-
1.
Effects of chronic decaffeinated green tea extract supplementation on lipolysis and substrate utilization during upper body exercise.
Blicher, S, Bartholomae, E, Kressler, J
Journal of sport and health science. 2021;(2):237-242
Abstract
BACKGROUND Decaffeinated green tea extract (dGTE) can increase fat oxidation during leg exercise, but dGTE is unsuitable for many people (e.g., those with injuries/disabilities), and its effects on arm exercise and women are unknown. METHODS Eight adults (23-37 years old, 4 women) performed an incremental arm cycle test to measure peak oxygen uptake (VO2peak), followed by four 1-h trials at 50% VO2peak. Subjects were randomly assigned to 650 mg of dGTE or placebo (PLA) for 4 weeks followed by a 4-week washout and crossover trial. Blood samples were obtained pre-exercise and post-exercise for glycerol and free fatty acid analysis. Respiratory gases were collected continuously. RESULTS VO2 showed no differences across trials ((0.83-0.89) ± (0.19-0.25) L/min, p = 0.460), neither did energy expenditure ((264-266) ± (59-77) kcal, p = 0.420) nor fat oxidation (dGTE = 0.11 to 0.12 g/min vs. PLA = 0.10 to 0.09 g/min, p = 0.220). Fat oxidation as percentage of energy expenditure was not different for dGTE vs. PLA (23% ± 12% to 25% ± 11% vs. 23% ± 10% to 21% ± 9%, p = 0.532). Glycerol concentration increased post-exercise in all trials, independent of treatments (pre = (3.4-5.1) ± (0.6-2.6) mg/dL vs. post = (7.9-9.8) ± (2.6-3.7) mg/dL, p = 0.867, η2 = 0.005 for interaction), as did free fatty acid ((3.5-4.8) ± (1.4-2.2) mg/dL vs. (7.2-9.1) ± (2.6-4.5) mg/dL, p = 0.981, η2 = 0.000). CONCLUSION Chronic dGTE supplementation had no effect on lipolysis and fat oxidation during arm cycle exercise in men and women.
-
2.
Impact of Green Tea Catechin Ingestion on the Pharmacokinetics of Lisinopril in Healthy Volunteers.
Misaka, S, Ono, Y, Uchida, A, Ono, T, Abe, O, Ogata, H, Sato, H, Suzuki, M, Onoue, S, Shikama, Y, et al
Clinical and translational science. 2021;(2):476-480
-
-
Free full text
-
Abstract
Lisinopril, a highly hydrophilic long-acting angiotensin-converting enzyme inhibitor, is frequently prescribed for the treatment of hypertension and congestive heart failure. Green tea consumption may reduce the risk of cardiovascular outcomes and total mortality, whereas green tea or its catechin components has been reported to decrease plasma concentrations of a hydrophilic β blocker, nadolol, in humans. The aim of this study was to evaluate possible effects of green tea extract (GTE) on the lisinopril pharmacokinetics. In an open-label, randomized, single-center, 2-phase crossover study, 10 healthy subjects ingested 200 mL of an aqueous solution of GTE containing ~ 300 mg of (-)-epigallocatechin gallate, a major catechin component in green tea, or water (control) when receiving 10 mg of lisinopril after overnight fasting. The geometric mean ratio (GTE/control) for maximum plasma concentration and the area under the plasma concentration-time curve of lisinopril were 0.289 (90% confidence interval (CI) 0.226-0.352) and 0.337 (90% CI 0.269-0.405), respectively. In contrast, there were no significant differences in time to reach maximum lisinopril concentration (6 hours in both phases) and renal clearance of lisinopril (57.7 mL/minute in control vs. 56.9 mL/minute in GTE). These results suggest that the extent of intestinal absorption of lisinopril was significantly impaired in the presence of GTE, whereas it had no major effect on the absorption rate and renal excretion of lisinopril. Concomitant use of lisinopril and green tea may decrease oral exposure to lisinopril, and therefore result in reduced therapeutic efficacy.
