Koichi Yasunaga

Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults

This study evaluated the influence of a green tea catechin beverage on body composition and fat distribution in overweight and obese adults during exercise-induced weight loss. Participants (n = 132 with 107 completers) were randomly assigned to receive a beverage containing approximately 625 mg of catechins with 39 mg caffeine or a control beverage (39 mg caffeine, no catechins) for 12 wk. Participants were asked to maintain constant energy intake and engage in >or=180 min/wk moderate intensity exercise, including >or=3 supervised sessions per week. Body composition (dual X-ray absorptiometry), abdominal fat areas (computed tomography), and clinical laboratory tests were measured at baseline and wk 12. There was a trend (P = 0.079) toward greater loss of body weight in the catechin group compared with the control group; least squares mean (95% CI) changes, adjusted for baseline value, age, and sex, were -2.2 (-3.1, -1.3) and -1.0 (-1.9, -0.1) kg, respectively. Percentage changes in fat mass did not differ between the catechin [5.2 (-7.0, -3.4)] and control groups [-3.5 (-5.4, 1.6)] (P = 0.208). However, percentage changes in total abdominal fat area [-7.7 (-11.7, -3.8) vs. -0.3 (-4.4, 3.9); P = 0.013], subcutaneous abdominal fat area [-6.2 (-10.2, -2.2) vs. 0.8 (-3.3, 4.9); P = 0.019], and fasting serum triglycerides (TG) [-11.2 (-18.8, -3.6) vs. 1.9 (-5.9, 9.7); P = 0.023] were greater in the catechin group. These findings suggest that green tea catechin consumption enhances exercise-induced changes in abdominal fat and serum TG.

Brown adipose tissue is involved in diet-induced thermogenesis and whole-body fat utilization in healthy humans

Background/Objectives:Brown adipose tissue (BAT) is a potential therapeutic target against obesity and diabetes through thermogenesis and substrate disposal with cold exposure. The role of BAT in energy metabolism under thermoneutral conditions, however, remains controversial. We assessed the contribution of BAT to energy expenditure (EE), particularly diet-induced thermogenesis (DIT), and substrate utilization in human adults.Methods:In this cross-sectional study, BAT activity was evaluated in 21 men using 18F-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) after cold exposure (19 °C). The subjects were divided into BAT-positive (n=13) and BAT-negative (n=8) groups according to the 18F-FDG-PET/CT findings. Twenty-four hour EE, DIT and respiratory quotient were measured using a whole-room indirect calorimeter at 27 °C.Results:Body composition, blood metabolites and 24-h EE did not differ between groups. DIT (%), calculated as DIT divided by total energy intake, however, was significantly higher in the BAT-positive group (BAT-positive: 9.7±2.5%, BAT-negative: 6.5±4.0%, P=0.03). The 24-h respiratory quotient was significantly lower (P=0.03) in the BAT-positive group (0.861±0.027) than in the BAT-negative group (0.889±0.024).Conclusion:DIT and fat utilization were higher in BAT-positive subjects compared to BAT-negative subjects, suggesting that BAT has a physiologic role in energy metabolism.

Fat utilization in healthy subjects consuming diacylglycerol oil diet: dietary and whole body fat oxidation.

Several studies in animals and humans have reported beneficial effects of diacylglycerol (DAG) on lipid and energy metabolism. We assessed the effect of DAG versus triacylglycerol (TAG) treatment on total energy expenditure (TEE), total fat oxidation (Fox) and respiratory quotient (RQ), and measured the oxidation rate of each oil using a respiratory chamber and the 13C-stable isotope. Eleven healthy subjects participated in a double-blind, randomized crossover study. Subjects consumed an energy maintenance diet consisting of 55% of total calories from carbohydrate, 15% from protein and 30% from fat during both the 3-day pre-chamber and 36-h chamber period. Fifty percent of the fat was test oil, containing either DAG oil or TAG oil. The oxidation rate of ingested test oils was determined by monitoring 13CO2 excretion in the breath from 13C-labeled diolein or 13C-labeled triolein. There were no significant differences in TEE, RQ and total Fox between the DAG and TAG treatment in the overall analysis. In the subgroup analysis, DAG treatment decreased RQ significantly in subjects with a high fat ratio (HFR) compared to TAG treatment. In addition, ingested diolein oxidation in DAG treatment was significantly faster than triolein oxidation in TAG treatment in the HFR group. Enhanced fat utilization with DAG treatment and rapid oxidation of ingested DAG may, at least in part, explain the greater loss of body weight and body fat related to DAG consumption found in the weight-loss studies.

