First clinical study to combine the two dietary supplements finds that omega-3 fish oil adds extra benefit for some people
by Craig Weatherby

Americans spend some $800 million annually for supplements intended to enhance cartilage health.

The leader among joint supplements is glucosamine sulfate
derived mostly from shrimp and crab shellsfollowed by chondroitin sulfate, made mostly from animal cartilage.

Both of these cartilage enhancers are used by people who suffer from osteoarthritis, in which cartilage wears out and joint movements become painful.

Glucosamine sulfate and chondroitin sulfate are key structural and functional components of human cartilage, and may exert mild anti-inflammatory effects. (Note: glucosamine hydrochloride is another supplemental form of glucosamine, with comparable effects.)

The clinical research record on both of these is mixed, but the preponderance of evidence indicates they offer potential benefits (Black C et al. 2009; AHRQ 2009).

According to the U.S. Agency for Healthcare Research and Quality, “Research shows that the combination of glucosamine hydrochloride plus chondroitin sulfate may reduce moderate to severe pain without causing serious problems” (AHRQ 2007).

Omega-3s from fish oil have also been the subject of study for possible benefit in arthritis, due primarily to their proven anti-inflammatory effects.

But omega-3s have mostly been studied as aids to people with the uncommon autoimmune condition known as rheumatoid arthritis... they've not been studied as much for osteoarthritis, which is less serious, but much more common.

And the combination of omega-3s and glucosamine had never been studied clinically until a German lab performed this randomized, double-blind trial.

German clinical trial finds that omega-3s boost glucosamine's benefits
A Berlin-based team recruited 177 people with moderate-to-severe hip or knee osteoarthritis.

They were randomly assigned to take one of two daily supplement regimens daily for 26 weeks:
  • Glucosamine sulfate capsules (1,500 mg per day)
  • Glucosamine (1,500 mg per day plus 200 mg of omega-3s per day (from fish oil capsules)
The study did not include a control group that received no supplements, because all of the patients had moderate-to-severe knee or hip osteoarthritis pain, and the researchers cited this as an ethical barrier to providing any of them with an inactive placebo.

While the study was funded by a fish oil maker, it was led by a credible researcher: Joerg Gruenwald, Ph.D., who authored the Physicians' Desk Reference for Herbal Medicines, is a member of the United States Pharmacopeia, and has authored more than 100 clinical and lab studies on dietary supplements.

After 26 weeks of daily supplements, the researchers tested pain levels using two established measures (Western Ontario and McMaster Universities Arthrosis indices).

While there was no significant difference between the number of people who reported a pain reduction of 20 percent, significant differences were observed in the number who reported pain reductionof at least 80 percent.

Indeed, the combination omega-3/glucosamine regimen reduced morning stiffness and pain in the hips and knees by between 48.5 and 55.6 percent respectively, compared to 41.7 to 55.3 per cent in the glucosamine only group.

The researchers calculated that these differences meant that 27 percent more patients in the glucosamine/omega-3 group  reported pain reduction of 80 percent or more, compared with the number of people in the glucosamine-only group who reported pain reduction of 80 percent or more.

In other words, among people who got serious relief from glucosamine alone, fish oil added substantially more relief, but fish oil did not bring much extra relief to folks who got relatively minor relief from glucosamine alone.

Based on the known effects of the two supplements, Dr. Gruenwald suggested that the omega-3s in the fish oil probably inhibited the inflammation process in osteoarthritis, while the glucosamine sulfate boosted cartilage health.

  • Agency for Healthcare Research and Quality U.S. Department of Health and Human Services (AHRQ). Choosing Pain Medicine For Osteoarthritis: Consumer Guide – Jan. 10, 2007. Accessed at
  • Agency for Healthcare Research and Quality U.S. Department of Health and Human Services. Choosing nonopioid analgesics for osteoarthritis: clinician summary guide. J Pain Palliat Care Pharmacother. 2009;23(4):433-57.
  • Black C, Clar C, Henderson R, MacEachern C, McNamee P, Quayyum Z, Royle P, Thomas S. The clinical effectiveness of glucosamine and chondroitin supplements in slowing or arresting progression of osteoarthritis of the knee: a systematic review and economic evaluation. Health Technol Assess. 2009 Nov;13(52):1-148.
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