Nutritional therapy of irritable bowel syndrome

Nutritional factors relative to IBS include diagnostic and therapeutic considerations. Etiologically, foods do not cause IBS. A small percentage of patients with childhood allergic diatheses, usually in association with atopic dermatitis and asthma, may be intolerant to one or more of wheat, corn, dairy products, coffee, tea, or citrus fruits. Diagnostically, many patients labeled as IBS subjects are in fact intolerant to the ingestion of lactose-containing foods, sorbitol, fructose, or combinations of fructose and sorbitol. A precise dietary history will characterize this group. Taken in its broadest context, IBS involves the entire hollow tract inclusive of esophagus, stomach, small bowel, and colon. The symptomatic presentation relative to the hollow organ involved allows the selection of dietary manipulations that may help to reduce symptoms. Gastroesophageal reflux, a consequence of low LES pressure in some IBS patients, may be treated with the elimination of fatty foods, alcohol, chocolate, and peppermint. Delayed gastric emptying may be helped by the elimination of fatty foods and reduction of soluble fiber. Aberrant small bowel motor function may be ameliorated by reduction of lactose, sorbitol, and fructose and the addition of soluble fiber. Gas syndromes may be improved by reduced intake of beans, cabbage, lentils, legumes, apples, grapes, and raisins. Colonic motor dysfunction may be overcome by the gradual addition of combinations of soluble and insoluble fiber-containing foods and supplements. The selective use of activated charcoal and simethicone may be helpful.     

Diet in irritable bowel syndrome: What to recommend,not what to forbid to patients!

A substantial proportion of patients with irritable bowel syndrome(IBS) associate their symptoms with the ingestion of specific foods. Therefore, in recent years, scientific research has increasingly focused on the role of diet in IBS and dietary management is now considered an important tool in IBS treatment. This article reviews the main dietary approaches in IBS emphasizing evidence from experimental and observational studies and summarizing the main diet and lifestyle recommendations provided by dietary guidelines and scientific literature. Despite the limited evidence for a beneficial role, general advice on healthy eating and lifestyle is recommended as the first-line approach in the dietary management of IBS. Standard recommendations include adhering to a regular meal pattern, reducing intake of insoluble fibers, alcohol, caffeine, spicy foods, and fat, as well as performing regular physical activity and ensuring a good hydration. Second-line dietary approach should be considered where IBS symptoms persist and recommendations include following a low FODMAP diet, to be delivered only by a healthcare professional with expertise in dietary management. The efficacy of this diet is supported by a growing body of evidence. In contrast, the role of lactose or gluten dietary restriction in the treatment of IBS remains subject to ongoing research with a lack of high-quality evidence. Likewise, further clinical trials are needed to conclude the efficacy of probiotics on IBS symptoms.     

Treatment of the irritable bowel syndrome

Individualization of treatment for patients with IBS is predicated on a thorough analysis of the patient's symptoms, consideration of the reasons for seeking health care, evaluation of symptom-precipitating factors, elimination of confounding features, and the absolute knowledge of the absence of organic illness. Collecting and codifying appropriate historical data allow the physician to educate the patient with respect to the origin of his symptoms, and to enlist the patient as a partner in his future health care. There is no single, universally accepted therapeutic agent available for the treatment of the IBS patient. As a result, treatment is directed at reducing the frequency and intensity of triggering factors as well as ameliorating the symptoms when they arise. Symptoms evoked by psychologic factors may be effectively reduced by psychotherapy or hypnotherapy. Situational anxiety may be treated for brief periods by using antianxiety agents such as diazepam, chlordiazepoxide, buspirone, or similar agents. Depressive reactions may be reduced with suitable doses of antidepressant agents such as amitriptyline. Smooth muscle hyperreactivity may be dulled with small amounts of selected anticholinergics, which are usually most effective in reducing meal-induced discomfort. Peppermint oil may be of additional benefit. Gas-related symptoms require elimination of contributory dietary factors, such as lactose-containing foods, sorbitol, or fructose, as well as certain oligosaccharides. Simethecone, charcoal, or beanase may be helpful. Functional constipation is best treated with graded doses of insoluble or soluble fiber. Diarrheal episodes may be reduced with either loperamide or diphenoxylate. Careful, continued follow-up assessment of therapeutic endeavors, a sincere interest in the patient's concerns, and surveillance for intercurrent organic illness are the cornerstones of complete ongoing care.     

