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

Abstract

BackgroundKrill 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.MethodsNineteen 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.ResultsNo 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.ConclusionSix 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.

Fit with good fat? The role of n-3 polyunsaturated fatty acids on exercise performance

“…Other measures that were found not to change with n-3 PUFA supplementation were neutrophil phagocytosis and oxidative burst, plasma IL-6 and cortisol, and PBMC IL-4 and IFN-γ production. Interestingly, we have also found similar results in our recent study employing krill oil (360 mg/day), versus placebo (oil mix similar to average European diet), when investigating young healthy individuals [54]. Summarising, it appears that n-3 PUFA does have some effect in modulating the immune system in the recovery period after exercise but whether it can reduce the incidence of URTI remains to be established.…”

“…For instance, no differences in VO 2max , maximal power or endurance performance (time to completion) were found in healthy well-trained cyclists after 3 weeks of n-3 PUFA (6 g/day), n-3 PUFA + vitamin E (300 IU) or placebo (microcrystalline cellulose) [55]. These findings have been supported by recent work demonstrating no effect of n-3 PUFA supplementation on endurance performance or recovery in Australian Rules footballers (treadmill run to exhaustion) [48], well-trained cyclists (cycle to exhaustion) [46] or young healthy people (cycling simulated time trial) [54]. On the other hand, one study did find that n-3 PUFA supplementation (1.1 g/day), versus placebo (lactose monohydrate), resulted in a 3.7 mL kg − 1 min − 1 increase in VO 2max , alongside an increase in endothelial function, although no endurance performance measure was made [56].…”

“…Furthermore in in vivo studies, in rat hindlimb muscle, n-3 PUFA supplementation reduced skeletal muscle oxygen consumption during contractions [52]. It is worth pointing out that in our own work we have been unable to find any differences in HR or oxygen consumption either a rest or during submaximal exercise with either fish or krill oil supplementation [53], [54].…”

Effects of dietary supplementation with krill meal on serum pro-inflammatory markers after the Iditarod sled dog race

“…Long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to have a positive influence on the immune system in both humans and dogs (8,9). It occurs via various mechanisms (10), among others a shift from pro-inflammatory arachidonic acid (ARA)-derived mediators to less potent EPA/DHA-derived alternative inflammatory mediators (11,12).…”

Eicosapentaenoic Acid and Docosahexaenoic Acid in Endurance Performance and Cardiovascular Function

“…Similarly, O'Keefe et al [32] found that patients with myocardial infarctions and depressed ejection fractions improved post-exercise HR recovery with 0.225 g/day of EPA and 0.585 g/day of DHA daily for 4 months. Conversely, EPA and DHA intake exhibited no changes in HR at rest or during a submaximal exercise [33][34][35]. Thus, although improvement of cardiac function can be assumed because of EPA and DHA intake, factors such as intake volume, period, and exercise load should be investigated in more detail in the future.…”