Role of food hypersensitivity in irritable bowel syndrome.

A significant proportion of IBS patients attribute their symptoms to adverse food reactions. Dietary elimination and re-challenge studies support the role of diet in the pathogenesis of IBS. The aetiopathogenesis of IBS is thought to be multifactorial involving an interaction between diet, infection, antibiotics and psychosocial factors. Serum IgE and IgG4 antibodies are elevated in food hypersensitivity induced atopic conditions and a similar mechanism has been postulated in IBS. Increased number of mast cells is present in the ileocaecal region of IBS patients. Once sensitized, they are capable of inducing secretory and sensorimotor abnormalities of the gut. The management of IBS is usually aimed at controlling symptoms, however, evaluation of food hypersensitivity may provide a useful adjunct in those with severe symptoms or a clear history of adverse food reaction. There are no well-established tests available but skin prick tests and food specific serum IgG4 and IgE antibodies may help in identifying the offending foods. Other options, which may be explored in individual cases, include sequential dietary exclusion, use of hypoallergenic diets, disodium cromoglycate and novel techniques such as colonoscopic allergen provocation test. Pathophysiology of hypersensitivity induced IBS has been discussed in the light of current data and a management algorithm has been proposed for managing food hypersensitivity in IBS.

Review article: bloating in functional bowel disorders.

Bloating is a frequently reported symptom in functional bowel disorders. It usually occurs in combination with other symptoms, but may also occur in isolation. The severity of bloating tends to worsen during the course of the day and improves overnight. Although frequently considered to be a subjective phenomenon, recent studies have shown that bloating is associated with a measurable increase in abdominal girth. The pathophysiology of bloating remains elusive, but the evidence supports a sensorimotor dysfunction of the bowel. The possible mechanisms include abnormal gas trapping, fluid retention, food intolerance and altered gut microbial flora. Further studies are needed to define the sensorimotor abnormalities associated with bloating, which might be segmental and transient rather than generalized and persistent. The lack of understanding of this symptom is paralleled by a limited availability of therapeutic options. Conventional medications used in functional bowel disorders are not helpful and may indeed worsen the symptoms. In future, new drugs with activity against serotonin and kappa receptors, or novel approaches such as the use of exclusion diets, probiotics and hypnotherapy, may prove to be useful.

Food hypersensitivity and irritable bowel syndrome.

Irritable bowel syndrome is a common condition but its pathophysiology remains poorly understood. Many irritable bowel syndrome patients give a history of food intolerance, but data from dietary elimination and re-challenge studies are inconclusive. Multiple aetio-pathological mechanisms have been postulated. The gut has an extensive immune system but current understanding of processing of food antigens in health and disease is limited. There is no clinically useful marker available to test for food hypersensitivity in irritable bowel syndrome. Researchers have employed both skin tests and serum immunoglobulins (IgG and IgE) as markers of food hypersensitivity in various disorders including irritable bowel syndrome, but published data are equivocal. In this article, the evidence for the role of food hypersensitivity in irritable bowel syndrome is reviewed and, based on the available data, a possible pathophysiological hypothesis has been formulated.

Clinical practice--strategies for management of dyspepsia.

If every person, particularly the young with dyspepsia, were initially tested for Helicobacter pylori and treated if positive and re-assured if negative, a substantial proportion of endoscopies could be saved, and it is difficult to conceive how this would add to the expense of managing dyspepsia if most H. pylori positive dyspeptics are going to receive treatment after endoscopy in any event. An algorithm for the management of dyspepsia is proposed.