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Dell'Oro R, Quarti-Trevano F, Facchetti R, Cuspidi C, Mancia G, Grassi G. Habitual Regular Coffee Consumption and Arterial Stiffness: Data From the 3rd Pamela Survey. Am J Hypertens 2024; 37:755-758. [PMID: 38801348 DOI: 10.1093/ajh/hpae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 05/20/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND We evaluated whether chronic coffee consumption affects arterial stiffness, assessed by cardio-ankle vascular index (CAVI). METHODS In 514 subjects, aged 66.6 ± 9.9 years (mean ± SD), recruited in the 3rd follow-up of the PAMELA study, subdivided into 3 groups according to the daily intake of regular coffee (0, 1-2, and ≥3 cups/day), we measured CAVI and clinic, ambulatory blood pressure (BP), and other variables. RESULTS The 3 groups displayed similar age, gender, metabolic, and renal profile. Clinic and ambulatory BPs were similar in the 3 groups, this being the case for CAVI (0 cup: 9.1 ± 1.8, 1-2 cups: 9.5 ± 2.3, and ≥3 cups: 9.2 ± 2.1 m/s, P = NS). No significant gender difference in CAVI and in participants under antihypertensive treatment was detected. CONCLUSIONS Our data show that chronic coffee consumption leaves unaffected arterial stiffness in the general population, this being the case in subgroups. The neutral vascular impact of coffee may favor the absence of any significant BP effect of habitual coffee intake.
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Affiliation(s)
- Raffaella Dell'Oro
- Department of Medicine and Surgery, Clinica Medica, University Milano-Bicocca, Milan, Italy
| | - Fosca Quarti-Trevano
- Department of Medicine and Surgery, Clinica Medica, University Milano-Bicocca, Milan, Italy
| | - Rita Facchetti
- Department of Medicine and Surgery, Clinica Medica, University Milano-Bicocca, Milan, Italy
| | | | | | - Guido Grassi
- Department of Medicine and Surgery, Clinica Medica, University Milano-Bicocca, Milan, Italy
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Yazdanpanah Z, Salehi-Abargouei A, Mozaffari Z, Hemayati R. The effect of green tea ( Camellia sinensis) on lipid profiles and renal function in people with type 2 diabetes and nephropathy: a randomized controlled clinical trial. Front Nutr 2023; 10:1253275. [PMID: 38162524 PMCID: PMC10755896 DOI: 10.3389/fnut.2023.1253275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
Introduction Diabetic nephropathy is one of the most important microvascular complications of diabetes. Despite the modern treatments, herbs or medicinal plants have gained wide attention. One of these herbs is green tea (Camellia sinensis), which may have an impact on renal function, lipid profiles, and HbA1c. However, the evidence for this is unclear and limited. The present study aimed to evaluate the effect of different doses of green tea on these parameters in type 2 diabetes patients (T2DM) with nephropathy. Methods Sixty-six individuals with T2DM nephropathy (aged 30-70 years) were randomly assigned to receive three cups of green tea/day (n = 22), two cups of green tea/day (n = 22), and the control group (n = 22) for 12 weeks. Lipid profiles, glycated hemoglobin A1c (HbA1c), and renal markers were measured before and after intervention. Data were analyzed using SPSS software version 23. One-way analysis of variance (ANOVA), least significant difference (LSD) post hoc, and analysis of covariance were used to compare quantitative variables. Results In total, 64 participants completed the study. Consuming three cups of infusion green tea per day (7.5 gr) led to a significant reduction in serum levels of total cholesterol (p = 0.009) and HbA1c (p = 0.006) and increased in high-density lipoprotein cholesterol (HDL-C) (p = 0.02) compared with the control group who did not drink green tea. However, no significant differences were observed for other variables. Conclusion In general, it was found that drinking three cups of green tea infusion (7.5 gr) per day produced beneficial effects on some lipid profiles and HbA1c without any adverse effects on renal function in patients with T2DM nephropathy. More studies are needed to fully elucidate these findings. Clinical trial registration Iranian Registry of Clinical Trials (www.irct.ir) under registry number: IRCT2014020114538N2.
