24-HOUR ENERGY-EXPENDITURE AND URINARY CATECHOLAMINES OF HUMANS CONSUMING LOW-TO-MODERATE AMOUNTS OF MEDIUM-CHAIN TRIGLYCERIDES - A DOSE-RESPONSE STUDY IN A HUMAN RESPIRATORY CHAMBER

Objective: To determine whether medium-chain triglycerides, in low-to- moderate amounts consumed with meals (at breakfast, lunch and dinner), can increase daily energy expenditure (EE) and 24-h urinary excretion of catecholamines in humans. Design: Dose-response study conducted un der double-blind randomised design. Setting: Respiratory chamber at th e Faculty of Medicine, University of Geneva.Subjects: Eight healthy yo ung men were recruited from the student population by advertisement in our Faculty. Methods: 24-h EE and urinary catecholamines were measure d in each subject during stay in a respiratory chamber on four separat e occasions. These were randomised between four different combinations of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT ), a total 30 g/day, which was consumed with their habitual diet in th ree equal parts (10g each) at breakfast, lunch, and dinner in the foll owing ratio of MCT : LCT (g/g) 0 : 30, 5 : 25, 15 : 15 and 30 : 0. Res ults: 24-h EE increased significantly with increasing MCT:LCT ratio (A NOVA, P < 0.001), with the diet providing a total of 15-30 g MCT per d ay stimulating 24-h EE by 5%: this corresponds to a mean absolute incr ease in daily EE of similar to 500kJ, with individual values varying b etween 268kJ and 756kJ. No significant differences were observed in re spiratory quotient nor in urinary nitrogen losses across diets, but 24 -h urinary noradrenaline was significantly increased (ANOVA, P < 0.025 ), whereas adrenaline and dopamine were unaltered. Conclusions: This s tudy suggests that relatively low-to-moderate intake of MCT (15-30g pe r day) as part of habitual diet may play a role in the control of huma n body composition by enhancing daily EE, and that this effect is medi ated at least in part through activation of the sympathetic nervous sy stem.