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).

Objective: The purpose of this study was to determine whether supplements of plant sterols and/or glucomannan improve lipid profile and cholesterol biosynthesis in mildly hypercholesterolemic type II diabetic and non-diabetic subjects and to compare the response of these two subject groups to the treatments. Design: A randomized, crossover study consisting of four phases of 21 days, with each phase separated by a 28-day washout. Setting: The Mary Emily Clinical Nutrition Research Unit of McGill University. Subjects: Eighteen non-diabetic individuals and 16 type II diabetic individuals aged 38-74 years. Interventions: Subjects were supplemented with plant sterols (1.8 g/day), glucomannan (10 g/day), a combination of glucomannan and plant sterols, and a placebo, provided in the form of bars. Results: Overall plasma cholesterol concentrations were lowered (Po0.05) after combination treatment (4.7270.20 mmol/l) compared to control (5.4770.18 mmol/l). Plasma low-density lipoprotein (LDL) cholesterol concentrations were decreased (Po0.05) after glucomannan (3.1670.14 mmol/l) and combination treatments (2.9570.16 mmol/l) compared to control (3.6070.16 mmol/l). The results of lipid profiles did not differ between subject groups. Overall plasma lathosterol concentrations, an index of cholesterol biosynthesis, were lowered (Po0.05) after the combination treatment compared to the plant sterol treatment. Conclusions:The results suggest that glucomannan and a combination of glucomannan and plant sterols substantially improves plasma LDL cholesterol concentrations.

In comparison with plant sterols or exercise alone, the combination of plant sterols and exercise yields the most beneficial alterations in lipid profiles. Implementation of such a combination therapy could improve lipid profiles in those at risk of coronary artery disease.

It has been suggested that phytosterol and phytostanol esters possess similar cholesterol-lowering properties, however, whether mechanisms responsible are identical has not been addressed. To address this question, cholesterol plasma levels, absorption, biosynthesis, and turnover were measured in 15 hypercholesterolemic subjects consuming prepared diets each over 21 d using a crossover design. Diets contained either i ) margarine (M), ii ) margarine with phytosterol esters (MSE) (1.84 g/d), or iii ) margarine with phytostanol esters (MSA) (1.84 g/d). Cholesterol absorption was measured using the ratio of [ 13 C]cholesterol oral :D 7 -cholesterol IV ; biosynthesis using D incorporation from D 2 O and turnover by D 7 -cholesterol IV decay rates. Plasma total cholesterol level at d 21/22 was lower ( P Ͻ 0.05) for MSE (13.4%) but not MSA (10.2%) versus M (6.0%) diets. Plasma low density lipoprotein-cholesterol (LDL-C) mean reductions at d 21/22 were larger ( P Ͻ 0.05) for MSE (12.9%) and MSA (7.9%) compared with M (3.9%). Plasma TG and high density lipoprotein-cholesterol (HDL-C) levels did not differ across diets. Cholesterol absorption was reduced ( P Ͻ 0.05) 36.2 and 25.9% at d 21 for MSE and MSA versus M, while cholesterol biosynthesis was reciprocally increased ( P Ͻ 0.05) 53.3 and 37.8% for MSE and MSA versus M, respectively. Cholesterol turnover was not influenced by diet. These data indicate that plant sterol and stanol esters differentially lower circulating total and LDL cholesterol levels by suppression of cholesterol absorption in hypercholesterolemic subjects. -