Effect of tea catechins with caffeine on energy expenditure in middle-aged men and women: a randomized, double-blind, placebo-controlled, crossover trial.

PURPOSE: It has been reported that tea catechins increase energy metabolism, but their effect on resting metabolic rate (RMR) remains under debate. This study aimed to examine the effect of repeated intake of tea catechins on energy metabolism in the resting state in middle-aged men and women. METHODS: A total of 30 middle-aged men and women [13 women; age (mean ± SD) 52 ± 4 years; BMI 21.9 ± 2.2 kg/m2] were recruited. A randomized, double-blind, crossover study was conducted using a tea catechin-enriched beverage (611 mg catechins, 88 mg caffeine) and a placebo beverage (0 mg catechins, 81 mg caffeine) as test beverages. After 2 weeks of continuous test beverage intake, fasting RMR and energy expenditure (EE) after the ingestion of test beverage were measured. Measurements of forehead temperature (proxy for core temperature) and skin temperature were also obtained simultaneously. RESULTS: Among participants who underwent measurements, 26 (10 women; mean age 52 ± 4 years; mean BMI 22.1 ± 2.1 kg/m2) were analyzed. The EE increased significantly after ingestion of the tea catechin beverage compared with the placebo beverage (placebo treatment: 5502 ± 757 kJ/day; catechin treatment: 5598 ± 800 kJ/day; P = 0.041). No between-treatment differences in fasting RMR or the respiratory quotient were detected. In addition, the forehead and skin temperature did not differ significantly between the placebo and catechin treatments. CONCLUSION: This study revealed that continuous intake of tea catechins with caffeine for 2 weeks significantly increased EE after ingestion of the tea catechin but not fasting RMR in middle-aged men and women. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE: This trial was registered at www.umin.ac.jp/ctr/ as UMIN000025810 and UMIN000025811.

Effects of catechin-enriched ion beverage intake on thermoregulatory function in a hot environment.

We examined the effect of intake of a catechin-enriched ion beverage (Cat-I) on the thermoregulatory response in a hot environment. Eight healthy men were exposed to a hot environment for 90 min at an ambient temperature of 35 °C (relative humidity: 75%) combined with lower leg water immersion at 40 °C. At that time, either Cat-I, an ion beverage (Ion), or mineral water (Placebo) was consumed at three points: (1) at the start of lower leg immersion, (2) at 30 min after immersion, and (3) at 60 min after immersion. In all conditions, tympanic temperature (Tty) increased gradually during lower leg water immersion. However, the rate of increase of Tty tended to be suppressed after 30 min. The effect of drinking Cat-I had a limited detection period of approximately 60-70 min, and the rate of sweating was clearly increased with Cat-I compared with Ion and Placebo. Cat-I also tended to decrease the body temperature threshold at which sweating was induced compared with Ion or Placebo. These findings suggest that Cat-I efficiently suppressed the increase of body temperature in a hot environment.

Coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone improves postprandial endothelial dysfunction in patients with borderline and stage 1 hypertension.

PURPOSE: The purpose of this study was to evaluate acute effects of coffee with a high content of chlorogenic acids and different hydroxyhydroquinone contents on postprandial endothelial dysfunction. METHODS: This was a single-blind, randomized, placebo-controlled, crossover-within-subject clinical trial. A total of 37 patients with borderline or stage 1 hypertension were randomized to two study groups. The participants consumed a test meal with a single intake of the test coffee. Subjects in the Study 1 group were randomized to single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone or coffee with a high content of chlorogenic acids and a high content of hydroxyhydroquinone with crossover. Subjects in the Study 2 group were randomized to single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone or placebo coffee with crossover. Endothelial function assessed by flow-mediated vasodilation and plasma concentration of 8-isoprostanes were measured at baseline and at 1 and 2 h after coffee intake. RESULTS: Compared with baseline values, single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone, but not coffee with a high content of chlorogenic acids and high content of hydroxyhydroquinone or placebo coffee, significantly improved postprandial flow-mediated vasodilation and decreased circulating 8-isoprostane levels. CONCLUSIONS: These findings suggest that a single intake of coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone is effective for improving postprandial endothelial dysfunction. CLINICAL TRIAL REGISTRATION: URL for Clinical Trial: https://upload.umin.ac.jp ; Registration Number for Clinical Trial: UMIN000013283.

