Hideto Takase

Diacylglycerol-induced improvement of whole-body insulin sensitivity in type 2 diabetes mellitus: A long-term randomized, double-blind controlled study

BACKGROUND & AIMS Diacylglycerol oil has been shown to lower postprandial and fasting serum triacylglycerol levels and reduce body fat. The aim of this study was to investigate the effect of diacylglycerol oil on risk factors of type 2 diabetes mellitus (DM) and cardiovascular disease in type 2 DM patients. METHODS This was a double-blind controlled parallel study with 127 type 2 DM patients (aged 40-65) recruited in Hangzhou, China. All subjects consumed triacylglycerol oil in the lead-in period (14 days), then they were randomly divided into two groups and consumed diacylglycerol or triacylglycerol oil with a similar fatty acid composition (25 g/day) for 120 days. Blood samples were collected on days 0, 60 and 120 and risk factors of type 2 DM and cardiovascular disease and biochemical parameters were measured by standard methods. RESULTS There were a total of 112 subjects who completed the study. Diet intake did not differ significantly between groups. Body weight, BMI, waist circumference, HOMA-IR, serum insulin and leptin levels were significantly reduced from baseline in the diacylglycerol oil group but not in the triacylglycerol oil group. Serum glucose was also significantly improved in patients with higher glucose levels at baseline (>7.00 mmol/L) in the diacylglycerol oil group. Parameters of liver and kidney functions and essential fatty acids in serum phospholipids did not differ between groups. CONCLUSIONS Diacylglycerol oil consumption improved biomarkers and anthropometric parameters of type 2 DM compared with triacylglycerol oil. No adverse reactions were observed with diacylglycerol oil consumption for type 2 DM patients. Diacylglycerol oil has an equivalent bioavailability as triacylglycerol oil in relation to providing essential fatty acids.

Minor effects of green tea catechin supplementation on cardiovascular risk markers in active older people: a randomized controlled trial.

Aim:  Although previous studies have shown that consumption of green tea catechins (GTC) and walking might prevent development of cardiovascular disease (CVD), the effects of GTC supplementation on CVD risk in active older people are unknown.

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.

Effect of low concentration of diacylglycerol on mildly postprandial hypertriglyceridemia

OBJECTIVE Previous studies have demonstrated that a high concentration of diacylglycerol (DAG) oil (approximately 80% in 10 g of test oil) suppressed increases in postprandial serum triglyceride (TG), particularly hypertriglyceridemia. However, the effects of a lower concentration of DAG oil have not been demonstrated. In the present study, the effective dose of DAG oil was determined in hypertriglyceridemia. METHODS Randomized, double-blind, cross-over design study was conducted using 22 patients with mild hypertriglyceridemia. Changes in postprandial serum lipid concentrations were analyzed after ingestion of 10 g of test oil containing 1.3% (control), 27.3% (low dose), 54.6% (medium dose) or 80.8% (high dose) of emulsified DAG. RESULTS The expanded Williams test indicated that the DAG dose that was most effective at altering postprandial serum TG and chylomicron-TG concentrations was ≥ 27.3% DAG in 10 g of test oil; ≥ 54.6% DAG in 10 g of test oil was needed to have an impact on postprandial serum apolipoprotein B-48 concentrations. Additionally, DAG was more effective in subjects with both hypertriglyceridemia and hypertension. In the current study, systolic blood pressure correlated with the increase in postprandial serum TG, suggesting that DAG improves hypertriglyceridemia, particularly when it is accompanied by hypertension. CONCLUSION DAG oil could be useful as an initial dietetic therapy for the treatment of postprandial hypertriglyceridemia with hypertension. The effective dose was ≥ 27.3% DAG in 10 g of oil.

The short-term effect of diacylglycerol oil consumption on total and dietary fat utilization in overweight women.

