Addressing the Role of Food in Irritable Bowel Syndrome Symptom Management

Published:February 23, 2016DOI:https://doi.org/10.1016/j.nurpra.2015.12.007

      Highlights

      • Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder denoted by abdominal pain and changes in bowel patterns, affecting 5% to 15% of the general population.
      • Patients with IBS have long associated certain foods with exacerbation of their symptoms. More than half of IBS patients have self-reported food intolerances and worsening of symptoms with certain foods or meal related.
      • IBS patients often attempt dietary modifications on their own by excluding foods they perceive to be causing their symptoms.
      • Research is starting to catch up with what patients have reported about food interaction and their symptoms, and the role of diet is being increasingly recognized for the management of IBS.
      • For clinicians, understanding the nuances of individual symptoms is vital to providing the most useful and beneficial dietary recommendations.

      Abstract

      Patients with irritable bowel syndrome (IBS) have often associated the worsening of symptoms with specific foods. Research is starting to catch up with what patients have reported about food interaction and their symptoms, and the role of diet is being increasingly recognized for the management of IBS. Clinical guidance for nurse practitioners can be challenging because of limited data and guideline consensus along with the nuances of symptoms associated with IBS subtypes. This article summarizes some of the key themes and dietary recommendations by various gastrointestinal organizations, public health agencies, and dietary associations. By addressing the relevance of diet for symptom alleviation, nurse practitioners are able to better support patients and collaborate with dietitians to improve symptom management.

      Keywords

      Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder denoted by abdominal pain and changes in bowel patterns affecting 5% to 15% of the general population.
      • Lovell R.M.
      • Ford A.C.
      Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis.
      • Ford A.C.
      • Moayyedi P.
      • Lacy B.E.
      • et al.
      American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation.
      According to the Rome III diagnostic criteria for IBS, a diagnosis of IBS is made if a patient experiences recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months with symptom onset at least 6 months before diagnosis with 2 or more of the following: improvement with defecation, change in frequency of stool, and/or change in form or appearance of the stool.
      • Ford A.C.
      • Moayyedi P.
      • Lacy B.E.
      • et al.
      American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation.
      IBS patients are subtyped by the predominant stool pattern as follows: IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), IBS mixed (IBS-M), or unsubtyped IBS (IBS-U). The pathology is understood to be multifactorial, including disturbed gut motility, enhanced visceral hypersensitivity, brain gut signaling problems, genetic factors, mucosal inflammation, immune abnormalities, intestinal microflora disruptions, and psychological and social aspects.
      • Lovell R.M.
      • Ford A.C.
      Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis.
      Patients with IBS have commonly associated certain foods with exacerbation of their symptoms. More than half of IBS patients have self-reported food intolerances and worsening of symptoms with certain foods or meal related, most within 3 hours after eating, with gas problems and abdominal pain being the most frequently reported symptoms.
      • Böhn L.
      • Störsrud S.
      • Törnblom H.
      • Bengtsson U.
      • Simrén M.
      Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      IBS patients often attempt dietary modifications on their own by excluding foods they perceive to be causing their symptoms, possibly lending them to nutritional deficiencies or poorer quality diets.
      The typical dietary advice for IBS symptom management is formulated more on common sense than clinical evidence. Some standard recommendations are establishing regular eating times, eating smaller frequent meals, and drinking enough fluids.
      National Institute of Diabetes and Digestive and Kidney Diseases
      Irritable Bowel Syndrome.

      Quigley E, Fried M, Gwee KA, et al. Irritable Bowel Syndrome: A Global Perspective. World Gastroenterology Organisation Global Guidelines. http://www.worldgastroenterology.org/guidelines/global-guidelines/irritable-bowel-syndrome-ibs. Published April 20, 2009. Accessed September 30, 2015.

