Dietary Treatment of the Irritable Bowel Syndrome

The Food-Specific Serum IgG Reactivity in Major Depressive Disorder Patients, Irritable Bowel Syndrome Patients and Healthy Controls

There is an increasing amount of evidence which links the pathogenesis of irritable bowel syndrome (IBS) with food IgG hyperreactivity. Some authors have suggested that food IgG hyperreactivity could be also involved in the pathophysiology of major depressive disorder (MDD). The aim of this study was to compare levels of serum IgG against 39 selected food antigens between three groups of participants: patients with MDD (MDD group), patients with IBS (IBS group) and healthy controls (HC group). The study included 65 participants (22 in the MDD group, 22 in the IBS group and 21 in the HC group). Serum IgG levels were examined using enzyme-linked immunosorbent assay (ELISA). Medical records, clinical data and laboratory results were collected for the analysis. IgG food hyperreactivity (interpreted as an average of levels of IgG antibodies above 7.5 µg/mL) was detected in 28 (43%) participants, including 14 (64%) from the MDD group, ten (46%) from the IBS group and four (19%) from the HC group. We found differences between extreme IgG levels in MDD versus HC groups and in IBS versus HC groups. Patients with MDD had significantly higher serum levels of total IgG antibodies and IgG against celery, garlic and gluten compared with healthy controls. The MDD group also had higher serum IgG levels against gluten compared with the IBS group. Our results suggest dissimilarity in immune responses against food proteins between the examined groups, with the highest immunoreactivity in the MDD group. Further studies are needed to repeat and confirm these results in bigger cohorts and also examine clinical utility of IgG-based elimination diet in patients with MDD and IBS.

Food-specific IgG antibodies directed restrictive dietary treatment of IBS

AIM: To investigate the role of food intolerance in the pathogenesis, diagnosis and treatment of irritable bowel syndrome (IBS).

METHODS: One hundred and seventeen patients with IBS diagnosed according to the Rome Ⅲ criteria and 50 healthy controls were enrolled from July 2011 to August 2013. Medical information was collected and disease severity score for each individual was calculated. Titres of serum IgG antibodies to 14 common foods were analyzed by ELISA. Patients underwent food elimination diets based on the results of IgG antibody analysis. The patients were followed for 12 weeks after food elimination and disease severity score was measured again.

RESULTS: All the IBS patients had higher titres of serum IgG antibodies to beans (40.17%), eggs (26.49%), or corn (16.23%), while the healthy volunteers had higher titres of serum IgG antibodies to tomato (34.00%), crab (18.00%), or milk (14.00%). The percentages of classified patients were mild (27.6%), moderate (53.1%), and severe IBS (19.3%) before food elimination diets, and mild (49.1%), moderate, (43.9%), and severe IBS (7.0%) after food elimination diets. Food elimination diets could significantly improve disease severity score in patients with diarrhea- or constipation-predominant IBS, but had no influence in those with mixed type or non-typed disease.

CONCLUSION: Food intolerance may be one of the reasons responsible for the pathogenesis of IBS. Food elimination based on IgG antibodies may be effective in reducing disease severity score and relieving IBS symptoms.

Progress in understanding the relationship between food intolerance and functional gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) are a group of conditions characterized by the presence of chronic or recurrent gastrointestinal symptoms. Currently, the exact pathogenesis of FGIDs is still unknown, and their diagnosis relies on the exclusion of organic diseases. A number of studies have found that food intolerances can induce FGIDs and therefore has important implications for the diagnosis and treatment of FGIDs. In this paper, we review the recent progress in understanding the relationship between FGIDs and food intolerances in terms of pathogenesis, diagnosis, treatment, detection, and relationship between food intolerance and other diseases.

