What is FODMAP?
FODMAP is an acronym that stands for Fermentable, Oligo-, Di-, Mono-saccharides And Polyols. FODMAPS refer to certain short chain carbohydrates present in our foods. These carbohydrates are not absorbed well in the small intestine, and can lead to gastrointestinal disturbances in certain individuals. It is believed that the residual nutrients irritate the gut and also serve as nutrition for the bowel bacteria which may contribute to digestive symptoms, as is seen in IBS.
How do FODMAPS work?
The concept of FODMAP gained popularity because of observations that restricting the intake of high-FODMAP foods improves gastrointestinal symptoms in people with functional gastrointestinal disorders such as irritable bowel syndrome (IBS). People with these conditions cannot tolerate high-FODMAP foods in their diet. Increased intake of FODMAP-rich diet causes gastrointestinal disturbances such as formation of excessive gas, abdominal bloating, diarrhea and constipation in individuals with functional gastrointestinal disorders.
The reason for the gastrointestinal disturbance are as follows:
- FODMAPs are osmotically active: FODMAPS are osmotically active molecules that draw water from the intestinal blood vessels into the intestine. This increases water content in the intestine, and leads to diarrhea.
- FODMAPs get fermented: The bacterial flora in the intestine ferment FODMAPs to produce large volumes of gases (hydrogen and carbon-di-oxide). This leads to abdominal bloating, belching, and flatulence.
Also read on irritable bowel syndrome.
What foods comprise FODMAP?
FODMAP is comprised of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (sugar alcohols). The following are some of the foods that are rich in FODMAPs.
Oligosaccharides are carbohydrates that are made up of a chain of few sugar molecules. They are named according to the nature of the sugar molecules that link together to form the oligosaccharide chain. The most common oligosaccharides that constitute FODMAP are fructans and galactans.
The oligosaccharide chains of fructans are composed of multiple units of fructose, and one unit of glucose at the end. Fructans are minimally absorbed in our intestines, and interfere with the absorption of fructose (a condition known as fructose malabsorption). Fructans with less than ten molecules of fructose are known as fructo-oligosaccharide (or oligofructose). Fructans with more than ten molecules of fructose are called inulins. Examples of fructan-rich foods include: white bread, pasta, cookies, pastries, artichokes, onions, asparagus, garlic, leek, chicory roots and chicory-based coffee substitutes.
Galactans are oligosaccharide chains made up of multiple units of galactose sugar, and one unit of fructose sugar at the end. Examples include stacchyose and raffinose. Foods rich in galactans include brussel sprouts, cabbage, and legumes like chickpeas, lentils, soy, and beans.
Lactose is an example of a FODMAP disaccharide. Milk is the most common source of lactose. In fact, lactose is also known as milk sugar. Other foods that contain lactose include diary sweets, beer, chocolate, packaged sauces and soups. Lactose absorption in the intestine is impaired in a variety of conditions such as lactose intolerance, Crohn’s disease, celiac disease, and small intestinal bacterial overgrowth (SIBO).
Fructose is the most common FODMAP monosaccharide. Also known as fruit sugar, fructose is the sweetest among sugars. Malabsorption and SIBO could result from excessive intake of fructose. Examples of fructose-rich foods include honey, pears, apples, peaches, cherries, figs, watermelon, dates, papaya, and prunes. High fructose corn syrup is often added to many packaged beverages and foods.
Polyols refer to several artificial sweeteners used in packaged foods and drinks. They are also known as sugar alcohols. Examples of polyols include sorbitol, xylitol, mannitol, arabitol, erythritol, glycerol, ribitol, lactitol, and glycol. Sorbitol is a common ingredient in chewing gums (the sugar-free variety) and low-calorie foods. It occurs naturally in fruits such as plums, apricots and peaches. Like sorbitol, xylitol is also commonly used in chewing gum. It is natural component of some species of berries. Consumption of polyol-rich foods aggravates fructose malabsorption and SIBO.
Effects of Eating FODMAPs
FODMAPs are fermentable sugars that are poorly absorbed in the intestine. They also affect absorption of other nutrients from the food. Excessive consumption of FODMAP-rich foods may lead to symptoms such as bloating, belching, flatulence, diarrhea, abdominal pain, headache, weight loss, tingling, paleness, tiredness, and depression. Many of these are symptoms of vitamin and mineral deficiency. In addition to primary effects, FODMAPs may also worsen gastrointestinal symptoms in individuals suffering from lactose intolerance, celiac disease, fructose malabsorption, Crohn’s disease, ulcerative colitis, small intestinal bacterial overgrowth, and rapid gastric emptying (dumping syndrome).
Also read on sulfur burps.
Low-FODMAP diet is a viable approach to managing any condition with unexplained diarrhea or bloating. Low-FODMAP diets have been shown to benefit both adults and children with irritable bowel syndrome (IBS). However, it is not entirely clear if they are effective measures for other functional gastrointestinal disorders such as inflammatory bowel disease.
In general, the efficacy of low-FODMAP diet for a particular condition can be tested for 6-8 weeks by limiting the amount of high-FODMAP foods in the daily diet. It is unnecessary (and dangerous) to eliminate all high-FODMAP foods from the diet. After six weeks, high-FODMAP foods can be introduced in the diet one by one to see the effect on the symptoms. In this way, offending food stuffs can be identified and eliminated from the diet.
Low-FODMAP diets could be dangerous for people with conditions such as diabetes, metabolic disorders, hypoglycemia, and malnutrition. Therefore, a low-FODMAP diet plan should be arrived at by a registered dietician, after consultation with a doctor.
List of Foods with Low FODMAP
The following are some of the low-FODMAP diet options to be considered by individuals with functional gastrointestinal disorders such as irritable bowel syndrome:
- Fruits: Although fruits are generally high in fructose, some are low on FODMAPs. Examples include melon, orange, grapes, banana and mandarin.
- Vegetables: Vegetables low in FODMAPs include bell pepper, green beans, sprouts, carrots, cucumber, tomato, bok choy, zucchini, choy sum, herbs, alfalfa, and chives.
- Protein: Protein-rich foods are usually low on FODMAPs. Examples include fish, chicken, various meats, and tofu.
- Dairy: Dairy products contain lactose, which causes gastrointestinal problems in many people. Consumption of lactose-free milk and yogurt may improve symptoms of gastrointestinal upset.
- Breads: Wheat is a high FODMAP item. Therefore, gluten-free pasta and bread are advised for people who cannot tolerate high FODMAP diets.
- Cereals: Cereals such as rice (boiled or puffed), quinoa and oats are also recommended as low FODMAP foods.
- Snacks: Rice cakes, gluten-free cookies and corn thins are low FODMAP snack options.
- Nuts: Almonds and pumpkin seeds are also good low-FODMAP snacks.
- Beverages: Instead of colas and other commercial sugary drinks, low-FODMAP beverages such as tea and coffee are recommended. Water is the best option.