Overview
About Fructans
Fructans are a FODMAP subgroup found in wheat, onion, garlic, leeks, and other inulin-rich foods, and are a common trigger for gas and bloating in sensitive guts.
Fructans are chains of fructose molecules found in wheat, onions, garlic, and many other foods. They're a type of FODMAP that can cause digestive symptoms in sensitive individuals because they're not well absorbed in the small intestine.
In the data
Where you will find fructans
- Rated high in fructans, the FODMAP behind the classic post-pasta bloat and gas
- Eaten in big portions, which multiplies the fructan and gluten load compared with a small side of wheat
- Rated high in fructans and FODMAPs, which is why floury sauces, roux and breaded foods can bloat sensitive guts
- Extremely high in fructans (grade E), the FODMAP behind gas, bloating and cramping in sensitive guts
- Concentrated: dehydrating garlic packs far more fructan per teaspoon than the same weight of fresh clove
- Fructans graded E, and there is no low FODMAP serving of fresh garlic: a single clove is already over the line during an elimination phase
- Garlic powder is not a lighter option. It is garlic with the water removed, so the fructans are concentrated by weight, and we grade it E for FODMAPs and E for SIBO against garlic at D and A
Examples
A few ingredients either way
Rated high
Grading
How we grade fructans
Every ingredient in the database carries one grade for fructans, and this page, the checker and the app all read that same grade. It describes the ingredient as it is usually eaten. Portion size and preparation move it.
Practical
Working with fructans
- Test wheat-based foods separately from onion and garlic.
- Try garlic-infused oil instead of raw garlic for flavor.
- Garlic-infused oil is low-FODMAP since fructans don't dissolve in oil
- Green parts of leeks and scallions are lower in fructans
- Sourdough bread may be better tolerated than regular wheat bread
- Spelt and ancient grains still contain fructans despite marketing claims
- Portion size matters - small amounts may be tolerable
Method
Test it with a diary
Most people find their own triggers by logging meals and symptoms for a few weeks and reading the result back. Three steps.
- 1Log every meal for a few weeks. Type it, say it out loud, or scan a barcode, and it lands as a list of ingredients.
- 2Rate how you feel through the day on whatever you are tracking, whether that is bloating, headaches, skin or sleep.
- 3Read the pattern back. Every ingredient you logged is scored against the days you felt worse, and the result ranks fructans against everything else you eat.
Questions
Questions people ask
Is my problem wheat gluten or wheat fructans?
Wheat contains both. If you have celiac disease or a wheat allergy, gluten and wheat protein are the issue and wheat has to go entirely. But many people who label themselves gluten sensitive actually react to fructans, the FODMAP that wheat is rated highest in. A low-FODMAP trial can help tell them apart.
More about wheat
Read next
Where to go next
Get started
Tracking fructans?
Log what you eat and how you feel, and the app finds the pattern for you. Or look an ingredient up here first.
Get the app
Browse ingredients