Glucosamine
Cartilage is made up of three main components: Water (70 to 80 percent), collagen (10 to 15 percent), and proteoglycans (10 to 15 percent). Combined, these are called the cartilage matrix. The cartilage matrix is where new cartilage is born. Water provides cartilage with buffering qualities, and also helps shape the "cartilage" sponge. It also feeds the cartilage. Cartilage contains no blood vessels, so the soaking up and squeezing out of water is what provides cartilage with nutrients.
Collagen also plays a role in giving cartilage its shape and resiliency, and it also absorbs shock. Think of collagen as super strong threads that create the framework to hold the third component of cartilage: proteoglycans.
Proteoglycans are large water-soluble molecules. They are woven in among the collagen threads, forming a kind of netting. This netting traps the water. Proteoglycans also act like magnets. The individual molecules push away from each other, again allowing for space and a buffering effect.
Finally, tiny factories called chondrocytes are located throughout this netting. They produce new collagen and proteoglycans, as well as enzymes that dispose of older, past-their-prime collagen and proteoglycans.
Glucosamine stimulates chondrocytes to produce more collagen and proteoglycans. The more glucosamine there is, the more collagen and proteoglycans there are, and the more water can be absorbed. The end result is healthier cartilage. Because of these properties, glucosamine can help the body help itself repair damaged or eroded cartilage. It works at the cellular level to reinforce our natural "repair" ability.
When cartilage is damaged, the chondrocytes go into high gear, manufacturing more proteoglycans and collagen. Unfortunately, these replacements may be of inferior quality, or be overproduced, resulting in bumpy joint surfaces. Chondrocytes also produce more of the enyzmes that "eat away" old matter. These enzymes may begin attacking the new, inferior cartilage, with an end result of diminished cartilage, not more cartilage. This also may result in fewer proteoglycans, which means the cartilage cannot hold water well. The cartilage can then dry out and wear out more quickly.
Up to the present, most glucosamine studies have been performed outside of North America. In all of these studies, glucosamine sulfate proves to maintain joint health.
-
An early study in Italy found that 20 percent of those using glucosamine sulfate became "symptom-free." Nearly 25 percent had no restriction of active or passive movement. The researchers concluded that glucosamine sulfate rebuilt damaged cartilage.
( Clinical Therapeutics 3, no. 4 (1980): 226-272 ) A large-scale study looked at over 1,200 patients with osteoarthritis. Results show that pain decreased throughout the trial, that both active and passive movement improved, and that glucosamine proved to work for six to 12 weeks after treatment had stopped.
( Pharmatherapeutica 3, no. 3 (1982): 157-168 ) In a study comparing glucosamine sulfate to the pain reliever ibuprofen, the ibuprofen proved more effective the first two weeks, but then faded. After eight weeks, the glucosamine sulfate group reported better results.
( Current Medical Research and Opinion 8, no. 3 (1982):145-149 ) More recently, Italian researchers found glucosamine to be more effective than placebos or traditional NSAIDs (nonsteroidal anti-inflammatory drugs) in treating osteoarthritis.
( Osteoarthritis and Cartliage 5, supplement A (1997): 82 )
It should be noted that although there are positive results in all of these studies, not all participants experience them. Thus, although glucosamine works for many people, it does not necessarily work for all people.