Fructose-sorbitol malabsorption

Important dietary carbohydrates such as fructose and sorbitol are incompletely absorbed in the normal small intestine. This malabsorption is sometimes associated with abdominal complaints and diarrhea development, symptoms indistinguishable from those of functional bowel disease. Recently, polymerized forms of fructose (fructans) also were implicated in symptom production in patients with irritable bowel syndrome (IBS). Evidence from uncontrolled and controlled challenge studies suggests that malabsorbed sugars (fructose, sorbitol, lactose) and fructans may act as dietary triggers for clinical symptoms suggestive of IBS. Further placebo-controlled studies are needed to obtain definite conclusions about the role of dietary sugar malabsorption in functional bowel disease.     

Breath tests and irritable bowel syndrome

Breath tests are non-invasive tests and can detect H2and CH4 gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath.These tests are used in the diagnosis of carbohydrate malabsorption,small intestinal bacterial overgrowth,and for measuring the orocecal transit time.Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome(IBS)-type symptoms such as diarrhea and/or constipation,bloating,excess flatulence,headaches and lack of energy.Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life.It may reflect dietary imbalance,such as excess fiber intake,or may be a manifestation of IBS.However,bloating may also represent small intestinal bacterial overgrowth.Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H2 breath testing to determine the presence or absence of bacterial overgrowth.If bacterial overgrowth is identified,patients are typically treated with antibiotics.Evaluation of IBS generally includes testing of other disorders that cause similar symptoms.Carbohydrate malabsorption(lactose,fructose,sorbitol)can cause abdominal fullness,bloating,nausea,abdominal pain,flatulence,and diarrhea,which are similar to the symptoms of IBS.However,it is unclear if these digestive disorders contribute to or cause the symptoms of IBS.Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS.Thus,diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients.     

膳食纤维与肠易激综合征

肠易激综合征(IBS)为常见功能性肠病,临床表现多样,严重影响患者生活质量,消耗大量医疗资源。饮食调整是IBS的重要治疗手段之一。膳食纤维一般指食物中不被人体小肠内源性酶水解的碳水化合物聚合物,具有增加粪便容积的作用。很多研究探讨了增加膳食纤维摄入对IBS的影响,但尚无明确结论。多数研究认为不溶性纤维对IBS症状无益,而可溶性纤维则有一定作用。分别研究不溶性和可溶性纤维对不同IBS亚型作用的设计良好的大样本随机对照试验有待开展。     

Role of alimentation in irritable bowel syndrome

BACKGROUND: Different food items are made responsible for irritable bowel syndrome (IBS) symptoms, but the physiopathology of IBS remains unclear. AIMS: During a meeting in Nice, France, experts of the European Working Team of the IBiS Club discussed selected data regarding the relationships between alimentation, food items (including fibers) and IBS symptoms. METHODS/RESULTS: Food allergy remains a difficult diagnosis, but medical and general history, presence of general symptoms such as skin rash, and hypersensitivity tests may help in achieving a positive diagnosis. On the other hand, food intolerance is more confusing because of the subjectivity of the relationship between ingestion of certain foods and the appearance of clinical symptoms. Different food items which are commonly implicated in adverse reactions mimicking IBS were found to be stimulants for the gut, suggesting that patients with predominant diarrhea IBS have to be carefully questioned about consumption of different kinds of food (i.e., coffee, alcohol, chewing gum, soft drinks) and not only on lactose ingestion. Gas production is discussed on the basis of retention of intestinal gas as well as on malabsorption of fermentable substrates. The role of a large amount of this kind of substrate reaching the colon is suggested as a potential mechanism of IBS-type symptoms in overeating patients. Regarding the role of fiber in IBS, the expert group concluded that fibers are not inert substances and that they could trigger pain or bloating in some IBS patients. CONCLUSION: Despite numerous reviews on this subject, it is very difficult to give general dietary advice to IBS patients, but dieteticians may have a positive role in managing such patients.     