      American Gastroenterology Association
      IBS: A Patient’s Guide to Living With Irritable Bowel Syndrome.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      Other dietary advice includes “eating foods that are low in fat and high in carbohydrates, such as pasta, rice, whole-grain breads and cereals, fruits, and vegetables”
      National Institute of Diabetes and Digestive and Kidney Diseases
      Irritable Bowel Syndrome.
      or reducing specific foods containing carbohydrates that are hard to digest.
      American Gastroenterology Association
      IBS: A Patient’s Guide to Living With Irritable Bowel Syndrome.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      A very low-carbohydrate diet may improve symptoms for IBS-D.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      For clinicians, understanding the nuances of individual symptoms is vital to providing the most useful and beneficial dietary recommendations. Determining which dietary approach to use can be challenging because of limited high-quality data and guideline consensus. This article discusses key evidence-based themes so nurse practitioners (NPs) can better support patients and collaborate with dietitians to provide optimal management of symptoms.

      Foods Associated With IBS Symptoms

      Many IBS patients associate certain foods with their IBS symptoms and perceive food intolerance. For individuals with IBS-D, there may be a higher prevalence of food trigger reactions.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      The most common foods reported as symptom triggers are fruits (citrus and banana), grains (wheat, barley, rye, oats, and corn), vegetables (onions, peas, and potatoes), dairy products (yogurt, milk, cheese, eggs, and butter), legumes (beans and lentils), wine, chocolate, coffee, tea, and fried foods.
      • Böhn L.
      • Störsrud S.
      • Törnblom H.
      • Bengtsson U.
      • Simrén M.
      Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      Using double-blind oral food challenges, items that have been confirmed include banana, coffee, corn, eggs, milk, peas, potatoes, and wheat.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      The obstacles are identifying the specifics of the food trigger as well as the physiologic stimuli. Foods contain an assortment of potential chemicals and physical components that are both absorbable and poorly absorbed, which may trigger in individuals with enhanced sensitivity.
      • Gibson P.R.
      • Shepherd S.J.
      Food choice as a key management strategy for functional gastrointestinal symptoms.
      For example, certain components of foods like biogenic amines and lectins that trigger histamine release (ie, lentils and beans) have not been fully studied in IBS.
      • Böhn L.
      • Störsrud S.
      • Törnblom H.
      • Bengtsson U.
      • Simrén M.
      Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life.

      Key Recommendations

      Alcoholic Beverages

      The direct contact of alcoholic beverages with the mucosa lining of the GI tract can lead to mucosal damage, disrupting the assimilation of nutrients and intestinal motility.
      • Reding K.W.
      • Cain K.C.
      • Jarrett M.E.
      • Eugenio M.D.
      • Heitkemper M.M.
      Relationship between patterns of alcohol consumption and gastrointestinal symptoms among patients with irritable bowel syndrome.
      Prior studies have been inconclusive or conflicting for alcohol, and alcohol intake was not correlated with IBS in epidemiologic studies.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      For individuals with IBS-D, alcohol intake may exert a more potent influence on symptom severity than for IBS-C or IBS-M.
      • Reding K.W.
      • Cain K.C.
      • Jarrett M.E.
      • Eugenio M.D.
      • Heitkemper M.M.
      Relationship between patterns of alcohol consumption and gastrointestinal symptoms among patients with irritable bowel syndrome.
      An association between alcohol intake, particularly binge drinking (4 or more drinks on 1 occasion), and symptoms like diarrhea and abdominal pain has been observed among females with IBS but not for moderate (maximum of 3 drinks per day) or light drinkers (1 drink per day). Psychosocial stress plays a role in IBS, and the misuse of alcohol to alleviate stress is a factor to consider when screening patients for heavy drinking and alcohol use disorders.

      Caffeine

      Caffeine stimulates gastric acid secretion and colonic motor activity, particularly coffee.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      In a study of 330 IBS patients, coffee was 1 of the top 10 most frequently reported foods producing symptoms, and the 3 most common symptoms reported were dyspepsia, pain, and loose stools.
      • Böhn L.
      • Störsrud S.
      • Törnblom H.
      • Bengtsson U.
      • Simrén M.
      Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life.
      There are no randomized controlled studies of low caffeine diets, but most dietary guidelines suggest modifying caffeine intake and encourage fluids from noncaffeinated sources.
      National Institute of Diabetes and Digestive and Kidney Diseases
      Irritable Bowel Syndrome.
      American Gastroenterology Association
      IBS: A Patient’s Guide to Living With Irritable Bowel Syndrome.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      The National Institute for Health and Care Excellence (NICE) guidelines suggest limiting the consumption of coffee and tea to no more than 3 cups per day.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      The bowel-stimulating qualities of coffee may be worse for people with IBS-D than IBS-C, and other sources of caffeine to watch for include soft drinks, coffee ice cream, dark chocolate, unsweetened baking chocolate, cocoa powder, and some over-the-counter analgesics.

      Lipids/Fatty Foods

      Fatty foods are often attributed to symptoms by IBS patients, and it is often recommended to avoid foods rich in fat, particularly for those IBS sufferers with gas-related symptoms and diarrhea.
      National Institute of Diabetes and Digestive and Kidney Diseases
      Irritable Bowel Syndrome.
      American Gastroenterology Association
      IBS: A Patient’s Guide to Living With Irritable Bowel Syndrome.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      Laboratory studies have shown intestinal gas transport is delayed by intraluminal lipids, and duodenal lipids inhibit small bowel motility.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      Furthermore, lipids’ effects on gastric emptying and enhancement of colorectal sensitivity or visceral perception have also been studied.
      • Feinle-Bisset C.
      • Azpiroz F.
      Dietary lipids and functional gastrointestinal disorders.
      Despite such laboratory studies, the evidence relating dietary fat intake to IBS is limited. Few studies have evaluated dietary intake and eating behavior, and most have been unable to determine the fat content of diets that may provide clinical benefit.
      • Feinle-Bisset C.
      • Azpiroz F.
      Dietary lipids and functional gastrointestinal disorders.
      For IBS-D patients who perceive certain fatty foods to be triggers, NPs can caution on the intake of low-fat processed foods, which may contain more sugar, and instead emphasize healthy and naturally lower-fat foods like fruits, vegetables, and lean meats/fish.
      Cross-sectional studies have shown that IBS symptom severity is associated with increased body mass index
      • Pickett-Blakely O.
      Obesity and irritable bowel syndrome: a comprehensive review.
      ; therefore, it is also important for NPs to screen patients for overweight (BMI 25-29.9 kg/m2) and obesity (BMI ≥ 30 kg/m2) conditions and offer or refer appropriate counseling and behavioral modifications.

      Fiber

      Dietary fiber intake is often less than recommended (25-38 g for adults in the United States) with usual intakes averaging only 15 g/d.
      • Chutkan R.
      • Fahey G.
      • Wright W.L.
      • McRorie J.
      Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits.
      A typical diet comprised of refined sugars and grains, dairy products, and processed foods is often low in dietary fiber, which may exacerbate constipation. For years, augmenting the intake of dietary fiber intake has been a common strategy, particularly for IBS-C.
      • Ford A.C.
      • Moayyedi P.
      • Lacy B.E.
      • et al.
      American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation.
      National Institute of Diabetes and Digestive and Kidney Diseases
      Irritable Bowel Syndrome.
      American Gastroenterology Association
      IBS: A Patient’s Guide to Living With Irritable Bowel Syndrome.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      • Heizer W.D.
      • Southern S.
      • McGovern S.
      The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      However, for some, fiber may exacerbate symptoms and can frequently cause bloating and abdominal discomfort.
      • Moayyedi P.
      • Quigley E.M.
      • Lacy B.E.
      • et al.
      The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.
      The efficacy of fiber requires careful investigation and discrimination. Fibers are often simply categorized into soluble and insoluble, but some fibrous foods have both attributes like psyllium, oats, and oat bran. Most plant-based foods contain both soluble and insoluble fibers. Fiber can also be considered by viscosity and fermentability (ie, insoluble, slowly fermentable fibers like wheat bran and soluble fibers with low viscosity like hydrolyzed guar gum) (Table 1). The rapid fermentability of soluble nonviscous dietary fiber (guar gum and wheat dextrin) can lead to gas, whereas the soluble viscous (psyllium and polycarbophil) and insoluble fibers (wheat bran and cellulose), which are relatively less fermentable, often result in less flatulence.
      • Chutkan R.
      • Fahey G.
      • Wright W.L.
      • McRorie J.
      Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits.
      Table 1Fiber Supplements and Foods
      • Chutkan R.
      • Fahey G.
      • Wright W.L.
      • McRorie J.
      Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits.
      Fiber Supplements
      Soluble and viscous (limited/less fermentable)

