Green and black tea for the primary prevention of cardiovascular disease

Association of tea consumption with all-cause/cardiovascular disease mortality in the chronic kidney disease population: an assessment of participation in the national cohort

BACKGROUND

While there are numerous benefits to tea consumption, its long-term impact on patients with chronic kidney disease (CKD) remains unclear.

METHOD

Our analysis included 17,575 individuals with CKD from an initial 45,019 participants in the National Health and Nutrition Examination Survey (NHANES) (1999-2018). Individuals with extreme dietary habits, pregnancy, or non-CKD conditions were excluded. Key cohort demographics revealed a mean age of 62.3 years, with 52.1% female participants, and 57.3% identified as non-Hispanic White. A total of 5,835 deaths were recorded during follow-up, including 1,823 cardiovascular-related deaths. Cox and restricted cubic spline regression was used to examine the linear or nonlinear association of tea consumption with mortality. The substitution analysis explored the effects of replacing a specific type of tea with another type of tea. Subgroup analysis stratified by sex, age, body mass index (BMI), diabetes, cancer, cardiovascular disease (CVD), and urinary albumin. Sensitivity analysis was performed to ensure the reliability of our findings.

RESULTS

After adjusting for age, sex, race, education level, marital, annual household income, energy intake, total water intake, protein intake, carbohydrate intake, dietary fiber, sugar beverages, milk whole, total monounsaturated fatty acids, total polyunsaturated fatty acids, total saturated fatty acids, smoking, metabolic equivalent of task for physical activity level (MET-PA), BMI, diabetes, hypertension, urinary albumin, estimated glomerular filtration rate (eGFR), CVD, cancer, serum sodium, serum potassium, and serum phosphorus, setting the individuals without tea consumption record as reference. Consuming up to 4 cups of tea per day was significantly associated with lower all-cause mortality compared with that never drinking tea, among CKD patients at 1-2 stages [Hazard Ratio (HR) = 0.89; 95% Confidence Interval (CI) = 0.79, 0.99; p = 0.04], while the association between tea consumption and CVD mortality didn't reach statistical significance. Dose-response effect was observed, showing that consuming up to three to five cups of tea per day was associated with mitigated risks of all-cause mortality, particularly in early CKD stages (non-linear p > 0.05). A 1 cup per day higher intake of oxidized tea was associated with a 10% lower risk of all-cause mortality in CKD stage 1-2 [HR = 0.90; 95%CI = 0.82, 0.99; p = 0.03]. Replacing 1 cup of green tea with 1 cup of oxidized tea per day was associated with an 8% and 11% lower risk of all-cause mortality [HR = 0.92; 95%CI = 0.86, 0.98; p = 0.01] and CVD mortality [HR = 0.89; 95%CI = 0.80, 1.00; p < 0.05], respectively, in individuals with CKD stages 1-2.

CONCLUSION

Tea consumption showed protective effects on all-cause mortality in CKD population, with potential benefits observed in terms of both the cups quantity and types of tea consumed. These findings appeared to be more prominent among early stages CKD population.

Bioactive Flavonoids in Protecting Against Endothelial Dysfunction and Atherosclerosis

Atherosclerosis is a common cardiovascular disease closely associated with factors such as hyperlipidaemia and chronic inflammation. Among them, endothelial dysfunction serves as a major predisposing factor. Vascular endothelial dysfunction is manifested by impaired endothelium-dependent vasodilation, enhanced oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, endothelial senescence, and endothelial-mesenchymal transition (EndoMT). Flavonoids are known for their antioxidant activity, eliminating oxidative stress induced by reactive oxygen species (ROS), thereby preventing the oxidation of low-density lipoprotein (LDL) cholesterol, reducing platelet aggregation, alleviating ischemic damage, and improving vascular function. Flavonoids have also been shown to possess anti-inflammatory activity and to protect the cardiovascular system. This review focuses on the protective effects of these naturally-occuring bioactive flavonoids against the initiation and progression of atherosclerosis through their effects on endothelial cells including, but not limited to, their antioxidant, anti-inflammatory, anti-thrombotic, and lipid-lowering properties. However, more clinical evidences are still needed to determine the exact role and optimal dosage of these compounds in the treatment of atherosclerosis.

The Acute Ingestion of Yerba Mate (Ilex paraguariensis) Infusion Does Not Modify Endothelial Function, Hemodynamics, or Heart Rate Variability: A Randomized Crossover Clinical Trial

BACKGROUND AND AIMS

Herbal plants may contribute to reducing the incidence of cardiovascular disease. Yerba mate (YM) emerges as a candidate to improve endothelial function, hemodynamics, and heart rate variability (HRV) due to its antioxidant and anti-inflammatory properties, potentially decreasing cardiovascular risk. Therefore, studies are needed to assess the effect of YM ingestion on these parameters. This study aimed to evaluate the impact of acute ingestion of YM infusion (hot or cold) on endothelial function, hemodynamics, and HRV.

METHODS AND RESULTS

In this crossover randomized clinical trial, 13 participants (18-40 years old) of both genders were evaluated under three conditions: control (water), cold YM infusion, and hot YM infusion. The primary outcome was endothelial function assessed through flow-mediated dilation (FMD), with the secondary outcomes including blood pressure (BP), heart rate (HR) and HRV. Parameters were evaluated before and after intervention (40' and 80'). Analysis of variance (ANOVA) showed an intervention effect on FMD (%) (p < 0.05), with both cold and hot YM associated to higher FMD% compared to control, although no time or time*intervention effects were found. ANOVA also showed a time effect on BP, HR, and HRV time and frequency domains variables (p < 0.05), though no time*intervention or intervention effect was observed.

CONCLUSION

We did not find acute effects of YM infusion on endothelial function, central hemodynamic, or autonomic parameters in healthy adults. These results were not impacted by the temperature of YM. Further studies should assess the dose-response of acute and chronic YM ingestion on endothelial function.

TRIAL REGISTRATION

U1111-1289-9324, retrospectively registered in May 2023.

Nomogram for predicting risk of mild renal dysfunction among general residents from rural Northeast China

Background and objectives

Cumulative evidence confirms that mild renal dysfunction (MRD) is correlated with many cardiovascular risk factors and increases cardiovascular morbidity and mortality. The purpose of this study was to establish an effective nomogram for predicting the risk of MRD in the rural population of Northeast China.

Methods

We analyzed the reports of 4944 subjects from the Northeast China Rural Cardiovascular Health Study (NCRCHS). All the participants completed the questionnaires, anthropometric measurements, and blood tests during the baseline study (2012-2013) and the follow-up study during 2015-2017 (an average of 4.6 years). The Chronic Kidney Disease Epidemiology (CKD-EPI) equation was used to calculate the estimated glomerular filtration rate (eGFR), and eGFR in the range of 60-90 mL/min/1.73m2 was defined as MRD.

Results

The study revealed that a total of 889 subjects (18.0%) had MRD. Multivariate logistic analysis showed that annual income, abdominal obesity, hypertension, hyperglycemia, and frequent tea consumption were the independent risk factors (P < 0.05) for MRD. Thereafter, a nomogram with an area under the receiver operating characteristic curve (AUC) of 0.705 was constructed to accurately predict MRD. The calibration plot also showed an excellent consistency between the probability of prediction and observation.

Conclusion

We constructed a nomogram based on epidemiological data, which could provide an individual prediction of MRD with good accuracy.

Impact of Green Tea Consumption on the Prevalence of Cardiovascular Outcomes: A Systematic Review

Cardiovascular diseases (CVDs) represent a major global health concern, responsible for significant morbidity, mortality, and disability. To mitigate the impact of CVDs, individuals often seek preventive measures, and one such approach is the consumption of green tea. This study aims to provide a comprehensive and up-to-date assessment of the effects of green tea consumption on the prevalence of cardiovascular outcomes. Following PRISMA guidelines, we conducted a systematic review using PubMed and Google Scholar databases to identify relevant studies. Our analysis revealed that the risk factors associated with CVDs can vary across different diseases, with hypertension being a common risk factor for CVD mortality and CVD. Notably, the consumption of green tea exhibited a positive effect on reducing the prevalence of cardiometabolic risks and hypercholesterolemia. Furthermore, green tea consumption was observed to have a beneficial impact on lowering both diastolic and systolic blood pressure. In conclusion, the studies reviewed in this research suggest that the consumption of green tea has a significant and positive influence on cardiovascular health. These findings highlight the potential of green tea as a valuable component of a healthy lifestyle, offering a promising avenue for its use as a dietary supplement to reduce the risk of CVDs.

