N-acylethanolamines (NAE) are endogenous lipid signaling molecules involved in satiety and energetics, however, how diet impacts circulating NAE concentrations and their downstream metabolic actions in humans remains unknown. Objectives were to examine effects of diets enriched with high-oleic canola oil (HOCO) or HOCO blended with flaxseed oil (FXCO), compared to a Western diet (WD), on plasma NAE levels and the association with energy expenditure and substrate oxidation. Using a randomized controlled crossover design, 36 hypercholesterolemic participants consumed three isoenergetic diets for 28d, each containing 36% energy from fat, of which 70% was HOCO, FXCO or WD. UPLC-MS/MS was used to measure plasma NAE levels and indirect calorimetry to assess energy expenditure and substrate oxidation. After 28d, compared with WD, plasma OEA and ALEA levels were significantly increased in response to HOCO and FXCO (p = 0.002; p < 0.001), respectively. Correlation analysis demonstrated an inverse association between plasma OEA levels and percent body fat (r= -0.21, p = 0.04) and a positive association was observed between the plasma AEA/OEA ratio and android:gynoid fat (r = 0.23, p = 0.02), respectively. Results suggest that plasma NAE levels are upregulated via their dietary lipid substrates and may modulate regional and total fat mass through lipid signaling mechanisms.
Copyright © 2014, The American Society for Biochemistry and Molecular Biology.