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Krill oil improves post-exercise immune function and Omega-3 Index in healthy adults, study shows


  • Krill oil supplementation significantly increases key immune cytokines after exercise
  • Krill oil supplementation increases Omega-3 Index by 28% (8% vs. 5.3%, respectively)
  • Effective dosage is 2 g/day for 6 weeks (providing 240 mg EPA, 120 mg DHA and 244 mcg astaxanthin)


This randomized, double-blind, placebo-controlled trial was designed to investigate the effect of krill oil on post-exercise immune function and performance in healthy, young adults.

For this study, researchers enrolled 19 healthy men and 18 healthy women (mean age 26±5 years) who were randomly assigned to one of two supplementation groups for 6 weeks: krill oil (2 g/day) (n=18) or placebo (n=19). All capsules were provided by Aker Biomarine Antarctic AS (Oslo, Norway). The placebo oil reflected the fatty acid composition of the average European diet. Each 500-mg krill oil capsule provided EPA (60 mg), DHA (30 mg) and astaxanthin (61 mcg).

A maximal incremental exercise test and cycling time trial were performed pre-supplementation with the time trial repeated post-supplementation. Blood samples were collected pre- and post-supplementation at rest, and at three times after exercise completion (immediately, 1-hour and 3-hours post-exercise). Plasma IL-6 and thiobarbituric acid reactive substances (TBARS) levels as well as Omega-3 Index were measured. Natural killer (NK) cell cytotoxic activity and peripheral blood mononuclear cell (PBMC) IL-2, IL-4, IL-10, IL-17 and IFN-gamma production were also measured.

All participants completed the study. Compared to placebo, krill oil supplementation significantly increased (P<.05) two immune parameters (PBMC IL-2 and NK cell cytotoxic activity) after 3 hours post-exercise. In addition, after 6 weeks of supplementation, the krill oil group had a significant 28% increase in the mean Omega-3 Index (6.8±1.7% vs. 5.3±1.4%, respectively), while the placebo group had no significant change (5.4 ± 1.2% vs. 5.2 ± 1.3%, respectively).

No between-group differences were reported for other immune parameters measured or for performance and physiological measures during exercise. No gender differences were noted for any variable.

These findings indicate that supplementation with krill oil (2 g/day for 6 weeks) offers benefits for post-exercise immune function and improves the Omega-3 Index in healthy young adults.


Da Boit M, Mastalurova I, Brazaite G, McGovern N, Thompson K, Gray SR. The effect of krill oil supplementation on exercise performance and markers of immune function. PLoS One. 2015;10(9):e0139174.

PMID: 26407095