Chicory Root is a Common Example of Fructooligosaccharides

November 15, 2025 •

3 min read

According to the Global Prebiotic Association, fructooligosaccharides (FOS) are recognized as the first prebiotic approved for food use. Chicory root is a common example of fructooligosaccharides, containing a high concentration of this valuable prebiotic fiber that supports digestive health.

Quick Summary

Chicory root is a primary and concentrated natural source of fructooligosaccharides (FOS), a prebiotic dietary fiber. FOS selectively nourishes beneficial gut bacteria, contributing to digestive health and overall wellness by fermenting in the large intestine. Many common foods like onions, garlic, and bananas also contain FOS, though typically in lower concentrations.

Key Points

Top Example: Chicory root is a highly concentrated and common example of fructooligosaccharides (FOS), a prebiotic fiber.
Prebiotic Function: FOS selectively feeds beneficial bacteria in the large intestine, such as Bifidobacterium, supporting a healthy gut microbiome.
Beyond Chicory: Everyday foods like onions, garlic, asparagus, and unripe bananas are also good sources of FOS.
Health Benefits: Regular FOS intake is linked to improved digestive function, enhanced mineral absorption, better blood sugar control, and potential weight management.
Forms of FOS: Commercial FOS is often derived from chicory and used as a low-calorie sweetener or fiber additive in processed foods.
Prebiotic vs. Probiotic: It's crucial to distinguish between prebiotics (fiber that feeds bacteria) and probiotics (the live bacteria themselves).

Chicory Root: The Top Natural Source of FOS

While fructooligosaccharides (FOS) are found in many fruits and vegetables, chicory root stands out as one of the most concentrated and widely recognized natural sources. The chicory plant (Cichorium intybus) has been cultivated for centuries, not just as a coffee substitute but specifically for the industrial extraction of its beneficial fructans, which include both inulin and oligofructose (a form of FOS).

Unlike most carbohydrates that are digested in the small intestine, the indigestible FOS from chicory root passes through to the large intestine. Here, it is fermented by anaerobic bacteria, stimulating the growth of beneficial microbes like Bifidobacterium and Lactobacillus. This process is what earns FOS its prebiotic status.

The Role of Chicory Root Inulin and FOS

Chicory root fiber contains a mix of both longer-chain inulin and shorter-chain fructooligosaccharides. The degree of polymerization (DP), or the number of fructose units, determines how these fibers are processed and their functional properties. Longer-chain inulin is less soluble and used in food manufacturing as a fat or sugar replacer, while shorter-chain FOS is more soluble and provides mild sweetness.

Other Common Food Examples of Fructooligosaccharides

While chicory root is a superstar, many other everyday foods provide a moderate amount of FOS, contributing to a healthy diet. Incorporating a variety of these foods can help diversify the prebiotic intake.

Garlic and Onions: These alliums contain FOS, contributing to their flavor.
Bananas: Bananas, especially less ripe ones, are a source of FOS, with content varying by type and ripeness.
Asparagus: This spring vegetable is another source of fructans.
Jerusalem Artichoke (Sunchoke): Similar to chicory, this tuber has a high concentration of fructans.

Natural vs. Commercial FOS: A Comparison

To understand the availability and uses of fructooligosaccharides, it's helpful to compare naturally occurring FOS with its commercially produced counterpart.


Feature	Naturally Occurring FOS	Commercial FOS
Source	Found in plants like onions, garlic, and bananas; more concentrated in chicory root and agave.	Extracted from natural sources like chicory or agave, or made from sucrose.
Concentration	Varies based on the plant, type, ripeness, and preparation.	High and standardized, allowing for precise addition to foods or supplements.
Degree of Polymerization (DP)	Ranges from low DP oligofructans to longer inulin polymers.	Can be standardized to specific DP ranges.
Uses	Consumed as part of whole foods for general digestive support.	Used as a food ingredient for prebiotic, low-calorie sweetener, and fiber properties.
Manufacturing	Consumed directly from food.	Involves extraction and purification; some products are chemically altered.

The Prebiotic Power and Health Benefits of FOS

Fructooligosaccharides are particularly valued for their prebiotic effects, supporting a healthy gut microbiome and overall health. FOS fermentation by colonic bacteria produces short-chain fatty acids (SCFAs), including butyrate.

List of FOS Health Benefits

Supports Digestive Health: Promotes beneficial gut bacteria, improving bowel function and potentially easing constipation.
Enhances Mineral Absorption: May improve the absorption of calcium and magnesium, supporting bone health.
Aids Blood Sugar Management: As a non-digestible carbohydrate, FOS does not cause blood sugar spikes, making it useful for glucose control.
Supports Weight Management: Some studies suggest FOS may help regulate appetite and reduce calorie intake.
Boosts Immune Function: A healthy gut microbiome, supported by FOS, is important for a strong immune system.

Conclusion: Incorporating FOS into Your Diet

Chicory root is an excellent and common source of fructooligosaccharides, providing a significant amount of prebiotic fiber to support gut health. However, many other everyday foods like onions, garlic, and bananas also contribute to FOS intake. Understanding these sources allows for a diverse approach to supporting digestive and overall health through diet.

For more scientific information on prebiotics, you can refer to the resources provided by the International Scientific Association for Probiotics and Prebiotics (ISAPP).

Frequently Asked Questions

Chicory root is a primary natural source of fructooligosaccharides (FOS) and is cultivated commercially for the industrial extraction of this prebiotic fiber.

Common vegetables containing FOS include onions, garlic, asparagus, leeks, and Jerusalem artichokes.

Yes, bananas contain fructooligosaccharides, particularly when they are less ripe. The FOS content varies depending on the cultivar and the stage of ripening.

FOS benefits gut health by acting as a prebiotic. It is not digested in the small intestine but is fermented by beneficial bacteria in the large intestine, promoting their growth and supporting a balanced gut flora.

Yes, FOS is considered a soluble dietary fiber. It is highly soluble in water and functions as a non-digestible carbohydrate that provides beneficial effects on digestion.

While FOS is a type of oligosaccharide (a short-chain carbohydrate), it is functionally categorized as a soluble dietary fiber because it is not digested by human enzymes and travels to the large intestine for fermentation.

FOS is a type of fructan with a shorter chain length (lower degree of polymerization) than inulin. Chicory root contains both longer-chain inulin and shorter-chain FOS.