Background: Cardioprotective effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) of marine origin are well recognized. Because of the shortness of marine resources vegetable oils are increasingly used in fish farming. The effects on human health of fish fed on vegetable oils are largely unknown.
Methods: In a double-blinded intervention study, 60 patients with coronary heart disease (CHD) were randomly allocated to three groups consuming approximately 700 g per week for 6 weeks of differently fed Atlantic salmon: 100% fish oil (FO), 100% rapeseed oil (RO) or 50% of each (FO/RO), resulting in fillets with high, intermediate and low levels of marine n-3 PUFAs. Patient analyses before and after the intervention period included serum fatty acid profile, serum lipoproteins, and markers of vascular inflammation.
Results: The serum fatty acid profiles of the patients after the intervention mirrored those of the corresponding salmon fillets and the respective salmon feeds. Significant differences between the groups were obtained, especially for the levels of total n-3 PUFAs and the n-3/n-6 FA ratio, which were markedly increased in the FO group in contrast to the two other groups (P < 0.02 for all). Additionally, significant reductions of serum triglycerides and of vascular cell adhesion molecule-1 and interleukin-6 were obtained in patients receiving the FO diet when compared with the two other groups (P < 0.05 for all).
Conclusions: Tailor-made Atlantic salmon fillets very high in n-3 PUFAs of marine origin seem to impose favourable biochemical changes in patients with CHD when compared with ingestion of fillets with intermediate and low levels of marine n-3 PUFAs, when replaced by rapeseed oil.