Presence of Fatty-Acid Ethyl Esters in Krill Oil Dietary Supplements.

Krill oil dietary supplements are increasingly used for their high concentrations of phospholipids (PL), which offer reportedly greater bioavailability of n-3 polyunsaturated fatty acids (PUFA) than those of triacylglycerols or fatty-acid ethyl esters (FAEE) commonly found in fish oils and fish-oil concentrates. This work evaluated the lipid composition of 22 commercial krill oil (CKO) supplements available in the US market, and found ten products (i.e. 45%) contained significant amounts of FAEE, varying from 41% to 75%, by weight. These concentrations of FAEE differed from the minor abundances of FAEE (<3%, by weight) found in manufacturer-supplied krill oil. The potential clinical and regulatory implications for these findings warrant further investigation.