FODMAP Diet for IBS

Background

FODMAP is an acronym for fermentable oligo-di-monosaccharides and polyols, which are carbohydrate molecules found in specific foods. Eliminating foods containing FODMAPS may help immensely with the symptoms of irritable bowel syndrome.

There are 5 categories of foods containing FODMAPS: foods with excess fructose, lactose, fructans, galactans, and polyols.

Normally when carbohydrates are eaten, they are broken down into monosaccharides (sugar molecules including glucose, galactose, and fructose) and absorbed in the small intestine. If malabsorption of carbohydrates occurs, fructose can pass into the large intestine and will ferment, leading to bloating and gas. It can also pull water into the lumen, resulting in diarrhea in some people.

Fructans, which consist of fructose molecules bound together, and galactans, which consist of galactose molecules bound together, can also be poorly absorbed and lead to symptoms. Fructose is more readily absorbed when bound to glucose in the form of sucrose, so malabsorption occurs when fructose is present in excess of glucose in a particular food. Pylols are very poorly absorbed and commonly contribute to symptoms in IBS patients.

FODMAP Categories
Excess Fructose: Apple, mango, nashi, pear, canned fruit in natural juice, watermelon, fructose, high fructose corn syrup, concentrated fruit sources, large servings of fruit, dried fruit, fruit juice, honey, corn syrup
Lactose: Milk, yogurt, soft cheese, custard, ice cream, goat’s milk
Fructans: Artichoke, asparagus, beet, broccoli, Brussels sprouts, cabbage, eggplant, fennel, garlic, leek, okra, onion, shallots, what, rye, (crackers, cookies, pasta), watermelon, persimmon, chicory, dandelion, inulin, pistachio
Galactans: Baked beans, chickpeas, kidney beans, lentils, soy beans
Polyols: Apple, apricot, avocado, blackberry, cherry, nectarine, peach, pear, plum, prune, cauliflower, bell pepper, mushroom, sweet corn, sorbitol, mannitol, maltitol, xylitol

It is recommended that before beginning the FODMAP diet, your gastroenterologist test you for celiac disease, and if available, lactose malabsorption. It is important to keep gluten from wheat, rye, and/or barley in your diet in significant amounts for a celiac antibody blood test to be accurate. If you are underweight, under the age of 18, or have a current or history of eating disorders, consult with your doctor before beginning an elimination diet such as the low FODMAP diet.

The purpose of the FODMAP elimination diet is to do a 2-3 week elimination of FODMAP-containing foods to help identify food triggers of IBS. If after this period of time there is no improvement, there is probably nothing more to be gained from this approach. At this time it is often helpful to test for food sensitivities to identify your individual food triggers. If improvement was seen on the FODMAP diet, a challenge phase begins in which each individual FODMAP category is tested back in one-by-one to determine which of the categories provoke symptoms.

A registered dietitian who is trained in the FODMAP approach can provide you with an extensive list of specific foods and ingredients to include and to avoid, recipes, restaurant ideas and help you build a FODMAP-free meal plan for your elimination phase. It is important to keep a food diary during this time and monitor symptoms. The dietitian will then guide you through the steps of the challenge phase to determine which FODMAP groups provoke symptoms.

Your healthcare provider is the best source of information for questions and concerns related to your health.