Symptom Provocation in Irritable Bowel Syndrome Effects of Differing Doses of Fructose-Sorbitol

The role of fructose and sorbitol, when ingested together, in the aetiology of irritable bowel syndrome (IBS) is controversial. The aims of this study in IBS patients, therefore, were to compare differences in symptom provocation with various doses of fructose-sorbitol and to relate differences in the extent of colonic hydrogen production after each dose to such symptom provocation. Two different mixtures of fructose and sorbitol-20 g fructose plus 3.5 g sorbitol ('lower' dose) and 25 g fructose plus 5 g sorbitol (‘higher’ dose)-were administered to 15 patients with IBS and to 24 healthy controls. Breath hydrogen concentrations were determined at 10-min intervals for 3 h after ingestion of each mixture, and the presence and severity of a range of gastrointestinal symptoms were recorded on a standard form before, during, and after the study. Total symptom score in IBS patients, but not controls, was greater (p > 0.05) after the higher than after the lower dose of fructose-sorbitol mixture, and, for the higher dose, symptoms were significantly greater in IBS patients than in controls (p > 0.05). Moreover, the increase in total symptom score between the higher and lower dose mixtures was of a greater magnitude (p = 0.01) in IBS patients than in controls. No significant correlation was observed between the increase in symptom score and the increase in peak hydrogen concentration or the increase in integrated hydrogen response between lower and higher dose mixtures, although these latter increases were at times substantial. We conclude that in patients with IBS who ingest fructose and sorbitol simultaneously, the degree of symptom provocation is related to the amounts present in such a mixture but is not related directly to the extent of colonic hydrogen production.     

Symptom provocation in irritable bowel syndrome. Effects of differing doses of fructose-sorbitol.

The role of fructose and sorbitol, when ingested together, in the aetiology of irritable bowel syndrome (IBS) is controversial. The aims of this study in IBS patients, therefore, were to compare differences in symptom provocation with various doses of fructose-sorbitol and to relate differences in the extent of colonic hydrogen production after each dose to such symptom provocation. Two different mixtures of fructose and sorbitol--20 g fructose plus 3.5 g sorbitol ('lower' dose) and 25 g fructose plus 5 g sorbitol ('higher' dose)--were administered to 15 patients with IBS and to 24 healthy controls. Breath hydrogen concentrations were determined at 10-min intervals for 3 h after ingestion of each mixture, and the presence and severity of a range of gastrointestinal symptoms were recorded on a standard form before, during, and after the study. Total symptom score in IBS patients, but not controls, was greater (p < 0.05) after the higher than after the lower dose of fructose-sorbitol mixture, and, for the higher dose, symptoms were significantly greater in IBS patients than in controls (p < 0.05). Moreover, the increase in total symptom score between the higher and lower dose mixtures was of a greater magnitude (p = 0.01) in IBS patients than in controls. No significant correlation was observed between the increase in symptom score and the increase in peak hydrogen concentration or the increase in integrated hydrogen response between lower and higher dose mixtures, although these latter increases were at times substantial.(ABSTRACT TRUNCATED AT 250 WORDS)     

