Comparative membrane incorporation of omega-3 fish oil triglyceride preparations differing by degree of re-esterification: A sixteen-week randomized intervention trial

PLoS One. 2023 Jan 27;18(1):e0265462. doi: 10.1371/journal.pone.0265462. eCollection 2023.

Abstract

Background: Fish oil is routinely concentrated into unmodified triglycerides, or trans-esterified into an ethyl ester form. Re-esterification of the ethyl ester form yields re-esterified triglycerides (rTG), which are reportedly more bioavailable than ethyl ester forms. However, the fidelity of the re-esterification process may yield variable triglyceride forms, with only 55-60% being rTG.

Objective: To determine whether the blood lipidomic response to supplementation with two rTG supplements, varying by degree of re-esterification, would differ between treatments.

Design: This was a double-blind, parallel-design, single-center, 128-day study with sixty young, healthy subjects randomized into two groups. One group received a >95% rTG (Ultimate Omega®), as 1,000 mg capsules containing 325 mg eicosapentaenoic acid (EPA) and 225 mg docosahexaenoic acid (DHA), and the other received a <70% rTG (MEG-3) as 1,000 mg capsules containing 300 mg EPA and 200 mg DHA. Total intake was 2,750 and 2,500 mg EPA+DHA for the Ultimate Omega® and MEG-3 groups, respectively, with blood drawn at 4, 16 and 24 weeks and analyzed for serum and erythrocyte phospholipid fatty acid (PLFA) content.

Results: For erythrocyte PLFA profiles, EPA, docosapentaenoic acid (DPA) and DHA percentage of total erythrocyte PLFA were significantly greater for the Ultimate Omega® group than for the MEG-3 group, at week 16 (P < 0.05), as were the EPA:arachidonic acid (AA) ratio, DHA:AA ratio and EPA+DHA:AA ratio. For serum PLFA profiles, increases in EPA:AA ratio and EPA+DHA:AA ratio were significantly greater at week 4 in the Ultimate Omega® group compared to the MEG-3 group (P < 0.05).

Conclusions: These data suggest that the percentage of rTG in rTG fish oil preparations may evolve as a new chemoprofile/quality control marker that can influence its lipidomic pharmacodynamics. Additional investigations to assess the physiologic/vascular and metabolic/inflammasome responses to concentrated fish oil preparations differing in the percentage of rTG are warranted.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arachidonic Acid
  • Capsules
  • Dietary Supplements
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid
  • Esterification
  • Esters
  • Fatty Acids
  • Fatty Acids, Omega-3*
  • Fish Oils*
  • Humans
  • Phospholipids
  • Triglycerides

Substances

  • Arachidonic Acid
  • Capsules
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid
  • Esters
  • Fatty Acids
  • Fatty Acids, Omega-3
  • fish oil triglycerides
  • Fish Oils
  • Phospholipids
  • Triglycerides

Grants and funding

SM reports personal fees from Nordic Naturals Inc. during the conduct of the study, and is an employee of Nordic Naturals, Inc. JO reports financial interests, as owner of Nordic Naturals, Inc., during the conduct of the study; in addition, Mr. Opheim has U.S. Patent No. 10596121 issued. The funder provided support in the form of salaries for one author [SM] but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. The funding organization (Nordic Naturals) did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials.