The largest, longest study to date shows modest drops in knee osteoarthritis pain and inflammation.
Krill oil shows some promise in safely reducing knee pain, stiffness and movement in adults with moderate knee osteoarthritis, according to an Australian study.
The research, published in The American Journal of Clinical Nutrition, randomly assigned 235 adults with mild to moderate pain from knee osteoarthritis to either receive 4g of krill oil daily or a placebo of vegetable oil over six months.
“This RCT represents the largest, longest, and highest-dose study to date investigating the effects of krill oil on OA knee pain,” wrote the study authors.
“The main results showed a significant increase in Omega-3 Index to 9% after 6 months of treatment, accompanied by a modest reduction in knee pain as well as knee stiffness and improvement in physical function as compared with placebo.”
The research found that while the omega-3 index remained unchanged in the control group, it increased from 6% at baseline to 9% at three and six months in the krill oil group.
Both groups saw declines in WOMAC pain scores at three and six months, but krill oil showed slightly bigger improvements at the six-month mark. On a 100-point pain scale, the krill oil group saw a reduction of almost 18.2 points compared to 13 in the control group, a statistically significant difference of 5.18 points.
Knee stiffness and physical functional were also tested in this group of healthy weight, middle-aged participants.
At six months, stiffness had dropped 12 points in the control group and 20.5 in the krill oil group on a 100-point WOMAC scale. Function improved 9.85 in the control group and 14.8 in the krill oil group.
While the improvements were modest overall, the authors pointed out that knee pain improved in a clinically meaningful way in the group with the highest inflammation at baseline.
“The krill oil was of modest benefit and at best may be a potentially useful adjunct to treatment,” rheumatologist and co-author Professor Stephen Hall told Rheumatology Republic.
“But it’s important to note that most studies on knee OA, whether NSAIDs or other treatments, have reported not much more than a modest benefit,” he added.
Sydney osteoarthritis expert Professor David Hunter said the findings were interesting but agreed that the benefits were minimal.
“The results of the trial are interesting but are unlikely to change clinical practice. As the authors recognise, the between-group differences are less than what is currently considered clinically meaningful.”
The benefits in the high inflammation group were particularly interesting, however, and they would need replication in a more highly powered trial, Professor Hunter added.
No safety concerns relating to the use of krill oil were found and there was even the suggestion that non-anti-inflammatory pathways played a role in patient improvement, indicating possible further investigation options for osteoarthritis treatment.
