The Low-FODMAP Diet Found to Be Helpful for Irritable Bowel Syndrome
By Lynn Grieger, RDN, CDE, CPT, CHWC
People with irritable bowel syndrome (IBS), a disease of the intestines that results in stomach pain, bloating, gas, diarrhea, and/or constipation, often try a variety of restrictive diets to get relief. The low-FODMAP diet helps approximately 70% of people with IBS live healthy, symptom-free lives.
IBS affects between 25 and 45 million people in the United States, and about 2 in 3 IBS sufferers are female. About 1 in 3 IBS sufferers are male. IBS affects people of all ages, even children. Worldwide it's estimated that 10-15% of the population has IBS. Most persons with IBS are under the age of 50, but many older adults suffer from it as well.
What is FODMAP?
FODMAP is an acronym for:
• Oligosaccharides (fructans and galacto-oligosaccharides)
• Disaccharides (lactose)
• Monosaccharides (excess fructose)
In the 1960’s, carbohydrate malabsorption was recognized as a cause for the diarrhea, pain, and bloating associated with IBS. Researchers initially looked at individual sources of carbohydrate, including lactose (the type of carbohydrate in milk), fructose (the type of carbohydrate in fruit), sorbitol (a polyol, or type of lower calorie sweetener), and oligosaccharides (also used as sweeteners). In 2004, the Monash group’s research led them to understand that malabsorption of all of these types of carbohydrates is the cause of IBS symptoms, and they coined the term FODMAP.
Which foods contain FODMAPs?
FODMAPs are found in foods that we enjoy every day:
• Lactose: milk and foods made from milk including cheese, yogurt, cottage cheese, ice cream and pudding.
• Excess fructose: fruits including apples, cherries, mangos and pears; vegetables including asparagus and sugar snap peas; sweeteners including agave, high fructose corn syrup, and honey.
• Foods high in fermentable oligosaccharides: vegetables including garlic and onions; fruit including bananas, dates, plums and watermelon; grains including wheat, rye and barley; pistachios and cashews; legumes including soybeans, black beans, baked beans and kidney beans; and chamomile tea, carob, chicory root and inulin (often used to improve the taste and texture in foods such as yogurt and energy bars).
• Foods high in polyols: vegetables including cauliflower, mushrooms and snow peas; fruit including apricots, blackberries, cherries and watermelon; sweeteners including sorbitol, mannitol, xylitol and isomalt
How does a low-FODMAP diet help people with IBS?
The FODMAP sources of carbohydrate aren’t completely absorbed in people with IBS, leading to the production of gas and changing the motility and function of the intestinal tract. This in turn leads to symptoms of gas, bloating, diarrhea, or constipation and pain. Even though digestive symptoms can be debilitating, they will not cause long-term damage to your body.
Over 12 years of research shows that strictly following a
low-FODMAP diet for 2-6 weeks and then gradually reintroducing specific foods based on individual tolerance, helps approximately 70% of people with IBS reduce or completely eliminate these symptoms. A low-FODMAP diet should not be followed longer than the initial 2-6 weeks because it could reduce the amount of beneficial bacteria in the digestive tract. These bacteria are important for both digestion and overall health.
Opiate addicts have been found to suffer calcium and magnesium deficits related to poor diet and addicts generally eat less than the recommended servings of fruits, vegetables, and grains. During heroin withdrawal, weight gain can occur due to higher intake of sweets and other “comfort foods,” which may provide similar dopamine responses in the brain. High-sugar foods should be limited as high sugar intake may lead to relapse. Carbohydrate metabolism may be altered during opiate withdrawal as well, and therefore higher protein intake is advised (3).
Opioids depress the central nervous system which slows down the all of the body’s systems, including digestion. Opioids can impact the gastrointestinal tract by causing chronic constipation, appetite loss, and malabsorption of nutrients. While undergoing detox, the patient may experience nausea, vomiting, diarrhea and anorexia, or a lack of desire to eat. Diarrhea and vomiting can lead to a low level of potassium which can cause potentially dangerous fluid and electrolyte imbalances.
Three Stages of the Diet
Always check with your doctor, because if you’ve not been diagnosed with IBS, it’s possible this diet could do more harm than good. Most of the foods on the FODMAPs are prebiotics, and support the growth of good gut bacteria.
The first stage is about avoiding all high-FODMAP foods. This stage should only last about 3–8 weeks because it's important to include some of the foods in the FODMAPs list.
Some people notice an improvement in symptoms in the first week, while others take the full eight weeks. When your symptoms have improved, you can go on to the second stage. If you are at eight weeks and your digestive symptoms have not improved, check with your doctor for other therapies that may work.
is the reintroduction of high-FODMAP foods. You will start testing specific foods one by one for three days each. You’ll find out which types of FODMAPs and amounts that you can tolerate. Many people are not sensitive to all of them. Meet with a trained dietitian who can guide you through this stage. Continue a low-FODMAP diet throughout this stage. Even if you can tolerate a certain high-FODMAP food, you must continue to restrict it until the next stage.
is where you develop your own modified low-FODMAP diet. You will still restrict some FODMAPs, but the amount and type are fine-tuned to your tolerance level. You will learn to increase the variety in your diet which will help ensure that you stick to your plan long-term, resulting in a good quality of life and a healthy digestive system.
Work With a Registered Dietician
It’s vital to work with a registered dietitian/nutritionist who has specialized training in the low-FODMAP diet to correctly identify the foods that you don’t tolerate, and to make sure that you consume an overall healthful, balanced diet while restricting only the FODMAPs that affect you personally.
The Monash University Low-FODMAP Diet smartphone application provides easy access to up-to-date FODMAP composition of foods. It features detailed and ongoing food analysis for a wide variety of food products. The app is available for iPhone, iPad, and Android systems.
*These statements have not been evaluated by the Food and Drug Administration.
This information is for educational purposes only. The statements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. Consult your physician if you have any question regarding a medical condition
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1. PubMed Health Glossary. Irritable Bowel Syndrome. Accessed 1-8-18
Gibson, P. R. (2017) History of the low FODMAP diet. Journal of Gastroenterology and Hepatology, 32: 5–7.
2. Gibson, P. R. (2017) The evidence base for efficacy of the low FODMAP diet in irritable bowel syndrome: is it ready for prime time as a first-line therapy? Journal of Gastroenterology and Hepatology, 32: 32–35.
3. Hill P, Muir JG, Gibson PR. Controversies and Recent Developments of the Low-FODMAP Diet. Gastroenterology & Hepatology. 2017;13(1):36-45.
4. Monash University. Low FODMAP Diet. Accessed 1-9-18