A randomized trial comparing omega-3 fatty acid plasma levels after ingestion of emulsified and non-emulsified cod liver oil formulations

Objectives: Emulsified formulations of omega-3 fatty acids may increase plasma concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) compared with non-emulsified formulations. The current study evaluated plasma concentrations of DHA + EPA as well as DHA and EPA individually following administration of emulsified vs non-emulsified cod liver oil formulations.

Methods: In this randomized, 2-period, crossover study (ClinicalTrials.gov NCT02428699), 47 healthy adults received single doses of an emulsified cod liver oil formulation and a non-emulsified cod liver oil formulation, each containing 10% cod liver oil plus 10% cod oil and closely matched DHA and EPA content. Blood samples were collected for 24 h after dosing to analyze DHA and EPA plasma concentrations using a validated methodology. DHA + EPA, DHA, and EPA pharmacokinetics were compared using an analysis of covariance model. The incremental area under the plasma concentration curve at 24 h (iAUC_{0-24 h}) for DHA + EPA was the primary endpoint.

Results: DHA + EPA, DHA, and EPA plasma concentrations reached higher levels in plasma following administration of the emulsified vs non-emulsified formulation. The emulsified cod liver oil formulation produced iAUC_{0-24 h} values for DHA + EPA, DHA, and EPA that were 1.66, 1.78, and 1.64 times higher, respectively, than the non-emulsified formulation; iAUC_{0-10 h} values were 1.84, 1.96, and 1.79 times higher, respectively (all p < 0.01). Maximum concentrations of DHA + EPA, DHA, and EPA in plasma were significantly higher for the emulsified than the non-emulsified formulation (p < 0.001).

Conclusions: DHA + EPA, DHA, and EPA plasma concentrations were significantly higher for the emulsified cod liver oil supplement vs the reference non-emulsified cod liver oil supplement.