Effect of Chlorogenic Acids on Cognitive Function: A Randomized, Double-Blind, Placebo-Controlled Trial.

(1) Background: Chlorogenic acids (CGAs) have been attracting interest of late, owing to their health benefits. Here, we performed a randomized, double-blind, placebo-controlled trial to investigate whether CGAs improved cognitive function in humans. (2) Methods: Thirty-eight healthy participants were assigned to either the CGA group, which was given CGA-added beverage daily for 16 weeks, or the placebo group. Cognitive functions were assessed using the Japanese version of the CNS Vital Signs (Cognitrax). (3) Results: The CGA group showed significant increase in the Cognitrax domain scores for motor speed, psychomotor speed, and executive function compared with the placebo group, as well as an improvement in the shifting attention test scores. In blood analysis, the CGA group showed increased levels of apolipoprotein A1 and transthyretin, both of which are putative biomarkers for early-stage cognitive decline. (4) Conclusions: These results suggest that CGAs may improve some cognitive functions, which would help in the efficient performance of complex tasks.

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.

Effect of Chlorogenic Acid Intake on Cognitive Function in the Elderly: A Pilot Study.

OBJECTIVE: To evaluate the effect of chlorogenic acids (CGAs) intake on cognitive function. METHODS: In this pilot study, the Cogstate and CNS Vital Signs test batteries were used to evaluate cognitive function in 8 healthy elderly men and women complaining of subjective memory loss after a 6-month intake of a test beverage containing 330 mg of CGAs just before bedtime. RESULTS: After a 6-month CGA intake period, significant improvement was observed in the One Back Test of the Cogstate, the Shifting Attention Test, and Finger Tapping Test as well as in the composite memory, verbal memory, complex attention, cognitive flexibility, executive function, and motor speed domains of the CNS Vital Signs test battery. CONCLUSION: A 6-month intake of CGAs may improve attentional, executive, and memory functions in the elderly with complaints of subjective memory loss.

Effects of Chlorogenic Acid-Enriched and Hydroxyhydroquinone-Reduced Coffee on Postprandial Fat Oxidation and Antioxidative Capacity in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial.

Chlorogenic acids (CGAs) reduce blood pressure and body fat, and enhance fat metabolism. In roasted coffee, CGAs exist together with the oxidant component hydroxyhydroquinone (HHQ). HHQ counteracts the antihypertensive effects of CGA, but its effects on CGA-induced fat oxidation (FOX) are unknown. Here we assessed the effects of CGA-enriched and HHQ-reduced coffee on FOX. Fifteen healthy male volunteers (age: 38 ± 8 years (mean ± SD); BMI: 22.4 ± 1.5 kg/m²) participated in this crossover study. Subjects consumed the test beverage (coffee) containing the same amount of CGA with HHQ (CGA-HHQ(+)) or without HHQ (CGA-HHQ(−)) for four weeks. Postprandial FOX and the ratio of the biological antioxidant potential (BAP) to the derivatives of reactive oxygen metabolites (d-ROMs) as an indicator of oxidative stress were assessed. After the four-week intervention, postprandial FOX and the postprandial BAP/d-ROMs ratio were significantly higher in the CGA-HHQ(−) group compared with the CGA-HHQ(+) group (4 ± 23 mg/min, group effect: p = 0.040; 0.27 ± 0.74, group effect: p = 0.007, respectively). In conclusion, reducing the amount of HHQ facilitated the postprandial FOX effects of CGA in coffee. Our findings also suggest that the mechanism underlying the inhibition of FOX by HHQ is related to postprandial oxidative stress.

Effects of subacute ingestion of chlorogenic acids on sleep architecture and energy metabolism through activity of the autonomic nervous system: a randomised, placebo-controlled, double-blinded cross-over trial.