饮食对肠易激综合征影响的研究进展

肠易激综合征(irritable bowel syndrome,IBS)患者的症状常与饮食有关。目前研究认为正常人群、IBS人群及IBS各亚型在饮食上存在差异,且饮食摄入量与症状的严重程度密切相关。研究结果显示:冷食、辛辣食品、水果和蔬菜、乳制品、茶、碳酸饮料、酒精等诸多食品和饮品均可引起IBS患者的症状,本文即针对饮食与IBS的关系进行分析,以期能够为IBS患者的饮食方案提供指导。     

Irritable bowel syndrome: Role of food in pathogenesis and management

Patients with the irritable bowel syndrome (IBS) commonly report the precipitation of symptoms on food ingestion. Though the role of dietary constituents in IBS has not been extensively studied, food could contribute to symptom onset or even the causation of IBS through a number of mechanisms. First, the physiological response of the intestine to food ingestion could precipitate symptoms in predisposed individuals; second, there is some evidence that allergy or intolerance to a particular food can produce IBS‐like symptoms, third, certain foods may alter the composition of the luminal milieu, either directly or indirectly through effects on bacterial metabolism, and thus induce symptoms and, finally, IBS may develop following exposure to food‐borne pathogens. Anticipatory, psychological factors generated by previous negative experiences with food ingestion or other factors may also contribute though their contribution has been scarcely quantified. Not surprisingly, there is considerable interest in the potential roles of diet and food supplements in the therapy of IBS; for the most part, the evidence base for such recommendations remains slim though certain probiotics show considerable promise.     

Importancia de la dieta en el síndrome del intestino irritable

About two-thirds of irritable bowel syndrome (IBS) patients associate their symptoms with certain foods. We reviewed food-related factors putatively associated with manifestations of IBS. Soluble fiber may improve constipation but frequently increases bloating and abdominal pain. Carbohydrate malabsorption seems to be more frequent in IBS. A low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet significantly reduces IBS symptoms and has been suggested as a therapeutic option. Serological screening for celiac disease should be done in patients without constipation. Moreover, non-celiac disease gluten sensitivity, defined as gluten intolerance once celiac disease and wheat allergy have been ruled out, should be considered in these patients. There is no specific diet for IBS patients but small and frequent meals, avoiding greasy foods, dairy products, many carbohydrates, caffeine and alcohol, is recommended.     

Effects of fructose ingestion on sorbitol and fructose 3-phosphate contents of erythrocytes from healthy men

To investigate the effect of fructose ingestion on sorbitol and fructose 3-phosphate (F3P) in erythrocytes, we administered 50 g fructose with and without treatment with an aldose reductase inhibitor, epalrestat, to seven healthy, normal-glucose-tolerant, male volunteers aged 20–43 years. The same subjects were given 50 g glucose on another day. The sorbitol and F3P contents in their erythrocytes increased significantly, reaching peak levels at 60 min and 180 min, respectively, following fructose ingestion. On the other hand, glucose ingestion did not cause any statistically significant change in sorbitol content in their erythrocytes, although it significantly elevated their F3P content. Treatment with epalrestat had no significant effect on incremental changes in erythrocyte sorbitol and F3P content following fructose ingestion. This suggests that oral fructose may be converted directly to sorbitol and F3P in erythrocytes instead of being converted via glucose. Thus, the dietary intake of fructose may affect the concentrations of sorbitol and F3P in erythrocytes in normal men.     

Lactose intolerance: problems in diagnosis and treatment

Lactose malabsorption and lactase deficiency are chronic organic pathologic conditions characterized by abdominal pain and distention, flatulence, and the passage of loose, watery stools. Though malabsorption of the sugar lactose is determinable by breath hydrogen test or jejunal biopsy, intolerance can only be confirmed by challenge with lactose-containing food, the response to which may not be immediate. The difficulty of making a positive diagnosis of these conditions has led to a proportion of lactose-intolerant patients being misdiagnosed with irritable bowel syndrome (IBS), which has a remarkably similar symptom complex and for which there is no current pathophysiologic marker. The incidence of the two disorders is approximately equal, but the actual proportion of patients with IBS incorrectly diagnosed in this way varies as a function of the methodology used. Once correct diagnosis is established, introduction of a lactose-free dietary regime relieves symptoms in most patients. Symptom similarity and the resultant incorrect diagnosis of IBS may explain the refractory nature of some patients labeled as IBS who remain largely unaware of the relationship between food intake and symptoms.     

