Krill oil increase plasma omega-3 fatty acids more than fish oil in healthy adults: a double blind randomized controlled trial.

BACKGROUND: Omega-3 fatty acids (ω-3 FAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are recognized for their health benefits. However, their circulating levels after supplementation may be modulated by several factors, including sex, carriage of the apolipoprotein E4 allele (APOE4), and the chemical form of the supplement. Krill-oil delivers ω-3 FAs primarily as phospholipids (PL), whereas fish oil provides them as triglycerides (TG). OBJECTIVE: To compare EPA and DHA concentrations after a supplementation with krill oil and fish oil and assess whether sex and APOE4 genotype modifies responses to supplementation. METHODS: This double-blind, randomized clinical trial included 72 healthy adults (53 females, 19 males) matched for age and body mass index (BMI). Participants received 1.1 g/day ω-3 FAs through either krill oil (n=36) or fish oil (n=36) for 12 weeks. Plasma fatty acids were measured at baseline and at weeks 1, 2, 4, and 12 by gas chromatography-flame ionization detection. Differences in plasma ω-3 FAs concentrations by treatment, sex and APOE4 status, were analyzed. RESULTS: Time-by-treatment interactions were significant for plasma delta over baseline concentrations of EPA (p = 0.0001) and DHA (p = 0.005), with krill oil resulting in ∼ 1.5-fold higher ΔEPA and ΔDHA compared to fish oil. The time-by-sex interaction was significant only for EPA (p = 0.026), with females having 1.5-fold greater increase than males at 12 weeks. Following supplementation with either krill oil or fish oil, APOE4 carriers had 3-fold and 1.6-fold higher EPA and DHA respectively, compared to baseline; however, these increases were not significantly different from those found in non-carriers. CONCLUSIONS: Krill oil increased plasma ω-3 FAs more than fish oil, regardless of APOE4 genotype. Individuals with higher ω-3 FA requirements may achieve adequate enrichment with lower doses of krill oil compared to fish oil supplementation. REGISTRATION NUMBER: NCT04279743. In https://clinicaltrials.gov.