Krill oil supplementation to a high-fat (Western) diet was effective in reducing plasma lipid levels, with the effects via a different mechanism to fish oil, says a new study with lab mice.
Six weeks of supplementation with fish oil or krill oil were associated with increased omega-3 levels in the lab animals, report researchers in Nutrition & Metabolism , with similar increases reported despite a lower krill oil dose being used.
Scientists from the prestigious Karolinska Institutet (Sweden), the University of Bergen (Norway), Haukeland University Hospital (Norway), and Aker BioMarine Antarctica also report that, while only fish oil supplementation reduced triglycerides, krill oil was more efficient at reducing levels of arachidonic acid in plasma and liver.
“When comparing krill and fish oil supplementation, we found differences in the metabolic regulation of genes involved in lipid degradation and synthesis,” commented author Veronika Tillander, PhD. “While fish oil mainly increased the degradation of lipids, krill oil decreased the expression of genes involved in endogenous fatty acid and cholesterol synthesis.”
Krill are deep-water marine planktonic crustaceans that look like tiny shrimps. Oil from the little critters is an excellent source of the long-chain omega-3 fatty acids EPA and DHA, which are carried by phospholipids rather than triglycerides (as in fish oil).
Krill oil supplements appear to be answering consumer demand for an alternative to fish oil supplements, and the smaller capsules and ‘improved consumer experience’ appears to be resonating with some consumers.
Indeed, Aker Biomarine has said that krill sales were up 43% in the natural channel in 2012, with krill accounting for 12% of total omega-3 supplement sales in the mass market.
For the new study, Dr Tillander and her co-workers fed three groups of male mice a high fat diet, and supplemented the diets of two groups with either fish oil or krill oil for six weeks.
Results showed that the two omega-3 fatty acid supplementation regime promoted different gene expression profiles in the livers and the intestines of the lab animals. With krill oil, an effect on cholesterol and lipid synthesis was observed. On the other hand, fish oil was associated with an increase in the expression of several genes involved in fatty acid metabolism.
“The major factors contributing to these differences are likely the different content and structure of the omega-3 PUFAs in fish oil and krill oil,” wrote the researchers.
The results were welcomed by Tove Flem Jacobsen, VP of R&D and Regulatory Affairs, Aker BioMarine Antarctic; “This study expands our knowledge base on the beneficial effects of krill oil on lipid metabolism. And it represents an important step in strengthening krill oil's position in the triglyceride-lowering market.”
Source: Nutrition & Metabolism
“Fish oil and krill oil supplementations differentially regulate lipid catabolic and synthetic pathways in mice”
Authors: V. Tillander, B. Bjorndal, L. Burri, P. Bohov, J. Skorve, R.K. Berge, S.E.H. Alexso