Tea consumption and risk of lung diseases: a two‑sample Mendelian randomization study

BACKGROUND

Numerous studies have reported the association between tea intake and lung diseases. However, the probable relationship between tea consumption on lung diseases still remain controversial and it is unclear whether these findings are due to reverse causality or confounding factor.

METHODS

In order to systematically investigate the causal connection between tea intake on respiratory system disorders, we employed a two-sample Mendelian randomized (MR) study. Genetic instruments for tea intake were identified from a genome-wide association study (GWAS) involving 447,385 individuals. Data on lung diseases were collected from a variety of publicly available genome-wide association studies. The main method used for MR analysis is the inverse variance weighting (IVW) method. To ensure the accuracy of the findings, further sensitivity analysis was conducted.

RESULTS

The IVW method in our MR analysis revealed no evidence to support a causal relationship between tea intake and lung diseases (IPF: OR = 0.997, 95% CI = 0.994-1.000, p = 0.065; Lung cancer: OR = 1.003, 95% CI = 0.998-1.008, P = 0.261; COPD: OR = 1.001, 95% CI = 0.993-1.006, p = 0.552; acute bronchitis: OR = 0.919, 95% CI = 0.536-1.576, p = 0.759; tuberculosis: OR = 1.002, 95% CI = 0.998-1.008, p = 0.301; pneumonia: OR = 0.789, 95% CI = 0.583-1.068, p = 0.125). The reliability of the results was further demonstrated by four additional MR analysis techniques and additional sensitivity testing.

CONCLUSION

We found no evidence of a link between tea intake on lung diseases in our MR results based on genetic information.

Sarcopenia, a condition shared by various diseases: can we alleviate or delay the progression?

Sarcopenia is a severe condition common to various chronic diseases and it is reckoned as a major health problem. It encompasses many different molecular mechanisms that have been for a while discovered but not definitely clarified. Although sarcopenia is a disability status that leads to serious health consequences, the scarcity of suitable animal models has curtailed research addressing this disorder. Another limitation in the field of clinical investigation of sarcopenic patients is the lack of a generally accepted definition coupled with the difficulty of adopting common diagnostic criteria. In fact, both do not permit to clarify the exact prevalence rate and consequently limit physicians to establish any kind of therapeutical approach or, when possible, to adopt preventive measures. Unfortunately, there is no standardized cure, apart from doing more physical activity and embracing a balanced diet, but newly discovered substances start being considered. In this review, authors try to give an overview addressing principal pathways of sarcopenia and offer critical features of various possible interventions.

Association between green tea and coffee consumption and body iron storage in Japanese men and women: a cross-sectional study from the J-MICC Study Saga

Purpose

This study examined the association between daily green tea and coffee consumption and body iron stores among Japanese middle-aged and older adults.

Methods

This cross-sectional study used data obtained from 2005 to 2007. A total of 10,435 participants were recruited for this study. The participants completed a validated, self-administered food frequency questionnaire on green tea and coffee consumption. A multivariate linear regression analysis was conducted to assess the relationship between green tea and coffee consumption and serum ferritin levels. Additionally, logistic regression analysis was performed to ascertain whether excessive consumption of these beverages was linked to iron deficiency.

Results

We observed that higher green tea and coffee consumption was associated with lower ferritin levels in men and postmenopausal women, even after adjusting for covariates (all P for trends <0.05). Among premenopausal women, we found an inverse association between green tea consumption and serum ferritin levels, while no significant association was observed for coffee consumption after adjusting for covariates (green tea, P for trend <0.05; coffee, P for trend = 0.08). Notably, the association between these beverages and iron deficiency was found only in postmenopausal women; the odds ratios (95% confidence intervals) for iron deficiency associated with almost None, <1 cup/day, 1-2 cups/day, and ≥ 3 cups/day were 1.00 (reference), 0.78 (0.26-2.49), 1.29 (0.49-3.39), and 1.59 (0.63-4.04) (P for trend = 0.05), respectively, for green tea and 1.00, 1.32 (0.64-2.73), 1.46 (0.68-3.13), and 2.20 (1.06-4.55) (P for trend <0.01), respectively, for coffee.

Conclusion

Higher green tea and coffee consumption was associated with lower serum ferritin levels in men and postmenopausal women. In premenopausal women, consumption of green tea, but not coffee, was associated with lower serum ferritin levels. However, postmenopausal women who ≥3 cups of coffee demonstrated a higher prevalence of iron deficiency compared to those who consumed almost none.

Physiological effects of yerba maté (Ilex paraguariensis): a systematic review

CONTEXT

Clinical studies have found an association between yerba maté intake and beneficial physiological effects. Nevertheless, no systematic reviews have been conducted to shed light on the data supporting this association.

OBJECTIVE

The present systematic review aimed to investigate the physiological effects of yerba maté.

DATA SOURCES

Searches were performed in 6 databases (Embase, LILACS, Scopus, PubMed, SciELO, Web of Science) and 3 grey literature databases (OpenGrey, ProQuest, Google Scholar). Relevant publications were identified, and the reference lists of included studies were searched manually for randomized clinical trials, nonrandomized clinical trials, and observational studies investigating the physiological effects of yerba maté.

DATA EXTRACTION

Risk of bias was assessed using the Cochrane risk of bias tool for randomized trials and the Cochrane ROBINS-I (Risk Of Bias In Nonrandomized Studies of Interventions) tool. Joanna Briggs Institute critical appraisal tools were used for cross-sectional, case series, cohort, and case-control studies. The overall certainty of the evidence was estimated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) working group summary of findings table.

DATA ANALYSIS

Of 1096 studies identified, 32 were included. Studies showed consistent effects of yerba maté intake on metabolism improvement and antioxidant and anti-inflammatory activities in different populations. Benefits for body weight and composition, exercise performance, mood, and appetite, in addition cardio- and neuroprotective effects, were also observed. Risk of bias was categorized as high in 22 studies, moderate in 9 studies, and low in 1 study. The certainty of evidence ranged from moderate to very low.

CONCLUSION

The available literature indicates that yerba maté can be used within a balanced and healthy diet for prevention and adjuvant treatment of chronic diseases.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020200196.

Causal effects of tea intake on multiple types of fractures: A two-sample Mendelian randomization study

Fracture is a global public health disease. Bone health and fracture risk have become the focus of public and scientific attention. Observational studies have reported that tea consumption is associated with fracture risk, but the results are inconsistent. The present study used 2-sample Mendelian randomization (MR) analysis. The inverse variance weighted method, employing genetic data from UK Biobank (447,485 cases) of tea intake and UK Biobank (Genome-wide association study Round 2) project (361,194 cases) of fractures, was performed to estimate the causal relationship between tea intake and multiple types of fractures. The inverse variance weighted indicated no causal effects of tea consumption on fractures of the skull and face, shoulder and upper arm, hand and wrist, femur, calf, and ankle (odds ratio = 1.000, 1.000, 1.002, 0.997, 0.998; P = .881, 0.857, 0.339, 0.054, 0.569, respectively). Consistent results were also found in MR-Egger, weighted median, and weighted mode. Our research provided evidence that tea consumption is unlikely to affect the incidence of fractures.

Preventive effect and mechanism of Tibetan tea extract on thrombosis in arachidonic acid-induced zebrafish determined via RNA-seq transcriptome profiles

Thrombosis is a key pathological event in cardiovascular diseases and is also the most important targeting process for their clinical management. In this study, arachidonic acid (AA) was used to induce thrombus formation in zebrafish larvae. Blood flow, red blood cell (RBCs) aggregation and cellular oxidative stress were measured to evaluate the antithrombotic effect of Tibetan tea (TT). Meanwhile, the potential molecular mechanism was further explored by transcriptome sequencing (RNA-seq). The results indicated that TT could significantly restore heart RBCs intensity of thrombotic zebrafish, whilst decreasing RBCs accumulation in the caudal vein. The transcriptome analysis revealed that the preventive effect of TT on thrombosis could be mostly attributed to changes in lipid metabolism related signaling pathways, such as fatty acid metabolism, glycerollipid metabolism, ECM-receptor interaction and steroid biosynthesis signaling pathway. This study demonstrated that Tibetan tea could alleviate thrombosis by reducing oxidative stress levels and regulating lipid metabolism.

Determining optimal strategies for primary prevention of cardiovascular disease: systematic review of cost-effectiveness analyses in the United Kingdom

BACKGROUND

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. The aim of the study was to guide researchers and commissioners of cardiovascular disease preventative services towards possible cost-effective interventions by reviewing published economic analyses of interventions for the primary prevention of cardiovascular disease, conducted for or within the UK NHS.