肠易激综合征患者症状发作与饮食关系的调查

背景：流行病学调查示肠易激综合征（IBS）患者症状发作与饮食相关。目的：调查诱发或加重IBS症状的饮食因素,了解饮食因素在IBS发病中的作用,以探讨IBS患者自行饮食调整的策略。方法：采用问卷方式调查IBS患者症状发作与饮食的关系以及症状发作时的应对策略。结果：共纳入58例IBS患者,其中腹泻型IBS（IBS-D）占84.5%。每例患者有（5.50±3.37）个食物诱因,最常见的10种诱发和（或）加重IBS症状的食物为冷食（66.7%）、辛辣饮食（61.1%）、生食（53.7%）、油腻饮食（53.7%）、奶制品（不包括酸奶）（37.0%）、水果（33.3%）、酒（29.6%）、葱或韭菜（24.1%）、肉类（22.2%）和酸奶（16.7%）。IBS患者缓解症状最常用的手段为选择性食物剔除（55.2%）,其中最常被剔除的食物/饮食习惯是辛辣饮食（79.5%）,其次是冷食（77.3%）、生食（65.9%）、油腻饮食（56.8%）、肉类（31.8%）和奶制品（27.3%）。结论：IBS症状的发作和缓解与饮食密切相关,了解IBS患者症状发作与饮食的关系,对制定IBS患者的饮食调整策略,有效防治IBS具有重要意义。     

Dietary fiber assessment of patients with irritable bowel syndrome from Northern India.

BACKGROUND: Data on the absolute fiber intake and the source of dietary fiber intake in patients with irritable bowel syndrome (IBS) have been lacking in northern Indians. OBJECTIVE: To find out the absolute fiber intake from different sources of food items in patients with IBS and healthy subjects from northern India. METHODS: Using the 72-hour recall method, dietary intake of macronutrients and fiber was determined in 33 consecutive adult patients with IBS and 33 age- and gender-matched healthy controls. RESULTS: The patients consumed lower amounts of macronutrients (protein 60.4 g vs 79.3 g, fat 47.7 g vs 65.7 g, and carbohydrates 294.6 g vs 339.8 g) and dietary fiber (8.1 g vs 15.7 g) than the control subjects. Though the patients consumed similar amount of pulses as the controls (46.6 [25.0] vs 46 [19.6] g/day), their fiber intake from pulses was lower (0.8 [0.7] vs 1.4 [0.9] g/day). The intake of fiber from vegetables and fruits was also significantly lower in patients (2.1 and 0.5 g/day, respectively) than in control subjects (5.8 and 3.9 g/day, respectively; p< 0.001 each). CONCLUSION: Total dietary fiber intake and intake of fiber from vegetables, fruits and pulses are lower in patients with IBS from northern India than in control subjects.     

Adult hereditary fructose intolerance

Hereditary fructose intolerance （HFI） is an under-recognized, preventable life-threatening condition. It is an autosomal recessive disorder with subnormal activity of aldolase B in the liver, kidney and small bowel. Symptoms are present only after the ingestion of fructose, which leads to brisk hypoglycemia, and an individual with continued ingestion will exhibit vomiting,abdominal pain, failure to thrive, and renal and liver failure. A diagnosis of HFI was made in a 50-year-old woman on the basis of medical history, response to Ⅳ fructose intolerance test, demonstration of aldolase B activity reduction in duodenal biopsy, and molecular analysis of leukocyte DNA by PCR showed homozygosity for two doses of mutant gene. HFI may remain undiagnosed until adult life and may lead to disastrous complications following inadvertent fructose or sorbitol infusion. Several lethal episodes of HFI following sorbitol and fructose infusion have been reported. The diagnosis can only be suspected by taking a careful dietary history, and this can present serious complications.     

