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Food Allergy and the Gut |
Conference Report - November 2000 |
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Dr Jonathan Brostoff, founder of the Allergy Research Association, discussed the distinction between food allergy and intolerance. The range and timing of symptoms, the range of culprit foods, the quality of the food challenge and the validity of blood tests. Professor Erika Isolauri from the Academy of Finland discussed the importance, for the maturation of immune function, of colonisation of the infant gut by bacteria during or immediately after birth. She suggested that: 1. The reduced exposure of infants to bacteria may be inhibiting the development of tolerance to antigens/allergens 2. Infants from atopic families have more clostridia bacteria and less bifida in their gut flora than normal infants 3. A recent study suggested that probiotics used in conjunction with an elimination diet could produce a significant improvement in infants with atopic eczema. Dr Tim King, specialist registrar in gastroenterology at Addenbrooke’s, discussed the reduced production of hydrogen (flatus) in IBS patients on an exclusion diet. Although the mechanisms are not yet understood it would appear that the exclusion diet actually changed the gut flora and that the reduction in flatus could be due to bacterial change in the colon not just that there is less substrate to ferment. Jenny Woolner, a research dietitian at Addenbrooke’s Hospital, described the enteral diets they used to achieve remission in Crohn’s patients although, again, they do not yet understand the mechanisms - low antigenicity, bowel rest, change in bowel flora, change in fatty acid content? Patients who then follow individualised elimination diets do significantly better than those relying on drug treatments - although patient compliance/support is a major problem. Professor Glen Gibson, head of the Food Microbial Sciences Unit at Reading University, described the role that sulphate reducing bacteria might have for sufferers of ulcerative colitis. Although 50% of the adult population carry the bacteria Desulfovibrio without apparent ill effects, it is universal in UC patients in whom it generates quantities of toxic sulphides and can cause substantial cell destruction. Professor Stephan Bischoff from the department of Gastroenterology in Hanover described the difficulty in diagnosing the estimated 1-2% prevalence of food allergic reactions in the gut. Blind oral challenges remain the diagnostic gold standard but work continues on endoscopic provocation tests, the role of IgE independent allergic mechanisms and the relationship to other inflammatory bowel diseases. Dr John Hunter, Director of Gastroenterology at Addenbrookes, discussed the possibility that food intolerance, as well as a number of chronic diseases such as Crohn’s and rheumatoid arthritis, may be related to metabolic activity of gut bacteria and abnormal fermentation in the large intestine. First published November 2000 • If this article was of interest you will find many other articles on unlikely allergies and allergy connections here – and links to many relevant research studies here. |
