Fructans are the single biggest FODMAP trigger for many people, concentrated in wheat, garlic and onion.
What is Fructans?
Fructans is a FODMAP (oligosaccharide) that plays a critical role in storing energy as chains of fructose in plants. While many general diets overlook it, maintaining optimal levels of Fructans is frequently tracked by people working to optimize their IBS symptom severity.
Top Foods High in Fructans
A data-driven breakdown of the foods with the highest concentration of Fructans per 100 g.
| Food | Fructans |
|---|---|
| Garlic | 17 g |
| Whole Wheat Bread | 2.5 g |
| Banana | 0.7 g |
| Chickpeas | 0.5 g |
| Pomegranate | 0.4 g |
How Fructans Impacts IBS symptom severity
Research links diets rich in Fructans to changes in IBS symptom severity. Optimizing intake of these foods can support healthy IBS symptom severity levels via fermenting rapidly in the colon because humans lack the enzyme to split fructose-fructose bonds.
How to Reduce Fructans
Fructans are water-soluble but not oil-soluble, so the trick is extraction and portion size rather than cooking.
| Method | Typical reduction | How it works |
|---|---|---|
| Garlic/onion-infused oil | avoids the trigger | Fructans do not dissolve into oil — keep the flavour, drop the FODMAP. |
| Smaller portions | dose-dependent | Tolerance is threshold-based; modest amounts may be fine. |
| Long sourdough ferment | partial | Extended fermentation degrades some wheat fructans. |
Scientific references & clinical evidence
This guide is built on peer-reviewed research — verify the primary sources below.
Written by the Nutrition Encyclopedia team · medically reviewed by Dr. Sunaina Tariq, MBBS
Last updated 21 June 2026
How we source & verify data · Medical disclaimer
Nutrition values are approximations compiled from public food-composition databases (USDA FoodData Central) and are provided for educational purposes only — not medical advice.