Mucopolysaccharides, also called glycosaminoglycans, are long chains of building blocks called disaccharides made of two sugar molecules bonded together. These long chains are usually attached to a protein core; they are then called proteoglycans. They are found in every type of body tissue and are an important component in cartilage, synovial fluid, and the extracellular matrix. Several disorders can occur if a body is unable to break down these chains, while other health problems can be addressed by increasing the body’s ability to produce higher amounts of these important carbohydrates.
The sugar molecules that make up mucopolysaccharides are six carbon sugars, or hexoses; one of the sugars in each disaccharide building block is special because it contains a nitrogen atom. Glucosamine is an example of a sugar that contains nitrogen, or an amino sugar. These disaccharides have a large number of negatively charged molecules on their surfaces that attract a coating of positively charged molecules. Chondroitin sulfate, dermatan sulfate, keratan sulfate, heparin, heparan sulfate, and hyaluronan are a few examples.
Glycosaminoglycans increase the viscosity of bodily fluids because the coating of positively charged molecules causes them to attract water molecules to their surface, effectively making them slippery. This makes them useful in synovial fluid — the lubricant in certain joints — and in the extracellular matrix, i.e., the fluid between cells. In the gel-like environment of the extracellular matrix, they enable the movement of nutrients and electrolytes throughout the body and also through the membranes of the cells. The large number of water molecules on their surface also make mucopolysaccharides perfect components of cartilage and tendons because it gives them a resiliency, or resistance to pressure. Another function of some of these carbohydrates is helping keep blood from coagulating until it is needed for wound healing.
Medical conditions that are caused by not having an enzyme, or not having enough of the enzyme, to break down mucopolysaccharides include Hunter syndrome, Hurler syndrome, Sanfilippo syndrome, Scheie syndrome, and Morquio syndrome. They can cause symptoms like unusually shaped facial features, deformed connective tissues, and mental retardation. Joint stiffness, deafness, clouded corneas, and enlarged heads are also common among many of these disorders. Health problems that can be improved by increasing the body’s production of these carbohydrates include arthritis, atherosclerosis, and blood clotting disorders. Cosmetic concerns like skin elasticity and the strength of hair and nails can also be improved by taking supplements that include them or their precursors that the body uses to build them.