Effects of daily medium-chain triglyceride ingestion on energy metabolism and endurance performance capacity in well-trained runners

Abstract

The purpose of this study was to assess the effect of medium-chain triglyceride (MCTG) supplementation on energy metabolism and endurance performance capacity in well-trained runners. Seven men (age 19.4±1.7 years, maximal O 2 uptake 67.5±4.8 ml · min −1 · kg −1) were tested before and after MCTG as well as placebo consumption daily for 7 days. The energy and nutrient intake of the subjects did not differ in MCTG and placebo trial. The running time to exhaustion after dietary intervention was respectively 3916±1225 s in placebo trial and 3498±559 s in MCTG trial. The concentration of β-hydroxybutyric acid in plasma was the highest (1.029±0.67 mmol · l −1) in post-test samples after MCTG supplementation, significantly differing from the pre-test concentration in the same trial as well as from that observed in post-test blood after placebo treatment. These results suggest that daily MCTG supplementation increases the availability of ketone bodies for oxidation in working muscle during high intensity endurance exercise, but does not improve endurance performance capacity.