Pilot Randomized Controlled Trial of Krill Oil Supplementation for Chronic Musculoskeletal Pain in Older Adults

J Nutr. 2026 Mar 31:101517. doi: 10.1016/j.tjnut.2026.101517. Online ahead of print.

ABSTRACT

BACKGROUND: Chronic musculoskeletal pain is highly prevalent in older adults and the leading cause of disability. Long-chain omega-3 polyunsaturated fatty acids have anti-inflammatory and analgesic properties, yet intake and circulating levels are low in older U.S. adults. Krill oil, a phospholipid-bound source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that also contains astaxanthin and choline, may represent a feasible nutrition-based intervention for chronic musculoskeletal pain.

OBJECTIVE: To evaluate the feasibility and acceptability of krill oil supplementation in older adults with chronic musculoskeletal pain and to characterize changes in omega-3 status and exploratory pain outcomes.

METHODS: A 12-week, randomized, double-blind, placebo-controlled pilot trial in 40 community-dwelling adults aged ≥60 years with moderate chronic musculoskeletal pain. Participants were stratified by sex and randomized 1:1 to krill oil (4 g/day; 1,288 mg EPA+DHA) or placebo. Primary outcomes were feasibility metrics (recruitment, retention, adherence, and acceptability). Secondary outcomes included biomarkers of omega-3 status and inflammation. Exploratory outcomes included pain intensity, pain interference, pain distribution, and global improvement.

RESULTS: Recruitment targets were met within 8 months; retention was 95%, adherence exceeded prespecified thresholds (>70%) in both groups, and overall acceptability was rated 7.7±2.3 out of 10. Krill oil supplementation increased the omega-3 index from 4.3% to 7.4%, approaching levels consistent with lower cardiometabolic risk (≥8%), whereas the placebo group showed no meaningful change. Preliminary analyses showed trends favoring krill oil for reduced pain intensity (ΔKO - ΔP = -1.05), fewer pain sites (rate ratio = 0.59; 95% CI 0.41-0.84), and global improvement (adjusted OR = 4.35, 95% CI 0.97-19.55). No serious adverse events occurred.

CONCLUSIONS: Krill oil supplementation was feasible and acceptable among older U.S. adults with chronic musculoskeletal pain. These findings support a fully powered randomized controlled trial to evaluate krill oil as a nutritional strategy for pain management in aging populations.

CLINICAL TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov (NCT06580912); full details are available at https://clinicaltrials.gov/study/NCT06580912.

PMID:41933837 | DOI:10.1016/j.tjnut.2026.101517