      Methycellulose

      Calcium polycarbophil

      Psyllium



      Soluble and viscous (rapidly fermented)

      Beta glucan (oat bran)

      Pectin



      Soluble and nonviscous (rapidly fermented)

      Inulin

      Partially hydrolyzed guar gum

      Wheat dextrin

      Acacia
      Insoluble fiber (limited/less fermentable)

      Wheat bran

      Corn bran

      Cellulose
      Fiber-rich foods

      Most plant-based foods contain mixtures of fiber
      Soluble fiber

      Grains: oats and barley

      Nuts

      Seeds: flaxseed, sunflower, and chia

      Beans/legumes

      Vegetables: carrot

      Fruits: orange and grapefruit
      Insoluble fiber

      Whole grains: whole wheat and brown rice

      Nuts

      Seeds

      Beans/legumes

      Vegetables: dark green leafy, corn, broccoli, cabbage, and cauliflower

      Fruits: with skins, apple, pear, and grapes
      Many of the early studies for fiber were conflicting because of poor quality and did not specify IBS subtypes.
      • Moayyedi P.
      • Quigley E.M.
      • Lacy B.E.
      • et al.
      The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.
      Most studies have investigated the use of dietary supplements as opposed to the intake of actual everyday high-fiber foods. Soluble fibers, particularly fermentable fiber like psyllium, may provide some benefit for some IBS-C patients as opposed to insoluble fibers like wheat bran, which is not advised.
      • Ford A.C.
      • Moayyedi P.
      • Lacy B.E.
      • et al.
      American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      • Moayyedi P.
      • Quigley E.M.
      • Lacy B.E.
      • et al.
      The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.
      A randomized controlled trial that compared the efficacy of psyllium (10 g/d) and wheat bran (10 g/d) found that psyllium resulted in a significantly greater proportion of patients reporting a reduction of symptom severity compared with placebo, except for abdominal pain and health-related quality of life. Meanwhile, bran showed no benefit, and the dropout rate was highest among patients receiving bran, mostly because of the exacerbation of symptoms.
      • Moayyedi P.
      • Quigley E.M.
      • Lacy B.E.
      • et al.
      The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.
      Flaxseed or linseed, a rich source of soluble fiber as well as α-linolenic acid and lignans, may affect GI transit time and/or motility. The British Dietetic Association has a recommendation of a 3-month trial of ground linseed for IBS-C individuals; however, there is limited clinical evidence for the relief of constipation, abdominal pain, and bloating.
      • McKenzie Y.A.
      • Alder A.
      • Anderson W.
      • et al.
      British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.
      A small randomized open pilot study comparing different preparation of linseeds for the relief of IBS symptoms reported no statistical significance in the improvement of stool frequency or consistency or symptom severity.
      • Moayyedi P.
      • Quigley E.M.
      • Lacy B.E.
      • et al.
      The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.
      For IBS-D or IBS-M, soluble viscous fiber with limited fermentability can aid with stool consistency. Although fibers with both soluble viscous and insoluble properties may be useful for their laxative effect for IBS-C, soluble viscous fibers with limited slow fermentability are preferable to avoid increased gas and cramping.
      • Chutkan R.
      • Fahey G.
      • Wright W.L.
      • McRorie J.
      Viscous versus nonviscous soluble fiber supplements: mechanisms and evidence for fiber-specific health benefits.

      Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols

      The incomplete absorption of lactose and fructose has been suspected to play a part for certain subgroups of IBS patients.
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      Yet, controlled studies have suggested that intolerance for sugars is not more prevalent in IBS, and incomplete absorption after 50 g of fructose has been noted in up to 75% of IBS sufferers and up to 80% of healthy subjects.
      • Fedewa A.
      • Rao S.S.
      Dietary fructose intolerance, fructan intolerance and FODMAPs.
      However, malabsorption of these sugars may lead to digestive problems such as bloating, flatulence, abdominal pain, and diarrhea. For those with lactase deficiency or lactose malabsorption, the amount tolerated varies individually, but research suggests that up to 12 g can be handled if spread out during the course of a day.
      National Institute for Health and Care Excellence
      Irritable Bowel Syndrome in Adults: Diagnosis and Management of Irritable Bowel Syndrome in Primary Care.
      A cup of milk or plain yogurt has approximately 12 g, whereas 1.5 oz low-fat hard cheese has less than 1 g.
      Recently, a broader collective term of short-chain carbohydrates, fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), has come into focus. FODMAPS are osmotically active; not easily absorbed; and prompt fermentation in the colon, luminal gas production, and distension.
      • Rao S.S.C.
      • Yu S.
      • Fedewa A.
      Systematic review: dietary fibre and FODMAP-restricted diet in the management of constipation and irritable bowel syndrome.
      A dietary approach has been developed in terms of “low” and “high FODMAP” content food for the management of functional GI symptoms. Sources of high FODMAPs are dissacharides in dairy products, galacto-oligosaccharides in legumes, fructans in wheat-containing breads and cereals, fructans and fructo-oligosaccharides in some vegetables (asparagus, artichokes, and onions), fructose in fruits (mangos, peaches, and apples), and polyols (sorbitol, mannitol, xylitol, and lactitol) (Table 2). Polyols are used as sweeteners; they are commonly found in food products labeled “sugar free,” and sorbitol is naturally found in dried fruits and stone fruits.
      Table 2Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs)
      • Eswaran S.
      • Tack J.
      Chey, WD. Food: the forgotten factor in the irritable bowel syndrome.
      • Gibson P.R.
      • Shepherd S.J.
      Food choice as a key management strategy for functional gastrointestinal symptoms.
      High FODMAP foodsLow FODMAP foods
      Asparagus, artichokes, broccoli, cabbage, cauliflower, garlic, leek, onion, and sugar snap peasAlfalfa, bean sprouts, green beans, bell peppers, bok choy, carrots, celery, cucumber, eggplant, kale, lettuce, radish, spinach, squash, tomato, turnip, and zucchini
      Apples, blackberries, pears, mango, watermelon, nectarines, peaches, plums, and dried fruitsBanana, blueberry, cantaloupe, honeydew, grapes, kiwi, orange, pineapple, raspberry, and strawberry
      Milk (cow, goat, and sheep), yogurt, soft cheese, cream, custard, and ice creamLactose-free milk, lactose-free yogurts, and hard cheese
      Legumes/pulsesMeats, fish, chicken, eggs, tofu, tempeh
      Rye, wheat breads, wheat-based cereals, and wheat pastaGluten-free bread and pasta, sourdough spelt bread, oats, rice, and quinoa
      Cashews and pistachiosAlmonds, hazelnuts, pumpkin seeds walnut, macadamia, peanut, pecan, and pine nut