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Affiliation(s)
- Zeinab Yazdanpanah
- Research Center for Food Hygiene and Safety, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amin Salehi-Abargouei
- Research Center for Food Hygiene and Safety, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Yazd Cardiovascular Research Center, Non-communicable Diseases Research Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Zohre Mozaffari
- Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Roya Hemayati
- Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Diabetes Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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Liu J, Li Y, Li J, Zheng D, Liu C. Sources of automatic office blood pressure measurement error: a systematic review. Physiol Meas 2022; 43. [PMID: 35952651 DOI: 10.1088/1361-6579/ac890e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/11/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Accurate and reliable blood pressure (BP) measurement is important for the prevention and treatment of hypertension. The oscillometric-based automatic office blood pressure measurement (AOBPM) is widely used in hospitals and clinics, but measurement errors are common in BP measurements. There is a lack of systematic review of the sources of measurement errors. APPROACH A systematic review of all existing research on sources of AOBPM errors. A search strategy was designed in six online databases, and all the literature published before October 2021 was selected. Those studies that used the AOBPM device to measure BP from the upper arm of subjects were included. MAIN RESULTS A total of 1365 studies were screened, and 224 studies were included in this final review. They investigated 22 common error sources with clinical AOBPM. Regarding the causes of BP errors, this review divided them into the following categories: the activities before measurement, patient's factors, measurement environment, measurement procedure, and device settings. 13 sources caused increased systolic and diastolic BP (SBP and DBP), 2 sources caused the decrease in SBP and DBP, only 1 source had no significant effect on BPs, and the other errors had a non-uniform effect (either increase or decrease in BPs). The error ranges for SBP and DBP were -14 to 33 mmHg and -6 to 19 mmHg, respectively. SIGNIFICANCE The measurement accuracy of AOBPM is susceptible to the influence of measurement factors. Interpreting BP readings need to be treated with caution in clinical measurements. This review made comprehensive evidence for the need for standardized BP measurements and provided guidance for clinical practitioners when measuring BP with AOBPM devices.
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Affiliation(s)
- Jian Liu
- School of Instrument Science and Engineering, Southeast University, Sipailou 2, Nanjing, Jiangsu, 210096, CHINA
| | - Yumin Li
- School of Instrument Science and Engineering, Southeast University, Sipailou 2, Nanjing, Jiangsu, 210096, CHINA
| | - Jianqing Li
- School of Instrument Science and Engineering, Southeast University, Sipailou road2, Nanjing, Jiangsu, 210096, CHINA
| | - Dingchang Zheng
- Research Centre of Intelligent Healthcare, Coventry University, West Midlands, Coventry, CV1 5FB, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Chengyu Liu
- School of Instrument Science and Engineering, Southeast University, Sipailou 2, Nanjing, Jiangsu, 210096, CHINA
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Xu R, Bai Y, Yang K, Chen G. Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials. Nutr Metab (Lond) 2020; 17:56. [PMID: 32670385 PMCID: PMC7350188 DOI: 10.1186/s12986-020-00469-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/24/2020] [Indexed: 01/02/2023] Open
Abstract
Background The results of human clinical trials investigating the effects of green tea on glycemic control are inconsistent. Methods We conducted a systematic review and meta-analysis of RCTs that examined the effects of green tea supplementation on glycemic control. A literature search in PubMed, Embase, and Cochrane Library databases for RCTs that investigated the effect of green tea consumption on glycemic control was performed up to February 2020. A random-effects model was used to estimate weighted mean difference (WMD) with 95% confidence intervals (CIs). Results Twenty-seven trials involving 2194 subjects were included in the meta-analysis. The pooled results showed that green tea significantly lowered fasting blood glucose by − 1.44 mg/dL (95%CI:-2.26, − 0.62 mg/dL; P < 0.001) with no obvious heterogeneity (I2 = 7.7%). However, green tea consumption did not significantly affect fasting insulin and HbA1c values. The mean differences were − 0.46μIU/mL (95% CI: − 1.10, 0.17μIU/mL; P = 0.21) for fasting insulin and − 0.06%; (95% CI: − 0.12, 0.01%; P = 0.07) for HbA1c concentrations. Heterogeneity was significant in fasting insulin (I2 = 46.8%) and mild in HbA1c (I2 = 1.7%). Conclusions In short-term trials, green tea supplementation significantly reduced fasting glucose, but had no significant effect on fasting insulin and HbA1c. Long-term trials assessing the effects of green tea supplementation on glycemic control are needed.
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Affiliation(s)
- Renfan Xu
- Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 P.R. China
| | - Yang Bai
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 P.R. China
| | - Ke Yang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 P.R. China
| | - Guangzhi Chen
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 P.R. China
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Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutr J 2020; 19:48. [PMID: 32434539 PMCID: PMC7240975 DOI: 10.1186/s12937-020-00557-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/22/2020] [Indexed: 12/14/2022] Open
Abstract
Background Strong epidemiologic evidence indicates that green tea intake is protective against hyperlipidemia; however, randomized controlled studies have presented varying results. In the present study, we aimed to conduct a literature review and meta-analysis to assess the effect of green tea on blood lipids. Methods PubMed, Embase, and the Cochrane Library were electronically explored from inception to September 2019 for all relevant studies. Random effect models were used to estimate blood lipid changes between green tea supplementation and control groups by evaluating the weighted mean differences (WMD) with 95% confidence intervals (CIs). The risk of bias for study was assessed using the Cochrane tool. Publication bias was evaluated using funnel plots and Egger’s tests. Results Thirty-one trials with a total of 3321 subjects were included in the meta-analysis. In general, green tea intake significantly lowered the total cholesterol (TC); WMD: − 4.66 mg/dL; 95% CI: − 6.36, − 2.96 mg/dL; P < 0.0001) and low-density lipoprotein (LDL) cholesterol (WMD:− 4.55 mg/dL; 95% CI: − 6.31, − 2.80 mg/dL; P < 0.0001) levels compared with those in the control. Green tea consumption did not affect high-density lipoprotein (HDL) cholesterol; however, it reduced the triglycerides compared with that in the control (WMD: − 3.77 mg/dL; 95% CI: − 8.90, 1.37 mg/dL; P = 0.15). In addition, significant publication bias from funnel plots or Egger’s tests was not evident. Conclusions Collectively, consumption of green tea lowers LDL cholesterol and TC, but not HDL cholesterol or triglycerides in both normal weight subjects and those who were overweight/obese; however, additional well-designed studies that include more diverse populations and longer duration are warranted.
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Visser E, Geleijnse JM, de Roos B. Inter-Individual Variation in Cancer and Cardiometabolic Health Outcomes in Response to Coffee Consumption: A Critical Review. Mol Nutr Food Res 2020; 64:e1900479. [PMID: 32045503 DOI: 10.1002/mnfr.201900479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 12/29/2019] [Indexed: 12/11/2022]
Abstract
SCOPE Coffee is associated with a lower risk of cancer, cardiovascular disease, and type 2 diabetes at the population level. However, individual susceptibility to the effects of coffee consumption will cause heterogeneity in health responses between individuals. In this critical review determinants of inter-individual variability in cancer and cardiometabolic health outcomes in response to coffee and caffeine consumption are systematically evaluated. METHODS AND RESULTS Embase and MEDLINE are searched for observational studies and clinical trials that examined variation in the response to coffee consumption. A total of 74 studies meet the inclusion criteria, which report variation in cancer (n = 24) and cardiometabolic health (n = 50) outcomes. The qualitative analysis shows that sex, BMI, smoking, alcohol intake, menopausal status, and genetic polymorphisms are probable or possible determinants of inter-individual variability in cancer and cardiometabolic health outcomes in response to coffee and caffeine consumption, albeit the majority of studies have insufficient statistical power to detect significant interaction between these factors and coffee consumption. CONCLUSION Several genetic and non-genetic determinants of inter-individual variability in the responses to coffee and caffeine consumption are identified, indicating that some of the health benefits of coffee may only occur in a subgroup of subjects.
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Affiliation(s)
- Edith Visser
- Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Johanna M Geleijnse
- Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Baukje de Roos
- Rowett Institute of Nutrition and Health, University of Aberdeen, Foresterhill, AB25 2ZD, Aberdeen, UK
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Xu R, Yang K, Ding J, Chen G. Effect of green tea supplementation on blood pressure: A systematic review and meta-analysis of randomized controlled trials. Medicine (Baltimore) 2020; 99:e19047. [PMID: 32028419 PMCID: PMC7015560 DOI: 10.1097/md.0000000000019047] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Although evidence from animal and observational studies has supported the beneficial effects of green tea intake for lowering blood pressure (BP), randomized placebo-controlled trials (RCTs) have yielded conflicting results. In this meta-analysis of RCTs, we aimed to assess the effects of green tea supplementation on measures of BP control. METHODS The PubMed, Embase, and Cochrane Library databases were electronically searched from inception to August 2019 for all relevant studies. The results were pooled using the generic inverse-variance method with random-effects weighting and expressed as mean differences (MDs) with 95% confidence intervals (CIs). The quality of studies was assessed using the Jadad score. Publication bias was evaluated using funnel plots, Egger test, and Begg test. RESULTS Twenty-four trials with 1697 subjects were included in the meta-analysis. The pooled results showed that green tea significantly lowered systolic BP (SBP; MD: -1.17 mm Hg; 95%CI: -2.18 to -0.16mm Hg; P = .02) and diastolic BP (DBP; MD: -1.24 mm Hg; 95%CI:-2.07 to -0.40mm Hg; P = .004). Significant heterogeneity was found for both SBP (I = 43%) and DBP (I = 57%). In addition, no evidence of significant publication bias was found from funnel plots or Egger test (P = .674 and P = .270 for SBP and DBP, respectively). CONCLUSION Overall, green tea significantly reduced SBP and DBP over the duration of the short-term trials. Larger and longer-term trials are needed to further investigate the effects of green tea supplementation on BP control and clinical events.
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Affiliation(s)
| | - Ke Yang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Jie Ding
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Guangzhi Chen
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
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Ponte B, Pruijm M, Ackermann D, Ehret G, Ansermot N, Staessen JA, Vogt B, Pechère-Bertschi A, Burnier M, Martin PY, Eap CB, Bochud M, Guessous I. Associations of Urinary Caffeine and Caffeine Metabolites With Arterial Stiffness in a Large Population-Based Study. Mayo Clin Proc 2018; 93:586-596. [PMID: 29551227 DOI: 10.1016/j.mayocp.2017.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/24/2017] [Accepted: 12/07/2017] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To assess the influence of caffeine on arterial stiffness by exploring the association of urinary excretion of caffeine and its related metabolites with pulse pressure (PP) and pulse wave velocity (PWV). PARTICIPANTS AND METHODS Families were randomly selected from the general population of 3 Swiss cities from November 25, 2009, through April 4, 2013. Pulse pressure was defined as the difference between the systolic and diastolic blood pressures obtained by 24-hour ambulatory monitoring. Carotid-femoral PWV was determined by applanation tonometry. Urinary caffeine, paraxanthine, theophylline, and theobromine excretions were measured in 24-hour urine collections. Multivariate linear and logistic mixed models were used to explore the associations of quartiles of urinary caffeine and metabolite excretions with PP, high PP, and PWV. RESULTS We included 863 participants with a mean ± SD age of 47.1±17.6 years, 24-hour PP of 41.9±9.2 mm Hg, and PWV of 8.0±2.3 m/s. Mean (SE) brachial PP decreased from 43.5 (0.5) to 40.5 (0.6) mm Hg from the lowest to the highest quartiles of 24-hour urinary caffeine excretion (P<.001). The odds ratio (95% CI) of high PP decreased linearly from 1.0 to 0.52 (0.31-0.89), 0.38 (0.22-0.65), and 0.31 (0.18-0.55) from the lowest to the highest quartile of 24-hour urinary caffeine excretion (P<.001). Mean (SE) PWV in the highest caffeine excretion quartile was significantly lower than in the lowest quartile (7.8 [0.1] vs 8.1 [0.1] m/s; P=.03). Similar associations were found for paraxanthine and theophylline, whereas no associations were found with theobromine. CONCLUSION Urinary caffeine, paraxanthine, and theophylline excretions were associated with decreased parameters of arterial stiffness, suggesting a protective effect of caffeine intake beyond its blood pressure-lowering effect.
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Affiliation(s)
- Belen Ponte
- Service of Nephrology, Department of Specialties, University Hospital of Geneva, Switzerland; Division of Chronic Diseases, Institute of Social and Preventive Medicine (IUMSP), University Hospital of Lausanne, Switzerland
| | - Menno Pruijm
- Service of Nephrology, University Hospital of Lausanne, Switzerland
| | - Daniel Ackermann
- Clinic for Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - Georg Ehret
- Department of Cardiology, University Hospital of Geneva, Switzerland
| | - Nicolas Ansermot
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Centre for Psychiatric Neurosciences, Department of Psychiatry, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Hospital of Cery, Prilly, Switzerland
| | - Jan A Staessen
- Studies Coordinating Centre, Division of Hypertension and Cardiovascular Rehabilitation, Department of Cardiovascular Diseases, University of Leuven, Belgium; Department of Epidemiology, Maastricht University, the Netherlands
| | - Bruno Vogt
- Clinic for Nephrology, Hypertension and Clinical Pharmacology, Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - Antoinette Pechère-Bertschi
- Unit of Hypertension, Department of Community Medicine and Primary Care and Emergency Medicine, University Hospital of Geneva, Switzerland
| | - Michel Burnier
- Service of Nephrology, University Hospital of Lausanne, Switzerland
| | - Pierre-Yves Martin
- Service of Nephrology, Department of Specialties, University Hospital of Geneva, Switzerland
| | - Chin B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Centre for Psychiatric Neurosciences, Department of Psychiatry, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Hospital of Cery, Prilly, Switzerland; School of Pharmacy Geneva-Lausanne, Universities of Geneva and Lausanne, Switzerland
| | - Murielle Bochud
- Division of Chronic Diseases, Institute of Social and Preventive Medicine (IUMSP), University Hospital of Lausanne, Switzerland
| | - Idris Guessous
- Unit of Population Epidemiology, Department of Community Medicine and Primary Care and Emergency Medicine, University Hospital of Geneva, Switzerland; Division of Chronic Diseases, Institute of Social and Preventive Medicine (IUMSP), University Hospital of Lausanne, Switzerland.
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Caffeine and cardiovascular health. Regul Toxicol Pharmacol 2017; 89:165-185. [DOI: 10.1016/j.yrtph.2017.07.025] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 02/07/2023]
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Coffee Consumption and Cardiovascular Health. Am J Cardiol 2015; 116:818-21. [PMID: 26141200 DOI: 10.1016/j.amjcard.2015.05.057] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/25/2015] [Accepted: 05/28/2015] [Indexed: 12/19/2022]
Abstract
Coffee is the most widely consumed beverage worldwide and is only second to water drinking and is consumed by 83% of adults in the United States. The long-held controversy regarding the association of coffee consumption with an increased incidence of cardiovascular diseases (CVDs) and hypertension has been reversed by several recent prospective cohort studies and meta-analyses, which have demonstrated that coffee consumption is not associated with increased incidence of CVDs and hypertension and instead it could have a beneficial effect. To get a better understanding of the effects of coffee consumption on cardiovascular health, a Medline search of the English language literature was conducted from 2010 to early 2015 and 25 pertinent reports with information on the effects of coffee drinking, the incidence of CVDs, and hypertension and its mechanism of action were selected for inclusion in this commentary. These studies have shown either a neutral or beneficial effect of coffee on cardiovascular health. In conclusion, coffee is safe to drink by both normal subjects and by those with preexisting CVDs and hypertension.
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Effects of tea intake on blood pressure: a meta-analysis of randomised controlled trials. Br J Nutr 2014; 112:1043-54. [PMID: 25137341 DOI: 10.1017/s0007114514001731] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The effect of tea intake on blood pressure (BP) is controversial. We performed a meta-analysis of randomised controlled trials to determine the changes in systolic and diastolic BP due to the intake of black and green tea. A systematic search was conducted in MEDLINE, EMBASE and the Cochrane Controlled Trials Register up to May 2014. The weighted mean difference was calculated for net changes in systolic and diastolic BP using fixed-effects or random-effects models. Previously defined subgroup analyses were performed to explore the influence of study characteristics. A total of twenty-five eligible studies with 1476 subjects were selected. The acute intake of tea had no effects on systolic and diastolic BP. However, after long-term tea intake, the pooled mean systolic and diastolic BP were lower by - 1·8 (95 % CI - 2·4, - 1·1) and - 1·4 (95 % CI - 2·2, - 0·6) mmHg, respectively. When stratified by type of tea, green tea significantly reduced systolic BP by 2·1 (95 % CI - 2·9, - 1·2) mmHg and decreased diastolic BP by 1·7 (95 % CI - 2·9, - 0·5) mmHg, and black tea showed a reduction in systolic BP of 1·4 (95 % CI - 2·4, - 0·4) mmHg and a decrease in diastolic BP of 1·1 (95 % CI - 1·9, - 0·2) mmHg. The subgroup analyses showed that the BP-lowering effect was apparent in subjects who consumed tea more than 12 weeks (systolic BP - 2·6 (95 % CI - 3·5, - 1·7) mmHg and diastolic BP - 2·2 (95 % CI - 3·0, - 1·3) mmHg, both P< 0·001). The present findings suggest that long-term ( ≥ 12 weeks) ingestion of tea could result in a significant reduction in systolic and diastolic BP.
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Ishizaka Y, Yamakado M, Toda A, Tani M, Ishizaka N. Relationship between coffee consumption, oxidant status, and antioxidant potential in the Japanese general population. Clin Chem Lab Med 2013; 51:1951-9. [DOI: 10.1515/cclm-2013-0146] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 03/14/2013] [Indexed: 11/15/2022]
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Ihm SH, Jang SW, Kim OR, Chang K, Oak MH, Lee JO, Lim DY, Kim JH. Decaffeinated green tea extract improves hypertension and insulin resistance in a rat model of metabolic syndrome. Atherosclerosis 2012; 224:377-83. [PMID: 22877868 DOI: 10.1016/j.atherosclerosis.2012.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 06/03/2012] [Accepted: 07/05/2012] [Indexed: 01/18/2023]
Abstract
BACKGROUND Oxidative stress and endothelial dysfunction are closely associated with hypertension and insulin resistance (IR) in metabolic syndrome (MetS). It is still controversial whether green tea extract (GTE) may have blood pressure (BP) lowering effect. Decaffeinated GTE might be presumed to have strong antioxidative effect and BP-lowering effect as compared with catechins. Thus we investigated whether decaffeinated-GTE could attenuate hypertension and IR by improving endothelial dysfunction and reducing oxidative stress in a rat model of MetS. METHODS AND RESULTS 20 Otsuka Long-Evans Tokushima Fatty (OLETF) rats at 13 weeks old, MetS rats, were randomized into a saline treated group (OLETF; n = 10) and a group treated with decaffeinated-GTE (25 mg/kg/day) (GTE-OLETF; n = 10). Intraperitoneal glucose tolerance tests and BP measurements were performed at 13 and 25 weeks. Decaffeinated-GTE significantly reduced BP (OLETF vs. GTE-OLETF; 130 ± 7 vs. 121 ± 3 mmHg, p = 0.01), fasting/postprandial 2 h glucose (141 ± 18/159 ± 13 vs. 115 ± 7/132 ± 16 mg/dL, p = 0.009/0.002) and insulin levels (4.8 ± 2.3 vs. 2.4 ± 1.3 ng/mL, p < 0.001). Decaffeinated-GTE significantly reduced vascular reactive oxygen species (ROS) formation and NADPH oxidase activity, and improved endothelium dependent relaxation in the thoracic aorta of OLETF rats. Decaffeinated-GTE also suppressed the expression of p47 and p22phox (NADPH oxidase subunits) in the immunohistochemical staining, and stimulated phosphorylation of endothelial nitric oxide synthase (eNOS) and Akt in the immunoblotting of aortas. CONCLUSIONS Decaffeinated-GTE reduced the formation of ROS and NADPH oxidase activity and stimulated phosphorylation of eNOS and Akt in the aorta of a rat model of MetS, which resulted in improved endothelial dysfunction and IR, and eventually lowered BP.
