An Oligosaccharide is a saccharide polymer containing a small number (typically two to ten) of simple sugars (monosaccharides). Oligosaccharides, except maltotriose, are indigestible, which means humans lack enzymes to break them down in the small intestine, so they reach the large intestine, where beneficial colonic bacteria break them down (ferment) to absorbable nutrients, which provide some energy–about 2 Calories (kilocalories) per gram in average. Certain breakdown products of oligosaccharides–namely short-chain fatty acids (SCFAs)–may have beneficial effect on large intestinal lining. Others can have functions including cell recognition and cell binding. For example, glycolipids have an important role in immune response.
Fructo-oligosaccharides (FOS), which are found in many vegetables, consist of short chains of fructose molecules. (Inulin has a much higher degree of polymerization than FOS and is a polysaccharide.)
Galactooligosaccharides (GOS), which also occur naturally, consist of short chains of galactose molecules. These compounds can be only partially digested by humans.
Mannan oligosaccharides (MOS) are widely used in animal feed to improve gastrointestinal health, energy levels and performance. They are normally obtained from the yeast cell walls of Saccharomyces cerevisiae. Research at the University of Illinois has demonstrated that mannan oligosaccharides differ from other oligosaccharides in that they are not fermentable and their primary mode of actions include agglutination of type-1 fimbrae pathogens and immunomodulation.
Cell recognition and adhension.
Most oligosaccharides act as a soluble fiber, which may help prevent constipation. Ingestion of large amount of oligosaccharides can result in abdominal bloating and excessive gas (flatulence).
All cells are coated in either glycoproteins or glycolipids, both of which help determine cell types. Lectins, or proteins that bind carbohydrates, which can recognize very specific oligosaccharides and provide useful information for cell recognition due to oligosaccharide binding.
An important example of oligosaccharide cell recognition is the role of glycolipids in determining blood types. The various blood types are distinguished by the glycan modification present on the surface of blood cells. These can be visualized using mass spectrometry. The oligosaccharides found on the A, B, and H antigen occur on the non-reducing ends of the oligosaccharide. The H antigen (which indicates an O blood type) serves as a precursor for the A and B antigen. Therefore, a person with A blood type will have the A antigen and H antigen present on the glycolipids of the red blood cell plasma membrane. A person with B blood type will have the B and H antigen present. A person with AB blood type will have A, B, and H antigens present. And finally, a person with O blood type will only have the H antigen present. This means all blood types have the H antigen, which explains why the O blood type is known as the "universal donor".
Many cells produce specific carbohydrate-binding ligands, known as lectins, which mediate cell-adhesion with oligosaccharides. Selectins - a family of lectins - mediate certain cell-cell adhesion processes, including those of leukocytes to endothelial cells. In an immune response, endothelial cells can express certain selectins transiently in response to damage or injury to the cells. In response, a reciprocal selectin-oligosaccharide interaction will occur between the two molecules which allows the white blood cell to help eliminate the infection or damage. Protein-Carbohydrate bonding is often mediated by hydrogen bonding and van der Waals forces.
Oligosaccharides are one of the components of fiber, found in plants. FOS and inulin are found naturally in Jerusalem artichoke, burdock, chicory, leeks, onions, and asparagus. FOS products derived from chicory root contain significant quantities of inulin, a fiber widely distributed in fruits, vegetables and plants. Inulin is a significant part of the daily diet of most of the world’s population. FOS can also be synthesized by enzymes of the fungus Aspergillus Niger acting on sucrose. GOS is naturally found in soybeans and can be synthesized from lactose (milk sugar). FOS, GOS, and inulin are available as nutritional supplements in capsules, tablets, and as a powder.
Not all natural oligosaccharides occur as components of glycoproteins or glycolipids. Some, such as the raffinose series, occur as storage or transport carbohydrates in plants. Others, such as maltodextrins or cellodextrins, result from the microbial breakdown of larger polysaccharides such as starch or cellulose.
Deficiency can cause gastrointestinal upset.
You can’t really have a fiber deficiency, per se, since your body doesn’t absorb it and there isn’t a way to measure how much you have in your body. But it is possible to have too little fiber in your diet. When your fiber intake is lacking, you’ll probably notice some gastrointestinal upset, and signs of a low-fiber diet may eventually show up during physical exams.
Soluble fiber ferments slightly in your gut. As it passes, the sludge that forms slows digestion and allows nutrients to fully absorb. So when fiber is lacking in your body, digestive processes suffer. You could have gas and bloating, as your system struggles to push out waste.
Amounts exceeding 20 g/day by healthy people, may cause abdominal bloating, pain or cramps, excessive gas (flatulence), loose stools or diarrhea.
Oligosaccharides like Fructo-oligosaccharides (FOS), when consumed in amounts exceeding 20 g/day by healthy people, may cause abdominal bloating, pain or cramps, excessive gas (flatulence), loose stools or diarrhea.
The bacterial fermentation of undigested carbohydrates increases the production of gases in the colon and may cause adverse gastrointestinal symptoms such as flatulence, which are common side-effects of increasing fiber intake. Because Galacto-oligosaccharides (GOS) are fermented in the colon, gastrointestinal symptoms may occur after their ingestion. Usually, tolerance to fiber depends on the amount of the product eaten. Similarly, the frequency of gastrointestinal symptoms increases when the dose of GOS increases. In most of the studies, amounts of 12 g of GOS or less daily were well tolerated, but 15 g of GOS per day increased flatulence. However, individuals vary considerably in their response to GOS 15, as with their response to any other easily fermented fiber.
The appropriate dose of oligosaccharides depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for oligosaccharides. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.