-
3.
Efficacy of green tea and its extract, epigallocatechin-3-gallate, in the reduction of cariogenic microbiota in children: a randomized clinical trial.
Vilela, MM, Salvador, SL, Teixeira, IGL, Del Arco, MCG, De Rossi, A
Archives of oral biology. 2020;:104727
Abstract
OBJECTIVE This study was conducted to evaluate and compare the antimicrobial efficacy of green tea and its extract epigallocatechin-3-gallate (EGCG) as a mouthwash in children. DESIGN The study group included 47 children aged 5-12 years at high caries risk and prevalence. Children selected were asked to rinse with one of the substances (EGCG, green tea, chlorhexidine and distilled water) for one min. A non-stimulated salivary sample (2 mL) was collected at baseline and after rinsing. The concentration of cariogenic microorganisms (mutans streptococci and lactobacilli) was determined before and after rinsing based on the count of colony-forming units (CFU). CFU were counted with the aid of a stereomicroscope through the perfunctory identification of the morphological characteristics of CFU. The microbial reduction percentage was then calculated. RESULTS The analysis of the effectiveness of the treatments showed that there was a significant reduction in relation to the values obtained before and after the mouthwash, both for mutans streptococci (pCHX = 0.001; pEGCG = 0.001; pGreen Tea = 0.005; pDistilled Water = 0.018) and lactobacilli (pCHX = 0.001; pEGCG = 0.002; pGreen Tea = 0.008; pDistilled Water = 0.033). The percentage of microbial reduction of both cariogenic microorganisms caused by the EGCG solution was higher than green tea and distilled water, but less than CHX. The percentage of microbial reduction by the EGCG solution for mutans streptococci was 79.9%, green tea 68.3%, distilled water 50.6% and CHX 95.5%. For lactobacilli, the percentage reduction of all solutions was relatively lower when compared to mutans streptococci. For the EGCG solution it was 72.09%, followed by green tea 59.17% and distilled water 41.96%, but less than CHX 86.02%. CONCLUSION Rinsing with EGCG solution reduced the levels of mutans streptococci and lactobacilli in the oral cavity of children. Although EGCG had better antimicrobial activity than green tea, this study supports the effectiveness of both as an antibacterial mouthwash option. Both EGCG and green tea could be used as alternatives to chlorhexidine-based mouthwashes.
-
4.
Effects of medium-term green tea extract supplementation combined with CrossFit workout on blood antioxidant status and serum brain-derived neurotrophic factor in young men: a pilot study.
Sadowska-Krępa, E, Domaszewski, P, Pokora, I, Żebrowska, A, Gdańska, A, Podgórski, T
Journal of the International Society of Sports Nutrition. 2019;(1):13
Abstract
BACKGROUND Potential health benefits are attributed to the antioxidant properties of green tea polyphenolic compounds. The main aim of the study was to evaluate the effects of a six-week green tea extract (GTE) supplementation combined with CrossFit workout on blood antioxidant status and serum brain-derived neurotrophic factor (BDNF) in men. METHODS Sixteen young males involved in CrossFit training were randomized into two groups supplemented with GTE or placebo for six weeks. Each participant performed an exercise test for the evaluation of maximum oxygen uptake (VO2max) twice, i.e., before starting (1st trial) and after completing the supplementation combined with CrosFit workout (2nd trial). Venous blood samples were drawn at rest, immediately post-test and after one hour of recovery in order to estimate activities of antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], reduced glutathione [GR]), non-enzymatic antioxidants (reduced glutathione [GSH], uric acid [UA], total phenolics), total antioxidant capacity (FRAP), lipid peroxidation products (TBARS), and BDNF. RESULTS Except for a significantly higher SOD activity and FRAP level recorded at rest and post-exercise in the 2nd trial compared to the corresponding values in the 1st trial, no significant differences were recorded among other assayed measures such as CAT, GPx, GR, GSH and BDNF. Moreover, a percentage increase in FRAP level was twice as high after six weeks' GTE consumption than after placebo. Regardless of the trial, an increase in plasma UA concentration and a decrease in plasma total phenolics level were observed after exercise test. Plasma TBARS concentrations were significantly higher in PLA group after six weeks' CrossFit training, while in GTE group they were slightly lower compared to the corresponding values in the 1st trial. Moreover, there was a significant inverse correlation between FRAP and TBARS in the GTE-supplemented group (r = - 0.40, p < 0.05). CONCLUSIONS A six weeks' consumption of GTE had marginal effect on aerobic capacity and serum BDNF level in CrossFit-trained men, but it caused a marked increase in the blood antioxidant capacity and a moderate attenuation of the training-induced lipid peroxidation.
