Fermentable Fiber
| Fermentable Fibres | Food Source |
|---|---|
| β-glucans | Oats; barley |
| Guar gum | Supplement; thickening agent/stabiliser |
| Resistant starch (specifically RS2) | Green bananas; legumes; raw potato; supplement |
| Pectin | Fruits (particularly citrus); root vegetables; jams; nuts; legumes |
| Xanthan gum | Supplement; thickening agent/stabiliser (often used in gluten free baking) |
Fermentable fiber, also called prebiotic fiber, is fiber that can be digested and used as fuel by the friendly bacteria in the gut. There are actually trillions of bacteria in our gastrointestinal tracts. Some of these are harmful while others help to keep our digestive system healthy by limiting the numbers of bad ones that make us sick. Â
Just as we need to eat to get energy and raw materials to do all the things associated with being alive bacteria also need an energy source. Fermentable fiber is the food source for good (beneficial) bacteria. Some fermentable fibers are soluble, while others are insoluble.
Some benefits of fermentable fiber include:
- Reducing the chances of developing diarrhea by feeding the competing bacteria.
- Inulin, a type of prebiotic fiber, helps to prevent constipation and also with the absorption of the calcium needed to maintain strong bones. Inulin is found in foods such as onions, garlic, and asparagus.
Beta-Glucans have a specific molecular structure that makes them highly viscous in the gut.  Beta-glucans can improve insulin sensitivity and lower blood sugar levels.
They can also significantly reduce cholesterol levels and increase feelings of fullness.
The main food sources of beta-glucans are oats and barley.
A fructan is the term used to describe a small chain of fructose molecules. Oligofructose and inulin are the two main fructan varieties in the diet. They feed the friendly bacteria in the gut, and also help treat certain types of diarrhea.
Fructans are also classified as FODMAPs, types of carbohydrates known to cause digestive issues in many people. Fructans and other FODMAPs trigger adverse symptoms in 3 out of 4 people with irritable bowel syndrome. The biggest source of fructans in the modern diet is wheat.