METHODS

In January 2021, electronic searches of MEDLINE and Embase were carried out to find economic evaluations of cardiovascular disease preventative services. We included fully published economic evaluations (including economic models) conducted alongside randomised controlled trials of any form of intervention that was aimed at the primary prevention of cardiovascular disease, including, but not limited to, drugs, diet, physical activity and public health. Full systematic review methods were used with predetermined inclusion/exclusion criteria, data extraction and formal quality appraisal [using the Consolidated Health Economic Evaluation Reporting Standards checklist and the framework for the quality assessment of decision analytic modelling by Philips et al. (Philips Z, Ginnelly L, Sculpher M, Claxton K, Golder S, Riemsma R, et al. Review of guidelines for good practice in decision-analytic modelling in health technology assessment. Health Technol Assess 2004;8(36)].

RESULTS

Of 4351 non-duplicate citations, eight articles met the review's inclusion criteria. The eight articles focused on health promotion (n = 3), lipid-lowering medicine (n = 4) and blood pressure-lowering medication (n = 1). The majority of the populations in each study had at least one risk factor for cardiovascular disease or were at high risk of cardiovascular disease. For the primary prevention of cardiovascular disease, all strategies were cost-effective at a threshold of £25,000 per quality-adjusted life-year, except increasing motivational interviewing in addition to other behaviour change strategies. Where the cost per quality-adjusted life-year gained was reported, interventions varied from dominant (i.e. less expensive and more effective than the comparator intervention) to £55,000 per quality-adjusted life-year gained.

FUTURE WORK AND LIMITATIONS

We found few health economic analyses of interventions for primary cardiovascular disease prevention conducted within the last decade. Future economic assessments should be undertaken and presented in accordance with best practices so that future reviews may make clear recommendations to improve health policy.

CONCLUSIONS

It is difficult to establish direct comparisons or draw firm conclusions because of the uncertainty and heterogeneity among studies. However, interventions conducted for or within the UK NHS were likely to be cost-effective in people at increased risk of cardiovascular disease when compared with usual care or no intervention.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in Health Technology Assessment. See the NIHR Journals Library website for further project information.

Metabolic Syndrome Programming and Reprogramming: Mechanistic Aspects of Oxidative Stress

Metabolic syndrome (MetS) is a worldwide public health issue characterized by a set of risk factors for cardiovascular disease. MetS can originate in early life by developmental programming. Increasing evidence suggests that oxidative stress, which is characterized as an imbalance between reactive oxygen species (ROS), nitric oxide (NO), and antioxidant systems, plays a decisive role in MetS programming. Results from human and animal studies indicate that maternal-derived insults induce MetS later in life, accompanied by oxidative stress programming of various organ systems. On the contrary, perinatal use of antioxidants can offset oxidative stress and thereby prevent MetS traits in adult offspring. This review provides an overview of current knowledge about the core mechanisms behind MetS programming, with particular focus on the occurrence of oxidative-stress-related pathogenesis as well as the use of potential oxidative-stress-targeted interventions as a reprogramming strategy to avert MetS of developmental origins. Future clinical studies should provide important proof of concept for the effectiveness of these reprogramming interventions to prevent a MetS epidemic.

Effectiveness of letters to patients with or without Cochrane blogshots on 10-year cardiovascular risk change among women in menopausal transition: 6-month three-arm randomized controlled trial

BACKGROUND

Health information and patient education on lifestyle changes may have a positive effect on the prevention of many chronic conditions, especially cardiovascular diseases (CVDs). We performed a parallel, three-arm randomized controlled trial (RCT) of 6-month educational intervention in a form of letters containing a reminder of the participant's CVD risk with or without Cochrane blogshots to reduce CVD risk among women aged 45-65 with one or more known CVD risk factors.

METHODS

The control group received a letter about their CVD risk at the beginning of the trial. The intervention groups received the initial letter about their CVD risk and remainder letters about their CVD risk every 2 months, with or without Cochrane blogshots: (1) effect of calcium in the prevention of high blood pressure, (2) effect of reducing saturated fat acids in eating habits, and (3) effects of green and black tea in CVD prevention. The primary outcome was CVD risk reduction calculated as the difference between the baseline and 6-month score for a 10-year risk of fatal CVD according to the ACC/AHA guidelines.

RESULTS

After both interventions, CVD risk reduction was significantly higher compared to the control group (P < 0.001, Kruskal-Wallis H test). The number of participants who decreased their CV risk was 29% (20/70) in the control group, 69% (48/70) in the group receiving the reminder letters, and 70% (49/70) in the group receiving the reminder letters and blogshots. The number needed to treat to achieve risk reduction was 2.41 (95% CI = 1.77 to 3.78) for letters with a CVD risk reminder and 2.50 (1.81 to 4.03) for letters with a reminder and a blogshot. The group receiving reminder letters with Cochrane blogshots had a significant change in the category of CVD risk, mainly from high to moderate and from moderate to low CVD risk category.

CONCLUSIONS

A simple and inexpensive intervention method in a form of letters reminding women about their CVD risk with or without providing additional health information in the form of Cochrane blogshots about interventions for important CVD risk factors may be effective in CVD management and could be considered by primary care providers.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04601558. Retrospectively registered on October 19, 2020.

Causal relationship between tea intake and cardiovascular diseases: A Mendelian randomization study

Background

Although studies suggest that tea consumption is associated with a reduced risk of cardiovascular disease (CVD). There is no unified conclusion about the potential relationship between tea drinking and CVD. We used a two-sample Mendelian randomized (MR) analysis to systematically explore the causal relationship between tea intake and CVD subtypes for the first time. Furthermore the mediating effect of hypertension was also explored by a two-step MR.

Methods

Genetic instruments for tea intake were identified from a genome-wide association studies (GWAS) involving 447,485 people. Summary data on cardio-vascular disease came from different GWAS meta-analysis studies. In the first step we explored the causal effect of tea intake and CVD. In the second step, we examined the association of hypertension with heart failure and ischemic stroke and estimated the mediating effect of hypertension. Inverse variance weighted MR analysis was used as the primary method for causal analysis. A further sensitivity analysis was performed to ensure robustness of the results.

Results

One standard deviation increase in tea intake was associated with a 25% (OR = 0.75, 95%CI = 0.61–0.91, p = 0.003) lower risk of hypertension, a 28% (OR = 0.72, 95%CI = 0.58–0.89, p = 0.002) lower risk of heart failure, and a 29% (OR = 0.71, 95%CI = 0.55–0.92, p = 0.008) lower risk of ischemic stroke, respectively. And the association between tea drinking and the risk of heart failure and ischemic stroke may be mediated by hypertension. Sensitivity analyses found little evidence of pleiotropy.

Conclusion

Our two-sample MR analysis provided genetic evidence that tea intake was significantly associated with a reduced risk of hypertension, heart failure, and ischemic stroke, and that hypertension may be a potential mediator. Further large randomized controlled trials should be conducted to confirm the causal effect of tea consumption on cardiovascular disease risk.

Consumer Choices and Habits Related to Tea Consumption by Poles

Tea is one of the most consumed beverages in the world. In the literature, much attention is paid to the influence of tea and its components on human health and consumer purchasing behavior. The aim of the study was to analyze the habits of Polish consumers regarding tea consumption, brewing methods, and their choices related to tea, to describe the characteristics of tea consumers, and present their segmentation based on consumer choices and habits regarding tea consumption. The study was performed using the computer-assisted web interviewing (CAWI) method on a group of 1700 adult consumers of tea. Information about consumer choices and habits related to tea consumption was collected, including brewing method, place of tea consumption, and factors determining tea choices. Using cluster analysis, six groups of tea consumers were identified. These are “Occasional tea gourmets”, “Yerba mate drinkers”, “Tea gourmets”, “Occasional consumers”, “Undemanding tea consumers,” and “Occasional strong tea consumers”. In summary, it can be said that Poles are not tea gourmets; they prefer black tea, in bags, brewed in cups or glasses for up to 3 min, and usually drink teas without any additives, at home, several times a week, during breakfast and between meals. The most popular brand among the respondents was Lipton. Consumers have little knowledge of the health benefits of tea.

Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank : A Prospective Cohort Study

BACKGROUND

Tea is frequently consumed worldwide, but the association of tea drinking with mortality risk remains inconclusive in populations where black tea is the main type consumed.

