Fructooligosaccharide

Structural formula of a fructooligosaccharide

Fructooligosaccharides (FOS) are a type of oligosaccharide, which are carbohydrates composed of short chains of fructose molecules. These compounds are found naturally in many plants, including onions, garlic, bananas, wheat, and asparagus. FOS are used as an alternative sweetener and are known for their prebiotic effects, promoting the growth of beneficial gut microbiota.

Structure and Composition

FOS consist of linear chains of fructose units, typically ranging from 2 to 10 fructose molecules, which are linked by β(2→1) glycosidic bonds. The chain may terminate with a glucose unit, forming a kestose structure. The general formula for FOS is GFn, where G is a glucose unit and Fn represents the number of fructose units.

Sources

FOS are naturally present in a variety of plants. Some of the richest sources include:

• Onions
• Garlic
• Leeks
• Asparagus
• Bananas
• Chicory root
• Jerusalem artichoke

Health Benefits

FOS are considered prebiotics, which means they stimulate the growth and activity of beneficial bacteria in the colon. These bacteria, such as Bifidobacteria and Lactobacilli, play a crucial role in maintaining gut health and enhancing the immune system. The consumption of FOS has been associated with several health benefits, including:

• Improved digestive health
• Enhanced mineral absorption, particularly calcium and magnesium
• Reduced levels of blood cholesterol
• Potential reduction in the risk of colon cancer

Uses

FOS are used in the food industry as a low-calorie sweetener and as a functional ingredient to improve the texture and taste of food products. They are commonly added to:

• Yogurt
• Baked goods
• Cereals
• Dietary supplements

Mechanism of Action

Once ingested, FOS pass through the upper gastrointestinal tract undigested and reach the colon, where they are fermented by the gut microbiota. This fermentation process produces short-chain fatty acids, such as butyrate, propionate, and acetate, which provide energy to colonocytes and have various health-promoting effects.

Potential Side Effects

While FOS are generally considered safe, excessive consumption can lead to gastrointestinal discomfort, including bloating, gas, and diarrhea. It is recommended to gradually increase the intake of FOS to allow the gut microbiota to adapt.

Related Pages

• Prebiotic (nutrition)
• Probiotic
• Dietary fiber
• Inulin