Krill oil supplementation is ineffective for osteoarthritis knee pain

About 654 million people aged 40 years or older worldwide have knee osteoarthritis (OA), with its associated pain, functional limitations and disability. Marine omega-3 polyunsaturated fatty acids such as fish oil, which is high in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), reduces inflammation. Fish oil has reduced joint pain, morning stiffness, number of painful/tender joints and nonsteroidal anti-inflammatory drug (NSAID) use in people with rheumatoid arthritis, but studies in OA have yielded conflicting results.1Krill oil also contains omega-3 fatty acids and has higher bioavailability than fish oil. As well, it contains the antioxidant astaxanthin, which may reduce free radicals, free oxygen and inflammation, thus hypothetically leading to greater benefits in OA than fish oil.1 Preliminary evidence suggests that krill oil supplementation may improve knee pain, but effects on knee osteoarthritis remain unclear.1 TRCHealthcare’s NatMed Pro concurs, stating that it is unclear whether oral krill oil is beneficial for knee osteoarthritis.2To further examine this issue, researchers evaluated the efficacy of krill oil supplementation on knee pain in people with knee osteoarthritis who had significant knee pain and effusion-synovitis. The multicentre, randomized, double-blind, placebo-controlled clinical trial was conducted in five Australian cities.1 Participants with clinical knee osteoarthritis, significant knee pain and effusion-synovitis on magnetic resonance imaging were enrolled in the study. They were randomized to receive krill oil 2 g/d (n = 130) or matching placebo (n = 132) for 24 weeks. The primary outcome was change in knee pain as assessed by a visual analog scale (VAS) (range, 0–100; 0 indicating least pain; minimum clinically important improvement = 15) over 24 weeks.1Results showed the following:The trial randomized 262 participants (mean age, 61.6 years; 53% women); 222 (85%) completed the trial. Krill oil did not improve knee pain compared with placebo (mean change in VAS score, −19.9 [krill oil] vs −20.2 [placebo]; between-group mean difference, −0.3; 95%CI, −6.9 to 6.4) over 24 weeks. One or more adverse events was reported by 51% in the krill oil group (67/130) and by 54% in the placebo group (71/132). The most common adverse events were musculoskeletal and connective tissue disorders, which occurred 32 times in the krill oil group and 42 times in the placebo group. Specifically reported were knee pain (n = 10 with krill oil; n = 9 with placebo), lower extremity pain (n = 1 with krill oil; n = 5 with placebo) and hip pain (n = 3 with krill oil; n = 2 with placebo).1The authors concluded that among people with knee osteoarthritis who have significantknee pain and effusion-synovitis on magnetic resonance imaging, krill oil 2 g/d supplementation did not improve knee pain over 24 weeks compared with placebo. These findings do not support the use of krill oil for treating knee pain in this population.1 The authors caution that the krill oil dose of 2 g/d may have been insufficient to generate sufficiently large anti-inflammatory effects to reduce pain and volume of knee effusion-synovitis. They also acknowledge that their results should not be extrapolated to people without knee effusions. In addition, their study did not collect any dietary information on omega-3 intake; therefore, the effects of dietary intake of omega-3 on the study outcomes could not be assessed.1ReferencesLaslett LL, Scheepers LEJM, Antony B, et al. Krill oil for knee osteoarthritis. A randomized clinical trial. JAMA 2024;331(23):1997-2006. (accessed June 20, 2024).TRCHealthcare. Krill oil. NatMed Pro. (accessed June 19, 2024).

Krill oil supplementation is ineffective for osteoarthritis knee pain

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