People who suffer from fructose intolerance is usually an acquired condition which is a functional problem in the small intestine where the ability to absorb fructose is decreased. Individuals with coeliac disease usually have acquired fructose intolerance. Hereditary fructose intolerance is a rare genetic disorder where the liver lacks a certain enzyme needed to metabolize fructose and only a few cases have been reported
Symptoms of fructose intolerance are similar to those of gluten intolerance and lactose intolerance. Symptoms include bloating, flatulence, burping, nausea, abdominal cramping, and diarrhoea. People who sufferer can have reactions ranging from mild symptoms to severe symptoms in some cases. If individuals on a strict gluten-free and lactose free diet whose symptoms do not improve may therefore consider screening for fructose intolerance.
Fructose intolerance can be diagnosed with a breath hydrogen test as increased level of breath hydrogen indicates fructose malabsorption resulting in a diagnosis of fructose intolerance. Before the test a beverage containing fructose is consumed which is absorbed by facilitated diffusion through the use of transporters known as GLUT 5 and GLUT 2. When these transporters are decreased or overloaded unabsorbed fructose passes directly into the colon where it is fermented and produces fatty acids and gases.
Fructose malabsorption has been increasing in the general population which has been detected by testing and it has therefore demonstrated that fructose malabsorption happens in many healthy individuals.
High fructose can be found in corn syrup, honey, fruits, vegetables, wheat, sucrose, and sucrose containing foods and beverages. Fructose that is found in vegetables and wheat is often in the form of complex carbohydrates.
Treatment of fructose intolerance includes limiting or eliminating fructose and sucrose from the diet. Remember sucrose becomes both fructose and glucose during digestion. Fructose tolerance dictates how strict the diet needs to be. One way to figure out individual tolerance is to try an elimination diet. By eliminate fructose containing foods and beverages until symptoms improve and then slowly reintroducing one food or beverage at a time to see if symptoms reappear. Before beginning a fructose elimination diet it may be better to consult with a registered dietitian.
Foods to avoid that may have high fructose and sucrose
Sugars and sugar substitutes* (especially fructose derived )
Corn syrup, golden syrup, molasses and other sweet syrups
Jams, Marmalade and conserves
Relishes, sweet sauces and preserves
Lollies, chocolates, cakes, biscuits and deserts
Sugared and sugar substitute beverages
Fruit and fruit juice
Vegetable and vegetable juice
*Sugar substitutes like splenda, equal, nutrasweet and saccharin in smaller amounts appear to be tolerated by individuals with fructose intolerance
Managing fructose intolerance is figuring out the fructose content in foods and beverages. Determining the fructose content in gluten-free grains can be difficult because labelling usually list total carbohydrate content rather than individual sugars such as fructose. Hidden sources of fructose include foods with added sugar that may not be obvious such as cured meats, commercial baked goods, sauces and condiments.
Gastrointestinal symptoms are a hallmark of coeliac disease even though not all individuals have obvious symptoms. If a strict gluten-free and fructose-free diet and lifestyle are started together the expected outcome may assist in the resolution of symptoms, but it may take as long as a year or more for symptoms to improve or resolve.
If gastrointestinal symptoms persist, do not improve, or improve and then reoccur consider consulting a physician or dietician regarding carbohydrate intolerance and other treatment to improved health and quality of life.
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