Chlorogenic acids (CGA) are the most abundant polyphenols in coffee. Continuous consumption of CGA reduces body fat and body weight. Since energy metabolism and sleep are controlled by common regulatory factors, consumption of CGA might modulate sleep. Lack of sleep has been identified as a risk factor for obesity, hypertension and type 2 diabetes. The aim of this study was to determine the effects of ingesting CGA over 5 d on energy metabolism and sleep quality in humans. A total of nine healthy subjects (four male and five female) completed a placebo-controlled, double-blinded, cross-over intervention study. Subjects consumed a test beverage containing 0 or 600 mg of CGA for 5 d. On the fifth night, subjects stayed in a whole-room metabolic chamber to measure energy metabolism; sleep was evaluated using polysomnographic recording. It was found that CGA shortened sleep latency (9 (sem 2) v. 16 (sem 4) min, P<0·05) compared with the control, whereas no effect on sleep architecture, such as slow-wave sleep, rapid eye movement or waking after sleep onset, was observed. Indirect calorimetry revealed that consumption of CGA increased fat oxidation (510 (sem 84) kJ/8 h (122 (sem 20) kcal/8 h) v. 331 (sem 79) kJ/8 h (81 (sem 19) kcal/8 h), P<0·05) but did not affect energy expenditure during sleep. Consumption of CGA enhanced parasympathetic activity assessed from heart-rate variability during sleep (999 (sem 77) v. 919 (sem 54), P<0·05). A period of 5-d CGA consumption significantly increased fat oxidation during sleep, suggesting that beverages containing CGA may be beneficial to reduce body fat and prevent obesity. Consumption of CGA shortened sleep latency and did not adversely affect sleep quality.

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 (ß = 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.

Safety evaluation of the consumption of high dose milk fat globule membrane in healthy adults: a double-blind, randomized controlled trial with parallel group design.

Consumption of milk fat globule membrane (MFGM) in combination with habitual exercise suppresses age-associated muscle loss. The effects of high dose MFGM, however, are not known. A double-blind, randomized controlled trial with parallel group design was conducted to evaluate the safety of consuming high dose MFGM tablets. The subjects were 32 healthy adult men and women. Subjects were given 5 times the recommended daily intake of the tablets containing 6.5 g of MFGM or whole milk powder for 4 weeks. Stomach discomfort and diarrhea were observed; however, these symptoms were transitory and slight and were not related to consumption of the test tablets. In addition, there were no clinically significant changes in anthropometric measurements or blood tests. Total degree of safety assessed by the physicians of all subjects was "safe." These findings suggest that consumption of the tablets containing 6.5 g MFGM for 4 weeks is safe for healthy adults.

Coffee bean polyphenols ameliorate postprandial endothelial dysfunction in healthy male adults.

To reveal the effect of coffee bean polyphenols (CBPs) on blood vessels, this study aimed to investigate the effect of CBPs on acute postprandial endothelial dysfunction. Thirteen healthy non-diabetic men (mean age, 44.9 ± 1.4 years) consumed a test beverage (active: containing CBPs, placebo: no CBPs) before a 554-kcal test meal containing 14 g of protein, 30 g of fat and 58 g of carbohydrates. Then, a crossover analysis was performed to investigate the time-dependent changes in flow-mediated dilation (FMD) in the brachial artery. In the active group, the postprandial impairment of FMD was significantly improved, the two-hour postprandial nitric oxide metabolite levels were significantly increased and the six-hour postprandial urinary 8-epi-prostaglandin F2α levels were significantly reduced compared to the placebo group. The test meal increased the levels of blood glucose, insulin and triglycerides in both groups with no significant intergroup differences. These findings indicate that CBPs intake ameliorates postprandial endothelial dysfunction in healthy men.

Coffee polyphenols improve peripheral endothelial function after glucose loading in healthy male adults.

