A recent clinical trial found no significant improvement in knee pain with krill oil supplementation in individuals with knee osteoarthritis and significant effusion-synovitis.

In a randomized clinical trial published in JAMA, investigators evaluated the efficacy of krill oil supplementation for knee pain in individuals with knee osteoarthritis (OA) and significant effusion-synovitis. The study sought to determine if krill oil could alleviate knee pain compared to a placebo.

The multicenter, double-blind, placebo-controlled trial enrolled 262 adults with symptomatic knee OA, significant knee pain, and effusion-synovitis confirmed by magnetic resonance imaging (MRI). Participants were randomized into 2 groups to receive either 2 g/d of krill oil (130 participants) or a matching placebo (132 participants) for 24 weeks. By the end of the trial, 222 participants (84.7%) were left, with 13% of the krill oil group and 17.4% of the placebo group withdrew or were lost to follow-up.

The investigators assessed the change in knee pain by a visual analog scale (VAS) ranging from 0 to 100, where higher scores indicate more severe pain. Their results demonstrated no significant difference in pain reduction between the krill oil and placebo groups. The mean change in VAS score was −19.9 for the krill oil group and −20.2 for the placebo group, with a between-group mean difference of 0.30 (95% CI, −6.9 to 6.4; P = .94). Adverse events were reported in 51% of the krill oil group and 54% of the placebo group, with the most common being musculoskeletal and connective tissue disorders.

"The hypothesis that marine-sourced omega-3 polyunsaturated fatty acids EPA [eicosapentaenoic acid] and DHA [docosahexaenoic acid] from krill oil may reduce pain and effusion-synovitis in knee OA was based on the role of inflammation in OA pathogenesis and findings that suggested benefit from krill oil in 2 small RCTs [randomized clinical trials],” investigators noted. “However, data reported herein demonstrated no effect of krill oil on pain or effusion-synovitis volume, indicating no change in intra-articular inflammation.”

Full list of disclosures can be found in the original study.