Review: Management of postprandial diarrhea syndrome

Unexpected, urgent, sometimes painful bowel movements after eating are common complaints among adults. Without a clear etiology, if pain is present and resolves with the movements, this is usually labeled "irritable bowel syndrome-diarrhea" based solely on symptoms. If this symptom-based approach is applied exclusively, it may lead physicians not to consider treatable conditions: celiac disease, or maldigestion due to bile acid malabsorption, pancreatic exocrine insufficiency, or an a-glucosidase (sucrase, glucoamylase, maltase, or isomaltase) deficiency. These conditions can be misdiagnosed as irritable bowel syndrome-diarrhea (or functional diarrhea, if pain is not present). Limited testing is currently available to confirm these conditions (antibody screens for celiac disease; fecal fat as a surrogate marker for pancreatic function). Therefore, empirical treatment with alpha amylase, pancreatic enzymes, or a bile acid-binding agent may simultaneously treat these patients and serve as a surrogate diagnostic test. This review will summarize the current evidence for bile acid malabsorption, and deficiencies of pancreatic enzymes or a-glucosidases as potential causes for postprandial diarrhea, and provide an algorithm for treatment options.

Irritable bowel syndrome and food allergy

Irritable bowel syndrome (IBS) is a kind of functional gastrointestinal disease characterized by abdominal pain or discomfort associated with changes in bowel habits. The alternating symptoms of IBS seriously affect the patients' quality of life. Some studies have found that food could cause or aggravate the symptoms of IBS possibly by inducing food allergy and food intolerance. However, the specific mechanisms have not been established yet. Currently there are "bacterial 'toxin' hypothesis", "immune or inflammatory response hypothesis" and "physical or chemical irritation hypothesis" explaining the role of food in the pathogenesis of IBS. It has been known that food factors play a very important role in the pathogenesis of IBS. This article reviews food allergy and the possible mechanisms, diagnosis and treatment of IBS caused by food.

The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review

This review summarizes what is known about the effect of diet on irritable bowel syndrome (IBS) symptoms emphasizing data from randomized, controlled clinical trials. Studies suggest that IBS symptoms in one quarter of patients may be caused or exacerbated by one or more dietary components. Recent studies indicate that a diet restricted in fermentable, poorly absorbed carbohydrates, including fructose, fructans (present in wheat and onions), sorbitol, and other sugar alcohols is beneficial, but confirmatory studies are needed. Despite a long history of enthusiastic use, fiber is marginally beneficial. Insoluble fiber may worsen symptoms. Some patients with IBS, especially those with constipation, will improve with increased intake of soluble fiber. Prebiotic fibers have not been adequately tested. Daily use of peppermint oil is effective in relieving IBS symptoms. The usefulness of probiotics in the form of foods such as live-culture yogurt and buttermilk for IBS symptoms is not established. In clinical practice, it is very difficult to establish that a patient's symptoms result from an adverse reaction to food. A double blind placebo-controlled food challenge is the most reliable method, but it is not suitable for routine clinical use. A modified exclusion diet and stepwise reintroduction of foods or trials of eliminating classes of food may be useful.

Food intolerance and diarrhea-dominant irritable bowel syndrome

AIM: To explore the relationship between food intolerance and diarrhea-dominant irritable bowel syndrome (dIBS).

METHODS: In 68 patients with Rome II dIBS, we semi-quantitatively measured specific IgG antibody to 14 food allergens in the serum, then eliminated the corresponding food. After 8 weeks, we observed changes in symptom frequency and disease severity index.

RESULTS: Compared with the normal control group, 48 patients with dIBS appeared positive to at least one food allergen, with a positive rate of 70.6%, and the difference was significant (P < 0.05). After 8 weeks diet therapy, clinical symptoms of dIBS were significantly relieved in 29 patients who were positive for >2 food allergens. Also, symptom frequency was significantly reduced from 3.62 ± 1.41 to 1.52 ± 0.62, and severity index from 3.21 ± 1.50 to 1.39 ± 0.66.

CONCLUSION: Food intolerance was involved in the pathogenesis of dIBS. According to the level IgG, eliminating the corresponding food can improve the clinical symptoms of dIBS.

Alterations of food antigen-specific serum immunoglobulins G and E antibodies in patients with irritable bowel syndrome and functional dyspepsia

BACKGROUND

Post-prandial worsening of symptoms as well as adverse reactions to one or more foods are common in the patients with functional gastrointestinal diseases, such as irritable bowel syndrome (IBS) and functional dyspepsia (FD). However, the role played by true food allergy in the pathogenesis of these diseases is still controversial and there are no well-established tests to identify food allergy in this condition.