OBJECTIVE

To evaluate the associations of tea consumption with all-cause and cause-specific mortality and potential effect modification by genetic variation in caffeine metabolism.

DESIGN

Prospective cohort study.

SETTING

The UK Biobank.

PARTICIPANTS

498 043 men and women aged 40 to 69 years who completed the baseline touchscreen questionnaire from 2006 to 2010.

MEASUREMENTS

Self-reported tea intake and mortality from all causes and leading causes of death, including cancer, all cardiovascular disease (CVD), ischemic heart disease, stroke, and respiratory disease.

RESULTS

During a median follow-up of 11.2 years, higher tea intake was modestly associated with lower all-cause mortality risk among those who drank 2 or more cups per day. Relative to no tea drinking, the hazard ratios (95% CIs) for participants drinking 1 or fewer, 2 to 3, 4 to 5, 6 to 7, 8 to 9, and 10 or more cups per day were 0.95 (95% CI, 0.91 to 1.00), 0.87 (CI, 0.84 to 0.91), 0.88 (CI, 0.84 to 0.91), 0.88 (CI, 0.84 to 0.92), 0.91 (CI, 0.86 to 0.97), and 0.89 (CI, 0.84 to 0.95), respectively. Inverse associations were seen for mortality from all CVD, ischemic heart disease, and stroke. Findings were similar regardless of whether participants also drank coffee or not or of genetic score for caffeine metabolism.

LIMITATION

Potentially important aspects of tea intake (for example, portion size and tea strength) were not assessed.

CONCLUSION

Higher tea intake was associated with lower mortality risk among those drinking 2 or more cups per day, regardless of genetic variation in caffeine metabolism. These findings suggest that tea, even at higher levels of intake, can be part of a healthy diet.

PRIMARY FUNDING SOURCE

National Cancer Institute Intramural Research Program.

Effects of the green tea catechin epigallocatechin-3-gallate on Streptococcus mutans planktonic cultures and biofilms: systematic literature review of in vitro studies

This study aimed at performing a systematic review of the literature on the effects of epigallocatechin-3-gallate (EGCG) on Streptococcus mutans planktonic cultures and biofilms. The selected references demonstrated that EGCG suppresses S. mutans acid production by inhibiting the activity of enzymes such as lactate dehydrogenase and FIF0-ATPase. Regarding virulence factors, one study reported a reduction in soluble and insoluble polysaccharide synthesis, another demonstrated that EGCG inhibited GTase activity, and another showed effects of EGCG on the expression of gtf B, C, and D. The effects of EGCG on S. mutans biofilms were reported only by 2 of the selected studies. Moreover, high variability in effective concentrations and microbial assessment methods were observed. The literature suggests that EGCG has effects against S. mutans planktonic cells viability and virulence factors. However, the literature lacks studies with appropriate biofilm models to evaluate the precise effectiveness of EGCG against S. mutans biofilms.

Novel Insights on Dietary Polyphenols for Prevention in Early-Life Origins of Hypertension: A Review Focusing on Preclinical Animal Models

Polyphenols are the largest group of phytochemicals with health benefits. Early life appears to offer a critical window of opportunity for launching interventions focused on preventing hypertension, as increasing evidence supports the supposition that hypertension can originate in early life. Although polyphenols have antihypertensive actions, knowledge of the potential beneficial action of the early use of polyphenols to avert the development of hypertension is limited. Thus, in this review, we first provide a brief summary of the chemistry and biological function of polyphenols. Then, we present the current epidemiological and experimental evidence supporting the early-life origins of hypertension. We also document animal data on the use of specific polyphenols as an early-life intervention to protect offspring against hypertension in adulthood and discuss underlying mechanisms. Continued research into the use of polyphenols to prevent hypertension from starting early in life will have far-reaching implications for future health.

Evaluation of the effects of four types of tea on the activity of cytochrome P450 enzymes with a probe cocktail and HPLC-MS/MS

Background

Tea, the world's second most popular drink, is an essential part of some people's lives. Thus, this study aimed to explore potential tea-drug interactions with a view to promoting the rational administration of drugs.

Methods

A specific and sensitive approach involving high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a probe cocktail was established and validated to evaluate the inhibitory effects of four teas on five cytochrome P450 (CYP450) enzymes in rats. Metoprolol tartrate (MT), omeprazole (OMP), phenacetin (PNT), tolbutamide (TOL), and testosterone (T) were selected as the probe drugs for CYP2D6, CYP2C19, CYP1A2, CYP2C6, and CYP3A1/2, respectively, and were simultaneously quantified in the multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+) in a single 12-min run.

Results

The extraction recoveries, matrix effect values, as well as intra/interday accuracy and precision met the determination standards. CYP1A2 and CYP2C6 were strongly inhibited by green tea, and CYP2C6 was also strongly inhibited by Pu'er tea. Ti Kuan Yin tea had a weak inhibitory effect, and black tea had only a slight inhibitory effect, on CYP1A2. Furthermore, the four types of tea did not have significantly altered the activity of CYP2D6, CYP2C19, and CYP3A1/2 in vitro.

Conclusions

The method used in the present study was successfully applied to assess the inhibitory effects of aqueous extracts of four types of tea on CYP450 isoforms in vitro. The results suggest that different types of tea have different effects on drug metabolism.

Selenium Supplementation Improved Cardiac Functions by Suppressing DNMT2-Mediated GPX1 Promoter DNA Methylation in AGE-Induced Heart Failure

Objective

Advanced glycation end products (AGEs) are featured metabolites associated with diabetic cardiomyopathy which is characterized by heart failure caused by myocyte apoptosis. Selenium was proved cardioprotective. This study was aimed at investigating the therapeutic effects and underlying mechanisms of selenium supplementation on AGE-induced heart failure.

Methods

Rats and primary myocytes were exposed to AGEs. Selenium supplementation was administrated. Cardiac functions and myocyte apoptosis were evaluated. Oxidative stress was assessed by total antioxidant capacity (TAC), reactive oxygen species (ROS) generation, and GPX activity. Expression levels of DNA methyltransferases (DNMTs) and glutathione peroxidase 1 (GPX1) were evaluated. DNA methylation of the GPX1 promoter was analyzed.

Results

AGE exposure elevated intracellular ROS generation, induced myocyte apoptosis, and impaired cardiac functions. AGE exposure increased DNMT1 and DNMT2 expression, leading to the reduction of GPX1 expression and activity in the heart. Selenium supplementation decreased DNMT2 expression, recovered GPX1 expression and activity, and alleviated intracellular ROS generation and myocyte apoptosis, resulting in cardiac function recovery. DNA methylation analysis in primary myocytes indicated that selenium supplementation or DNMT inhibitor AZA treatment reduced DNA methylation of the GPX1 gene promoter. Selenium supplementation and AZA administration showed synergic inhibitory effect on GPX1 gene promoter methylation.

Conclusions

Selenium supplementation showed cardioprotective effects on AGE-induced heart failure by suppressing ROS-mediated myocyte apoptosis. Selenium supplementation suppressed ROS generation by increasing GPX1 expression via inhibiting DNMT2-induced GPX1 gene promoter DNA methylation in myocytes exposed to AGEs.

Improved yield of theaflavin-3,3'-digallate from Bacillus megaterium tyrosinase via directed evolution

Theaflavin-3,3'-digallate (TFDG) in black tea possesses several health benefits. However, low TFDG yields limit its application. Herein, tyrosinases from Bacillus megaterium (Bmtyrc) were used to synthesize TFDG. To improve the catalytic efficiency of tyrosinase, a directed evolution strategy and a high-throughput screening method was employed. Compared with the wild type, mutant Bmtyrc-3 (N205D/D166E/D167G/F197W) showed 6.46 and 4.91-folds higher specific activity and 51.97- and 1.95-folds higher Vmax values towards epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), respectively. Moreover, Bmtyrc-3 displayed significantly enhanced catalytic efficiencies, and the space-time yield of TFDG was 35.35 g L^-1d^-1. Bmtyrc-3 presents a broader substrate binding area, caused by a mutation (N205D) encompassing the active site. Changes in the potential of the substrate binding site and hydrogen bonds, and the electrostatic effect on the protein surface resulted in an increased activity of the substrates EGCG and ECG.