Greater fat oxidation with diacylglycerol oil consumption for 14 days compared with triacylglycerol oil consumption in overweight men and women.

Background:Several studies have reported increased fat oxidation with diacylglycerol (DAG) oil consumption. However, the effects of long-term DAG oil consumption on energy metabolism remain to be investigated.Objective:The objective of this study was to compare the effects of 14 days of either DAG or triacylglycerol (TAG) oil consumption on substrate oxidation, energy expenditure (EE) and dietary fat oxidation.Design:Eight males and six females participated in this randomized, double-blind, crossover feeding study. Each patient consumed the 14-day controlled test diet containing either 10 g day−1 of DAG or TAG oil for acclimatization before a respiratory chamber measurement, followed by a 2-week washout period between diet treatments. Substrate oxidation and EE were measured in the respiratory chamber at the end of each dietary treatment. The patients consumed test oil as 15% of total caloric intake in the respiratory chamber (mean test oil intake was 36.1±6.6 g day−1).Results:Twenty-four hour fat oxidation was significantly greater with 14 days of DAG oil consumption compared with TAG oil consumption (78.6±19.6 and 72.6±14.9 g day−1, respectively, P<0.05). There were no differences in body weight or body composition between diet treatments. Dietary fat oxidation was determined using the recovery rate of 13CO2 in breath, and was significantly enhanced with DAG oil consumption compared with TAG oil consumption, measured over 22 h after ingestion of 13C-labelled triolein. Resting metabolic rate (RMR) was significantly greater with DAG oil consumption compared with TAG oil consumption (1766±337 and 1680±316 kcal day−1, respectively, P<0.05).Conclusion:Consumption of DAG oil for 14 days stimulates both fat oxidation and RMR compared with TAG oil consumption, which may explain the greater loss of body weight and body fat with DAG oil consumption that has been observed in weight-loss studies.

Tea catechin and caffeine activate brown adipose tissue and increase cold-induced thermogenic capacity in humans

Background: The thermogenic effects of green tea catechin have been repeatedly reported, but their mechanisms are poorly understood.Objective: The aim of this study was to investigate the acute and chronic effects of catechin on brown adipose tissue (BAT), a site specialized for nonshivering thermogenesis, in humans.Design: Fifteen healthy male volunteers underwent fluorodeoxyglucose-positron emission tomography to assess BAT activity. To examine the acute catechin effect, whole-body energy expenditure (EE) after a single oral ingestion of a beverage containing 615 mg catechin and 77 mg caffeine (catechin beverage) was measured. Next, to investigate the chronic catechin effects, 10 men with low BAT activity were enrolled. Before and after ingestion of the catechin beverage 2 times/d for 5 wk, cold-induced thermogenesis (CIT) after 2 h of cold exposure at 19°C, which is proportional to BAT activity, was examined. Both the acute and chronic trials were single-blinded, randomized, placebo-controlled, season-matched crossover studies.Results: A single ingestion of the catechin beverage increased EE in 9 subjects who had metabolically active BAT (mean ± SEM: +15.24 ± 1.48 kcal, P < 0.01) but not in 6 subjects who had negligible activities (mean ± SEM: +3.42 ± 2.68 kcal). The ingestion of a placebo beverage containing 82 mg caffeine produced a smaller and comparative EE response in the 2 subject groups. Multivariate regression analysis revealed a significant interaction between BAT and catechin on EE (β = 0.496, P = 0.003). Daily ingestion of the catechin beverage elevated mean ± SEM CIT (from 92.0 ± 26.5 to 197.9 ± 27.7 kcal/d; P = 0.009), whereas the placebo beverage did not change it.Conclusion: Orally ingested tea catechin with caffeine acutely increases EE associated with increased BAT activity and chronically elevates nonshivering CIT, probably because of the recruitment of BAT, in humans. These trials were registered at www.umin.ac.jp/ctr/ as UMIN000016361.