OBJECTIVE

To investigate serum food antigen-specific IgG, IgE antibody and total IgE antibody titres in controls and patients with IBS and FD, and to correlate symptoms with the food antigen-specific IgG titres in IBS and FD patients.

METHODS

Thirty-seven IBS patients, 28 FD patients and 20 healthy controls participated in this study. Serum IgG and IgE antibody titres to 14 common foods including beef, chicken, codfish, corn, crab, eggs, mushroom, milk, pork, rice, shrimp, soybean, tomatoes and wheat were analysed by ELISA. Serum total IgE titres were also measured. Last, symptomatology was assessed in the study. Results IBS patients had significantly higher titres of IgG antibody to crab (P=0.000), egg (P=0.000), shrimp (P=0.000), soybean (P=0.017) and wheat (P=0.004) than controls. FD patients had significantly higher titres of IgG antibody to egg (P=0.000) and soybean (P=0.017) than controls. The percentage of individuals with detectable positive food antigen-specific IgE antibodies of the three groups did not show any significant differences (P=0.971). There were no significant differences between IBS patients, FD patients and controls in the serum total IgE antibody titres (P=0.978). Lastly, no significant correlation was seen between symptom severity and serum food antigen-specific IgG antibody titres both in IBS and FD patients.

CONCLUSION

Serum IgG antibody titres to some common foods increased in IBS and FD patients compared to controls. But there is no significant correlation between symptom severity and elevated serum food antigen-specific IgG antibodies in these patients.

The general practitioner's approach to irritable bowel syndrome: from intention to practice

BACKGROUND

Although general practitioners play a critical role in the management of irritable bowel syndrome because they deal with the most patients, guidelines are developed mainly by specialists.

AIMS

To evaluate the clinical features of irritable bowel patients and the general practitioners' approach to irritable bowel syndrome in Italy.

SUBJECTS AND METHODS

A questionnaire focusing on the management of this syndrome was completed by 28 general practitioners. Clinical features and diagnostic and treatment measures taken in 229 patients were analysed.

RESULTS

Only 35.7% of the general practitioners were familiar with the Rome II criteria. Changes in bowel habits and abdominal pain/discomfort were the most common symptoms. Constipation (74.2%) was more frequent as the main symptom than diarrhoea. Routine blood tests (76.4%) and abdominal ultrasound (42.2%) were requested more frequently than colonoscopy (31.1%). At least one specialist consultation was recommended in 63.3% of patients. Drugs (mainly antispasmodics) were prescribed more frequently for diarrhoea (91.4%) than for constipation (55.7%).

CONCLUSIONS

General practitioners are little acquainted with the Rome II criteria. Diagnostic tests and specialist consultations are often recommended; antispasmodics are the most frequently prescribed drug. Guidelines should be developed together by general practitioners and gastroenterologists to effectively manage patients at a lower cost.

Food allergy and irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome is a common and likely a multifactorial gastrointestinal disorder in which a disturbed brain-gut axis has been thought to have a mandatory role. Recent clinical and experimental studies imply that dietary factors may be more important in the pathogenesis of irritable bowel syndrome than was earlier anticipated. The purpose of this review is to present those studies and discuss their findings in relation to the crosstalk between the gastrointestinal immune and nervous systems.

RECENT FINDINGS

Food elimination based on serum immunoglobulin G antibodies in irritable bowel syndrome has been found to result in a significant decrease in symptoms, compared with diets in which dietary restrictions are not guided by those antibodies. Both numbers of mast cells and their mediators have been shown to be increased in intestinal mucosa in patients with irritable bowel syndrome, especially in the close proximity of intestinal nerves. Animal studies have demonstrated that this increase in intestinal mast cell density could be a consequence of local hypersensitivity to food antigens. That kind of local gastrointestinal hypersensitivity seems to be beyond the reach of current diagnostic methods available in clinical practice.

SUMMARY

Dietary factors may significantly contribute to the pathophysiology of irritable bowel syndrome. Elimination diets based on the detection of local food hypersensitivity may offer a treatment option for irritable bowel syndrome patients in the future.