Effect of Herring Oil Concentrate on LDL Cholesterol Concentration in Adults

September 28, 2025 updated by: Oddrun Anita Gudbrandsen, University of Bergen

A Study on the Effect of Consuming a Herring Oil Concentrate on LDL Cholesterol Concentration in Adults With Overweight or Obesity

High cholesterol concentration is a major risk factor for cardiovascular disease (CVD), and consumption of fish has been associated with a lower CVD risk in several studies. The beneficial health effects of consuming fish have traditionally been ascribed to the long-chain PUFA (LC-PUFA) EPA (C20:5n-3) and DHA (C22:6n-3), although consumption of fish oils or concentrates with high EPA and DHA contents does not affect the cholesterol concentration in humans and lowers the cholesterol concentration in rats and mice only when given in very high doses. Fish oils contain a plethora of fatty acids besides EPA and DHA, and in recent years, increased focus has been on the long-chain MUFA (LC-MUFA) cetoleic acid (C22:1n-11). Cetoleic acid is found in high amounts in oils from certain fish species such as herring, which has relatively low contents of both EPA and DHA. The investigators have recently summarised and meta-analysed the available literature that investigates the effects of diets containing fish oils or fish oil concentrates that have a high content of cetoleic acid but low or no content of EPA and DHA on cholesterol concentration in rodents, showing that cetoleic acid-rich fish oils and concentrates prevent high cholesterol concentration.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

80

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 Locations

  • Norway
      • Bergen, Norway
        • University of Bergen

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • BMI over 25 kg/m2
  • Stable body weight last 3 months

Exclusion Criteria:

  • Allergies towards fish, milk, egg, gluten
  • Tobacco use (cigarettes or snus)
  • Diseases affecting the heart, intestinal function, kidney function or insulin secretion
  • Use of medications targeting cholesterol -or glucose metabolism
  • Use of dietary supplements
  • Pregnant or breastfeeding
  • Following a strict diet
  • Had bariatric surgery or using medications for weight loss
  • Recent or planned surgical procedures
  • High intake of fish/seafood

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: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Herring oil concentrate
Dietary supplement: herring oil concentrate in capsules, 4 g oil daily for 8 weeks
Dietary supplement: Herring oil concentrate
Capsules containing herring oil concentrate, taken daily for 8 weeks.
Placebo Comparator: Control oil
Dietary supplement: control oil in capsules, 4 g oil daily for 8 weeks
Dietary supplement: Control
Capsules containing control oil, taken daily for 8 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum concentration of LDL-cholesterol
Time Frame: 8 weeks
LDL-cholesterol will be measured in fasting serum samples
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Body composition
Time Frame: 8 weeks
Percent body fat will be measured using bioimpedance
8 weeks
Serum concentration of HDL-cholesterol
Time Frame: 8 weeks
HDL-cholesterol will be measured in fasting serum samples
8 weeks
Serum concentration of total cholesterol
Time Frame: 8 weeks
Total cholesterol will be measured in fasting serum samples
8 weeks
Serum concentrations of apolipoproteins
Time Frame: 8 weeks
Lipoproteins will be measured in fasting serum samples
8 weeks
Serum concentrations of amino acids metabolites
Time Frame: 8 weeks
Metabolites of amino acids will be measured in fasting serum samples
8 weeks
Serum concentration of one-carbon pathway metabolites
Time Frame: 8 weeks
Metabolites in the one-carbon pathway will be measured in fasting serum samples
8 weeks
Fatty acid composition in leukocytes
Time Frame: 8 weeks
Leukocytes will be isolated from fasting serum before quantification of fatty acids
8 weeks
Serum concentration of glucose
Time Frame: 8 weeks
Glucose will be measured in serum sampled in fasting condition
8 weeks
Serum concentration of insulin
Time Frame: 8 weeks
Insulin will be measured in serum sampled in fasting condition
8 weeks

Collaborators and Investigators

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

Sponsor

University of Bergen

Collaborators

The Norwegian Seafood Research Fund

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 (Actual)

August 12, 2024

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

April 6, 2024

First Submitted That Met QC Criteria

April 10, 2024

First Posted (Actual)

April 15, 2024

Study Record Updates

Last Update Posted (Estimated)

October 2, 2025

Last Update Submitted That Met QC Criteria

September 28, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 697716

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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