Metabolic Impact of VLCPUFA-Rich Fish Oil: A Clinical Study on Omega-3 Index Enhancement in Healthy Individuals

November 3, 2026 updated by: National Heart, Lung, and Blood Institute (NHLBI)

Background:

Fish oils contain omega-3 fatty acids that play important roles in the body. Researchers are studying a new type of fish oil that contains very-long-chain omega-3 fatty acids (VLCPUFAs). They want to learn how this fish oil affects omega-3 levels in the blood and other measures related to health.

Objective:

To learn how a VLCPUFA-enriched fish oil changes omega-3 levels in the blood compared with a standard fish oil.

Eligibility:

Healthy adults ages 18 to 60 years with a body mass index (BMI) between 18 and 30 kg/m^2 may be eligible.

Design:

Participants will take part in the study for about 28 to 30 weeks and will have approximately 4 to 5 clinic visits plus a follow-up phone call.

Participants will complete screening tests to determine whether they are eligible. These may include a physical examination, blood tests, measurement of height and weight, visual testing, cognitive testing, and questions about their diet, exercise, medications, and daily habits.

Participants will take 2 fish oil capsules by mouth every day for 8 weeks. They will then stop taking study capsules for about 12 weeks. After that, they will take a different fish oil capsule for another 8 weeks.

One fish oil contains very-long-chain omega-3 fatty acids (VLCPUFAs), and the other contains standard omega-3 fatty acids. Participants will not know which type they are taking during each study period.

Blood samples and other study assessments will be collected at the beginning and end of each treatment period to measure changes in omega-3 levels and other study markers.

Participants will receive a follow-up phone call about one week after taking their last dose of study supplement.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Study Description:

This study is designed to investigate changes in the omega-3 index (ratio of omega-3 fatty acids (eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)) over total RBC fatty acids) following supplementation with a fish oil enriched in very long chain polyunsaturated fatty acids (VLCPUFA) versus a standard, commercially available, over-the-counter (OTC), fish oil enriched in DHA. VLCPUFA-enriched fish oil provides roughly 10-fold the amount of VLCPUFA found in conventional fish oils. The oil was developed as a dietary supplement by Epax Norway AS. It may offer several potential advantages over standard fish oils in the improvement of risk factors for age-related macular degeneration (AMD) and cardiovascular disease (CVD) because of its higher content of VLCPUFAs. The study is designed as a double-blinded, randomized crossover study measuring differences in the omega-3 index following fish oil supplementation in healthy subjects.

Objectives:

Primary Objective: Compare the Omega-3 index score of participants given a DHA-rich fish oil versus those given VLCPUFA-rich fish oil.

Secondary Objective: Evaluate changes of biomarkers related to lipoprotein metabolism for VLCPUFA-rich fish oil.

Exploratory Objective:

  • Evaluate changes in clinical markers of cardiometabolic health, neurocognition and visual acuity with the VLCPUFA-rich fish oil.
  • Characterize the early absorption profile and interindividual variability of VLCPUFA-rich fish oil under standardized fasting conditions following a single oral dose in participants who elect to complete the optional overnight Metabolic Unit visit.

Endpoints:

Primary Endpoint: Changes in patient Omega-3 index in participants given DHA-rich fish oil (control) versus those given VLCPUFA-rich fish oil.

Secondary Endpoint: Changes in standard lipid panel and Nuclear Magnetic Resonance (NMR) lipoprotein profile in participants given DHA-rich fish oil versus those given VLCPUFA-rich fish oil.

Exploratory Endpoints:

  • Changes from baseline markers of glucose, fatty acid (FA) metabolism, red blood cell fatty acid profile, inflammation and coagulation in participants given a DHA-rich fish oil versus those given VLCPUFA-rich fish oil.
  • Evaluate changes in neurocognitive tests and visual acuity tests from baseline in participants given a DHA-rich fish oil versus those given VLCPUFA-rich fish oil.
  • Baseline-adjusted changes in plasma fatty acid concentrations (including VLCPUFAs and related omega-3 fatty acids) over the first approximately 2 hours following administration of the study product during the optional overnight Metabolic Unit visit.

