What are FODMAPs?

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols, or FODMAPs, are specific carbohydrate chains found in various foods. These short carbohydrates can cause irritable bowel syndrome symptoms including bloating, abdominal pain and flatulence. The reason for these symptoms is that FODMAPs are poorly absorbed by the gut and instead are rapidly fermented by bacteria in the large intestine. FODMAPs are also osmotic, which means they draw extra water into the large intestine, leading to diarrhea.

FODMAPs can cause bloating, abdominal pain and diarrhea. 

Sources of FODMAPs

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols are found in a wide range of foods, such as:

  • Oligosaccharides - onions, leeks, spring onions, garlic, artichokes, shallots, beetroot, peas, fennel, chicory, pistachio, legumes, cashews, lentils, chickpeas, wheat, barley and rye;
  • Disaccharides - milk, yoghurt, custard and ice cream;
  • Monosaccharides - apples, mangoes, pears, cherries, asparagus, watermelon, snow peas, high-fructose corn syrup, honey, and;
  • Polyols - apples, pears, apricots, nectarines, peaches, plums, cherries, watermelon, cauliflower and artificially-sweetened chewing gum.

Alternative food sources

If you are experiencing symptoms including bloating, abdominal pain, flatulence and diarrhea caused by FODMAPs, there are alternative foods for all food groups. Some alternatives may include:

  • Fruits, including bananas, cantaloupe, grapes, lemons, limes, mandarins, oranges, passionfruit, raspberries, strawberries and blueberries;
  • Vegetables, including potatoes, carrots, parsnips, zucchini, eggplant, capsicum, olives, lettuce, green beans, ginger, chili and chives;
  • Breads and cereals, including corn, oats, polenta, quinoa, and rice;
  • Protein sources, including fresh beef, chicken, lamb, pork and veal;
  • Dairy products, including butter, lactose-free milk and yoghurt, rice milk, and;
  • Other products including golden syrup, maple syrup and sucrose.

The low FODMAPs diet

Recent research has discovered the link between avoiding foods containing high amounts of FODMAPs and a decrease in gastrointestinal symptoms. It has been shown that up to 86% of people with irritable bowel syndrome showed an improvement in their symptoms, particularly bloating, when on a low FODMAPs diet, compared to a traditional diet for irritable bowel syndrome. [1]  The low FODMAPs diet has also been shown to reduce symptoms in Crohn's disease and ulcerative colitis. The low FODMAPs diet can be done in consultation with a registered dietitian, so it is best to be referred to one by your doctor or specialist.

Staudacher H.M. Whelan K. Irving P.M. et al. (2011) Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. Journal of Human Nutrition and Dietetics: The Official Journal of the British Dietetic Association 24:487–495.

Carbohydrate absorption breath test

It is possible to test your ability to absorb certain carbohydrates using a breath test that measures the hydrogen and methane levels on your breath. This involves eating a low FODMAPs and low-fiber diet the day before, as well as fasting overnight. At the start of the test, the baseline breath sample will be taken. You will then be given a carbohydrate to consume (e.g. fructose) and regular breath samples will be taken to measure the levels of hydrogen and methane on your breath. If the levels of hydrogen and methane are high, this indicates that the carbohydrate is not being absorbed. This test can be used to check your ability to absorb the other types of carbohydrates.

Staudacher H.M. Whelan K. Irving P.M. et al. (2011) Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. Journal of Human Nutrition and Dietetics: The Official Journal of the British Dietetic Association 24:487–495.

FODMAPs reintroduction test

To reduce the symptoms caused by malabsorption of FODMAP carbohydrates, it is possible to trial a low FODMAPs diet. After a period of four weeks on a low FODMAPs diet, the different types of carbohydrates can be reintroduced one at a time to test your ability to absorb them. It is important to introduce foods that contain only one FODMAP carbohydrate, for example, milk for lactose, honey for fructose, mushrooms for mannitol and apricots for sorbitol. It is important to test the absorption of each carbohydrate to assess your tolerance. If there is no change in gastrointestinal symptoms, the carbohydrate can then be reintroduced into the diet.

Staudacher H.M. Whelan K. Irving P.M. et al. (2011) Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. Journal of Human Nutrition and Dietetics: The Official Journal of the British Dietetic Association 24:487–495.

References

  1. Staudacher H.M. Whelan K. Irving P.M. et al. (2011) Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. Journal of Human Nutrition and Dietetics: The Official Journal of the British Dietetic Association 24:487–495.
  2. 2013 Central Clinical School Public Lecture. Accessed July 31 2014. link here
  3. American Journal of Gastroenterology - Short-Chain Carbohydrates and Functional Gastrointestinal Disorders. Accessed September 10 2014. link here
  4. Barrett Jacqueline S. Extending Our Knowledge of Fermentable Short-Chain Carbohydrates for Managing Gastrointestinal Symptoms. Nutrition in Clinical Practice: Official Publication of the American Society for Parenteral and Enteral Nutrition 28 no. 3 (June 2013): 300306. doi:10.1177/0884533613485790.
  5. Frequently Asked Low FODMAP Diet Questions. Accessed July 31 2014. link here
  6. Frequently Asked Questions in the Area of Diet and IBS. Accessed July 31 2014. link here
  7. Gearry Richard B. Peter M. Irving Jacqueline S. Barrett Debbie M. Nathan Sue J. Shepherd and Peter R. Gibson. Reduction of Dietary Poorly Absorbed Short-Chain Carbohydrates (FODMAPs) Improves Abdominal Symptoms in Patients with Inflammatory Bowel Disease-a Pilot Study. Journal of Crohns & Colitis 3 no. 1 (February 2009): 814. doi:10.1016/j.crohns.2008.09.004.
  8. GESA - Gastroenterological Society of Australia. Accessed July 31 2014. link here
  9. Kings College London - FAQ. Accessed July 31 2014. link here
  10. Low FODMAP Diet | Shepherd Works. Accessed July 31 2014. link here
  11. Low FODMAP Diet for Irritable Bowel Syndrome. Accessed July 31 2014. link here
  12. Staudacher H. M. K. Whelan P. M. Irving and M. C. E. Lomer. Comparison of Symptom Response Following Advice for a Diet Low in Fermentable Carbohydrates (FODMAPs) versus Standard Dietary Advice in Patients with Irritable Bowel Syndrome. Journal of Human Nutrition and Dietetics: The Official Journal of the British Dietetic Association 24 no. 5 (October 2011): 48795. doi:10.1111/j.1365-277X.2011.01162.x.
  13. The Monash University Low FODMAP Diet. Accessed July 31 2014. link here
  14. The Monash University Low FODMAP Diet. Accessed July 31 2014. link here
  15. The Monash University Low FODMAP Diet. Accessed July 31 2014. link here
  16. The Monash University Low FODMAP Diet. Accessed July 31 2014. link here

FAQ Frequently asked questions