPs, especially those with IBS.9
FODMAPs are poorly absorbed in the small intestine and so enter the large intestine where they present gastrointestinal symptoms in susceptible individuals and may even cause bacterial overgrowth. Gut microbiota naturally found in the large intestine ferment FODMAPs. And rather than absorbing water, the large intestine holds onto water in an attempt to dilute the FODMAPs when they are present. This can lead to watery stools, bloating, and abdominal pressure, swelling and pain. When the bacteria feed off of FODMAPs, IBS symptoms ensue, including bloating, gas, belching, abdominal pain and distension, nausea, constipation, diarrhea, alternating constipation and diarrhea, and fatigue.14,15
Individuals have different responses to the type of and threshold for FODMAP molecules. Furthermore, each FODMAP type may interact with other FODMAP types and collectively contribute to individuals reaching a tolerance threshold.7
Below is a fabulous animation by Monash University,16 the institution at which researchers developed the low FODMAP diet, about how FODMAPs provoke IBS symptoms.
IDENTIFYING FODMAPs IN FOODS
FODMAP types that are possible symptom triggers include:
Fructose is a naturally occurring monosaccharide sugar found in many foods (e.g. fruits, vegetables, honey, grains). As a single molecule, fructose is a monosaccharide, but fructose molecules may join to form fructans. In addition to the IBS symptoms associated with other FODMAP-type intolerances, fructose malabsorption may contribute to depression and susceptibility to nutritional deficiencies.17-20
A hydrogen breath test (or, in some cases, a methane breath test) is a helpful diagnostic tool for confirming fructose malabsorption. It’s important to distinguish fructose malabsorption from hereditary fructose intolerance (HFI), which requires fructose to be completely removed from the diet.21
Research indicates that those with fructose malabsorption better tolerate foods and beverages with a fructose-to-glucose ratio of 1:1.15 And they are triggered by consumption of foods and beverages with a high fructose-to-glucose ratio—classified as higher than 0.5 grams of fructose in excess of glucose per 100 grams content and/or more than 3 grams of fructose in one serving.20,22
Fructans are oligosaccharides (chains of bonded fructose molecules) with a higher concentration of fructose than that in a single fructose molecule and they are often the most difficult to digest. Inulin and Fructo-oligosaccharides (FOS) are fructans often added to foods to increase fiber content. These prebiotics feed healthy bacteria, but may present digestive disturbances in those with fructan intolerance. Even in healthy individuals, fructans are malabsorbed because the small intestine does not produce the enzymes required to digest them. Elimination Diet with reintroduction challenges is needed for diagnosis.13,15
Polyol (including mannitol) Intolerance
Mannitol and polyols are sugar alcohols that are naturally present in some fruits and vegetables, and are added to some sugar-free products such as chewing gum, mints, cough drops, and medications. When consumed in large quantities, they often produce a laxative effect. The molecular size of the polyol impacts the extent to which it can be absorbed and, thus, the consequential bowel disturbance. Intolerance can be diagnosed by a hydrogen breath test; in some cases, a methane breath test may be used. An Elimination Diet may be beneficial as well.13,15,22
Lactose is a dissacharide sugar found in milk and milk products that requires the lactase enzyme to break it down into its simpler constituents, glucose and galactose. Lactose intolerance results when the lactase enzyme—normally produced by the cells lining the small intestine—is reduced or absent, preventing the lactose sugar from being digested. A hydrogen breath test (or, in some cases, a methane breath test) is a useful diagnostic tool for determining lactose intolerance, as is an Elimination Diet. In some cases, especially in infants and young children, a stool acidity test may be employed.6,23
Galactans are oligosaccharides formed by chains of galactose sugar molecules with one fructose molecule on the end. They include the carbohydrates raffinose and stachyose. Galactans act like fructans, and intolerance occurs when they are inefficiently absorbed in the small intestine. Although they are always malabsorbed because the small intestine does not produce the enzymes needed to digest them, galactans generally just contribute to severe gastrointestinal symptoms in those with gut dysbiosis, gut hypersensitivity, and gut motility disorders.15,22 Elimination Diet with reintroduction challenges is needed for diagnosis.
Common examples of specific FODMAP molecules in foods:
Fructose: apples, honey, pears
Fructans: artichokes (globe and Jerusalem), garlic, onions, wheat, barley, inulin,
Lactose: milk, yogurt, soft cheeses, ice cream
Galactans: legumes, lentils, chickpeas, broccoli
Polyols: apples, avocado, cherries, plums, prunes, mushrooms, sorbitol, mannitol,
xylitol, maltitol, isomalt
If you’re new to FODMAPs and want to start identifying the different types of FODMAPs that might be contributing to your IBS symptoms, you can use this simple reference sheet. It will give you a general idea of which foods are considered to contain low and high amounts of FODMAPs.
It’s essential to track your food intake and symptoms. If you haven’t already done so, download my free Bye Bye Belly Bloat Journal for a comprehensive food and symptoms tracking tool.
Another helpful resource is the smartphone app developed by Monash University (available on the App Store and Google Play for 12.99 USD at the time of publication). It contains information about FODMAPs, FODMAP contents for hundreds of foods, recipes, shopping lists, and a food and symptoms journal. Please be aware that some of the foods and brands are unique to Australia, which is where Monash University is located.
Research is always providing more information about the FODMAP content of foods.
ARE THERE DIAGNOSTIC TESTS FOR FODMAP INTOLERANCE?
Testing for FODMAP intolerance is incomplete, as limited types of FODMAPs can be tested for via breath tests (i.e. lactose, fructose, sorbitol, and mannitol). Consequently, an Elimination Diet with controlled reintroduction challenges is the most comprehensive means by which individuals with IBS can identify FODMAP triggers.15,17,24
A low FODMAP diet helps manage functional gastrointestinal disorder symptoms such as those associated with IBS, but improvements will vary among individuals. Moreover, limiting—not entirely excluding—FODMAPs is intended to be temporary, not a life-long diet. Many FODMAP-containing foods are rich in nutrients and FODMAP-containing foods are important sources of prebiotics; limiting them may increase the risk for other gastrointestinal issues22 and nutritional deficiencies.19 It is best to work with a qualified healthcare provider to identify the least restrictive low FODMAP diet based on individual tolerances and thresholds.
A qualified healthcare practitioner must diagnose IBS by exclusion, using medical tests to rule out other conditions because its symptoms mimic those of serious illnesses. There is no known cause of IBS and it impacts individuals in myriad ways.8,19 Thus, treatment involves self-management through an individualized approach, including a low FODMAP diet, probiotics and stress management. To get started on managing stress, be sure to download this free Stress Buster Toolkit.
Have you tried a low FODMAP diet to manage IBS symptoms? Share in the comments below!