Tea intake and cardiovascular disease: an umbrella review

Brewed tea (Camellia sinensis) is a major dietary source of flavonoids, in particular flavan-3-ols. Tea consumption has been suggested to be inversely associated with a decreased risk of cardiovascular disease (CVD). Several biological mechanisms support the inverse relationship between tea flavonoid intake and CVD risk. Given the recent accumulating evidence from various systematic reviews regarding the role of tea as a beverage in reducing CVD risk and severity, we conducted an umbrella review to describe and critically evaluate the totality of evidence to date. We searched the PubMed, Web of Science, Cochrane Database of Systematic Reviews, and BIOSIS databases for systematic reviews published between January 1, 2010 and February 22, 2020 reporting relationships between tea (C. sinensis) consumption and CVD mortality, CVD diagnosis or incidence, CVD events, stroke events, blood pressure, endothelial function, blood lipids and triglycerides, and inflammatory markers. Herein, we describe results from 23 included systematic reviews. Consistently consuming 2 cups of unsweet tea per day offers the right levels of flavonoids to potentially decrease CVD risk and its progression. This is supported by the consistency between a recent high-quality systematic review and dose-response meta-analyses of population-based studies demonstrating beneficial effects of consumption on CVD mortality, CVD events and stroke events and medium- to high-quality systematic reviews of intervention studies that further elucidate potential benefits on both validated (i.e., SBP, DBP, total cholesterol, and LDL-cholesterol) and emerging risk biomarkers of CVD (TNF-ɑ and IL-6). On the basis of this umbrella review, the consumption of tea as a beverage did not seem to be harmful to health; therefore, the benefits of moderate consumption likely outweigh risk. Future large, clinical intervention studies will provide better mechanistic insight with the ability to confirm the outcome effects shown across observational studies. The review protocol was registered on PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) as CRD42020218159.KEY MESSAGESIt is reasonable to judge that 2 cups of unsweet tea per day has the potential to decrease CVD risk and progression due to its flavonoid content.The primary side effects of tea documented in human studies are hepatotoxicity and gastrointestinal disturbances (i.e., vomiting and diarrhea) after high-dose supplemental intake.Additional clinical research is needed to fully elucidate the effects of tea flavonoids on markers of CVD, as many studies were under-powered to detect changes.[Figure: see text].

Association between Tea Consumption and Hypertension Risk among Middle-Aged and Older Chinese Adults

BACKGROUND

Current evidence on tea consumption and hypertension is inconclusive, and prospective studies among habitual tea drinkers remain limited.

OBJECTIVE

We investigated the associations of habitual tea consumption with hypertension risk and longitudinal blood pressure changes in 2 large cohorts.

METHODS

This study included participants aged 40-75 y from the Shanghai Women's Health Study (n = 31,351) and the Shanghai Men's Health Study (n = 28,342), without hypertension, diabetes, cardiovascular disease, or cancer at baseline. Information on tea consumption was assessed during in-person interviews at enrollment and follow-up visits. Incident hypertension was identified by self-reported diagnosis, medication use, or blood pressure measurements.

RESULTS

Current tea drinkers had a 7% higher risk than the non-current tea drinker group [HRs (95% CIs): women, 1.07 (1.01, 1.14); men, 1.07 (1.02, 1.12)]. The amount of tea drinking showed significant dose-response associations with hypertension: compared with the non-current group, HRs (95% CIs) for women and men were 1.01 (0.90, 1.14) and 1.02 (0.96, 1.08) for low (women/men: <100/200 g/mo), 1.07 (1.01, 1.15) and 1.05 (0.99, 1.12) for medium (women/men: 100-250/200-250 g/mo), and 1.18 (1.01, 1.39) and 1.10 (1.03, 1.17) for the high-amount group (women/men: >250 g/mo). Among participants without hypertension, compared with non-current tea drinkers, least-squares means of 3-y changes in blood pressure were 0.3-0.4 mm Hg higher for women and men as current drinkers and 0.7-0.9 mm Hg higher for men in the high-consumption group. Compared with those who never drank tea, women who drank tea consistently had 0.5 (0.2, 0.7) mm Hg higher diastolic blood pressure (DBP), whereas men had 0.5 (0.04, 0.9) mm Hg higher systolic blood pressure and 0.3 (0.04, 0.6) mm Hg higher DBP, respectively.

CONCLUSIONS

Our findings suggest that habitual tea drinking is associated with a slightly higher risk of hypertension and a minor increase in blood pressure among middle-aged and older Chinese adults, which warrants confirmation by long-term intervention studies.

Green Tea from the Far East to the Drug Store: Focus on the Beneficial Cardiovascular Effects

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Evidence from observational and randomized controlled studies showing the potential benefits of green tea on lowering CVD risk has been emerging rapidly during the past few decades. These benefits include reduced risk for major cardiovascular events, lowering of blood pressure, decreased LDL cholesterol levels and weight loss. At the same time, the understanding of the physiological mechanisms behind these alterations is advancing. Consumption of green tea originated from China thousands of years ago, but since then, it expanded all over the world. Recent advances in understanding the role of tea polyphenols, mainly catechins, as mediators of tea's health benefits, have caused the emergence of various types of green tea extracts (GTE) on the market. While taking green tea is generally considered safe, there are concerns about the safety of using tea extracts. The present article reviews the current evidence of green tea consumption leading to reduced CVD risk, its potential biological mechanisms and the safety of using GTE.

The Effects of Medicinal Plants and Bioactive Natural Compounds on Homocysteine

BACKGROUND

Among non-communicable diseases, cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity in global communities. By 2030, CVD-related deaths are projected to reach a global rise of 25 million. Obesity, smoking, alcohol, hyperlipidemia, hypertension, and hyperhomocysteinemia are several known risk factors for CVDs. Elevated homocysteine is tightly related to CVDs through multiple mechanisms, including inflammation of the vascular endothelium. The strategies for appropriate management of CVDs are constantly evolving; medicinal plants have received remarkable attention in recent researches, since these natural products have promising effects on the prevention and treatment of various chronic diseases. The effects of nutraceuticals and herbal products on CVD/dyslipidemia have been previously studied. However, to our knowledge, the association between herbal bioactive compounds and homocysteine has not been reviewed in details. Thus, the main objective of this study is to review the efficacy of bioactive natural compounds on homocysteine levels according to clinical trials and animal studies.

RESULTS

Based on animal studies, black and green tea, cinnamon, resveratrol, curcumin, garlic extract, ginger, and soy significantly reduced the homocysteine levels. According to the clinical trials, curcumin and resveratrol showed favorable effects on serum homocysteine. In conclusion, this review highlighted the beneficial effects of medicinal plants as natural, inexpensive, and accessible agents on homocysteine levels based on animal studies. Nevertheless, the results of the clinical trials were not uniform, suggesting that more well-designed trials are warranted.

Phytotherapy for Cardiovascular Disease: A Bench-to-Bedside Approach

At present, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and global trends suggest that this panorama will persist or worsen in the near future. Thus, optimization of treatment strategies and the introduction of novel therapeutic alternatives for CVD represent key objectives in contemporary biomedical research. In recent years, phytotherapy-defined as the therapeutic use of whole or minimally modified plant components-has ignited large scientific interest, with a resurgence of abundant investigation on a wide array of medicinal herbs (MH) for CVD and other conditions. Numerous MH have been observed to intervene in the pathophysiology of CVD via a myriad of molecular mechanisms, including antiinflammatory, anti-oxidant, and other beneficial properties, which translate into the amelioration of three essential aspects of the pathogenesis of CVD: Dyslipidemia, atherosclerosis, and hypertension. Although the preclinical data in this scenario is very rich, the true clinical impact of MH and their purported mechanisms of action is less clear, as large-scale robust research in this regard is in relatively early stages and faces important methodological challenges. This review offers a comprehensive look at the most prominent preclinical and clinical evidence currently available concerning the use of MH in the treatment of CVD from a bench-to-bedside approach.

The Association between Tea Consumption and the Risk of Fracture: A Dose-Response Meta-Analysis of Prospective Cohort Studies

OBJECTIVES

Inconsistent results exist on the role of tea consumption on subsequent risk of fracture. A dose-response meta-analysis was therefore conducted to assess the association of tea consumption with the risk of fracture based on prospective cohort studies.

METHODS

The electronic databases of PubMed, Embase, and the Cochrane library were systematically searched to identify prospective cohort studies from inception until September 2020. The categories of high versus low and dose-response meta-analyses for tea consumption on the risk of fracture were calculated using the random-effects model. Eight prospective cohort studies recruited 774,134 individuals selected for the final meta-analysis.

RESULTS

An increment of 1 cup in tea consumption was not associated with the risk of fracture [relative risk (RR), 0.98; 95% confidence interval (CI), 0.96-1.00; P = 0.102]. Moreover, the highest tea consumption category was associated with a reduced risk of fracture (RR, 0.93; 95% CI, 0.88-0.98; P = 0.005). Furthermore, heavy (RR, 0.91; 95% CI, 0.85-0.98; P = 0.008) and mild (RR, 0.97; 95% CI, 0.94-1.00; P = 0.046) tea consumption were associated with lower risk of fracture. However, moderate tea consumption was not associated with the risk of fracture (RR, 0.98; 95% CI, 0.94-1.02; P = 0.281).

CONCLUSION

This study found that increased tea consumption may provide a protective role in the risk of fracture. The benefits of tea consumption should be further explored according to the characteristics of the individuals.

Effects of Matcha Green Tea Powder on Cognitive Functions of Community-Dwelling Elderly Individuals

Matcha Green Tea Powder contains a variety of active ingredients beneficial to health, such as tea catechins, lutein and vitamin K. It is also known that these ingredients confer benefits upon cognitive functions of elderly people. Therefore, we aimed to investigate the relationship between a daily supplementation of Matcha and the change in cognitive functions of community-dwelling elderly people. A randomized, double-blind, placebo-controlled 12-week trial was performed. Sixty-one participants were recruited and randomly assigned to receive test drink containing 3 g powder from fresh Matcha or placebo powder per day. Changes in cognitive function were assessed utilizing a psychometric test battery. Daily food intake was assessed by a Brief-type Self-administered Diet History Questionnaire (BDHQ). In the gender-specific analysis, a significant cognitive enhancement was observed in the Montreal Cognitive Assessment (MoCA) score in the active group of women. In dietary analysis, we found a significant inverse correlation between consumption of vitamin K in daily diet, excluding test drinks, and change in MoCA. The present study suggests that daily supplementation of Matcha Green Tea Powder has protective effects against cognitive decline in community-dwelling elderly women.

Theaflavins decrease skeletal muscle wasting in disuse atrophy induced by hindlimb suspension in mice

We previously found that a single dose of theaflavins induced skeletal muscle metabolic changes. In this study, we examined the effect of theaflavins on disuse muscle atrophy model mice by hindlimb suspension. Mice were assigned to 4 groups; ground-vehicle, ground-theaflavins, suspension-vehicle, and suspension-theaflavins, dosed with theaflavins (250 mg/kg/day) for 2 weeks. The peak of myotube size of cross sectional area was significantly moved to the smaller side in the suspension-vehicle group compared with the ground-vehicle group, and these shifts were significantly reduced by the treatment with theaflavins in both soleus and extensor digitorum longus. The level of phosphorylated eukaryotic translation initiation factor 4E-binding protein (4EBP)-1, located downstream of the Akt/mTOR pathway, was significantly different between suspension-vehicle and suspension-theaflavins in soleus. The ratio of forkhead box O (FoxO) 3a to phosphorylated FoxO3a significantly increased in soleus or tended to rise in extensor digitorum longus of suspension-vehicle group compared with ground-vehicle. In contrast, these changes were not observed in suspension-theaflavins group. These results suggested that theaflavins inhibited the progress of disuse muscle atrophy through modulation of protein metabolism.

Habitual Coffee and Tea Consumption and Cardiometabolic Biomarkers in the UK Biobank: The Role of Beverage Types and Genetic Variation

BACKGROUND

Mechanisms linking habitual consumption of coffee and tea to the development of type 2 diabetes and cardiovascular diseases remain unclear.

OBJECTIVES

We leveraged dietary, genetic, and biomarker data collected from the UK Biobank to investigate the role of different varieties of coffee and tea in cardiometabolic health.

METHODS

We included data from ≤447,794 participants aged 37-73 y in 2006-2010 who provided a blood sample and completed questionnaires regarding sociodemographic factors, medical history, diet, and lifestyle. Multivariable linear regression was used to examine the association between coffee or tea consumption and blood concentrations of glycated hemoglobin, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, fasting triglycerides (TGs), apoA-1, apoB, lipoprotein-a, and C-reactive protein (CRP). Lifestyle and genetic factors affecting caffeine metabolism, responses, or intake were tested for interactions with beverage intake in relation to biomarker concentrations.

RESULTS

Compared with coffee nonconsumers, each additional cup of coffee was significantly associated with higher total cholesterol, HDL-cholesterol, and LDL-cholesterol concentrations and lower TG and CRP concentrations in both men and women (P-trend < 0.002). Higher consumption of espresso coffee (≥2 compared with 0 cups/d) was associated with higher LDL cholesterol in men (β: 0.110 mmol/L; 95% CI: 0.058, 0.163 mmol/L) and women (β: 0.161 mmol/L; 95% CI: 0.088, 0.234 mmol/L), whereas no substantial association was observed for instant coffee. Compared with tea nonconsumers, higher tea consumption was associated with lower total and LDL cholesterol and apoB and higher HDL cholesterol (P-trend < 0.002); these associations were similar for black and green tea. Associations were not modified by genetics.

CONCLUSIONS

In the UK Biobank, consumption of certain coffee brews such as espresso had unfavorable associations with blood lipids, whereas consumption of tea had favorable associations. Findings were not modified by genetic variants affecting caffeine metabolism, suggesting a role of noncaffeine constituents of these beverages in cardiometabolic health.

A Comprehensive Insight on the Health Benefits and Phytoconstituents of Camellia sinensis and Recent Approaches for Its Quality Control

Tea, Camellia sinensis, which belongs to the family Theaceae, is a shrub or evergreen tree up to 16 m in height. Green tea is very popular because of its marked health benefits comprising its anticancer, anti-oxidant, and antimicrobial activities, as well as its effectiveness in reducing body weight. Additionally, it was recognized by Chinese people as an effective traditional drink required for the prophylaxis against many health ailments. This is due to the complex chemical composition of green tea, which comprises different classes of chemical compounds, such as polyphenols, alkaloids, proteins, minerals, vitamins, amino acids, and others. The beneficial health effects of green tea ultimately led to its great consumption and increase its liability to be adulterated by either low-quality or non-green tea products with concomitant decrease in activity. Thus, in this review, green tea was selected to highlight its health benefits and phytoconstituents, as well as recent approaches for its quality-control monitoring that guarantee its incorporation in many pharmaceutical industries. More research is needed to find out other more biological activities, active constituents, and other simple and cheap techniques for its quality assurance that ascertain the prevention of its adulteration.

Tea consumption and risk of fractures: an updated meta-analysis

This meta-analysis included 16 studies, involving seven cohort studies and nine case-control studies, and the results indicated that tea consumption may be associated with a reduced the risk of fractures.

INTRODUCTION

Regarding relationship of tea consumption with the risk of fractures remains controversial. We performed a meta-analysis to elucidate the association between tea consumption and the risk of fractures.

METHODS

Relevant articles were identified up to March 2019 by searching PubMed, Web of Science, and Embase databases. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were computed utilizing fixed or random effects model based on heterogeneity.

RESULTS

Altogether 16 studies (seven cohort and nine case-control studies) were included in this meta-analysis, involving 772,707 participants with 37,166 fracture cases. The RRs (95% CIs) of fracture for the highest versus lowest category of tea consumption were 0.86 (0.78-0.94). Subgroup analysis indicated significant associations in cohort studies (0.90 (0.86-0.94)) and case-control studies (0.77 (0.69-0.85)).

CONCLUSIONS

The current meta-analysis indicates that tea consumption may be associated with a reduced the risk of fractures.

Effects of Nutritional Supplements and Dietary Interventions on Cardiovascular Outcomes: An Umbrella Review and Evidence Map

BACKGROUND

The role of nutritional supplements and dietary interventions in preventing mortality and cardiovascular disease (CVD) outcomes is unclear.

PURPOSE

To examine evidence about the effects of nutritional supplements and dietary interventions on mortality and cardiovascular outcomes in adults.

DATA SOURCES

PubMed, CINAHL, and the Cochrane Library from inception until March 2019; ClinicalTrials.gov (10 March 2019); journal Web sites; and reference lists.

STUDY SELECTION

English-language, randomized controlled trials (RCTs) and meta-analyses of RCTs that assessed the effects of nutritional supplements or dietary interventions on all-cause mortality or cardiovascular outcomes, such as death, myocardial infarction, stroke, and coronary heart disease.

DATA EXTRACTION

Two independent investigators abstracted data, assessed the quality of evidence, and rated the certainty of evidence.

