The study， published in the journal Advances in Therapy， is said to be the first clinical trial to employ the combination of glucosamine omega-3 fatty acids in people suffering from osteoarthritis. UK-based Seven Seas funded the study.

Approximately seven million people in the UK alone are reported to have long-term health problems associated with arthritis. Around 206 million working days were lost in the UK in 1999-2000， equal to £18 billion (€26 billion) of lost productivity.

Talking to NutraIngredients， lead author and president of the CRO which performed the trial， Analyze & Realize， Dr Joerg Gruenwald said: “In a randomized controlled clinical trial with 177 patients with osteoarthritis， we could prove that the combination of glucosamine sulfate and omega -3-fatty acid is superior to glucosamine alone.

“Using the classical WOMAC pain score we could show 27 per cent more responders (80 per cent reduction of WOMAC pain score) in the combination group compared to glucosamine alone， this difference was statistically significant，” he added.

The joint health market is dominated by glucosamine， which is extracted from the shell of crabs， lobster and shrimps. Cargill also markets a non-animal， non-shellfish derived product. The ingredient is often used in combination with chondroitin sulphate， extracted from animal cartilage， such as sharks.

According to the Nutrition Business Journal， US sales for these combined supplements were $810 million (€563 million) in 2005.

Study details

Dr Gruenwald and his co-workers recruited 177 people with moderate-to-severe hip or knee osteoarthritis and randomly assigned them to receive either a glucosamine sulfate supplement (1500 milligrams per day) or glucosamine plus omega-3 fatty acids (providing 444 mg of fish oil， of which 200 mg were omega-3-fatty acids).

“Because the patients studied had moderate-to-severe knee or hip osteoarthritis pain， a placebo group was not used for ethical reasons，” explained the researchers.

After 26 weeks of supplementation， the researchers tested pain levels using the established Western Ontario and McMaster Universities Arthrosis index (WOMAC) score.

While there was no significant difference between the number of responders in each group when a minimal pain reduction of at least 20 per cent was used， significant differences were observed when a higher responder criterion of at least 80 pain reduction was used.

Indeed， the combination product reduced morning stiffness and pain in the hips and knees by between 48.5 and 55.6 per cent， compared to 41.7 to 55.3 per cent in the glucosamine only group.

Commenting on the potential mechanism， Dr Gruenwald and his co-workers note that the ingredient probably acted synergistically. “Omega-3 fatty acids inhibit the inflammation process in OA， whereas glucosamine sulfate further supports the rebuilding of lost cartilage substance，” they stated.