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Glucosamine

Sandra Justice, P.D., FACA

Among the natural therapies for osteoarthritis, glucosamine sulfate is probably the best known. It is used extensively as a drug for osteoarthritis in Europe and Asia, and it has been readily available in the United States in recent years.

Glucosamine is a compound that provides the body with the raw material needed to manufacture important components of joint cartilage. Glucosamine shows great promise in treating and possibly slowing the progression of osteoarthritis, a degenerative joint disease that is considered the most common form of arthritis. Osteoarthritis affects more than 16 million Americans, especially the elderly. It results from continuous wear and tear on the joints and progressive loss of both cartilage and the protective coating that covers the ends of bones in a joint.

How It Works

Glucosamine is a naturally occurring substance in the body, synthesized in the chondrocytes. In osteoarthritis this synthesis is defective and insufficient and supplementation with glucosamine has proven to be useful. The body uses supplemented glucosamine to synthesize the proteoglycans and the water-binding glycosaminoglycans in the cartilage matrix. In addition to providing raw material, the presence of glucosamine seems to stimulate the chondrocytes in their production of these substances. Glucosamine also inhibits certain enzymes, which destroy the cartilage. By blocking pathogenic mechanisms that lead to articular degeneration, glucosamine delays the progression of the disease and relieves symptoms even for weeks after termination of the treatment.

Dosage Forms

Glucosamine is available as a supplement in several forms, including the following.

  • Glucosamine sulfate: 500, 750, and 1,000 mg capsules and tablets
  • N-acetyl glucosamine: 500 and 750 mg capsules and tablets
  • Glucosamine hydrochloride (HCL): 500, 750, and 1,000 mg capsules and tablets
  • Glucosamine/chondroitin sulfate combination products

Chondroitin sulfate deserves special mention. It has been included in many combination formulas and research trials. However, researchers and industry members are split over its potential value. Chondroitin sulfate is one of a group of long chains of modified sugars (glucosaminoglycans) that form the structural molecules in cartilage. It is theorized that the arrangements of chondroitin sulfates in cartilage attracts water and gives cartilage a gel-like property. Opponents of that position say that because glucosamine is the precursor to cartilage production, there is no need to further supplement. They also claim that because the chondroitin sulfate molecule is estimated to be 50 to 300 times larger than that of glucoamine sulfate, it is not as readily absorbed. A major study by the National Institute of Health is underway and will further define the usefulness of this combination therapy.

How To Take It

Recommended dosage is 1,500 mg glucosamine per day (500 mg, three times a day). Some patients notice partial relief within two weeks or a month, but a trial of at least 4 months is recommended before making a decision on whether or not to continue. After a few months of using a dose of 500 to 1,00 mg three times a day, the dose can be lowered to 500 mg once a day as a maintenance dose. If symptoms recur, the dose can be increased again. This therapy should be done under the guidance of a health care practitioner.

Precautions

The majority of studies indicate that glucosamine is safe, nontoxic, and causes only minor side effects, such as gas, bloating, and diarrhea in some patients. However, people with certain health conditions may need to take precautions. Glucosamine sulfate may contain high amounts of sodium or potassium, so individuals on a restricted diet or taking potassium-sparing diuretics should carefully check the label before taking. People with diabetes should have their blood sugar checked regularly, since glucosamine may raise insulin resistance. Individuals with shellfish allergies should check with a health care professional before taking glucosamine.

Possible Interactions

Glucosamine may increase the anti-inflammatory activity of NSAIDs drugs such as ibuprofen. This interaction may result in the need for lower doses of these medications. Dosage adjustments should be made only under the advisement of your physician.

A Natural Alternative

Glucosamine and chondroitin dietary supplements have sufficiently positive outcomes in controlled clinical trials to warrant their use in osteoarthritis. With few adverse effects compared to the conventionally prescribed NSAIDs- which can cause ulcers and other serious gastrointestinal disruptions, especially in the elderly- glucosamine and chondroitin are the only treatments that have been shown to retard progression of the disease, as opposed to merely alleviating its symptoms. Glucosamine therapy therefore deserves a selected place in the management of osteoarthritis.