Diacylglycerol (DAG) is a natural component of edible oils with metabolic characteristics distinct from those of triacylglycerol (TAG). Consumption of DAG oil (containing >80% DAG) induces greater fat oxidation than consumption of TAG oil. We compared the effects of 4 days of DAG oil consumption with those of TAG oil consumption on total and dietary fat oxidation over 24 h in overweight women using a whole‐room respiratory chamber. Overweight (BMI (kg/m2) ≥25) females participated in this double‐blind, crossover‐controlled trial. The subjects consumed test diets containing either TAG or DAG oil as 15% of their total caloric intake (mean test oil intake was 33.0 ± 3.1 g/day) during each 4‐day treatment. Fat oxidation and energy expenditure were measured in a respiratory chamber on the 4th day of each treatment. Compared with TAG oil, DAG oil consumption significantly increased total fat oxidation and dietary fat oxidation in overweight subjects. Total energy expenditure (TEE) and carbohydrate (CHO) oxidation did not significantly differ between DAG oil and TAG oil consumption in overweight subjects. Compared with TAG oil, DAG oil consumption enhanced total fat oxidation and dietary fat oxidation in overweight subjects. The enhanced fat metabolism in overweight subjects that consumed DAG oil partly explains the greater loss of body weight and body fat related to DAG oil consumption in weight‐loss studies.

Effectiveness and safety of 1-year ad libitum consumption of a high-catechin beverage under nutritional guidance.

BACKGROUND It has been reported that a continuous intake of a catechin beverage will reduce body fat. Traditionally, improvement of eating and exercise habits has been the basis for prevention and reduction of obesity. In this study, we conducted a trial involving human subjects who ingested a catechin beverage for 1 year under nutritional guidance. METHODS This study was conducted based on a comprehensive cohort design using a catechin beverage (containing 588 mg of tea catechins) and a control beverage (containing 126 mg of tea catechins). At both the start and the end of the trial, the subjects underwent an annual health check and computer tomography for measurement of their abdominal fat. In addition, a food intake survey was conducted and all subjects were provided nutritional guidance by a registered dietitian every 3 months. RESULTS Data were analyzed using per protocol samples of 134 subjects (catechin group, n = 77; control group, n = 57). Body weight and body mass index were reduced significantly in the catechin group compared to the control group. Changes in body weight during the study period were -1.1 kg in the catechin group and 0.2 kg in the control group. In the catechin group, the visceral fat areas at the start of the trial were significantly correlated with the magnitude of fat reduction at the end of the trial. Under the guidance of a registered dietitian, subjects in the catechin group who showed a reduction in their fat-derived energy percentage during the test period tended to reduce more body weight than those with an increase in this percentage, although no difference in total energy intake was noted between the two groups. One-year ad libitum consumption of a catechin beverage posed no health risks and resulted in a reduction in body weight. CONCLUSIONS An overall improvement in dietary habits might enhance the weight-reduction effect of the beverage.

Association of dietary factors with abdominal subcutaneous and visceral adiposity in Japanese men

OBJECTIVE The aim of this study was to assess the relationship between dietary factors and abdominal subcutaneous and visceral adipose tissue in overweight and obese men. METHODS A pooled cross-sectional analysis was conducted to evaluate the associations between dietary factors (nutrition, dietary pattern and alcohol consumption) and subcutaneous fat area (SFA) and visceral fat area (VFA) in 301 Japanese men, aged 21-65 years. RESULTS The standardized regression coefficients of major dietary items (total energy intake, energy intake from breakfast, lunch, supper, between-meal, protein, fat, carbohydrate and alcohol) were positive for VFA in multiple linear regression analyses with the use of age and dietary items as independent variables. The energy intake from between-meal snacks correlated with SFA (standardized regression coefficient β = 0.174, p = 0.002). The coefficient of alcohol intake was positive for VFA and negative for SFA, and alcohol intake correlated with the VFA/total fat area (TFA) ratio (β = 0.130, p = 0.009). Alcohol intake was positively correlated with the blood non-esterified fatty acid concentration. Alcohol consumption additively increased energy intake from supper. The risk of an increase to VFA ≥ 100 cm(2) was 2.02 times higher (95% CI: 1.15, 3.56) for subjects whose energy intake was ≥ 2200 kcal/d, and 2.07 times higher (95% CI: 1.26, 3.42) in those who consumed ≥ 3 g/d alcohol. The risk of an increase to a VFA/TFA ratio ≥ 0.4 was 1.81 times higher (95% CI: 1.01, 3.23) for subjects whose energy intake from supper was ≥ 1000 kcal/d. CONCLUSION Our results indicate that habitual alcohol drinking and high-energy intake from supper are associated with disproportionate accumulation of visceral fat.