Fructose intolerance in IBS and utility of fructose-restricted diet

INTRODUCTION: Whether dietary fructose intolerance causes symptoms of irritable bowel syndrome (IBS) is unclear. We examined the prevalence of fructose intolerance in IBS and long-term outcome of fructose-restricted diet. METHODS: Two hundred and nine patients with suspected IBS were retrospectively evaluated for organic illnesses. Patients with IBS (Rome II) and positive fructose breath test received instructions regarding fructose-restricted diet. One year later, their symptoms, compliance with, and effects of dietary modification on lifestyle were assessed using a structured interview. RESULTS: Eighty patients (m/f=26/54) fulfilled Rome II criteria. Of 80 patients, 31 (38%) had positive breath test. Of 31 patients, 26 (84%) participated in follow-up (mean=13 mo) evaluation. Of 26 patients, 14 (53%) were compliant with diet; mean compliance=71%. In this group, pain, belching, bloating, fullness, indigestion, and diarrhea improved (P<0.02). Of 26 patients, 12 (46%) were noncompliant, and their symptoms were unchanged, except belching. The mean impact on lifestyle, compliant versus noncompliant groups was 2.93 versus 2.57 (P>0.05). CONCLUSIONS: About one-third of patients with suspected IBS had fructose intolerance. When compliant, symptoms improved on fructose-restricted diet despite moderate impact on lifestyle; noncompliance was associated with persistent symptoms. Fructose intolerance is another jigsaw piece of the IBS puzzle that may respond to dietary modification.     

Prevalence of irritable bowel syndrome in young adult Malaysians: a survey among medical students

BACKGROUND AND AIMS: Irritable bowel syndrome (IBS) is a common functional bowel disease in the West. Information on the prevalence of IBS in the Asian population is relatively scanty. The aims of the present study were to determine the prevalence of IBS and to assess the symptom subgroups based on the predominant bowel habit in a young adult population of Asian origin. METHODS: Basic demographic data and symptoms of IBS using the Rome I criteria were sought using a questionnaire administered to all apparently healthy students in a medical school. Other questions asked related to alcohol intake, smoking, chili consumption, dietary fiber intake, and to psychological and psychosomatic symptoms of anxiety, depression, insomnia, headache, and backache. The health-care seeking behavior of the subjects was also analyzed. RESULTS: Of the 610 questionnaires administered, 533 complete responses were received (response rate of 87.4%). The responders comprised 229 men (43.0%) and 304 (57.0%) women with a mean age of 22 +/- 1.8 years. The ethnic distribution was Malays 278 (52.2%), Chinese 179 (33.6%), Indians 46 (8.6%), and others 30 (5.6%). Eighty-four (15.8%) reported symptoms consistent with the diagnosis of IBS, predominantly women. Sixty-five (77.4%) and six (7.1%) were of the constipation-predominant and diarrhea-predominant IBS subgroups, respectively. Thirteen (15.5%) subjects fell into the non-specific IBS subgroup. The self-reported psychological and psychosomatic symptoms of anxiety (P = 0.02), depression (P = 0.002), insomnia (P = 0.006), headache (P = 0.04), and backache (P = 0.006) were encountered more frequently in the subjects with IBS. Only 13.1% of the IBS group had consulted their health-care practitioner, and 20.2% reported self-medication. CONCLUSIONS: Symptoms supportive of the diagnosis of IBS were common among young Malaysians, with a prevalence rate of 15.8%. There were significantly more women with IBS than men. Within the IBS population, the majority (77.4%) was of the constipation-predominant IBS subgroup. A significantly higher prevalence of psychological and psychosomatic symptoms was found in individuals with IBS. Only a minority sought medical advice for their symptoms.