Six weeks of supplementation of diets with 2.5 percent krill oil or 2.5 percent fish oil were associated with cholesterol reduction of 33 and 21 percent, respectively, and liver triglyceride level reductions of 20 and 10 percent, respectively, Italian scientists report in the Journal of Animal Physiology and Animal Nutrition.
“We believe that the present investigation opens up new possibilities regarding the use of dietary krill oil as a preventive factor for dyslipidaemia,” wrote the researchers from the Department of Biological and Environmental Sciences and Technologies at the University of Salento.
The new study used Aker Biomarine’s Superba Krill Oil ingredient. The company donated the ingredient for use but did not fund the study.
Understanding krill
Krill are tiny shrimp gaining attention as a rich source of omega-3, as well as other nutrients.
There are about 85 species of the deepwater marine planktonic crustacean, or deepwater shrimp, which are the planet's most abundant animal biomass and which when captured and converted to oil, pack 48 times the antioxidant punch of standard fish oils, according to ORAC antioxidant scales.
The new study appears in line with recently reported findings from a human study, which found that krill oil may combat metabolic symptoms including raised fat levels in the heart and liver in obese individuals.
According to findings published in Nutrition & Metabolism (2011, 8:7), a daily two gram dose of krill oil was associated beneficial effects on the endocannabinoid system, which consists of a group of neuromodulatory lipids and receptors that influence appetite, pain sensation, mood and memory.
New study
The Italian researchers divided lab rats into three groups: One group was fed the control diet only, and the other two groups had their diets supplemented with 2.5 percent of either krill (Aker Biomarine) or fish oil (Lysi, Iceland).
Results showed that the activity of enzymes in the liver (acetyl-CoA carboxylase (ACC) and fatty acid synthetase (FAS)) involved in the metabolism of fat in the liver were significantly inhibited by both fish and krill oil, with the effect being more pronounced for krill after two and three weeks.
However, after six weeks, there was no difference between fish and krill oil, with inhibition of about 60 percent measured for both supplements.
“These data suggest a higher potency of krill oil in decreasing hepatic lipogenesis when compared to fish oil at relatively short periods of dietary treatment (2–3 weeks). Whether this effect is due to a better bioavailability of n-3 polyunsaturated fatty acids in krill oil, or to a different ratio of EPA to DHA in the two oils is currently unknown,” said the researchers.
“The inhibition of lipogenesis observed in krill oil-fed animals is most probably the cause of the decrease in the liver concentration of both triglycerides and cholesterol,” they added. “And this, in turn, may play a role in the hypolipidemic effects of krill oil.”
Aker welcome
The results were welcomed by Kjetil Berge, PhD, R&D director at Aker BioMarine. "These studies confirm the beneficial effects of krill oil on liver lipid levels that we have previously seen in two different animal models of obesity,” said Berge.
“Moreover, the study elucidated the mechanism behind the beneficial effects of omega-3 supplementation, by demonstrating regulation of lipid synthesizing enzymes. This study gives us a foundation to study cellular mitochondrial processes in more detail in future studies,” he added.
Source: Journal of Animal Physiology and Animal Nutrition
Published online ahead of print, DOI: 10.1111/j.1439-0396.2011.01135.x
“A krill oil supplemented diet reduces the activities of the mitochondrial tricarboxylate carrier and of the cytosolic lipogenic enzymes in rats”
Authors: A. Ferramosca, L. Conte, V. Zara