Study suggests Omega-11-rich fish oil can lower cholesterol levels, according to research conducted on rats

After five weeks of supplementation with Cetoleic acid-rich fish oil, there were significant improvements in insulin sensitivity and glucose levels. The oil used in the study is a natural oil from North Atlantic fish, which is naturally rich in LCMUFAs with cetoleic acid as the predominant fatty acid. The oil is sourced from Pelagia and refined by Epax.

Researchers based in Norway published their findings from a rat study in the British Journal of Nutrition and observed that standard fish oil with EPA/DHA has limited to no effects on cholesterol, insulin sensitivity, and glucose levels.

According to the researchers, herring oil (containing cetoleic acid) and anchovy oil (low in cetoleic acid) had significantly different effects on cholesterol metabolism in diabetic rats. Consuming a diet with herring oil led to lower cholesterol concentrations in a relevant rat model for T2D compared to anchovy oil.

Most of the fish oil used for human consumption comes from anchovies and sardines due to their high concentrations of EPA and DHA omega-3s. Conversely, North Atlantic fish like herring and mackerel have lower EPA and DHA levels but are rich in long-chain monounsaturated fatty acids (LC-MUFAs).

Cetoleic acid, the most abundant LC-MUFA, makes up 10-22% of the overall LC-MUFA content, followed by gadoleic acid and gondoic acid, depending on the fish species.

Study details

The study led by Professor Oddrun Anita Gudbrandsen investigated the impact of consuming fish oil with or without cetoleic acid for five weeks on cholesterol levels. Male Zucker Diabetic Sprague Dawley rats were fed diets containing herring oil (HERO) or anchovy oil (ANCO) or a control diet with soybean oil.

Results showed that after five weeks, serum total cholesterol levels were 14% lower in the HERO group compared to the ANCO and control groups.

Professor Gudbrandsen commented on the findings, stating that the cholesterol reduction in a rat model with type 2 diabetes is significant given the increased risk of coronary heart disease in humans with diabetes.

The study was conducted by the University of Bergen, Norway and funded by the Norwegian Seafood Research Fund.

Building the science

Pelagia and Epax have been exploring the potential health benefits of various cetoleic acid-rich fish oils.

Earlier this year, supplementation with different cetoleic acid-rich herring oil increased the Omega-3 Index and improved various measures of skin health.

Published data indicated that cetoleic-rich oil had similar Omega-3 Index increases as anchovy oil despite containing 33% less EPA and DHA. Further results from the skin health study showed reduced skin redness in participants consuming the cetoleic-rich oil.

Source: British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S0007114524001454
“Intake of herring oil, but not of anchovy oil, resulted in a lower serum cholesterol concentration in male Zucker Diabetic Sprague Dawley rats”
Authors: E.V. Rimmen et al.

EDITOR’S NOTE: The previous version inaccurately stated that the oil used was CETO3 by Grøntvedt Biotech. The correct oil used in the study is herring oil from Pelagia/Epax. We apologize for any confusion.