Fish oil in knee osteoarthritis: a randomised clinical trial of low dose versus high dose

Double-blind, multicentre randomized controlled trial; participants >40 years with knee osteoarthritis (ACR criteria) and knee pain; randomised N=202 (101 per arm); 4-week run-in with sunola oil to assess tolerability; three Australian centers.

High-dose: fish oil, 15 mL daily providing 4.5 g EPA+DHA per day for 24 months. Low-dose: oil blend of fish oil and sunola oil (1:9), 15 mL daily providing 0.45 g EPA+DHA per day for 24 months.

Low-dose oil reduced knee pain and improved function at 2 years more than high-dose fish oil; no difference in cartilage volume loss or bone marrow lesion changes; analgesic/NSAID use and quality of life showed no between-group differences. Weight gain was greater with high-dose oil and did not explain the pain/function difference. No oil-free control group; the combination oil warrants further investigation as a potential option for knee OA.

No oil-free control group; MRI data incomplete due to one site sequence inconsistency and loss to follow-up; reduced power for imaging endpoints; higher discontinuation due to GI intolerance in the high-dose group; baseline gender imbalance; run-in period may bias tolerability and generalizability.