What is inulin?

Inulin is a type of fructan (a collective name for a chain of the sugar, fructose). Really long chains of fructose (more than 10 fructose molecules) are known as inulin. Shorter chained fructans (2-9 fructose molecules) are known as fructo-oligosaccharides (FOS). They are found in a variety of natural foods, like fruits, vegetables and cereal based products and also as additives in some processed foods.

What is a fructans intolerance or sensitivity?

We all lack the necessary enzymes to break down these long chains of fructose molecules. Our bodies are unable to digest inulin in the small intestine. This means it will always travel along to the large intestine, where some level of fermentation will occur. Thankfully, the bacteria in our gut have the necessary enzymes to break down these undigested sugars. However for some of us (depending on our mix of gut microbes), even the smallest amount of gas produced can result in very uncomfortable digestive symptoms.

Many people unnecessarily avoid gluten (a protein found in wheat products), because they experience digestive symptoms after eating wheat based products. Maintaining a gluten free diet is only required if you have been diagnosed with coeliac disease. Potentially, the source of your digestive issues is the presence of fructans in foods, rather than gluten. Continue reading to find out how you can test this.

What can doing an Inulin Challenge with my FoodMarble AIRE tell me?

By performing an Inulin Challenge, you will be able to get an understanding of how well your body can tolerate and digest inulin. It is important to assess your level of symptoms during and after the testing period. Since inulin is such a long chained sugar molecule, it travels quite slowly through the digestive system. The time that this can take varies a lot from person to person.

We have taken a selection of results from our users who have already performed an Inulin Challenge. We selected three different results for interpretation. Each user consumed 10g of inulin. This is approximately equal to the level of inulin present in 1.5 Jerusalem artichokes.

Finding the foods that are absorbed well and don’t cause symptoms for you is important, so that you can avoid the unnecessary elimination of foods.

PLEASE NOTE: FODMAP Challenges are tested in a fasting state, which reduces the chance of experiencing uncomfortable symptoms. However, if you were to eat or drink something containing inulin after a meal containing a large amount of fermentable foods, that could result in symptoms, as the combination could result in an excessive amount of gas production. Since the effect of what you eat and drink is cumulative, it’s important to log your meals on the app and take multiple breath readings over the day to see the combined effect of your meals.

Inulin Challenge Result: Low Fermentation Score

screenshot of FoodMarble AIRE app showing low score for inulin challenge

The final result for this user was 1.9/10. They didn’t experience any uncomfortable symptoms during the challenge. However, they did notice that the level of hydrogen on their breath had started to increase towards the end of the three hours. They decided to take a few more breath tests over the next two hours.

At this point they became very bloated. Their level of breath hydrogen had reached a fermentation score of 6/10 at this point. This would be considered a medium level of fermentation. They had eaten a meal after the test, containing more fructans and some lactose, which likely resulted in a rapid build-up of gas, and accelerating the transit of the inulin. Our recommendation to this user would be to be careful when meal planning and not to include too many other FODMAPs in a meal already containing inulin. A good option would be to select food alternatives which are low in FODMAPs. You can use our food database on the FoodMarble app to help you select your ingredients.

Inulin Challenge Result: Medium Fermentation Score 

screenshot of FoodMarble AIRE app showing medium result for inulin challenge

The final result for this test was 3.5/10. You can see from the graph that there was an increase in hydrogen production starting at 75 minutes. It remained at a similar level until the end of the testing period.

This particular user has IBS and found that they became bloated towards the end of the test. This developed into abdominal pain later that day. For some people, certain symptoms appear after the peak in breath hydrogen. For others, they might occur later on in the day.

This is why we ask users to always track their symptoms, as their response will be different to others. The level of hydrogen produced was at a medium level, resulting in some uncomfortable digestive symptoms. We would recommend them to reduce their inulin intake. Since gases can build up over the day, an option would be to eat a smaller amount of inulin earlier in the day, so they can still feed their gut bacteria and get all of the beneficial effects with a tolerable level of fermentation.

 Inulin Challenge Result: High Fermentation Score

screenshot of FoodMarble AIRE app showing high score for inulin challenge

The final result for this challenge was 9.7/10. This user experienced quite a significant and rapid rise in breath hydrogen during the testing period. The rate at which inulin was fermented would strongly suggest that they have a fast gut transit time (movement of food through the digestive tract).

This user initially felt quite bloated with some minor flatulence. They felt an urge to pass gas but were unable, suggesting a build-up of gases. Towards the end of the challenge, they compared their level of bloating to an inflated balloon. This was closely followed by abdominal pain.

They measured their breath hydrogen one and two hours after the testing period ended, and their fermentation levels had nearly returned to baseline. This would suggest that were able to effectively clear the gas build up.

From looking the breath test results and the symptoms that occurred, we can see that this user has a low tolerance to 10g of inulin. We would recommend keeping the level of inulin in their daily diet at a more tolerable level. For example, an option would be to choose sourdough bread instead of one higher in FODMAPs (e.g. wholemeal bread). There are lots of good alternatives available.

This Challenge was done in a fasted state, which reduces the likelihood and severity of symptoms during the testing period. Considering they experienced many uncomfortable symptoms during this test, they should be extra vigilant when consuming inulin containing foods, especially alongside other foods containing FODMAPs.

Before you go…

Check out my previous blogs on the Lactose, Fructose and Sorbitol Challenges. If you’re interested in testing a custom food (like sourdough bread), check out my blog on Custom Challenges with your FoodMarble AIRE. If you complete a challenge and would like to discuss your result, please feel free to contact us! You can email hello@foodmarble.com or contact us on any of our social media channels!

FoodMarble AIRE is the world’s first personal hydrogen breath tester. It is a pocket-sized breath analysis device. It helps people with chronic digestive issues determine the foods that work best with their digestive system. To learn more about FoodMarble, visit foodmarble.com or follow us on