What exactly is glucosamine?

In the body, glucosamine is an amino monosaccharide produced by chondrocyte cells and used to make glycosaminoglycans and proteoglycans. It is water soluble and well-absorbed in the small intestine. Glucosamine has an affinity for articular (joint) cartilage. Many scientists believe that glucosamine is the most important and rate-limiting substance for the synthesis of healthy cartilage.

 

 

 

What are glycosaminoglycans?

Glycosaminoglycans (GAGs) are long chains of modified disaccharides. They are the main component of proteoglycans which, along with chondrocyte cells and collagen, make up cartilage. Chondroitin sulfate is one of the six known GAGs and a main compenent found in connective tissue.

What are proteoglycans?

Proteoglycans (PGs), along with collagen and chondrocyte cells, make up cartilage. PGs have a gel-like consistency and the ability to fill space in three dimensions while intertwined collagen fibers give them body. If PGs are not synthesized in adequate amounts, then normal cartilage function is impaired and breakdown is accelerated.

 

 

 

What are chondrocytes?

 

 

Chondrocytes (along with PGs and GAGs) make up cartilage. They are cells that are involved in both anabolism and catabolism of PGs and collagen. In other words, they are responsible for the synthesis, maintenance, and regeneration of cartilage.

What is glucosamine's role in GAGs?

Glucosamine makes up 50% of two out of six GAG molecules. It is the immediate precursor to chondroitin sulfate. Without adequate glucosamine, GAG synthesis would essentially shut down. In turn, this would cause proteoglycan synthesis to also cease.

 

How does glucosamine work?

Glucosamine has numerous effects on the health of cartilage. There must be adequate glucosamine, whether from supplements or internal production in order for cartilage to be healthy. Glucosamine stimulates GAG and PG production which make up cartilage.

Glucosamine accomplishes this in two ways. When glucosamine is available for chondrocytes, they are able to produce connective tissue faster because they can skip three chemical reactions (needing only a phosphorylation reaction to make glucosamine 6 phosphate).

The second way glucosamine appears to work is as a stimulating agent. As chondrocytes increase GAG production from supplemental glucosamine the once-starved chondrocytes are now being supplied with the raw materials necessary (sugar and amino acids) to stimulate the synthesis of GAGs and PGs. and fibrotic articular tissues begin to heal.

Glucosamine may have an effect on the biochemistry of nonsteroidal anti-inflammatory drugs...

Many people with arthritis take nonsteroidal anti-inflammatories to reduce inflammation and pain, as well as prevent excessive adhesions. However, NSAIDs accomplish these functions at a high cost. In addition to being very hard on the stomach, intestines, and, in some cases, liver and kidneys, NSAIDs also inhibit the production of GAGs, which means that even though a patient may have a reduction in pain, their body's ability to heal itself is impaired. This explains why many patients with arthritis who take anti-inflammatories have symptomatic relief with they use them, but never seem to get better.

Glucosamine

Precursor to chondroitin

Analgesic, antioxidant, and anti-inflammatory

1500mg/day elemental glucosamine sulfate in divided doses recommended

Chondroitin

Much bigger molecule than glucosamine

Absorbed less

Increases joint viscosity

Decreases collagen breakdown

Reduces inflammation

800-1200mg/day