Background – Numerous health benefits have been attributed to both eicosapentaenoic acid (EPA, 20:5n3) and docosahexaenoic acid (DHA, 22:6n3) found in fish oil. However, docosapentaenoic acid (DPA, 22:5n3) found particularly in red meat has been less well studied. Australians consume 6 times more meat than we do fish. The richest commercial capsule source of DPA available is seal oil.
Objective – To compare the effects of DPA rich seal oil supplementation with DHA rich fish oil, on measures of plasma lipids in hypertriglyceridaemic subjects.
Design – A randomised, parallel, placebo controlled, double blind study was conducted in 52 hypertriglyceridaemic subjects. They were randomly allocated to one of three groups receiving a total of 1g/d EPA, DPA & DHA but different relative amounts: seal oil capsules (360mg EPA, 250mg DPA, 450mg DHA), fish oil capsules (210mg EPA, 30mg DPA, 810mg DHA) or placebo capsules (containing a vegetable oil) for 6 weeks. Fasting blood samples were taken at baseline and at 6 week post intervention. Blood samples were tested for red blood cell (RBC) fatty acids and plasma lipids (triglycerides, total cholesterol, LDL-C and HDL-C).
Outcomes – Seal oil supplementation significantly increased incorporation of DPA (from 2.5-2.7%), DHA (from 4.9-5.8%) and EPA (from 1-1.8%), p<0.0005), whereas fish oil increased incorporation of DHA only (from 5.2- 6.2%), p<0.01 into RBC. Plasma triglycerides remained unchanged in the placebo group (2.30-2.36mmol/l), whilst reductions of 7% (2.24-2.09mmol/l) and 14% (2.54-2.19mmol/l) were seen in the fish oil and seal oil groups respectively, but only the seal oil group reached significance (p<0.05).
Conclusion – Seal oil supplementation increased RBC levels of DPA, EPA and DHA whilst DHA rich fish oil supplementation increased RBC levels of DHA only. It appears that seal oil may be more effective than fish oil at lowering plasma triglyceride levels in hypertriglyceridaemic subjects.
Acknowledgement – Supported by funding from Meat and Livestock Australia.