The study also suggests the oil’s intake plays an important role in the metabolism of cholesterol, adding to its cardiovascular benefiting credentials.
Another oil used in the study, high-oleic sunflower oil (HOSO) also appeared to down-regulate sixteen genes, including those involved in inflammation.
“We are very satisfied with this long-term collaboration and that we manage to show that krill oil is effective in reducing fasting plasma levels of glucose,” said Dr Inge Bruheim, research manager at Rimfrost.
“To our knowledge this has not been shown in humans before, however, studies in animal have predicted this effect. These interesting results will be investigated further in new clinical trials focusing on prevention of type 2 diabetes.”
Krill’s bioavailability edge?
The study, carried out in cooperation with Oslo Metropolitan University and the University of Oslo, points to krill oil’s advantages that add to its established sustainability positives.
In krill oil, up to 65 % of omega-3 fatty acids are stored as phospholipids, possibly explaining its superior bioavailability and bioactivity when compared to fish-derived omega-3 fatty acids.
In addition to omega-3 fatty acids, krill oil contains astaxanthin, an antioxidant with potential health-beneficial effects.
Although the mechanisms underlying the beneficial effects of omega-3 fatty acids are not fully understood, they include alteration of membrane fatty acid composition and modulation of gene expression.
As well as Rimfrost, major players in the European market include, Akerbiomarine, Nordic Naturals and Iceland-based omega-3 and fish oil specialist Lysi.
Study details
In the study, the team began an eight-week trial, involving 36 healthy men and women aged 18–70 years with fasting triglyceride (TAG) of 1·3–4·0 millimols per litre (mmol/l)
These men and women were randomised to receive krill oil capsules (sample - 12), HOSO capsules (12) or lean and fatty fish (12).
The weekly intakes of marine omega-3 fatty acids from the interventions were 4654, 0 and 4103 milligrams (mg), respectively.
The research team found intake of both krill oil and fish increased plasma levels of omega-3 fatty acids. The astaxanthin-rich krill oil also reduced fasting glucose.
Interestingly, krill oil altered the peripheral blood mononuclear cell mRNA expression of genes involved in glucose and cholesterol metabolism.
Fish altered the mRNA expression of four genes and HOSO down-regulated sixteen genes, including several inflammation-related genes.
Gene down-regulation
“In conclusion, analysis of PBMC gene expression after intake of krill oil, HOSO and lean and fatty fish revealed that intake of krill oil and HOSO with added astaxanthin regulated more genes than intake of fish,” the study said.
“Furthermore, krill oil down-regulated the expression of several genes, such as genes involved in glucose and cholesterol metabolism as well as β-oxidation, while HOSO down-regulated several genes, including genes involved in inflammation.”
However, as the team analysed a limited number of genes in each pathway, they recommended the need for further studies investigating the whole-genome transcriptome after intake of krill oil and lean and fatty fish.
Source: Journal of Nutritional Science
Published online: doi.org/10.1017%2Fjns.2018.2
“Effects of fish and krill oil on gene expression in peripheral blood mononuclear cells and circulating markers of inflammation: a randomised controlled trial”
Authors: Rundblad et al.