Krill Oil Reduces Pain in Adults With Knee Osteoarthritis | Latest news for doctors, nurses and pharmacists | rheumatology

A krill oil supplement is not only safe to consume, but also slightly improves knee pain, stiffness and physical function in adults with mild to moderate knee osteoarthritis (OA), a study shows.

On the other hand, “[t]here there was insufficient evidence to suggest treatment-related effects in relation to nonsteroidal anti-inflammatory drug (NSAID) use, any of the serum lipids, or inflammatory or safety markers,” the researchers said.

This double-blind, randomized, placebo-controlled, multicentre study was conducted over 6 months and included 235 healthy adults (aged 40 to 65 years; body mass index > 18.5 to < 35 kg/m).²) with clinically diagnosed mild to moderate osteoarthritis of the knee joint, regular knee pain and intake of <0.5 g/day of long-chain omega-3 polyunsaturated fatty acids (PUFA).

Participants were randomly assigned to receive either 4 g krill oil/d (0.60 g EPA/d, 0.28 g DHA/d, 0.45 mg astaxanthin/d) or placebo (mixed vegetable oil). Researchers assessed knee scores using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) numeric scale (normalized to scores 0-100) at baseline, 3 months and 6 months.

Krill oil supplementation increased the omega-3 index compared to placebo (from 6.0 percent to 8.9 percent vs. from 5.5 percent to 5.4 percent; p<0.001). [Am J Clin Nutr 2022;116:672-685]

Knee pain score improved in both groups, but improvements were greater for krill oil than placebo (difference in adjusted mean change between groups at 6 months, -5.18, 95 percent confidence interval [CI], -10.0 to -0.32; p=0.04).

Krill oil also resulted in greater improvements in knee stiffness and physical function compared to placebo (difference in adjusted mean change between groups at 6 months, -6.45, 95 percent CI, -12.1 to -0.9 and -4.67, 95 percent CI, -9.26). to -0.05; p<0.05).

In addition, no differences were found between groups in NSAID use, serum lipids, and inflammatory and safety markers.

“Krill oil is believed to reduce pain through anti-inflammatory mechanisms due to its high content of long-chain omega-3 PUFAs and astaxanthin,” the researchers said. [Biochimie 2020;178:105-123;
Molecules 2020;25:5342]

“EPA and DHA affect inflammation through multiple mechanisms, including modulation of the pro-inflammatory eicosanoids toward a more anti-inflammatory profile and through the formation of pro-dissolving lipid mediator compounds, including resolvins, protectins, and maresins,” they added. [Biochimie 2020;178:105-123; J Clin Rheumatol 2017;23:330-339]

Regarding safety, no difference was observed between the groups in the incidence of treatment-emergent adverse events. Previous studies of krill oil in OA participants also did not report any treatment-related side effects. [J Am Coll Nutr 2007;26:39-48;
PloS One 2016;11:e0162769]

“The current study did not report treatment-emergent adverse events previously reported in fish oil studies, including fishy regurgitation, gastrointestinal distress (e.g., bloating and diarrhea), or bleeding/vascular complications,” the researchers said. [Ann Rheum Dis 2016;75:23-29; Arthritis Res Ther 2009;11:R192]

OA, a leading cause of chronic pain and disability, is typically treated with NSAIDs and analgesics, which can have side effects. Krill oil, rich in anti-inflammatory long-chain omega-3 PUFAs and astaxanthin, could be a safe and effective alternative treatment, according to the researchers.