In this Randomized Controlled Trial (RCT) we want to study the effect of an oil with high concentrations of cetoelic acid (C22:n1-11) (intervention) compared to supplements with a low concentration of cetoleic acid (control), but with equivalent content of EPA og DHA, on plasma levels of epa and dha as well as atherosclerotic markers, glucose, c-peptide and triglycerides in a patient group with a metabolically unfavorable phenotype.

Our primary endpoints are changes in the concentration of EPA and DHA in plasma.

This is a randomized double-blinded controlled trial (randomized 1:1). Study population: men and women 20-70 years with a metabolically unfavorable phenotype defined as: triglycerides > 1.7 mmol/L and waist measurement > 80 cm (women) and > 94 cm (men).

Study design:

• 3 weeks run-in-period where all participants consume control capsules every morning.
• Randomization intervention: control (1:1). All participants consume their capsules (control or intervention) for 4 weeks.

The intervention oil is consists of an oil high in cetoleic acid and the control oil is low in cetoleic acid. Both the intervention oil and the control oil are a mix of different oils; fish oils, olive oil, "high-oleic sunflower oil" and rapeseed oil so that the content of EPA, DHA and ALA is similar in the two oils.

Power calculation and sample size:

It was expected a difference of 15% in n-3 between the groups after the intervention (Østbye et al. 2019, doi:10.1017/S0007114519001478).

The level of significance was set to 5% (two-sided) and the power to 80%. A total of thirty-eight subjects were required to participate in the study, but a high dropout rate was expected (20%) and it was considered necessary to include a total of seventy (n=70) subjects (thirty-five per arm).

Inclusion Criteria:

• Triglycerides > 1.7 mmol/L
• Waist measurement > 80 cm (women) and > 94 cm (men)

Exclusion Criteria:

• Chronic disease (liver/kidney/metabolism)
• Ongoing active cancer treatment
• Excessive alcohol consumption (>40g/day)
• Pregnant/breastfeeding or planned pregnancy during the intervention
• High intake of fish (>3 weekly meals)
• Level of free thyroxine (T4) and triiodothyronine (T3) outside reference ranges.
• Hypertension (≥ 160/ 100 mmHg)
• Total cholesterol > 7.8 mmol/L
• Blood donation during the intervention period
• Difficulty following the protocol
• Smoking or sniffing
• Regular use (> 1 day/week) of anti-inflammatory drugs
• Regular use of omega-3 supplements/cod liver oil
• Drug use other than stable use of statins, hypertension drugs (Ca antagonists, diuretics and beta blockers).
• Hormonal treatment excluding stable use of thyroxine and birth control pills/contraceptive rod

All participant, the major investigator, study coordinator and the study staff are blinded for the randomizing. The capsules and capsule containers will only be identifiable by the ID (identifying) numbers on the containers.

Allocation of participants to the specific intervention group is carried out by a statistician and one person not involved in conducting the study.