ST-ONGE, MARIE-PIERRE, ROBERT ROSS, WILLIAM D. PARSONS, AND PETER J.H. JONES. Medium-chain triglycerides increase energy expenditure and decrease adiposity in overweight men. Obes Res. 2003;11:395-402. Objective: The objectives of this study were to compare the effects of diets rich in medium-chain triglycerides (MCTs) or long-chain triglycerides (LCTs) on body composition, energy expenditure, substrate oxidation, subjective appetite, and ad libitum energy intake in overweight men. Research Methods and Procedures: Twenty-four healthy, overweight men with body mass indexes between 25 and 31 kg/m 2 consumed diets rich in MCT or LCT for 28 days each in a crossover randomized controlled trial. At baseline and after 4 weeks of each dietary intervention, energy expenditure was measured using indirect calorimetry, and body composition was analyzed using magnetic resonance imaging. Results: Upper body adipose tissue (AT) decreased to a greater extent (p Ͻ 0.05) with functional oil (FctO) compared with olive oil (OL) consumption (Ϫ0.67 Ϯ 0.26 kg and Ϫ0.02 Ϯ 0.19 kg, respectively). There was a trend toward greater loss of whole-body subcutaneous AT volume (p ϭ 0.087) with FctO compared with OL consumption. Average energy expenditure was 0.04 Ϯ 0.02 kcal/min greater (p Ͻ 0.05) on day 2 and 0.03 Ϯ 0.02 kcal/min (not significant) on day 28 with FctO compared with OL consumption. Similarly, average fat oxidation was greater (p ϭ 0.052) with FctO compared with OL intake on day 2 but not day 28.Discussion: Consumption of a diet rich in MCTs results in greater loss of AT compared with LCTs, perhaps due to increased energy expenditure and fat oxidation observed with MCT intake. Thus, MCTs may be considered as agents that aid in the prevention of obesity or potentially stimulate weight loss.

These data indicate that, in their free unesterified form, sterols and stanols lower plasma LDL cholesterol equivalently in hypercholesterolemic persons by suppressing cholesterol absorption.

The elimination of caffeine from saliva was compared in groups of healthy smokers (n = 13) and nonsmokers (n = 13). Mean caffeine t1/2 in smokers (3.5 hr) was shorter than that in the nonsmokers (6.0 hr). The body clearance of caffeine in the smokers (155 +/- 16 ml . kg-1 . hr-1) was greater than that in the nonsmokers (94 +/- 18 ml . kg-1 . hr-1) (p less than 0.05). No significant difference was noted in the apparent volume of distribution in smokers (720 +/- 67 ml . kg-1) and nonsmokers (610 +/- 80 ml . kg-1). These differences probably reflect the induction of hepatic aryl hydrocarbon hydroxylase (AHH) activity in smokers. The increased clearance of caffeine by smokers may contribute to the higher consumption of coffee reported to occur in this group.

OBJECTIVE:To determine the effects of long-term consumption of medium chain (MCT) versus long chain triglycerides (LCT) on energy expenditure (EE), substrate oxidation and body composition. HYPOTHESIS: MCT consumption will not result in greater EE, substrate oxidation, and body weight loss compared with LCT consumption. RESEARCH METHODS AND PROCEDURES: Seventeen healthy obese women participated in this randomized, crossover inpatient trial. Meals were prepared and consumed on site for two periods of 27 days. Diets containing 40% of energy as fat, with treatment fat comprising 75% of the total fat, were designed to supply each subject with their individual weight-maintaining energy needs. The MCT diet contained 67% of treatment fat as MCT oil (49% octanoate, 50% decanoate) whereas the LCT diet contained exclusively beef tallow as treatment fat. Body composition was assessed by magnetic resonance imaging (MRI) on day 1 and 28 of each phase while energy expenditure was measured on day 2 and 27. RESULTS: Changes in total and subcutaneous adipose tissue volumes following consumption of MCT and LCT were not different (70.61 AE 0.38 l vs 70.54 AE 0.48 l and 70.58 AE 0.35 l vs 70.48 AE 0.40 l, respectively). Average EE and fat oxidation were greater (P < 0.05) during MCT than LCT consumption (0.95 AE 0.019 vs 0.90 AE 0.024 kcal=min, respectively, for EE and 0.080 AE 0.0026 vs 0.075 AE 0.0022 g=min, respectively for fat oxidation). DISCUSSION: These results show that long-term consumption of MCT enhances EE and fat oxidation in obese women, when compared to LCT consumption. The difference in body composition change between MCT and LCT consumption, although not statistically different, was consistent with differences predicted by the shifts in EE. It can be concluded that substitution of MCT for LCT in a targeted energy balance diet may prevent long-term weight gain via increased EE.

To characterize further the pharmacokinetics of theophylline in premature infants, its concentraion in blood was measured by high-pressure liquid chromatography after intravenous infusion given to six apneic premature newborns three to 15 days of age. Theophylline's apparent volume of distribution was 0.690 +/- 0.095 liters per kilogram (mean +/- S.E.), a value similar to that of children, but the half-life (30.2 +/- 6.5 hours) was nine times longer. Blood clearance rate (17.6 +/- 2.3 ml per kilogram per hour) was lower than plasma clearance rate (100 ml per kilogram per hour) of young children. At a total plasma concentration of 17 mg per liter, 56.4 +/- 3.8 and 36.4 +/- 3.8 per cent of the theophylline was bound to adult or full-term cord plasma proteins, respectively. Bilirubin and theophylline did not compete for plasma protein. Calculations suggest that a loading doses of 5.5 mg per kilogram and a maintenance dose rate of 1.1 mg per kilogram per eight hours would achieve and maintain a mean blood concentration of 8 mg per liter (about 10 mg per liter in plasma).