, Volume 36, Issue 1, pp 7-13

First online:

A long-term seal- and cod-liver-oil supplementation in hypercholesterolemic subjects

  • Jan BroxAffiliated withDepartment of Clinical Chemistry, University Hospital of Tromsø Email author 
  • , Kirsten OlaussenAffiliated withHammerfest Hospital
  • , Bjarne ØsterudAffiliated withDepartment of Biochemistry, Institute of Medical Biology, University of Tromsø
  • , Edel O. ElvevollAffiliated withNorwegian Institute of Fisheries and Aquaqulture Ltd.
  • , Eivin BjørnstadAffiliated withUniversity College of Finnmark
  • , Tormod BrennAffiliated withInstitute of Community Medicine, University of Tromsø
  • , Guttorm BrattebøAffiliated withUniversity Hospital of Bergen
  • , Hanne IversenAffiliated withHammerfest Hospital

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In this long-term study, we wanted to explore the effect of dietary supplementation of seal oil (SO) as compared cod-liver oil (CLO) on subjects with moderate hypercholesterolemia. The test parameters included fatty acid composition in serum, blood lipids, platelet aggregation, and the activity of blood monocytes. After a run-in period of 6 mon, 120 clinically healthy hypercholesterolemic (7.0–9.5 mmol/L; 270–366 mg/dL) subjects were randomly selected to consume either 15 mL of SO or CLO daily for 14 mon followed by a 4-mon wash-out period. A third group was not given any dietary supplement (control). Consumption of marine oils (SO and CLO) changed the fatty acid composition of serum significantly. Maximal levels were achieved after 10 mon. No further changes were seen after 14 mon. A wash-out period of 4 mon hardly altered the level of n−3 fatty acids in serum. Addition of SO gave 30% higher level of eicosapentaenoic acid, as compared to CLO. Subjects taking SO or CLO had lower whole-blood platelet aggregation than the control group. Neither SO nor CLO had any effects on the levels of serum total cholesterol, high-density lipoprotein cholesterol, postprandial triacylglycerol, apolipoproteins A1 and B100, lipoprotein (a), monocyte function expressed as monocyte-derived tissue factor expression, and tumor necrosis factor.