Study Type

Interventional

Enrollment (Estimated)

200

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • Recruiting
        • National Institutes of Health Clinical Center
        • Contact:
          • NIH Clinical Center Office of Patient Recruitment (OPR)
          • Phone Number: TTY dial 711 800-411-1222
          • Email: ccopr@nih.gov

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

  • INCLUSION CRITERIA

In order to be eligible to participate in this study, an individual must meet all the following criteria:

  1. Male or female, age 18-60 years, in good general health in accordance with PI evaluation.

  2. Body Mass Index (BMI) >18 and <30 kg/m^2.

  3. Ability to take oral medication.

  4. Participant demonstrates willingness to sign the informed consent form, comply with all study procedures.

  5. For females of childbearing potential, stated willingness to use an accepted method of contraception for the duration of the study. Accepted methods of contraception are:

    • Contraceptive implant
    • Intrauterine device (hormonal or copper IUD)
    • Permanent procedures: vasectomy, bilateral salpingectomy, or tubal occlusion
    • Oral contraceptives (the pill)
    • Contraceptive patch
    • Contraceptive vaginal ring
    • Injectable contraceptives
    • Male or female condoms (typically as a secondary method)
    • Diaphragm or cervical cap
    • Sterilization (of either partner)
    • Previously documented menopause for women as applicable

  6. Screening labs within normal levels. Minor deviations from the normal screening labs are allowed per PI discretion.

EXCLUSION CRITERIA

An individual who meets any of the following criteria will be excluded from participation in this study:

  1. Current or recent (2 months or less) use of omega-3 fatty acid supplements or foods enriched with omega-3 fatty acids (no more than two servings of fish per week), bile-acid sequestrants, plant sterol supplements, anticoagulants, fibrates, Niacin, or daily use of NSAIDs or medication that can affect lipid metabolism or any endpoint of the study (to be reviewed by the PI).
  2. Subjects who have started or stopped medications that did not reach a stable baseline; subjects taking chronic medications or supplements.
  3. Pregnancy (or planned pregnancy) or lactation.
  4. Subjects planning a significant change in diet or exercise levels.
  5. Known allergic reactions to fish or shellfish or omega-3 fatty acids supplements, and subjects with bleeding disorders.
  6. Current use of anticoagulant or antiplatelet drugs.
  7. History of heavy menstruation, chronic diarrhea, gastric bypass or lap-band procedures, ostomies, bowel motility problems, or presence of other conditions that could affect intestinal fat absorption.
  8. Acute and life-threatening conditions, such as prior sudden cardiac arrest, acute myocardial infarction (last three months), stroke, embolism.
  9. Subject with known history of Atrial Fibrillation.
  10. Anticipated surgery during the study period.
  11. Previous blood donation within 3 months of the start of the study.
  12. Any other reason or clinical condition that the PI judges would interfere with study participation and/or be unsafe for a participant.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: DHA-rich Fish Oil VLCPUFA-rich Fish Oil

Participants receive DHA-rich fish oil during the first intervention period, followed by VLCPUFA-rich fish oil during the second intervention period, according to the study crossover design.
Dietary supplement: VLCPUFA-rich fish oil

Fish oil enriched in very-long-chain polyunsaturated fatty acids (VLCPUFAs), developed by Epax Norway AS.

Dietary supplement: DHA-rich fish oil

Standard commercially available over-the-counter fish oil enriched in docosahexaenoic acid (DHA), used as the comparator. In this randomized crossover study, participants receive both the DHA-rich fish oil and the VLCPUFA-rich fish oil in a randomized sequence.
Experimental: VLCPUFA-rich Fish Oil DHA-rich Fish Oil

Participants receive VLCPUFA-rich fish oil during the first intervention period, followed by DHA-rich fish oil during the second intervention period, according to the study crossover design.
Dietary supplement: VLCPUFA-rich fish oil

Fish oil enriched in very-long-chain polyunsaturated fatty acids (VLCPUFAs), developed by Epax Norway AS.

Dietary supplement: DHA-rich fish oil

Standard commercially available over-the-counter fish oil enriched in docosahexaenoic acid (DHA), used as the comparator. In this randomized crossover study, participants receive both the DHA-rich fish oil and the VLCPUFA-rich fish oil in a randomized sequence.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Omega-3 Index
Time Frame: Baseline and after each 8-week intervention period

Change in the Omega-3 Index, defined as the percentage of EPA plus DHA relative to total red blood cell fatty acids, following supplementation with VLCPUFA-rich fish oil compared with control fish oil.
Baseline and after each 8-week intervention period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • Principal Investigator: Marcelo J Amar, M.D., National Heart, Lung, and Blood Institute (NHLBI)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

November 9, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

October 17, 2026

First Submitted That Met QC Criteria

October 19, 2026

First Posted (Actual)

October 20, 2026

Study Record Updates

Last Update Posted (Actual)

November 4, 2026

Last Update Submitted That Met QC Criteria

November 3, 2026

Last Verified

October 14, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 10002202
  • 002202-H

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All IPD that underlie results in a publication

IPD Sharing Time Frame

3-6 months after the publication

IPD Sharing Access Criteria

Data for this study will be shared in open access repositories

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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