      Sauce, jam, salsa, or salad dressing with high fructose corn syrup, honey, agave, carob powder, and artificial sweeteners (mannitol, sorbitol, and xylitol)Jelly, marmalade, butter, nut butters, mustard, mayonnaise, olives, cocoa powder, vinegar, soy sauce, and cooking oils
      Recent studies of low FODMAP diets in reducing GI symptoms have shown promising preliminary data emerging from Australia and the United Kingdom.
      • Rao S.S.C.
      • Yu S.
      • Fedewa A.
      Systematic review: dietary fibre and FODMAP-restricted diet in the management of constipation and irritable bowel syndrome.
      One study showed that a low FODMAP diet decreased the severity of GI symptoms in 30 subjects (10 IBS-D, 13 IBS-C, 5 IBS-M, and 2 IBS-U), specifically lessening abdominal pain, bloating, and flatulence.
      • Halmos E.P.
      • Power V.A.
      • Shepherd S.J.
      • Gibson P.R.
      • Muir J.G.
      A diet low in FODMAPs reduces symptoms of irritable bowel syndrome.
      In that study, a low FODMAP diet was defined as less than 0.5 g oligosaccharides, fructose, and polyols per meal, whereas a typical Australian daily diet contains approximately 4 g oligosaccharides and 2 g polyols.
      Dietary advice of reducing FODMAP intake may be beneficial for short-term management for those suffering with abdominal pain, bloating, or flatulence.
      • Rao S.S.C.
      • Yu S.
      • Fedewa A.
      Systematic review: dietary fibre and FODMAP-restricted diet in the management of constipation and irritable bowel syndrome.
      In a nonrandomized observational study of 90 IBS patients, a low FODMAP dietary consultation improved abdominal pain/discomfort, bloating, constipation, and bowel urgency, with almost 75% reporting symptom relief satisfaction.
      • de Roest R.H.
      • Dobbs B.R.
      • Chapman B.A.
      • et al.
      The low FODMAP diet improves gastrointestinal symptoms in patients with irritable bowel syndrome: a prospective study.
      However, a more recent study comparing a low FODMAP dietary recommendation with traditional dietary advice for IBS (ie, regular eating times and reduced coffee/alcohol intake) determined that a low FODMAP diet was not superior and that symptom severity was reduced in both groups with no significant difference.
      • Böhn L.
      • Störsrud S.
      • Liljebo T.
      • et al.
      Diet low in FODMAPs reduces symptoms of irritable bowel syndrome as well as traditional dietary advice: a randomized controlled trial.
      Most of the FODMAP diets studied have been strict in that all food was provided to the subjects during the study, mostly in a one to one setting by a registered dietitian for up to 6 to 8 weeks, and their exact contribution to IBS needs clarification. How much FODMAP intake should be reduced in 1 meal or 1 day? Does a food’s measurement of FODMAPs vary depending on its processing, temperature, or maturation? Is it more helpful for symptoms of gas and bloating or stool frequency? More research is needed because studies have shown that a low FODMAP diet significantly reduced luminal bifidobacteria and may have effects on gut microbiota composition.
      • Halmos E.
      • Christophersen C.T.
      • Bird A.R.
      • et al.
      Diets that differ in their FODMAP content alter the colonic luminal microenvironment.
      For now, the long-term effects of low FODMAP diets on gut microbiota remain unclear, and it is not recommended for long-term adherence or asymptomatic populations.

      Gluten/Wheat

      Gluten is the main protein found within the wheat germ that provides the consistency of dough. Gluten is a conglomeration of proteins (ie, the prolamins gliadin and glutenin [found in wheat]). Secalin in rye and hordein in barley are similar proteins to gliadin. Gliadin induces the release of zonulin, a protein that modulates intestinal permeability.
      • Lammers K.M.
      • Vasagar B.
      • Fasano A.
      Definition of celiac disease and gluten sensitivity.
      The consumption of foods that contain gluten and the symptom aggravation experienced by IBS patients who are negative for celiac disease deserves further investigation. A small study of 34 nonceliac IBS subjects (approximately half were IBS-D and a third were IBS-M) whose symptoms were controlled by a gluten-free diet experienced exacerbation of symptoms such as pain and fatigue during a gluten rechallenge.
      • Biesiekierski J.R.
      • Newnham E.D.
      • Irving P.M.
      • et al.
      Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial.
      For those consuming the gluten diet, changes in symptom severity for abdominal pain (P = .02), satisfaction with stool consistency (P = .03), and tiredness (P = .001) were statistically significant, but overall symptoms (P = .15) were not over the 6-week study period.
      • Biesiekierski J.R.
      • Newnham E.D.
      • Irving P.M.
      • et al.
      Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial.
      Another study of 45 IBS-D patients on a diet including gluten experienced a small increase in stool frequency in comparison with a gluten-free diet, which also suggests that cutting out gluten may be beneficial.
      • Vazquez–Roque M.I.
      • Camilleri M.
      • Smyrk T.
      • et al.
      A controlled trial of gluten-free diet in patients with irritable bowel syndrome-diarrhea: effects on bowel frequency and intestinal function.
      However, a double-blind, randomized, controlled, crossover rechallenge study of 37 patients with IBS (43% diarrhea, 35% constipation, and 22% mixed or alternating) and nonceliac gluten sensitivity who followed a low FODMAP diet showed no specific or dose-dependent effects of gluten.
      • Biesiekierski J.R.
      • Peters S.L.
      • Newnham E.D.
      • et al.
      No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates.
      As more research develops on this topic, increasing the consumption and variety of other kinds of grains/cereals may be helpful for some patients. For those nonceliac patients with IBS who are avoiding gluten, NPs need to be aware of potential nutritional deficiencies because many fortified wheat-based products and cereals are sources of B vitamins and dietary fiber. Some patients may be eating processed gluten-free products, which can be laden with excess calories, fat, salt, and sugar and may contribute to risk factors for heart disease and diabetes.

      Food Additives

      There have been no studies investigating chemical additives in foods and GI reactions in IBS, but intolerance or sensitivity to additives in processed foods (preservatives, emulsifiers, and artificial flavorings/colors) may be associated with hypersensitivity reactions for some.
      • Gibson P.R.
      • Shepherd S.J.
      Food choice as a key management strategy for functional gastrointestinal symptoms.
      Until further research is conducted, knowledge of the presence and availability in certain foods may be noted for some patients.

      Conclusion

      In clinical practice, the reporting of specific foods with IBS symptoms by patients is sometimes viewed with uncertainty or oversight, but the role of food and diet is being increasingly recognized to play a pivotal role in the management of symptoms. With the variation of IBS symptom presentation, successful management with diet and lifestyle changes involves the careful discrimination of dietary treatments based on the predominant symptoms and severity. Current dietary recommendations are broad, and a “one size” approach is not optimal because symptoms may change over time. Diet recommendations need to be individualized, and NPs can work with trained dietitians to provide the guidance and attention required to avoid restrictive diets and the risk of nutritional deficiencies. Future studies are needed on the efficacy and safety of dietary therapies with explicit consideration of IBS predominant symptoms and long-term follow-up.

      Acknowledgment

      This work was supported by the National Institutes of Health research grants R01NR013695 and R01NR010730 .

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      Biography

      All authors are affiliated with New York University College of Nursing. Bernadette Capili, PhD, NP-C, is an assistant professor of nursing and an associate director at the Division of Special Studies in Symptom Management and can be reached at [email protected].
      Joyce K. Anastasi, PhD, DrNP, FAAN, is a director of Special Studies in Symptom Management and the Herbs, Nutraceuticals, and Supplements Program.
      Michelle Chang, MS, Lac, is research associate at the Division of Special Studies in Symptom Management.