Postprandial fatty acid metabolism with coconut oil in young females: a randomized, single-blind, crossover trial

Abstract

Background: Approximately 84% of the fatty acids contained in coconut oil (CO) are saturated fatty acids (SFAs), and approximately 47% of the SFA are lauric acid with 12 carbon atoms. Lauric acid carbon chain length is intermediate between medium and long-chain fatty acids (LCFAs). We examined how CO acts on lipid-related substances in the blood to determine whether its properties were similar to medium-chain fatty acids (MCFAs) or LCFAs.

Methods: This is a randomized controlled, single-blind, crossover study. Fifteen females were enrolled, using 3 test meals containing 30 g each of 3 different oils: CO (CO-meal), medium-chain triacylglycerol oil (MCT-meal), and long-chain triacylglycerol oil (LCT-meal). Blood samples were collected at fasted baseline and every 2 h for 8 h after the intake of each test meal.

Results: Repeated measures ANOVA of the ketone bodies and triglyceride (TG) showed an interaction between time and the test meal (P < 0.01 and P < 0.001, respectively). In subsequent Tukey's honestly significant difference (HSD) test of the ketone bodies, statistically significant differences were observed between the CO-meal and the LCT-meal (P < 0.05) 83.8 (95% CI, 14.7, 153.0) and between the MCT-meal and the LCT-meal (P < 0.05) 79.2 (95% CI, 10.0, 148.4). The incremental area under the curve (iAUC) and maximum increase in very low-density lipoprotein cholesterol (VLDL-C) and intermediate-density lipoprotein cholesterol (IDL-C) were the lowest for CO-meal intake.

Conclusions: The characteristics of lauric acid contained in CO, including the kinetics of β-oxidation and effects on blood TG, were very similar to those of MCFA. Moreover, regarding the iAUC and peak increment, VLDL-C and IDL-C were the lowest with the CO-meal. These results suggest that the intake of CO after fasting does not increase the TG, VLDL-C, and IDL-C, and may help prevent dyslipidemia. This trial was registered at UMIN (URL of registration: https://www.umin.ac.jp) as UMIN000019959.

Keywords: IDL-cholesterol; VLDL-cholesterol; coconut oil; free fatty acids (FFA); ketone bodies; lauric acid; long-chain fatty acid (LCFA); medium-chain fatty acid (MCFA); triglyceride (TG).