Background/Aims: Although, the health benefits of long chain n-3PUFA are well known, the effects of n-3PUFA status on blood lipid modulation by background dietary fats is not well understood.Therefore, this study aimed to determine the effects of diets high in either saturated fatty acids (SFA) or n-6PUFA following pre-supplementation with n-3PUFA.
Methods: This was a randomised, controlled, parallel, dietary intervention trial involving 22 healthy adults aged 18 to 65 years. Participants consumed 2.4g n-3PUFA daily for 4 weeks and then were randomized to one of 2 diets, enriched either with SFA or n-6PUFA combined with 2.4g n-3PUFA daily for at least 10 days. Blood samples and anthropometric measurements were collected after an overnight fast, at baseline, after 4 weeks and post-intervention. Blood samples were assessed for lipid [total, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol and triglyceride] levels.
Results: Pre-supplementation with n-3PUFA decreased plasma triglycerides (P=0.006) and increased HDL cholesterol (P=0.032) and body mass index (BMI) (P<0.001) significantly. After the SFA and n-6PUFA diets no further change was observed in plasma triglycerides, HDL cholesterol or BMI. The SFA diet caused an increase in total and LDL cholesterol (P=0.008 and P=0.013, respectively), while the n-6PUFA diet caused a decrease in total and LDL cholesterol (P=0.003, both).
Conclusions: Pre-supplementation with n-3PUFA does not influence changes in blood lipid levels induced by type of background dietary fat.
Funding source(s): Hunter Medical Research Institute (HMRI) and Coordenação Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil).