FODMAPs stand for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. They are small osmotically active molecules that often trigger functional symptoms in patients with irritable bowel syndrome (IBS).
Several studies showed that a low FODMAP diet often leads to complete or partial symptom relief in up to 77% of patients with IBS.
IBS is a chronic and often disabling condition because it is not easily treated by medication or dietary means. Elimination diets were often used, but despite being extremely restrictive, they did not work so uniformly as to provide a predictably effective therapeutic intervention.
There are other conditions involving functional bowel disorders which have the same type of symptomatology. For these reasons, a low FODMAP diet is often recommended for such patients and provides significant benefit in a high percentage of them.
There are many foods that are considered high FODMAP. They can be divided into categories, according to the type of FODMAP that they contain.
Foods that are rich in fructose include:
These foods should be substituted with citrus fruit, papaya, durian, banana, strawberries, or blueberries. Possible sweeteners include maple syrup or golden syrup, and any non-polyol artificial sweetener.
Any food rich in fructose must be eaten only in combination with glucose-containing foods which enhance its absorption.
Fructose preponderance leads to malabsorption symptoms in most cases because the mucosal transporters in such patients require more glucose to effectively transport fructose as well out of the lumen and into the mucosal cells, making it unavailable for luminal fermentation.
These may be substituted for by almond, soy, or coconut milk, rice milk, lactose-free milk and yogurt, sorbet or gelato for ice cream, and hard or ripened cheeses
Foods rich in galactooligosaccharides and fructans:
These may be replaced by green beans, capsicum, carrots, celery, chives, lettuce, pumpkin, and bamboo shoots. It is advised to use gluten-free and spelt flour in place of wheat flour.
Oil in which garlic has been lightly sautéed may be used after removing the garlic, to obtain the savory taste without the short-chain carbohydrates.
Permissible grains include rice, oats, and quinoa, while most nuts (such as almonds, walnuts, peanuts and pecans) may be used in moderation.
These should be replaced with the fruits permitted above, sugar or glucose. All medications should be reviewed by the doctor or pharmacist to ensure they do not contain polyols or lactose, such as many liquid painkillers, and cough medications. Tablets are preferable to these forms.
A low-FODMAP diet should be formulated with the help of a dietitian to make sure that each substitution makes nutritional sense, avoids deficiencies, and caters to individual dietary preferences and aversions.
Providing lists of preferred and avoided foods can help the patient greatly with long-term compliance. Total FODMAP abstinence for a few weeks (6-8 weeks) can be followed by systematic slow food challenges to identify potentially harmful foods, if any.