Replacement of dietary saturated fat with unsaturated fats increases numbers of circulating endothelial progenitor cells and decreases number of microparticles: findings from the randomized, controlled DIVAS study

Abstract

Background Endothelial progenitor cells (EPC) and microparticles (MP) are emerging novel markers of cardiovascular disease (CVD) risk, which could potentially be modified by dietary fat. We have previously shown that replacing dietary saturated fat (SFA) with monounsaturated (MUFA) or n-6 polyunsaturated fat (PUFA) improved lipid biomarkers, blood pressure and markers of endothelial activation, but their effects on circulating EPCs and MPs are unclear. Objective The Dietary Intervention and VAScular function (DIVAS) study investigated the replacement of 9.5-9.6% total energy (%TE) SFA with MUFA or n-6 PUFA for 16 weeks on EPC and MP numbers in UK adults with moderate CVD risk. Design In this randomized, controlled, single-blind, parallel group dietary intervention, men and women aged 21-60 y (n=190) with moderate CVD risk (≥50% above the population mean) consumed one of three 16-week isoenergetic diets. Target compositions for total fat, SFA, MUFA and n-6 PUFA (%TE) were: SFA-rich diet (36:17:11:4, n=64), MUFA-rich diet (36:9:19:4, n=62) and n-6 PUFA-rich diet (36:9:13:10, n=66). Circulating EPC, endothelial MP (EMP) and platelet MP (PMP) numbers were analysed by flow cytometry. Dietary intake, vascular function and other cardio-metabolic risk factors were determined at baseline. Results Relative to the SFA-rich diet, MUFA and n-6 PUFA-rich diets decreased EMP (-47.3%, -44.9%) and PMP numbers (-36.8%, -39.1%) (overall diet effects P<0.01). The MUFA-rich diet increased EPC numbers (+28.4%; P=0.023). Additional analyses using stepwise regression models identified the augmentation index (measuring arterial stiffness determined by pulse wave analysis) as an independent predictor of baseline EPC and MP numbers. Conclusions Replacing 9.5-9.6%TE dietary SFA with MUFA increased EPC numbers and replacement with either MUFA or n-6 PUFA decreased MP numbers, suggesting beneficial effects on endothelial repair and maintenance. Further studies are warranted to determine the mechanisms underlying the favourable effects on EPC and MP numbers following SFA replacement