-
5.
Green Tea Catechin Extract Supplementation Does Not Influence Circulating Sex Hormones and Insulin-Like Growth Factor Axis Proteins in a Randomized Controlled Trial of Postmenopausal Women at High Risk of Breast Cancer.
Samavat, H, Wu, AH, Ursin, G, Torkelson, CJ, Wang, R, Yu, MC, Yee, D, Kurzer, MS, Yuan, JM
The Journal of nutrition. 2019;(4):619-627
-
-
Free full text
-
Abstract
BACKGROUND Consumption of green tea has been associated with reduced risk of breast cancer. Hormonal modulation has been suggested as one of the potential underlying mechanisms; however, it has yet to be fully elucidated in large, long-term human clinical trials. OBJECTIVE We investigated the effects of decaffeinated green tea extract (GTE) on circulating sex hormones and insulin-like growth factor (IGF) proteins. METHODS We conducted a placebo-controlled double-blind randomized clinical trial recruiting from 8 clinical centers in Minnesota. Participants were 538 healthy postmenopausal women randomly assigned to the GTE group (463 completed the study; mean age = 60.0 y) and 537 to the placebo group (474 completed; mean age = 59.7 y). Women in the GTE group orally took 4 decaffeinated capsules containing 1315 mg total catechins including 843 mg epigallocatechin-3-gallate daily for 1 y, whereas women in the placebo group took similar capsules containing no tea catechins. Blood sex hormones (estrone, estradiol, androstenedione, testosterone, and sex hormone-binding globulin) and IGF proteins (IGF-1 and IGF binding protein-3) were quantified at baseline and months 6 (for IGF proteins only) and 12, and were assessed as secondary outcomes of the study using a mixed-effect repeated-measures ANOVA model. RESULTS Women in the GTE group had significantly higher blood total estradiol (16%; P = 0.02) and bioavailable estradiol (21%; P = 0.03) than in the placebo group at month 12. There was a statistically significant interaction between GTE supplementation and duration of treatment on estradiol and bioavailable estradiol (both Ps for interaction = 0.001). The catechol-O-methyltransferase genotype did not influence blood sex hormones before or after GTE supplementation. The circulating concentrations of IGF proteins were comparable between GTE and placebo groups at all 3 time points. CONCLUSION These results suggest that a 12-mo GTE supplementation significantly increases circulating estradiol concentrations in healthy postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00917735.
-
6.
Effect of green tea extract on arterial stiffness, lipid profile and sRAGE in patients with type 2 diabetes mellitus: a randomised, double-blind, placebo-controlled trial.
Quezada-Fernández, P, Trujillo-Quiros, J, Pascoe-González, S, Trujillo-Rangel, WA, Cardona-Müller, D, Ramos-Becerra, CG, Barocio-Pantoja, M, Rodríguez-de la Cerda, M, Nérida Sánchez-Rodríguez, E, Cardona-Muñóz, EG, et al
International journal of food sciences and nutrition. 2019;(8):977-985
Abstract
Type 2 diabetes mellitus (T2DM) is associated with premature atherosclerosis and arterial stiffening due to the accumulation of advanced glycation end-products in vessel walls. Green tea polyphenols are considered cardio-protective substances. In this randomised double-blind placebo-controlled trial (NCT02627898), we evaluated the effect of Green tea extract on arterial stiffness parameters, lipids, body composition and sRAGE levels. Twenty normotensive patients with T2DM treated with the standard therapy and statins, mean age 53.2 ± 9.4 years and mean BMI 30.1 ± 4.5 kg/m2, were randomised to receive a daily dose of 400 mg of green tea extract (polyphenols ≥90%, EGCG ≥45%) or placebo for 12 weeks. Compared to placebo, administration of green tea extract decreased central augmentation index (-3.05 ± 10.8% vs. 6.7 ± 0.1%, p = .04). These findings suggest that green tea extract could be used as an adjunct to the standard therapy to improve arterial stiffness in T2DM.
-
7.
Metabolic Signature of a Functional High-Catechin Tea after Acute and Sustained Consumption in Healthy Volunteers through 1H NMR Based Metabolomics Analysis of Urine.
Madrid-Gambin, F, Garcia-Aloy, M, Vázquez-Fresno, R, Vegas-Lozano, E, Sánchez-Pla, A, Misawa, K, Hase, T, Shimotoyodome, A, Andres-Lacueva, C
Journal of agricultural and food chemistry. 2019;(11):3118-3124
Abstract
Functional tea beverages have emerged as a novel approach to achieving health benefits associated with tea. The use of metabolomics may improve the evaluation of their consumption and their effects. The current study aimed at exploring the urinary signature of exposure to a functional high-catechin tea (HCT) using untargeted NMR-based metabolomics. Ten volunteers participated in a crossover intervention study. Individuals consumed an HCT or a control beverage over a period of 28 days. Multilevel partial least-squares discriminant analysis (ML-PLS-DA) was used for paired comparisons. A further crossover model was performed to assess the significant changes. The consumption of the HCT resulted in the excretion of theanine, epicatechin, pyrogallol sulfate, and higher levels of 3-methyl-2-oxovalerate and succinate, as well as unknown compounds. In conclusion, the present work established novel urinary signatures of a functional drink. Such signatures may be potential biomarkers and/or reflect certain benefits of functional tea beverages.
-
8.
Prevention of Acute Upper Respiratory Infections by Consumption of Catechins in Healthcare Workers: A Randomized, Placebo-Controlled Trial.
Furushima, D, Nishimura, T, Takuma, N, Iketani, R, Mizuno, T, Matsui, Y, Yamaguchi, T, Nakashima, Y, Yamamoto, S, Hibi, M, et al
Nutrients. 2019;(1)
Abstract
Catechins, phytochemicals contained mainly in green tea, exhibit antiviral activity against various acute infectious diseases experimentally. Clinical evidence supporting these effects, however, is not conclusive. We performed a placebo-controlled, single-blind, randomized control trial to evaluate the clinical effectiveness of consumption of catechins-containing beverage for preventing acute upper respiratory tract infections (URTIs). Two hundred and seventy healthcare workers were randomly allocated to high-catechin (three daily doses of 57 mg catechins and 100 mg xanthan gum), low-catechin (one daily dose of 57 mg catechins and 100 mg xanthan gum), or placebo (0 mg catechins and 100 mg xanthan gum) group. Subjects consumed a beverage with or without catechins for 12 weeks from December 2017 through February 2018. The primary endpoint was incidence of URTIs compared among groups using a time-to-event analysis. A total of 255 subjects were analyzed (placebo group n = 86, low-catechin group n = 85, high catechin group n = 84). The URTI incidence rate was 26.7% in the placebo group, 28.2% in the low-catechin group, and 13.1% in the high-catechin group (log rank test, p = 0.042). The hazard ratio (95% confidence interval (CI)) with reference to the placebo group was 1.09 (0.61-1.92) in the low-catechin group and 0.46 (0.23-0.95) in the high-catechin group. These findings suggest that catechins combined with xanthan gum protect against URTIs.
-
9.
Olive leaf tea is beneficial for lipid metabolism in adults with prediabetes: an exploratory randomized controlled trial.
Araki, R, Fujie, K, Yuine, N, Watabe, Y, Nakata, Y, Suzuki, H, Isoda, H, Hashimoto, K
Nutrition research (New York, N.Y.). 2019;:60-66
Abstract
Olive leaves are rich in oleuropein, which has been shown to have beneficial effects on dyslipidemia, type 2 diabetes, and obesity. However, we previously found no significant health benefits of olive leaf tea (OLT) on nonobese and nondiabetic individuals. Thus, we performed this study to further explore the health benefits of OLT in individuals with prediabetes and compare the health benefits between low-concentration OLT (LOLT) and OLT. We hypothesized that OLT will have a more pronounced effect on abdominal obesity as well as glucose and lipid metabolism in prediabetic individuals. Individuals between 40 and 70 years of age with a body mass index of 23.0-29.9 kg/m2 and prediabetes status were recruited and randomly assigned to the OLT or the LOLT group. The intervention, which was the consumption of 330 mL of the test beverage 3 times daily during mealtime, lasted for 12 weeks. After the intervention, serum levels of log-transformed triglycerides (P < .05) and low-density lipoprotein cholesterol (P < .01) decreased significantly in the OLT group (n = 28), with the reductions higher in the OLT group than those in the LOLT group (n = 29, log-transformed triglycerides: P = .079, low-density lipoprotein cholesterol: P < .05). Whereas body weight, waist circumference, and insulin levels were not significantly changed in both groups, fasting plasma glucose levels in the OLT group were significantly decreased compared to those in the LOLT group (P < .05). In conclusion, although the effect of OLT on abdominal obesity and glucose metabolism remains unclear, OLT has been found to have lipid-lowering effects.
-
10.
A Randomized, Placebo-Controlled Study on the Safety and Efficacy of Daily Ingestion of Green Tea (Camellia sinensis L.) cv. "Yabukita" and "Sunrouge" on Eyestrain and Blood Pressure in Healthy Adults.
Maeda-Yamamoto, M, Nishimura, M, Kitaichi, N, Nesumi, A, Monobe, M, Nomura, S, Horie, Y, Tachibana, H, Nishihira, J
Nutrients. 2018;(5)
Abstract
The green tea (Camellia sinensis L.) cultivar “Sunrouge” contains anthocyanins, catechins and flavonols. To determine whether ingesting green tea containing anthocyanins improves visual function and blood pressure (BP) in healthy adults, a randomized, double-blind, placebo-controlled study was performed. A total of 120 healthy subjects, aged between 20 and 60 years and with a systolic BP (SBP) value of ≤125 and <155 and a diastolic BP (DBP) value <95, or a DBP of ≤75 mmHg and <95 mmHg and a SBP <155 mmHg, were randomly assigned to one of three groups. For 12 weeks, the placebo group received barley extract without catechin; another group received “Sunrouge” extract containing 11.2 mg anthocyanin and 323.6 mg epigallocatechin-3-O-gallate (EGCG); and a third group received “Yabukita” extract containing 322.2 mg EGCG. Home BP, accommodation ability, visual analog scale questionnaires for eyestrain, and metabolic-associated markers were analyzed at weeks 0, 4, 8, and 12 of the intake period. The ingestion of “Sunrouge” tea significantly improved accommodation ability and eyestrain in subjects younger than 45 years and in subjects who operated visual display terminals every day. It also elevated BP. “Yabukita” tea ingestion significantly increased serum adiponectin levels. No adverse effects were observed. We conclude that long-term intake of “Sunrouge” tea containing anthocyanins and flavonols might improve visual function.