Background: Bioavailability of krill oil has been suggested to be higher than fish oil as much of the EPA and DHA in krill oil are bound to phospholipids (PL). Hence, PL content in krill oil might play an important role in incorporation of n-3 PUFA into the RBC, conferring properties that render it effective in reducing cardiovascular disease (CVD) risk. The objective of the present trial was to test the effect of different amounts of PL in krill oil on the bioavailability of EPA and DHA, assessed as the rate of increase of n-3 PUFA in plasma and RBC, in healthy volunteers.
Methods and design: In a semi randomized crossover single blind design study, 20 healthy participants consumed various oils consisting of 1.5 g/day of low PL krill oil (LPL), 3 g/day of high PL krill oil (HPL) or 3 g/day of a placebo, corn oil, for 4 weeks each separated by 8 week washout periods. Both LPL and HPL delivered 600 mg of total n-3 PUFA/day along with 600 and 1200 mg/day of PL, respectively.
Results: Changes in plasma EPA, DPA, DHA, total n-3 PUFA, n-6:n-3 ratio and EPA + DHA concentrations between LPL and HPL krill oil supplementations were observed to be similar. Intake of both forms of krill oils increased the RBC level of EPA (p < 0.001) along with reduced n-6 PUFA (LPL: p < 0.001: HPL: p = 0.007) compared to control. HPL consumption increased (p < 0.001) RBC concentrations of EPA, DPA, total and n-3 PUFA compared with LPL. Furthermore, although LPL did not alter RBC n-6:n-3 ratio or the sum of EPA and DHA compared to control, HPL intake decreased (p < 0.001) n-6:n-3 ratio relative to control with elevated (p < 0.001) sum of EPA and DHA compared to control as well as to LPL krill oil consumption. HPL krill oil intake elevated (p < 0.005) plasma total and LDL cholesterol concentrations compared to control, while LPL krill oil did not alter total and LDL cholesterol, relative to control.
Conclusions: The results indicate that krill oil with higher PL levels could lead to enhanced bioavailability of n-3 PUFA compared to krill oil with lower PL levels.
Trial registration: Clinicaltrials.gov# NCT01323036.