Fish oils rich in omega-11 (Cetoleic acid) may significantly reduce cholesterol by a 14%, according to a new study from the University of Bergen and Haukeland University Hospital in Norway.
Five weeks of supplementation with Cetoleic acid-rich fish oil also led to significant improvements in insulin sensitivity and glucose levels. The oil used in the study is a natural oil from North Atlantic fish, naturally rich in LCMUFAs, with cetoleic acid as the predominant fatty acid. The oil is from Pelagia and refined by Epax.
The Norway-based researchers published the findings of their rat study in the British Journal of Nutrition and noted that cholesterol, insulin sensitivity and glucose levels are measures where standard fish oil with EPA/DHA has shown little or no effects.
"The two marine oils, that is, herring oil (containing cetoleic acid) and anchovy oil (virtually devoid of cetoleic acid), had remarkably different effects on the cholesterol metabolism in diabetic rats," they wrote. "We conclude that consumption of a diet containing herring oil leads to a lower cholesterol concentration in a relevant rat model for T2D in humans."
The majority of the fish oil used for human nutrition is derived from anchovies and sardines because of the naturally high concentrations of EPA and DHA omega-3s. These are long-chain polyunsaturated fatty acids, or LC-PUFAs. On the other hand, North Atlantic fish like herring and mackerel have lower EPA and DHA concentrations, but high levels of long-chain monounsaturated fatty acids (LC-MUFAs).
Cetoleic acid is the most abundant LC-MUFA, representing between 10-22% of the overall LC-MUFA content, followed by gadoleic acid and gondoic acid, depending on the type of fish.
The new study, led by Professor Oddrun Anita Gudbrandsen, examined the effect of consuming fish oil with or without cetoleic acid for five weeks on cholesterol levels. The researchers used male Zucker Diabetic Sprague Dawley rats and fed them diets containing herring oil (HERO) or anchovy oil (ANCO) or a control diet with soybean oil.
The results showed that serum total cholesterol levels were 14% lower in the HERO group after five weeks, compared to both the ANCO and control groups.
"This finding in a rat model with type 2 diabetes induced by a Western diet is of great interest, especially since diabetes increases the risk for developing CHD in humans," Professor Gudbrandsen said.
Indeed, previous research suggests that a reduction in total cholesterol concentration of 3% may reduce the risk of CHD by 15%.
The study was run by University of Bergen, Norway and funded by Norwegian Seafood research fund.
Pelagia and Epax have been exploring the potential health benefits of different cetoleic acid-rich fish oils.
Earlier this year, supplementation with different Cetoleic acid-rich herring oil increased the Omega-3 Index and improved different measures of skin health.
Data published in Prostaglandins, Leukotrienes and Essential Fatty Acids indicated that 2 g per day of the cetoleic-rich oil lead to similar increases in the Omega-3 Index as the same dose of omega-3 oil from anchovy, despite containing 33% less EPA and DHA than the anchovy-derived oil.
Additional results from the skin health study, which employed a 4 g per day dose, showed that people consuming the cetoleic-rich oil had significantly less skin redness, which is connected to a lower inflammatory response to the facial cleansing process.
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.