DATA SYNTHESIS

Nine systematic reviews and 4 new RCTs were selected that encompassed a total of 277 trials, 24 interventions, and 992 129 participants. A total of 105 meta-analyses were generated. There was moderate-certainty evidence that reduced salt intake decreased the risk for all-cause mortality in normotensive participants (risk ratio [RR], 0.90 [95% CI, 0.85 to 0.95]) and cardiovascular mortality in hypertensive participants (RR, 0.67 [CI, 0.46 to 0.99]). Low-certainty evidence showed that omega-3 long-chain polyunsaturated fatty acid (LC-PUFA) was associated with reduced risk for myocardial infarction (RR, 0.92 [CI, 0.85 to 0.99]) and coronary heart disease (RR, 0.93 [CI, 0.89 to 0.98]). Folic acid was associated with lower risk for stroke (RR, 0.80 [CI, 0.67 to 0.96]; low certainty), whereas calcium plus vitamin D increased the risk for stroke (RR, 1.17 [CI, 1.05 to 1.30]; moderate certainty). Other nutritional supplements, such as vitamin B6, vitamin A, multivitamins, antioxidants, and iron and dietary interventions, such as reduced fat intake, had no significant effect on mortality or cardiovascular disease outcomes (very low- to moderate-certainty evidence).

LIMITATIONS

Suboptimal quality and certainty of evidence.

CONCLUSION

Reduced salt intake, omega-3 LC-PUFA use, and folate supplementation could reduce risk for some cardiovascular outcomes in adults. Combined calcium plus vitamin D might increase risk for stroke.

PRIMARY FUNDING SOURCE

None.

Studies on the Prevention of Cancer and Cardiometabolic Diseases by Tea: Issues on Mechanisms, Effective Doses, and Toxicities

This article presents a brief overview of studies on the prevention of cancer and cardiometabolic diseases by tea. The major focus is on green tea catechins concerning the effective doses used, the mechanisms of action, and possible toxic effects. In cancer prevention by tea, the laboratory results are strong; however, the human data are inconclusive, and the effective doses used in some human trials approached toxic levels. In studies of the alleviation of metabolic syndrome, diabetes, and prevention of cardiovascular diseases, the results from human studies are stronger in individuals who consume 3-4 cups of tea (600-900 mg of catechins) or more per day. The tolerable upper intake level of tea catechins has been set at 300 mg of (-)-epigallocatechin-3-gallate in a bolus dose per day in some European countries. The effects of doses and dosage forms on catechin toxicity, the mechanisms involved, and factors that may affect toxicity are discussed.

Tea, coffee, caffeine intake and the risk of cardio-metabolic outcomes: findings from a population with low coffee and high tea consumption

Background

This study aimed to assess the potential effects of long-term intake of caffeine and habitual consumption of coffee and tea on the occurrence of cardio-renal events among an Iranian population with low coffee and high tea consumption.

Methods

Adult participants of the Tehran Lipid and Glucose Study (2006-2008 to 2012-2014) who met the study inclusion criteria, were recruited. Habitual dietary intakes were assessed using a validated food frequency questionnaire. Demographics, anthropometrics, blood pressure, and biochemical variables were evaluated at baseline and during follow-up examinations. Multivariate Cox proportional hazard and logistic regression models adjusted for potential confounders were used to estimate the risk of cardiovascular disease (CVD), hypertension (HTN) and chronic kidney disease (CKD).

Results

During median 6 years of follow-up, the incidence rate of CVD outcomes, HTN, and CKD were 3.3%, 15.5%, and 17.9%, respectively. The risk of CVD was increased more than two-fold in the highest tertile of tea consumption (HR = 2.44, 95% confidence interval, CI = 1.40-4.27; P for trend = 0.001), and caffeine intakes (HR = 2.22, 95% CI = 1.23-4.01; P for trend = 0.005). A 42% lower incidence of CVD was observed in coffee drinkers, compared to non-drinkers (HR = 0.58, 95% CI = 0.36-0.93; P for trend = 0.023). No significant association was observed between tea, coffee or caffeine intakes and the risk of HTN or CKD.

Conclusions

Findings of our study support previous data regarding the protective effects of coffee on CVD. Contrary to the previous studies, we found that higher intakes of tea and caffeine, mainly originated from tea in our population, may increase risk of CVD events. It may be related to the type of tea and its preparation methods, additives or artificial colors in tea consumed in Iran, and sweets or sugar that mostly consumed accompanied by tea. Also, genetic variants of the liver enzymes may modify the association of dietary caffeine sources and incidence of CVD. Further prospective studies with incorporation of different population with different dietary habits and genetic backgrounds are needed to clarify the contradictions.

Lost in Translation: The Promise and Problems of the Globalization of Research

The purpose of this article is to consider the promise and problems of the globalization of research for nurses and other healthcare professionals. Over the past decade, there has been an impressive increase in research activity in many regions of the world, such as in several of the Asian countries. This increasing capacity to conduct research and create innovations has great promise for shared health, prosperity, and well-being, but it also has some significant problems and limitations that are often not reported. One area of research that has drawn considerable international research attention is aging and longevity. In the United States, there is much to learn from the work of international colleagues in terms of clinical application; it is unclear how generalizable the findings are or, in other words, what may be lost in translation.

Synthesis of Theaflavins and Their Functions

Numerous epidemiological and interventional clinical studies have consistently reported that black tea is good for human health. The polyphenolic compound, theaflavin, and its galloyl esters (theaflavins) are the primary red pigments in black tea that possess several health benefits, including fat-reducing and glucose-lowering capabilities and lifestyle-related disease prevention related to anti-obesity, anticancer, anti-atherosclerotic, anti-inflammatory, antiviral, antibacterial, anti-osteoporotic, and anti-dental caries properties. These compounds are produced by key enzymes, such as polyphenol oxidase and peroxidase, from parent green tea catechins present in fresh green tea leaves during the production of black tea leaves or the fermentation of green tea. However, theaflavins are only present in low concentrations in black tea; thus, their extraction from black tea leaves at sufficient levels for use in medical studies has been difficult. To circumvent this issue, different procedures for the synthesis of theaflavins using chemical oxidizing reagents or enzymes have been studied; however, low yields have limited their utility. Recently, however, several biosynthetic methods have been developed for the mass production of theaflavins. Using these methods, the physiological functions of theaflavins in lifestyle-related diseases in mice and humans have also been studied. In this review, we present the synthesis of theaflavins and their health benefits.

Principles of pharmacological research of nutraceuticals

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Role of Dietary Antioxidants in the Preservation of Vascular Function and the Modulation of Health and Disease

In vascular diseases, including hypertension and atherosclerosis, vascular endothelial dysfunction (VED) occurs secondary to altered function of endothelial nitric oxide synthase (eNOS). A novel redox regulated pathway was identified through which eNOS is uncoupled due to S-glutathionylation of critical cysteine residues, resulting in superoxide free radical formation instead of the vasodilator molecule, nitric oxide. In addition, the redox sensitive cofactor tetrahydrobiopterin, BH₄, is also essential for eNOS coupling. Antioxidants, either individually or combined, can modulate eNOS uncoupling by scavenging free radicals or impairing specific radical generating pathways, thus preventing oxidative stress and ameliorating VED. Epidemiological evidence and dietary guidelines suggest that diets high in antioxidants, or antioxidant supplementation, could preserve vascular health and prevent cardiovascular diseases (CVDs). Therefore, the purpose of this review is to highlight the possible role of dietary antioxidants in regulating eNOS function and uncoupling which is critical for maintenance of vascular health with normal blood flow/circulation and prevention of VED. We hypothesize that a conditioned dietary approach with suitable antioxidants may limit systemic oxidation, maintain a beneficial ratio of reduced to oxidized glutathione, and other redox markers, and minimize eNOS uncoupling serving to prevent CVD and possibly other chronic diseases.

Potential benefit of (-)-epigallocatechin-3-gallate for macrovascular complications in diabetes

Vascular problems are the most common complications in diabetes. Substantial evidence from epidemiological and pathophysiological studies show that hyperglycemia is a major risk factor for macrovascular complications in patients with diabetes. (-)-Epigallocatechin-3-gallate (EGCG), the major catechin derived from green tea, is known to exert a variety of cardiovascular beneficial effects. The protective effects of EGCG in diabetes are also evident. However, whether EGCG is beneficial against macrovascular complications that occur in diabetes remains unknown. Our previous studies demonstrated that treatment of EGCG inhibits high glucose-induced vascular smooth muscle cell proliferation and suppresses high glucose-mediated vascular inflammation in human umbilical vein endothelial cells. Therefore, we hypothesize that EGCG might be an effective potential candidate to reduce the macrovascular complications in diabetes.

