In this long-term study, we wanted to explore the effect of dietary supplem
entation of seal oil (SO) as compared cod-liver oil (CLO) on subjects with
moderate hypercholesterolemia, The test parameters included fatty acid comp
osition in serum, blood lipids, platelet aggregation, and the activity of b
lood monocytes. After a run-in period of 6 mon, 120 clinically healthy hype
rcholesterolemic (7.0-9.5 mmol/L; 270-366 mg/dL) subjects were randomly sel
ected to consume either 15 mi 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 (c
ontrol). Consumption of marine oils (SO and CLO) changed the fatty acid com
position 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 hard
ly altered the level of n-3 fatty acids in serum. Addition of SO gave 30% h
igher level of eicosapentaenoic acid, as compared to CLO. Subjects taking S
O 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 cholestero
l, high-density lipoprotein cholesterol, postprandial triacylglycerol, apol
ipoproteins A1 and B100, lipoprotein (a), monocyte function expressed as mo
nocyte-derived tissue factor expression, and tumor necrosis factor.