Effects of krill oil and lean and fatty fish on cardiovascular risk markers: a randomised controlled trial

Abstract

Fish consumption and supplementation with n-3 fatty acids reduce CVD risk. Krill oil is an alternative source of marine n-3 fatty acids and few studies have investigated its health effects. Thus, we compared krill oil supplementation with the intake of fish with similar amounts of n-3 fatty acids on different cardiovascular risk markers. In an 8-week randomised parallel study, thirty-six healthy subjects aged 18–70 years with fasting serum TAG between 1·3 and 4·0 mmol/l were randomised to receive either fish, krill oil or control oil. In the fish group, subjects consumed lean and fatty fish, according to dietary guidelines. The krill and control group received eight capsules per d containing 4 g oil per d. The weekly intake of marine n-3 fatty acids from fish given in the fish group and from krill oil in the krill group were 4103 and 4654 mg, respectively. Fasting serum TAG did not change between the groups. The level of total lipids (P = 0·007), phospholipids (P = 0·015), cholesterol (P = 0·009), cholesteryl esters (P = 0·022) and non-esterified cholesterol (P = 0·002) in the smallest VLDL subclass increased significantly in response to krill oil supplementation. Blood glucose decreased significantly (P = 0·024) in the krill group and vitamin D increased significantly in the fish group (P = 0·024). Furthermore, plasma levels of marine n-3 fatty acids increased significantly in the fish and krill groups compared with the control (all P ≤ 0·0003). In conclusion, supplementation with krill oil and intake of fish result in health-beneficial effects. Although only krill oil reduced fasting glucose, fish provide health-beneficial nutrients, including vitamin D.

Effects of fish and krill oil on gene expression in peripheral blood mononuclear cells and circulating markers of inflammation: a randomised controlled trial

“…In summary, the down-regulation of these three genes may induce a shift toward glucose utilisation and away from gluconeogenesis. We have previously reported that intake of krill oil reduced fasting glucose in the same intervention ( 18 ) , and here we show that the change in fasting glucose correlates with the change in gene expression of PDK4 and PPARGC1A . The reduction in fasting glucose observed after krill oil intake may thus be partly mediated through down-regulation of the expression of these two genes.…”

“…We have previously reported that fasting glucose decreased in the krill group, vitamin D levels increased in the fish group and plasma n -3 levels increased in both the krill and fish groups ( 18 ) ; hence, we wanted to correlate these changes with the change in gene expression of glucose metabolism-related genes, inflammation-related genes and all the genes analysed, respectively. First, we found a positive and significant correlation between the change in fasting glucose and the change in gene expression of PDK4 and PPAGC1A , but not SLC25A12 ( Fig.…”

“…Compliance, estimated by capsule count in the krill group and the control group and a compliance checklist in the fish group, was 97, 97 and 100 %, respectively. The recruitment of subjects, eligibility criteria, description of study products and the design of the study have previously been described in detail ( 18 ) .…”

“…Routine laboratory analyses, including fasting serum TAG, glucose, cholesterol and vitamin D, were measured at a standard clinical routine laboratory (Fürst Medical Laboratory, Oslo, Norway). Plasma fatty acid analysis was performed at a certified chemical analysis laboratory (Vitas Analytical Service, Oslo, Norway), as previously described ( 18 ) .…”

Anticancer Properties of Krill Oil

“…It has been reported that krill oil contains more EPA than fish oil and they are similar in terms of DHA content (Tou et al, 2007). In fish and fish oil, almost all of EPA and DHA are in triglyceride (TG) form, whereas in krill oil, the majority of EPA and DHA (65%) are in phospholipid form (Rundblad, Holven, Bruheim, Myhrstad & Ulven, 2018;Winther, Hoem, Berge & Reubsaet, 2011). It has been reported that EPA and DHA in krill oil are better incorporated into the tissues thanks to the phospholipid form and exhibit a stronger effect than the TG form (Xie et al, 2017).…”