Brewed coffee is a widely consumed beverage, and many studies have examined its effects on human health. We investigated the vascular effects of coffee polyphenols (CPPs), hypothesizing that a single ingestion of CPP during glucose loading would improve endothelial function. To test this hypothesis, we conducted a randomized acute clinical intervention study with crossover design and measured reactive hyperemia index (RHI) to assess the acute effects of a 75-g glucose load with CPP in healthy, nondiabetic adult men. Blood glucose and insulin levels were elevated after glucose loading with and without CPP, with no significant differences between treatments. The RHI did not significantly decrease after glucose loading without CPP. With CPP, however, RHI significantly (P < .05) increased over baseline after glucose loading. The difference between treatments was statistically significant (P < .05). No significant changes were observed in an oxidative stress marker after glucose loading with or without CPP. These findings suggest that a single ingestion of CPP improves peripheral endothelial function after glucose loading in healthy subjects.

Elimination of glycidyl palmitate in diolein by treatment with activated bleaching earth.

In this study, activated bleaching earth (ABE) was used to eliminate glycidyl esters from both triacyl- and diacylglycerol oils. To investigate the mechanism, glycerol dioleate containing glycidyl palmitate (GP) was treated with ABE and the fate of the GP was monitored by analyzing the feed, treated, and ABE-absorbed oils using a gas-liquid chromatograph equipped with a flame-ionized detector. GP was completely removed from both the treated and absorbed oils. This indicates that this treatment is useful for GE removal from diacylglycerol oil, although it was not achieved by absorption of GE on ABE but rather by modification of GP. The results of composition analysis demonstrate that GP is transformed to glycerol monopalmitate, glycerol palmitate oleate, and glycerol dipalmitate at a recovery rate of 99.1 ± 1.3 %. An increase in glycerol monooleate and trace amounts of free glycerol and fatty acids were also observed after treatment. The transformation is proposed to involve a ring-opening reaction of GP with water contained in the ABE and in the bulk oil followed by an interesterification reaction among the resultant monopalmitate and the glycerol dioleate of the bulk oil. All the generated compounds were simple acylglycerols and glycerol. Therefore, ABE treatment could be useful for GE removal during the manufacture of edible oils.

Comparison of indirect and direct quantification of glycidol fatty acid ester in edible oils.

Two different methods for determining the levels of glycidol fatty acid esters (GEs) in edible oil-the German official indirect method and the direct LC-MS method-are compared. In some cases, the indirect method showed lower GE levels than the direct method. This was investigated using model studies, which revealed two possible causative factors during the acid treatment of the indirect method: (1) incomplete elimination of GE in oil that was high in GEs initially and (2) generation of GEs and/or its relevant compounds in oil that was rich in partial acylglycerol. Both these factors contributed to the subsequent underestimation of GE levels. The above technical limitations of the indirect method found in the present study has led to the inference that the direct method can more precisely determine the GE levels for a wider range of fats and oil products than the indirect method.

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.

Hydroxyhydroquinone-free coffee: a double-blind, randomized controlled dose-response study of blood pressure.

BACKGROUND AND AIM: Coffee is rich in chlorogenic acids (CGA), whose metabolites may have beneficial effects such as anti-hypertensive effects. However, trial results concerning the effects of coffee on blood pressure (BP) are not consistent. A recent study suggested that hydroxyhydroquinone (HHQ), produced by the roasting of green coffee beans, inhibits the effect of CGA. In the present study, the dose-response for CGA in HHQ-free coffee on BP were investigated in mildly hypertensive men and women. METHODS AND RESULTS: The trial design was a double-blind, randomized controlled trial, with five study groups including, control, zero-dose, low-dose, middle-dose and high-dose. The control beverage was identical to ordinary coffee. The others contained reduced HHQ levels, compared to ordinary coffee, and the CGA were adjusted in target concentration. A total of 203 subjects were randomly allocated. Each subject drank one cup of coffee per day. The study involved a screening and a baseline observation period of 6 weeks and an intervention period of 4 weeks. BP response showed CGA has an anti-hypertensive effect in a dose-dependent manner in HHQ-free coffee, and ordinary coffee showed almost no effect. As a result, a significant correlation between BP change and the three dose-response patterns was observed (p<0.001). CONCLUSIONS: This study demonstrates a dose-dependent decrease in BP for CGA in HHQ-free coffee.