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Affiliation(s)
- Sang-Hyun Ihm
- Division of Cardiology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Abstract
DATA SOURCES Pooled individual-level data from nine case-control studies of head and neck cancers, including 5,139 cases and 9,028 controls. STUDY SELECTION Nine case-control studies were selected from the International Head and Neck Cancer Epidemiology (INHANCE) consortium pool of 33 studies, which included information on coffee (caffeinated and decaffeinated) and tea drinking and cancer of the oral cavity and pharynx. Seven studies also included information on laryngeal cancer. DATA EXTRACTION AND SYNTHESIS Data from individual studies were checked for inconsistencies and pooled in a standardised way into a common database, including a range of sociodemographic, behavioural, lifestyle and health information. Data on consumption across studies were then converted into cups of de/caffeinated tea or coffee per day. The association between head and neck cancers and caffeinated coffee, decaffeinated coffee or tea intake was assessed by estimating the odds ratios (OR) and the corresponding 95% confidence intervals (95% CI) using a two-stage random-effects logistic regression model with the maximum likelihood estimator. Pooled ORs were also estimated with a fixed-effects logistic regression model. In addition, a test for heterogeneity among studies was conducted. RESULTS Caffeinated coffee intake was inversely associated with the risk of cancer of the oral cavity and pharynx: the ORs were 0.96 (95% CI, 0.94-0.98) for an increment of one cup per day and 0.61 (95% CI, 0.47-0.80) in drinkers of >4 cups per day versus non-drinkers. This latter estimate was consistent for different anatomic sites (OR, 0.46; 95% CI, 0.30-0.71 for oral cavity; OR, 0.58; 95% CI, 0.41-0.82 for oropharynx/hypopharynx; and OR, 0.61; 95% CI, 0.37-1.01 for oral cavity/pharynx not otherwise specified) and across strata of selected covariates. No association of caffeinated coffee drinking was found with laryngeal cancer (OR, 0.96; 95% CI, 0.64-1.45 in drinkers of >4 cups per day versus non-drinkers). Data on decaffeinated coffee were too sparse for detailed analysis, but indicated no increased risk. Tea intake was not associated with head and neck cancer risk (OR, 0.99; 95% CI, 0.89-1.11 for drinkers versus non-drinkers). CONCLUSIONS This pooled analysis of case-control studies supports the hypothesis of an inverse association between caffeinated coffee drinking and risk of cancer of the oral cavity and pharynx.
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Sae-tan S, Grove KA, Lambert JD. Weight control and prevention of metabolic syndrome by green tea. Pharmacol Res 2010; 64:146-54. [PMID: 21193040 DOI: 10.1016/j.phrs.2010.12.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 12/22/2022]
Abstract
Green tea (Camellia sinensis, Theaceace) is the second most popular beverage in the world and has been extensively studied for its putative disease preventive effects. Green tea is characterized by the presence of a high concentrations of polyphenolic compounds known as catechins, with (-)-epigallocatechin-3-gallate (EGCG) being the most abundant and most well-studied. Metabolic syndrome (MetS) is a complex condition that is defined by the presence of elevated waist circumference, dysglycemia, elevated blood pressure, decrease serum high-density lipoprotein-associated cholesterol, and increased serum triglycerides. Studies in both in vitro and laboratory animal models have examined the preventive effects of green tea and EGCG against the symptoms of MetS. Overall, the results of these studies have been promising and demonstrate that green tea and EGCG have preventive effects in both genetic and dietary models of obesity, insulin resistance, hypertension, and hypercholesterolemia. Various mechanisms have been proposed based on these studies and include: modulation of dietary fat absorption and metabolism, increased glucose utilization, decreased de novo lipogenesis, enhanced vascular responsiveness, and antioxidative effects. In the present review, we discuss the current state of the science with regard to laboratory studies on green tea and MetS. We attempt to critically evaluate the available data and point out areas for future research. Although there is a considerable amount of data available, questions remain in terms of the primary mechanism(s) of action, the dose-response relationships involved, and the best way to translate the results to human intervention studies.
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Affiliation(s)
- Sudathip Sae-tan
- Department of Food Science, The Pennsylvania State University, University Park, PA 16802, United States
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