We see many patients with presumed wheat intolerance, but who test negative for gluten intolerance and wheat allergy despite debilitating symptoms such as bloating, abdominal cramps and diarrhoea with constipation. Despite these negative tests, they respond favorably to a wheat exclusion diet.
These symptoms may be attributed to fructans (sugars derived from fruit juice such as sucrose and fructose) which are either added or naturally occur in honey, cereals (wheat and rye), legumes, onions, leeks, asparagus and root vegetables. Fructose is also found naturally in Rosacea family fruits such as apple, cherry, apricot, plum and pear juices and may be added as Sorbitol sweetener found in processed foods and chewing gum. With excessive intake, these short chain carbohydrate Fructans, may pass unabsorbed into the lower bowel where they ferment under influence of bowel microorganisms producing unpleasant gases (hydrogen, methane, carbon dioxide and hydrogen sulphide). These gases then lead to the typical bloating and flatulent symptoms similar to those experienced by individuals with lactose intolerance to dairy products. Fermentable dietary oligosaccharides, disaccharides, monosaccharides and polyols or FODMAPs exacerbate Irritable Bowel Syndrome (IBS) symptoms as well. Corn, rice, potato, spelt and gluten-free products tend not to contain fructans or FODMAPs
Reference: Bolin T. IBS or intolerance. Australian Family Physician 38 12 962-965
http://ibs.about.com/od/ibsfood/a/The-FODMAP-Diet.htm
