Ask the Nutritionist: Low FODMAP

Dear nutritionist: I have been diagnosed with IBS and struggle with severe GI symptoms after almost anything I eat. It greatly impacts my quality of life and my relationship with food. Is there a diet you would recommend I try to help alleviate some of the distressful symptoms I am experiencing?

Dear Member: Digestive distress (including gas, bloating, constipation, frequent stools, etc.) is a common struggle for many individuals. IBS (Irritable Bowel Syndrome) in particular is the most common gastrointestinal condition seen by general practitioners. Typical suggestions for bowel regularity include: eat plenty of fiber-rich foods, drink adequate water, take a probiotic, and exercise daily. While on the other hand recommendations to reduce frequency include limiting caffeine, high fat foods, and insoluble fiber. Although these are great recommendations for the public, individuals with IBS may not find any relief, and may even experience further exacerbation of symptoms from some of the above suggestions.

Welcome, the Low FODMAP diet! The Low FODMAP is a clinically studied diet, originally developed by a team of researchers and doctors at Monash University in Australia. It was designed to help manage GI symptoms in functional gut disorders like IBS by limiting specific short-chain carbohydrates called FODMAPs. The FODMAP acronym stands for the following:

F—Fermentable

O—Oligosaccharides (prebiotics such as beans/legumes, garlic, onions, leeks, asparagus, inulin, wheat, barley, rye, etc.)

D—Disaccharides (lactose and therefore dairy products rich in lactose such as milk and yogurt)

M—Monosaccharides (fructose found in apples, pears, watermelon, cherries, high fructose corn syrup, honey, etc.)

And

P—Polyols (sugar alcohols such as sorbitol, mannitol, and xylitol as well as avocados, nectarines, peaches, plums, prunes, etc.)

Note: Check out the Monash University website for a comprehensive list of high FODMAP foods.

Why does this diet work?

FODMAPs are poorly absorbed in the small intestine and rapidly fermented by gut bacteria in the colon as fuel, leading to natural gas production. This is a normal process that even provides us with health benefits. However, if too many FODMAPs are not absorbed, gas production increases to a much greater extent in the colon causing severe distention, pain, and discomfort. Furthermore, if the bacteria have migrated up to the small intestine, this fermentation process can lead to even more uncomfortable and painful bloating because the small intestine is not designed to stretch like the colon. Finally, these malabsorbed carbohydrates can also draw water into the small intestine via osmosis causing urgent loose stools.

How do you know if the Low FODMAP diet is for you?

Try it out! Up to 86 percent of individuals with IBS find improvement in their gastrointestinal symptoms. Most will notice positive results within 3 to 7 days on a strict low FODMAP diet. However, this diet is not one for the long term as it can decrease bacterial diversity and be quite restrictive leading to possible nutrient deficiencies. Rather it should be seen as an elimination trial followed strictly for 4 to 6 weeks with an additional 3 to 4 week food challenge. Each individual has a unique FODMAP tolerance and unique total FODMAP load tolerance (the total amount consumed per day before symptoms arise). Therefore, it is recommended to work with a nutritionist or dietitian that specializes in the Low FODMAP diet to help you find your unique modified FODMAP diet. The end goal is to liberalize the diet as much as possible without an increase in symptoms.

Learn more about the efficacy of the Low FODMAP diet.