Another Trial for Glucosamine

Yet another study has examined whether glucosamine, the popular dietary supplement for sufferers of osteoarthritis, was actually effective at alleviating symptoms. There has been a great deal of uncertainty in recent years that the supplement helps, yet it remains a staple of many arthritis patients’ routines, and they testify anecdotally that it does indeed reduce pain and joint stiffness.

In the present double-blind randomized placebo-controlled clinical trial, glucosamine and/or chondroitin were studied for their potential ability to reduce joint space narrowing and pain in people with symptomatic knee OA.

The study looked at 605 participants, age 45 to 75 years, reporting chronic knee pain and with evidence of “medial tibio-femoral” compartment narrowing. Subjects were once daily either given 1,500 mg of glucosamine sulfate; 800 mg of chondroitin sulfate; both supplements; or matching placebo capsules. There was a two-year follow-up during which joint space narrowing was measured by knee radiograph, with maximum knee pain self-reporting for seven days every two months for one year.

After adjusting for factors like gender, BMI, and others which the researchers determined were associated with structural disease progression, the study found those assigned the dietary supplement combination (glucosamine-chondroitin) had a statistically significant reduction of two-year joint space narrowing  compared to the placebo group.

Yet “no significant structural effect for the single treatment allocations was detected.” All four groups demonstrated reduced knee pain over the first year, but, importantly, no significant between-group differences were detected.

So it appears that though some gains in reducing joint space narrowing can be achieved with glucosamine/chondroitin sulfate supplementation, actual relief of symptoms—most notably pain—does not appear different from placebo. Such supplementation seems to do little harm (though a small number of participants reported adverse medical effects for one reason or another, including allergic reaction) and may have a genuine placebo effect on knee OA pain.

The Mayo Clinic advises:

Glucosamine is likely safe when taken by mouth in studied doses (500 milligrams three times daily) for a short time by healthy adults. Drowsiness or sedation may occur. Glucosamine may also cause insomnia. Use cautiously in people who have asthma, kidney disorders, active peptic ulcer disease, depression, skin conditions, or in people who need to restrict potassium intake.

Use cautiously in people who are at risk for cataracts, or in older people who have dry eyes. Glucosamine may cause increased cataract risk or dry eyes. Use cautiously in people taking agents that increase the flow of urine. Glucosamine may increase the risk of bleeding. Caution is advised in people with bleeding disorders or taking drugs that may increase the risk of bleeding.

Avoid using glucosamine-chondroitin supplements that contain Chinese skullcap. Liver damage has been reported with use of the Chinese skullcap contained in the Move Free® Advanced dietary supplement.

Ann. Rheum. Dis., 2015, Vol. 74, No. 5, pp. 851-858, http://www.ncbi.nlm.nih.gov/pubmed/24395557

Mayo Clinic, http://www.mayoclinic.org/drugs-supplements/glucosamine/safety/hrb-20059572

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