Oligosaccharides
Oligosaccharides are carbohydrates that are composed of several monosaccharide residues joined through glycosidic linkage, which can be hydrolyzed by acid to give the constituent monosaccharide units. While a strict definition of an oligosaccharide is not established, it is generally agreed that a carbohydrate consisting of two to ten monosaccharide residues with a defined structure is an oligosaccharide.
Some oligosaccharides, for example maltose, sucrose, and lactose, were trivially named before their chemical constitution was determined, and these names are still used today.
Understanding Oligosaccharides
Oligosaccharides are a type of carbohydrate that play a crucial role in various biological processes. They are composed of a small number of monosaccharide units, typically ranging from three to ten. These carbohydrates are less complex than polysaccharides but more complex than simple sugars like monosaccharides and disaccharides. Oligosaccharides are found naturally in many plants and are also present in human milk, where they serve important functions.
Structure and Types
Oligosaccharides are formed when monosaccharides are linked together by glycosidic bonds. The structure of these carbohydrates can vary significantly, depending on the types of monosaccharides involved and the nature of the glycosidic linkages. This structural diversity allows oligosaccharides to perform a wide range of functions in biological systems.
There are several types of oligosaccharides, including:
- Fructo-oligosaccharides (FOS): Composed of short chains of fructose molecules, FOS are commonly found in plants like onions, garlic, and asparagus. They are known for their prebiotic properties, promoting the growth of beneficial gut bacteria.
- Galacto-oligosaccharides (GOS): These are made up of galactose units and are often added to infant formulas to mimic the beneficial effects of human milk oligosaccharides.
- Mannan-oligosaccharides (MOS): Derived from the cell walls of yeast, MOS are used in animal feed to improve gut health and boost the immune system.
- Human Milk Oligosaccharides (HMOs): These are a complex mixture of oligosaccharides found in human breast milk. They play a vital role in infant nutrition and immune system development.
Biological Functions
Oligosaccharides serve several important functions in biological systems:
- Prebiotic Effects: Many oligosaccharides, such as FOS and GOS, act as prebiotics. They are not digested in the upper gastrointestinal tract and reach the colon, where they stimulate the growth of beneficial bacteria like Bifidobacteria and Lactobacilli. This can lead to improved gut health and enhanced immune function.
- Immune System Modulation: Oligosaccharides can influence the immune system by acting as signaling molecules. They can modulate immune responses and help in the development of the immune system, particularly in infants.
- Cell Recognition and Communication: Oligosaccharides are often found on the surfaces of cells, where they play a role in cell-cell recognition and communication. They are involved in processes such as cell adhesion, signaling, and the immune response.
- Protection Against Pathogens: Some oligosaccharides can prevent the adhesion of pathogens to the gut lining, thereby reducing the risk of infections. This is particularly important in infants, where HMOs help protect against gastrointestinal infections.
Dietary Sources
Oligosaccharides are naturally present in a variety of foods. Some common dietary sources include:
- Vegetables: Onions, garlic, leeks, asparagus, and artichokes are rich in oligosaccharides, particularly FOS.
- Legumes: Beans, lentils, and chickpeas contain significant amounts of oligosaccharides, which can contribute to their prebiotic effects.
- Whole Grains: Wheat, barley, and rye are good sources of oligosaccharides.
- Dairy Products: Some dairy products, especially those with added GOS, can provide oligosaccharides.
Health Benefits
The consumption of oligosaccharides is associated with several health benefits:
- Improved Digestive Health: By promoting the growth of beneficial gut bacteria, oligosaccharides can enhance digestive health and reduce symptoms of constipation and irritable bowel syndrome (IBS).
- Enhanced Immune Function: The immune-modulating effects of oligosaccharides can lead to a stronger immune system and reduced risk of infections.
- Reduced Risk of Chronic Diseases: Some studies suggest that oligosaccharides may help lower the risk of chronic diseases such as obesity, type 2 diabetes, and cardiovascular disease by improving gut health and metabolic function.
ARTICLES/STUDIES
Why you should add oligosaccharides to your diet
Recent research and application prospect of functional oligosaccharides on intestinal disease treatment. Functional oligosaccharides are carbohydrates with a low degree of polymerization and exhibit beneficial effects on human intestinal health. Laboratory experiments and clinical studies indicate that functional oligosaccharides repair the damaged intestinal tract and maintain intestinal homeostasis by regulating intestinal barrier function, immune response, and intestinal microbial composition. Functional oligosaccharides treat intestinal disease such as inflammatory bowel disease (IBD) and colorectal cancer (CRC) and have excellent prospects for therapeutic application.
Health Benefits of Non-Digestible Oligosaccharides
Impacts of functional oligosaccharide on intestinal immune modulation in immunosuppressive mice
Direct action of non-digestible oligosaccharides against a leaky gut.
Dietary polyunsaturated fatty acids and non-digestible oligosaccharides reduce dermatitis in mice.
Unsaturated alginate oligosaccharides attenuated obesity.
Oligosaccharides modulate rotavirus-associated dysbiosis and TLR gene expression.
Non-digestible oligosaccharides are complex carbohydrates of the non-a-glucan type which, because of the configuration of their osidic bonds, resist hydrolysis by salivary and intestinal digestive enzymes. In the colon they are fermented by anaerobic bacteria. Among the non-digestible oligosaccharides, the chicory fructooligosaccharides occupy a key position and, in most european countries, they are recognised as natural food ingredients. The other major products are the short chain fructooligosaccharides and galactooligosaccharides obtained by enzymatic synthesis using sucrose and lactose as substrates respectively, the soybean oligosaccharides, the xylooligosaccharides produced by partial hydrolysis of xylans and polydextrose or pyrodextrins prepared by a chemical treament of carbohydrates. The most well known effect of most non-digestible oligosaccharides, and in particular of the fructooligosaccharides, is the selective stimulation of the growth of Bifidobacteria thus modifying significantly the composition of the colonic microbiota. Such a modification, which has clearly been demonstrated in human volunteers, is meant to be benificial in part because it is accompanied by a significant reduction in the number of bacteria reported to have pathogenic potential. Within the framework of research and development of “functional foods”, such an effect justifies a “functional claim” for fructooligosaccharides namely “bifidogenesis”. They are also typical “prebiotics”. Besides their bifidogenic effect, the chicory fructooligosaccharides have additional nutritional properties on digestive physiological parameters like colonic pH and stool bulking which justify their classification as dietary fibers. Moreover, in experimental models, it has also been reported that they improve the bioavailability of essential minerals and that they reduce serum triglyceridemia by lowering hepatic lipogenesis. Such effects demonstrate interactions between the chicory fructooligosaccharides and key functions in the body but their significance for humans still need to be proven before being used to justify additional claims. (source)
Oligosaccharides exert a beneficial effect on the antioxidant protection of the diabetic rats.