Transient energy deficit induced by exercise increases 24-h fat oxidation in young trained men

Whole body fat oxidation increases during exercise. However, 24-h fat oxidation on a day with exercise often remains similar to that of sedentary day, when energy intake is increased to achieve an energy-balanced condition. The present study aimed to examine a possibility that time of the day when exercise is performed makes differences in 24-h fat oxidation. As a potential mechanism of exercise affecting 24-h fat oxidation, its relation to exercise-induced transient energy deficit was examined. Nine young male endurance athletes underwent three trials of indirect calorimetry using a metabolic chamber, in which they performed a session of 100 min of exercise before breakfast (AM), after lunch (PM), or two sessions of 50 min of exercise before breakfast and after lunch (AM/PM) at 65% of maximal oxygen uptake. Experimental meals were designed to achieve individual energy balance. Twenty-four-hour energy expenditure was similar among the trials, but 24-h fat oxidation was 1,142 ± 97, 809 ± 88, and 608 ± 46 kcal/24 h in descending order of its magnitude for AM, AM/PM, and PM, respectively (P < 0.05). Twenty-four-hour carbohydrate oxidation was 2,558 ± 110, 2,374 ± 114, and 2,062 ± 96 kcal/24 h for PM, AM/PM, and AM, respectively. In spite of energy-balanced condition over 24 h, exercise induced a transient energy deficit, the magnitude of which was negatively correlated with 24-h fat oxidation (r = -0.72, P < 0.01). Similarly, transient carbohydrate deficit after exercise was negatively correlated with 24-h fat oxidation (r = -0.40, P < 0.05). The time of the day when exercise is performed affects 24-h fat oxidation, and the transient energy/carbohydrate deficit after exercise is implied as a factor affecting 24-h fat oxidation.

Fat mass, abdominal fat distribution, and C-reactive protein concentrations in overweight and obese men and women.

BACKGROUND Previous work suggests a positive correlation between intraabdominal adipose tissue and high-sensitivity C-reactive protein (hsCRP). We sought to further explore the relationships between body fat mass/distribution and hsCRP levels in sedentary overweight and obese men and women. METHODS Body composition and abdominal fat areas were measured using dual-energy X-ray absorptiometry and abdominal computed tomography, respectively. Concentrations of hsCRP were measured in serum by nephelometry. RESULTS Values for hsCRP were 3.2 ± 0.3 mg/L and 4.8 ± 0.6 mg/L in men and women, respectively. Fat mass was nonsignificantly (P=0.09) higher in women (38.8 ± 1.0 kg) than men (36.2 ± 1.1 kg). Abdominal visceral adipose tissue (VAT) area was greater in men than women (104.5 ± 5.7 vs. 59.6 ± 4.3 cm(2), P<0.001) whereas women had greater abdominal subcutaneous adipose tissue (SAT) area compared to men (334.6 ± 11.6 vs. 285.0 ± 13.4 cm(2), P<0.01). Significant associations were present between hsCRP concentrations (natural log transformed) and total fat mass (r=0.502, P<0.01), VAT (r=0.241, P<0.05), and SAT (r=0.418, P<0.01) in men, whereas a significant association for women was found only for total fat mass (r=0.359, P<0.01). Multiple regression analyses showed that men and women had similar concentrations of hsCRP for a given age and fat mass. In both men and women, neither VAT nor SAT area independently predicted hsCRP when included individually or separately in models with age and fat mass. CONCLUSIONS Results suggest that whole body fat mass, but not abdominal fat distribution, is associated with hsCRP concentrations in overweight and obese men and women.

Actual Daily Intakes of Tea Catechins and Thier Estimation According to Four Season 3 Day Weighed Dietary Records and a Short Food Frequency Questionnaire among Japanese Men and Women

Background: Tea catechins are considered to be important preventive factors of cancer on several organs; however, the relationships of the actual daily intakes (ADIs) on the preventive effects have not been adequately addressed. We measured the ADIs of tea catechins as annual averages derived from every their ingested cups recorded by each subject, and the estimation models were established considering tea origin. Methods: Fifty-nine Japanese men and women completed four season 3 day weighed dietary records (WDRs) and a food frequency questionnaire (FFQ), and samples of green, oolong and black teas, ingested during a total 12 days were collected for the analysis. The ADIs of the total and composed catechins of all tea samples were measured by a high-performance liquid chromatography. The estimation models for the ADIs (R2: coefficient of determination) based on the WDRs and FFQ were established with multiple regression analysis using appropriate confounding factors. V Results: The ADIs of total catechins and epigallocatechin gallate (EGCg) were 110 and 21.4 mg/day in men and 157 and 34.7 mg/day in women, respectively. The total catechins ADIs were positively associated with green tea consumption based on WDRs and FFQ (adjusted R2 =0.421 and 0.341 for men and 0.346 and 0.238 for women, p<0.05 for all, respectively). Likewise, the EGCg ADIs were associated with green tea intake derived from WDRs and FFQ, respectively. Conclusions: We revealed the ADIs of total catechins and EGCg as annual averages could establish their estimation models. These provide reference information to clarify their relationships with cancer risks.