The Effect of Krill Oil Supplementation on Exercise Performance and Markers of Immune Function

PLoS One. 2015 Sep 25;10(9):e0139174. doi: 10.1371/journal.pone.0139174. eCollection 2015.


Background: Krill oil is a rich source of the long-chain n-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which may alter immune function after exercise. The aim of the study was to determine the effects of krill oil supplementation on post exercise immune function and performance.

Methods: Nineteen males and 18 females (age: 25.8 ± 5.3 years; mean ± S.D.) were randomly assigned to 2 g/day of krill oil (n = 18) or placebo (n = 19) supplementation for 6 weeks. A maximal incremental exercise test and cycling time trial (time to complete set amount of work) were performed pre-supplementation with the time trial repeated post-supplementation. Blood samples collected pre- and post- supplementation at rest, and immediately, 1 and 3h post-exercise. Plasma IL-6 and thiobarbituric acid reactive substances (TBARS) concentrations and, erythrocyte fatty acid composition were measured. Natural killer (NK) cell cytotoxic activity and peripheral blood mononuclear cell (PBMC) IL-2, IL-4, IL-10, IL-17 and IFNγ production were also measured.

Results: No effects of gender were noted for any variable. PBMC IL-2 and NK cell cytotoxic activity were greater (P < 0.05) 3h post exercise in the krill oil compared to the control group. Plasma IL-6 and TBARS, PBMC IL-4, IL-10, IL-17 and IFNγ production, along with performance and physiological measures during exercise, were not different between groups.

Conclusion: Six weeks of krill oil supplementation can increase PBMC IL-2 production and NK cell cytotoxic activity 3h post-exercise in both healthy young males and females. Krill oil does not modify exercise performance.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Biomarkers / metabolism*
  • Case-Control Studies
  • Cell Death / drug effects
  • Dietary Supplements*
  • Erythrocytes / drug effects
  • Erythrocytes / metabolism
  • Euphausiacea / chemistry*
  • Exercise / physiology*
  • Fatty Acids, Omega-3 / pharmacology*
  • Female
  • Humans
  • Immunity / drug effects*
  • Interleukin-6 / blood
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / metabolism
  • Male
  • Placebos
  • Thiobarbituric Acid Reactive Substances / metabolism
  • Time Factors


  • Biomarkers
  • Fatty Acids, Omega-3
  • Interleukin-6
  • Placebos
  • Thiobarbituric Acid Reactive Substances

Grant support

This work was supported with funding from Aker Biomarine Antarctic AS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.