A Systematic Review and Meta-Analysis of the Effects of Flavanol-Containing Tea, Cocoa and Apple Products on Body Composition and Blood Lipids: Exploring the Factors Responsible for Variability in Their Efficacy

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m², non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders.

A Balanced Risk-Benefit Analysis to Determine Human Risks Associated with Pyrrolizidine Alkaloids (PA)-The Case of Tea and Herbal Infusions

Humans are exposed to pyrrolizidine alkaloids (PA) through different sources, mainly from contaminated foodstuff. Teas and herbal infusions (T&HI) can be contaminated by PA producing weed. PA can possess toxic, mutagenic, genotoxic, and carcinogenic properties. Thus, possible health risks for the general population are under debate. There is a strong safety record for T&HI and additionally epidemiological evidence for the preventive effects of regular tea consumption on cardiovascular events and certain types of cancer. There is no epidemiological evidence, however, for human risks of regular low dose PA exposure. Recommended regulatory PA-threshold values are based on experimental data only, accepting big uncertainties. If a general risk exists through PA contaminated T&HI, it must be small compared to other frequently accepted risks of daily living and the proven health effects of T&HI. Decision making should be based on a balanced riskbenefit analysis. Based on analyses of the scientific data currently available, it is concluded that the benefits of drinking T&HI clearly outweigh the negligible health risk of possible PA contamination. At the same time, manufacturers must continue their efforts to secure good product quality and to be transparent on their measures of quality control and risk communication.

Antioxidants from black and green tea: from dietary modulation of oxidative stress to pharmacological mechanisms

The consumption of tea (Camellia sinensis) has been correlated with a low incidence of chronic pathologies, such as cardiovascular disease and cancer, in which oxidative stress plays a critical role. Tea catechins and theaflavins are, respectively, the bioactive phytochemicals responsible for the antioxidant activity of green tea (GT) and black tea (BT). In addition to their redox properties, tea catechins and theaflavins could have also pharmacological activities, such as the ability to lower glucose, lipid and uric acid (UA) levels. These activities are mediated by pharmacological mechanisms such as enzymatic inhibition and interaction with transporters. Epigallocatechin gallate is the most active compound at inhibiting the enzymes involved in cholesterol and UA metabolism (hydroxy-3-methyl-glutaryl-CoA reductase and xanthine oxidase respectively) and affecting glucose transporters. The structural features of catechins that significantly contribute to their pharmacological effect are the presence/absence of the galloyl moiety and the number and positions of the hydroxyl groups on the rings. Although the inhibitory effects on α-glucosidase, maltase, amylase and lipase, multidrug resistance 1, organic anion transporters and proton-coupled folate transport occur at higher concentrations than those apparent in the circulation, these effects could be relevant in the gut. In conclusion, despite the urgent need for further research in humans, the regular consumption of moderate quantities of GT and BT can effectively modulate their antioxidant capacity, mainly in people subjected to oxidative stress, and could improve the metabolism of glucose, lipid and UA.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

The Combination of Green Tea Extract and Eriodictyol Inhibited High-Fat/High-Sucrose Diet-Induced Cholesterol Upregulation Is Accompanied by Suppression of Cholesterol Synthesis Enzymes

Western diets induce obesity associated with an increased risk of hypercholesterolaemia. Indeed, obesity-induced hypercholesterolaemia is correlated with increased coronary cardiovascular disease (CVD) risk. Male C57BL/6J mice were fed a normal diet, high-fat and high-sucrose diet (HF/HS), HF/HS with green tea extract powder diet (HF/HS+GT), HF/HS with eriodictyol diet (HF/HS+Eri), or HF/HS with green tea extract powder and eriodictyol diet (HF/HS+GT+Eri) for 8 wk. Body weight was lower in the HF/HS+GT+Eri group than in the HF/HS group (-8.3%, p<0.01). The HF/HS diet elicited an upregulation of total cholesterol levels (-63%, p<0.001), and low-density lipoprotein (LDL) levels (-89%, p<0.001) were significantly suppressed by the GT+Eri diet. Conversely, no change (p>0.05) was observed in the HF/HS+GT and HF/HS+Eri groups. The HF/HS diet-induced hepatic mRNA increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) was ameliorated (-73%) by the oral administration of green tea extract and eriodictyol. Moreover, the GT+Eri diet suppressed HF/HS diet-induced upregulation of 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGCS) (-75%, p<0.05). Furthermore, the LDL receptor (LDLR) levels were higher in the HF/HS+GT+Eri group (+50%, p<0.05) than in the HF/HS group. These results suggest that a combination of green tea and eriodictyol decreases cholesterol levels, particularly LDL levels, accompanied by the suppression of HMGCR and HMGCS levels and upregulation of LDLR levels in the liver.

Effect of epigallocatechin-3-gallate, major ingredient of green tea, on the pharmacokinetics of rosuvastatin in healthy volunteers

Previous in vitro studies have demonstrated the inhibitory effect of green tea on drug transporters. Because rosuvastatin, a lipid-lowering drug widely used for the prevention of cardiovascular events, is a substrate for many drug transporters, there is a possibility that there is interaction between green tea and rosuvastatin. The aim of this study was to investigate the effect of green tea on the pharmacokinetics of rosuvastatin in healthy volunteers. An open-label, three-treatment, fixed-sequence study was conducted. On Day 1, 20 mg of rosuvastatin was given to all subjects. After a 3-day washout period, the subjects received 20 mg of rosuvastatin plus 300 mg of epigallocatechin-3-gallate (EGCG), a major ingredient of green tea (Day 4). After a 10-day pretreatment of EGCG up to Day 14, they received rosuvastatin (20 mg) plus EGCG (300 mg) once again (Day 15). Blood samples for the pharmacokinetic assessments were collected up to 8 hours after each dose of rosuvastatin. A total of 13 healthy volunteers were enrolled. Compared with the administration of rosuvastatin alone, the concomitant use at Day 4 significantly reduced the area under the concentration-time curve from time 0 to the last measurable time (AUC_last) by 19% (geometric mean ratio 0.81, 90% confidence interval [CI] 0.67-0.97) and the peak plasma concentration (C_max) by 15% (geometric mean ratio 0.85, 90% CI 0.70-1.04). AUC_last or C_max of rosuvastatin on Day 15 was not significantly different from that on Day 1. This study demonstrated that co-administration of EGCG reduces the systemic exposure of rosuvastatin by 19%, and pretreatment of EGCG can eliminate that effect of co-administration of EGCG.

Functional foods and dietary supplements for the management of dyslipidaemia

Dyslipidaemia is characterized by increased blood levels of total or LDL cholesterol and triglycerides, or decreased HDL cholesterol levels, and is a risk factor for cardiovascular disease. Dyslipidaemia has a high worldwide prevalence, and many patients are turning to alternatives to pharmacotherapy to manage their lipid levels. Lifestyle modification should be emphasized in all patients to reduce cardiovascular risk and can be initiated before pharmacotherapy in primary prevention of cardiovascular disease. Many functional foods and natural health products have been investigated for potential lipid-lowering properties. Those with good evidence for a biochemical effect on plasma lipid levels include soy protein, green tea, plant sterols, probiotic yogurt, marine-derived omega-3 fatty acids and red yeast rice. Other products such as seaweed, berberine, hawthorn and garlic might confer some limited benefit in certain patient groups. Although none of these products can reduce lipid levels to the same extent as statins, most are safe to use in addition to other lifestyle modifications and pharmacotherapy. Natural health products marketed at individuals with dyslipidaemia, such as policosanol, guggulsterone and resveratrol, have minimal definitive evidence of a biochemical benefit. Additional research is required in this field, which should include large, high-quality randomized controlled trials with long follow-up periods to investigate associations with cardiovascular end points.

The role of nutraceuticals in the prevention of cardiovascular disease

Cardiovascular disease (CVD) ranks among the most common health-related and economic issues worldwide. Dietary factors are important contributors to cardiovascular risk, either directly, or through their effects on other cardiovascular risk factors including hypertension, dyslipidemia and diabetes mellitus. Nutraceuticals are natural nutritional compounds, which have been shown to be efficacious in preventative medicine or in the treatment of disease. Several foods and dietary supplements have been shown to protect against the development of CVD. The aim of this review is to present an update on the most recent evidence relating to the use of nutraceuticals in the context of the prevention and treatment of CVD.