The effects of diacylglycerol oil on fat oxidation and energy expenditure in humans and animals

Studies in animals and humans indicate that diets containing diacylglycerol (DAG) oil (containing >80% DAG) decrease body weight gain and body fat accumulation, especially visceral fat. Body weight and body fat are controlled by energy expenditure, fat oxidation, fat storage capacity, and appetite control. Recent researches indicate that DAG oil, compared with conventional oils, has distinct metabolic effects. We review the evidence concerning the effects of DAG oil intake on fat oxidation and energy expenditure. In humans, dietary DAG is more susceptible to oxidation, and in animals 1,3‐DAG, a major component of DAG oil, is rapidly oxidized. Short‐term human studies with indirect calorimetry demonstrate greater fat oxidation with DAG oil consumption compared with triacylglycerol (TAG) oil consumption. Furthermore, DAG oil consumption for 14 days stimulates energy expenditure. Based on these reports, enhanced fat oxidation and energy expenditure by daily DAG oil intake could contribute to long‐term reductions in body weight and fat accumulation. The literature provides support for the notion that dietary DAG is more rapidly oxidized than dietary TAG, and that, compared with TAG oil, DAG oil consumption increases whole body fat oxidation. The effects of DAG oil consumption on energy expenditure, however, remain inconclusive.

Efficacy of tea catechin-rich beverages to reduce abdominal adiposity and metabolic syndrome risks in obese and overweight subjects: a pooled analysis of 6 human trials

This post hoc pooled analysis assessed the effectiveness of green tea catechins (GTC) to reduce the risk of metabolic syndrome (MetS) associated with abdominal fat reduction, because previous findings are unclear. Data were pooled from six human trials (n=921, 505 men) comparing the effects of GTC-containing beverages (540-588 mg GTC/beverage) and a placebo beverage. Outcome measures were abdominal fat [total fat area (TFA), visceral fat area (VFA), subcutaneous fat area (SFA)], and MetS risk. We estimated mean changes from baseline and calculated confidence intervals (CI) to assess reductions in abdominal fat accumulation and MetS improvement. Subclass analyses were performed by classifying subjects as Pre-MetS or MetS at trial initiation. Additional subclass analyses were performed with Pre-MetS and MetS subjects further stratified according to whether GTC intake reduced TFA, VFA, or SFA. Consumption of GTC-containing beverages for 12 weeks significantly reduced TFA (-17.7cm2, 95%CI: -20.9 to -14.4), VFA (-7.5cm2, 95%CI: -9.3 to -5.7), SFA (-10.2cm2, 95%CI: -12.5 to -7.8), body weight, body mass index, and waist circumference; and improved blood pressure. Subclass analyses of Pre-MetS and MetS subjects showed improved MetS in the GTC group [odds ratio (OR), 1.67; 95%CI: 1.08-2.57]. The ORs for improved MetS in the TFA- and VFA-reduced groups were 2.79 (95%CI: 1.28-6.09) and 4.36 (95%CI: 2.03-9.39), respectively. Continual consumption of GTC-containing beverages reduced abdominal fat and improved MetS, suggesting its potential to prevent diabetes and cardiovascular disease. Additional large-scale intervention trials are needed to evaluate the effects of GTC on the risk of MetS in high-risk populations.