Differential effects of saturated and n-6 PUFA on blood lipids when co-administered with n-3 PUFA

Background/Aims: The influence of diets rich in saturated fatty acids (SFA) or n-6PUFA in modulating blood lipid levels remains unclear. Recently we hypothesised that the lipemic effects of saturated fats are dependent on n-3PUFA status. This study aimed to examine the effects of consuming diets rich in SFA or n-6PUFA when co-administered with marine n-3PUFA.
Methods: This was a randomised, controlled, parallel, dietary intervention trial involving 16 healthy adults aged 18 to 65 years. Subjects consumed a diet high in either SFA or n-6PUFA, each supplemented with 2.4g n-3PUFA daily for 6 weeks. Blood samples were collected after an overnight fast, at baseline and post-intervention, for analysis of blood lipid profile.
Results: A reduction in plasma triglyceride levels was noted post-intervention, which was similar following consumption of the SFA+n-3PUFA or the n-6PUFA+n-3PUFA diets (28% versus 27% respectively). The SFA diet caused a significant rise in LDL (P=0.043) and HDL-cholesterol (P=0.05), while the n-6PUFA had no effect on LDL or HDL-cholesterol levels. Total/HDL-cholesterol or LDL/HDL-cholesterol ratios were not significantly different post-intervention for either of the diets. The change in total/HDL-cholesterol or LDL/HDL-cholesterol ratios following SFA diet was also similar to those on n-6PUFA diet.
Conclusions: Dietary SFA and n-6PUFA differentially modulates plasma lipid profile when co-administered with n-3PUFA. The mechanism and consequence of concomitant increase in HDL and LDL-cholesterol following saturated fat consumption in association with n-3PUFA are worthy of further examination.
Funding source(s): CBD was supported by a scholarship from the Coordenação Nacional de Desenvolvimento Científico e Tecnológico, Brazil.