Osteoarthritis (OA) is a noninflammatory disorder of the movable joints.
It is characterized by two features: loss of articular cartilage and formation of new bone at the joint surfaces and margins. Structural abnormalities, excessive stress, and repetitive stresses play a role in the etiology of OA. OA leads to the inability of the joint articular surfaces to withstand the demands that are placed on them. The pathology of OA manifests as both structural and metabolic changes in the articular cartilage and surrounding bony structures. The articular cartilage undergoes a loss of proteoglycans, a disruption of the collagen matrix, and an increase in hydration; the combination of these events is what causes articular cartilage to lose its supportive and cushioning properties. Osteoarthritis (OA) is the most common joint disease in the United States. By age 65, an estimated 85% of this age group exhibits some degree of OA.
The most common herbal supplements taken for the treatment of OA are Glucosamine and Chondroitin. Frequently described as “nutraceuticals” because they are supplied as food supplements, these compounds have been known to offer symptomatic relief equal to that of the NSAIDS, but with fewer adverse effects.
What is Glucosamine?
Glucosamine sulfate is what is studied and used in supplementation. It is produced from Chitin, the second most common polymer on earth, found in the exoskeletons of many invertebrates like Crab, Lobster, and Shrimp shells. Glucosamine is the principal component of glycosaminoglycan and a proteoglycan precursor to the fundamental building blocks of articular cartilage. Glucosamine constitutes half of the repeating disaccharide subunit of both keratin sulfate and hyaluronic acid. These two glycosaminoglycans are found in articular cartilage and seen in reduced amounts in persons with OA.
What is Chondroitin?
Chondroitin is a mucopolysaccharid and one of the more abundant glycosaminoglycans found in articular cartilage. Chondroitin is most often manufactured from cow and shark cartilage in the form of a sulfate salt. Its mechanism of action is similar to glucosamine in that it stimulates cartilage cells. It may have a greater anti-inflammatory effect when compared to glucosamine. Recent studies compare its anti-inflammatory properties to be as effective as some NSAIDS, such as ibuprofen.
How do they work?
Glucosamine is largely found in articular cartilage and plays an important role in its health and resiliency. As we age, we gradually lose cartilage and this leads to the onset and progression of arthritis. Glucosamine can slow down cartilage degeneration caused by natural process of aging by increasing the production of glycosaminoglycans and enhancing synovial production of hyaluronic acid because it is a precursor of its synthesis. Hyaluronic acid is the major constituent of synovial fluid and is responsible for synovial fluid’s high viscosity, as well as, its protective lubricating and shock absorbing properties. Decreased levels of hyaluronic acid are seen in the synovial fluid of patients with OA.
Absorption of the oral supplementation of Glucosamine Sulfate has recently been studied and findings reveal Glucosamine is nonionized in the intestinal PH, with the result that up to 90% of orally administered glucosamine is rapidly absorbed. Under a process called Radiolabeling it is shown that 8-12% of oral glucosamine is retained into tissues such as cartilage. Researchers suggest it is best to take Glucosamine in morning on an empty stomach.
The body is more likely to rapidly absorb the multiple compound supplement and diffuse it into most tissues that have a special attraction for articular tissues and bones. Less than 10% of orally administered chondroitin is absorbed in the gastrointestinal system and even less is retained in the tissues, which includes cartilage because of its larger molecular size. Thus “micronized” products may be more bioavailable (better absorbed).
What are its Indications/Should I be taking it?
Glucosamine and Chondroitin are indicated for the treatment of the symptoms of osteoarthritis. Studies have shown their efficacy in reducing the pain and other symptoms of osteoarthritis. Neither product has yet to be proven to arrest progression of the disease or regeneration of damaged cartilage. However, patients taking glucosamine and chondroitin for long term are shown by radiographs to display a less measurable loss of joint space within the medial compartment when compared to placebo patients. These supplements were tolerated well by patients who were unable to use NSAIDS due to a medical history with a gastrointestinal disorder.
Glucosamine and chondroitin sulfate are easily absorbed through the stomach and does not exhibit any side effects. It can be taken on a long-term basis without affecting the kidneys or liver functions. On a side note, glucosamine is derived from crab, lobster, and shrimp shells, so if you are allergic to shellfish, consult your physician before deciding to take glucosamine. However, allergies are caused by proteins in shellfish, not chitin, the carbohydrate that glucosamine is derived from. Dosage recommendations include:
Glucosamine – 1,500 mg per day divided in three doses of 500 mg/dose.
Chondroitin – 1,200 mg per day divided in three doses of 400 mg/dose.
Both supplements require approximately one month of continuous use before symptom relief is experienced. Other Information: Other alternatives for the treatment of osteoarthritis include:
- – Acetaminophen: The American College of Rheumatology recommendation as first line treatment for OA.
- – NSAIDS – aspirin, ibuprofen, indomethicin, naproxen, Vioxx, Celebrex, Bextra
- – Steroids
- – Intra-articular viscosupplements: hyaluronic acid including Hyalgan and Synvisc
- – S-adenosylmethionine (SAMe)
- – Cetyl Meristoleate
- – Ginger
- – Dimethyl Sulfoxide (DMSO)
- – Boron
- – Herbals: tipi, capsaicin, reumalex, and avocado/soybean, unsaponifiables
- – Non-drug treatments: exercise and physical therapy
Over-The-Counter Medications/Herbals:
The FDA does not monitor OTC medications and Herbal drugs. This means that manufacturers are not regulated in the production of their product and do not have the same standards and regulations that they must follow as with prescription medications. Claims of efficacy by the manufacturer can sometimes be misleading as they are allowed to make most any claim short of a “cure”.
Conclusion:
Glucosamine and chondroitin are safe and well tolerated by patients taking it on a long-term basis. There is continuing evidence that oral glucosamine alone or combined, provides symptomatic relief for OA. The only draw back that presents is the lack of long-term data that exists on glucosamine use.
Resources:
Doulens K. Joshi B. Lichtman D. Glucosamine and Chondroitin in the Treatment of Osteoarthritis: An Interpretation of Current Research Findings. Women’s Health: Orthopedic Edition, Jan-Feb 2003: Vol 6 pgs 27-32. Pharmacist’s Letter/Prescriber’s Letter. Continuing Education Booklet. Natural Medicines Comprehensive Database; 2003. Adams ME. Hype about Glucosamine.Lancet, 1999; 353-354. Pavelka K. Glucosamine Sulfate use and delay of progression of knee osteoarthritis. A 3-year randomized, placebo-controlled, double blind study. Arch Intern Med. 2002: 162:2113-2123. Delafuente JC. Glucosamine in the Treatment of Osteoarthritis. Rheumatic Diseases Clinics of North America. Vol 26, No1. Feb 2000. 1-11.
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