Biotechnology company Rimfrost (Fosnavåg, Norway) announced the online publication of a study1 in the Journal of Molecular Nutrition and Food Research showing that krill-derived ingredients—the company’s specialty—reduce atherosclerosis in mice.
The study is the latest product of a long-term collaboration that Rimfrost established with the University of Bergen in Norway for the purpose of learning more about the biological effects and mechanisms of action of proteins and lipids derived from Antarctic krill.
Aware of Antarctic krill as an excellent source of omega-3 fatty acids and high-quality proteins, the researchers set out to investigate the effect of those components on blood lipid levels and atherosclerosis development in 60 ApoE knockout (apoEKO) mice—experimental models for dyslipidemia and atherosclerosis. The researchers assigned the mice to four groups that they then fed either a Western diet containing casein protein and fat (the control) or “Western-like diets” differing from the control in that the casein and/or fat was partially replaced by krill proteins, krill oil or both krill oil and proteins.
Study results showed that the mice fed krill oil plus protein and krill oil alone saw a significant reduction in cholesterol levels vis-à-vis the control. Further, atherosclerosis development in the aorta was lower in all experimental groups—krill protein, krill oil and krill oil plus protein—compared to the control. However, atherosclerosis reduction in the aortic sinus was apparent only among mice in the krill oil group. Liver steatosis, or fatty liver—another measure the researchers tracked—was sporadic in the krill oil and krill oil plus protein mice, but common in the control and krill protein groups.
Based on the results, the researchers conclude that diets containing krill oil not only inhibit plaque development and prevent liver damage but can reduce cholesterol levels by affecting expression of genes involved in cholesterol metabolism, including the gene that codes for the key enzyme HMG-CoA reductase. But while krill proteins also reduce atherosclerosis, they do so through mechanisms unrelated to lipid metabolism.
“It was interesting to find that krill protein reduced atherosclerosis by a different mechanism than krill oil,” notes Rolf Kristian Berge, a professor at the University of Bergen and one of the study’s authors, in a press release. One explanation for its action might be krill protein’s high level of arginine, an amino acid precursor to the synthesis of nitric oxide (NO), which improves human vascular function. Another explanation Berge posits is that proteins digested in the gastrointestinal track might release bioactive peptides “also known from the literature to have cardiovascular protective effects,” he says.
- Parolini C et al. “Effect of dietary components from Antarctic krill on atherosclerosis in apoE-deficient mice.” Journal of Molecular Nutrition and Food Research. Published online ahead of print August 15, 2017.