GLUCOSAMINE GLUCOSAMINECommon Uses
Osteoarthritis, inflammatory bowel disease
Glucosamine is the most commonly used chondroprotective supplement used for the treatment of osteoarthritis (chondroitin is the second most commonly used supplement for the treatment of osteoarthritis). Glucosamine is produced naturally in the body, where it is a key building block for making cartilage (it serves as a building block for the glycosaminoglycans and proteoglycans). Glucosamine is an aminosugar (made from glutamine and glucose) that is incorporated into articular (joint) cartilage; it is supplied as a supplement in one of three forms: glucosamine sulfate, glucosamine hydrochloride (a salt of D-glucosamine; D-glucosamine is eventually converted by the body into glucosamine sulfate), or N-acetylglucosamine.
N-acetylglucosamine and D-glucosamine (for which glutamine, another supplement recommended for pets with inflammatory bowel disease, is a precursor) may be helpful for pets with inflammatory bowel disease. The cells of the intestinal mucosa have a high rate of cell turnover, and patients with inflammatory bowel disease have a cell turnover rate that is at least three times higher than healthy patients. Patients with inflammatory bowel disease cannot make N-acetylglucosamine. This deficiency of N-acetylglucosamine leads to further intestinal damage including increased permeability (leaky gut syndrome). Supplementing N-acetylglucosamine and D-glucosamine (and giving additional glutamine) can help heal the intestinal mucosa by supporting glycoprotein synthesis. Since glucosamines also are important in producing the glycoproteins that make up the mucous membranes of the urinary and respiratory tracts, supplementing with glucosamine for pets with bladder disorders and chronic respiratory disease might be helpful.
As we are just beginning to understand how glucosamine products can be helpful in pets, future studies may indicate a variety of disorders for which glucosamine products may be useful.
Glucosamine is not usually obtained directly from food; supplements are derived from chitin, a substance found in the shells of shrimp, lobsters, and crabs.
Studies show that while all three forms of glucosamine are effective, glucosamine hydrochloride (which is a salt of D-glucosamine) and glucosamine sulfate were more effective than N-acetylglucosamine. Results take 4 to 8 weeks to develop. Interestingly, these improvements often last for several weeks after glucosamine supplements are discontinued.
Glucosamine is rapidly taken up by cartilage cells and helps stimulate the synthesis of synovial fluid and cartilage and also helps inhibit the destructive enzymes that can destroy cartilage and proteoglycans. The anti-inflammatory aspect of glucosamine may result from the scavenging of harmful free radicals (similar to antioxidants). Glucosamine is used by the cartilage for the synthesis of glycosaminoglycans.
A number of studies in people and pets show that glucosamine is equally effective for treating osteoarthritis when compared to NSAIDs without the side effects. In fact, glucosamine and chondroitin are among the few supplements for which we actually have good studies in people and pets.
In both people and pets, solid evidence indicates that glucosamine supplements effectively relieve pain and other symptoms of osteoarthritis.
In both people and dogs, patients given glucosamine experienced significantly reduced pain and improved movement, to a greater extent than the improvements seen in the placebo groups.
Other studies showed that nonsteroidal medications and glucosamine proved equally effective at reducing symptoms. In people, one group that received combination treatment (the nonsteroidal piroxicam plus glucosamine) didn’t show significantly better results than either treatment taken alone.
In this same study, after 90 days into the study, treatment was stopped and the participants were followed for an additional 60 days. The benefits of piroxicam rapidly disappeared, but the benefits of glucosamine lasted for the full 60 days.
While a number of glucosamine products are available from reputable manufacturers, many of the early major studies done in pets have used a proprietary product (Cosequin and Cosequin-DS) containing glucosamine and chondroitin. Clinical evidence indicates other products from well-known manufacturers are also effective.
Dosages vary depending upon the product. As a guideline for combination products, a starting dose of 1,000 to 1,500 mg of glucosamine with 800 to 1,200 mg of chondroitin is recommended per day for a 50- to 100-pound dog. This dose is then lowered after 4 to 8 weeks.
While arthritis is rare in cats when compared with dogs, clinical experience suggests that glucosamine and chondroitin products may also be quite helpful for arthritic cats. In general, the doses for smaller dogs are used.
Glucosamine appears to be extremely safe with no side effects; mild GI upset is rarely observed. No significant side effects have been reported in any of the studies of glucosamine.