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Abstract

Purpose: Our aim was examine the association between black tea consumption and risk of total stroke and stroke types in a prospective study. Methods: A total of 74,961 Swedish women and men who were free of cardiovascular disease and cancer at baseline in 1997 were followed up through December 2008. Tea consumption was assessed with a questionnaire at baseline. Stroke cases were ascertained from the Swedish Hospital Discharge Registry. Results: During a mean follow-up of 10.2 years, we ascertained 4089 cases of first stroke, including 3159 cerebral infarctions, 435 intracerebral hemorrhages, 148 subarachnoid hemorrhages, and 347 unspecified strokes. After adjustment for other risk factors, high tea consumption was associated with a significantly lower risk of total stroke; however, there was no dose-response relation (P for trend = .36). Compared with no tea consumption, the multivariable relative risk for four or more cups per day (median, 5) was 0.79 (95% confidence interval [CI], 0.62-0.998). The corresponding relative risks were 0.80 (95% CI, 0.61-1.04) for cerebral infarction and 0.68 (95% CI, 0.35-1.30) for hemorrhagic stroke. Conclusions: These findings suggest that daily consumption of four or more cups of black tea is inversely associated with risk of stroke.

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... Experimental evidence has shown that polyphenols, which are important constituents of tea, can inhibit the development of atherosclerosis, have anti-inflammatory properties, improve endothelial function, and contribute to protection against stroke (8,9). Many previous populationbased cohort studies have explored the relation between tea consumption and stroke risk (1,(10)(11)(12)(13)(14). Nevertheless, these prospective studies have failed to reach a consistent conclusion: some studies confirmed the negative correlation between tea intake and stroke risk (13), but the others did not obtain similar results (14). ...
... The commonly consumed tea types (green tea or black tea), habits of tea drinking (drinking tea with or without milk), production regions, and manufacturing technologies of tea (i.e., different technologies for green removal) are very different between populations from various countries (15)(16)(17), which might also result in inconsistent associations of tea consumption with stroke risk. As mentioned, most of the related cohort studies focusing on tea consumption and stroke risk were conducted in Western and Japanese populations (1,(10)(11)(12). However, in China, a country with one of the highest amounts of tea consumption, evidence related to this association from a cohort study is still lacking. ...
... Several prior prospective studies have explored the association of tea consumption with stroke (1,(10)(11)(12)(13)(14). Nevertheless, previous cohort studies have shown inconsistent results. ...
Article
Background: Many cohort studies have explored the relation between tea consumption and stroke risk; however, the conclusions have been inconsistent. In addition, evidence is lacking in China, where the patterns of tea consumption and main types of tea consumed differ substantially from those in high-income countries. Objective: We aimed to systematically assess the association of tea consumption with the risk of stroke based on a Chinese large-scale cohort study. Methods: A total of 487,377 participants from the China Kadoorie Biobank were included in the present study. Detailed information about tea consumption (including frequency, duration, amount, and tea type) was self-reported at baseline. After ∼4.3 million person-years of follow-up, 38,727 incident cases of stroke were recorded, mainly through linkage with mortality and morbidity registries and based on the national health insurance system. Results: Overall, 128,280 adults (26.3%) reported drinking tea almost daily (41.4% men, 15.9% women), predominantly green tea (86.7%). Tea consumption had an inverse and dose-response relation with the risk of stroke (Ptrend < 0.001). Compared with nonconsumers, those who consumed tea occasionally, weekly, and daily had adjusted HRs and 95% CIs of 0.96 (0.94, 0.99), 0.94 (0.90, 0.98), and 0.92 (0.89, 0.95) respectively, with little difference by stroke type. Among those who consumed tea daily, the HRs for stroke decreased with the increasing duration and amount of tea consumed (all P < 0.001). These inverse associations were significant for green tea but not for other types of tea. Among men, but not women, the inverse relations could be detected, and similar inverse associations could be found for male noncurrent alcohol-consumers and noncurrent smokers as well. Conclusions: Among Chinese adults, higher consumption of tea, especially green tea, was associated with a lower risk of ischemic and hemorrhagic stroke.
... Stroke symptoms include sudden numbness or weakness, sudden confusion, trouble speaking or understanding speech, sudden issues related to balance, and/or sudden severe headache with no known cause. 10 Overall, 31 total studies evaluated the relationship between caffeine consumption and stroke incidence and/or mortality (Bidel et al., 2006;de Koning Gans et al., 2010;Ding et al., 2015;Floegel et al., 2012;Freedman et al., 2012;Greenberg et al., 2007;Grobbee et al., 1990;Hakim et al., 1998;Jacobsen et al., 1986;Kokubo et al., 2013;Kuriyama et al., 2006;Larsson et al., 2008Larsson et al., , 2011Larsson et al., , 2013Leurs et al., 2010;Loomba et al., 2016;Lopez-Garcia et al., 2009;Marchioli et al., 1996;Martin et al., 1988;Mineharu et al., 2011;Mostofsky et al., 2010;Mukamal et al., 2009;Saito et al., 2015;Sesso et al., 2003;Silletta et al., 2007;Sugiyama et al., 2010;Tanabe et al., 2008;Zhang et al., 2009aZhang et al., , 2009bLiebeskind et al., 2015;Loftfield et al., 2015). All of these observational studies assessed correlations between stroke and self-reported coffee and/ or tea consumption. ...
... All of these observational studies assessed correlations between stroke and self-reported coffee and/ or tea consumption. Ten of the 31 stroke-related studies evaluated stroke risk by subtype (Hakim et al., 1998;Kokubo et al., 2013, Kuriyama et al., 2006Larsson et al., 2008Larsson et al., , 2011Larsson et al., , 2013Lopez-Garcia et al., 2009;Mostofsky et al., 2010;Sugiyama et al., 2010;Tanabe et al., 2008;Liebeskind et al., 2015;Loftfield et al., 2015). ...
... Nine out of 31 studies reported statistically significant decreased risks of stroke in some coffee and tea consumers, though these decreases in risk were not always consistent across consumption groups, study sub-populations or stroke subtype within individual studies (Freedman et al., 2012;Kokubo et al., 2013;Kuriyama et al., 2006;Larsson et al. 2011Larsson et al. , 2013Mineharu et al., 2011;Saito et al., 2015;Tanabe et al., 2008;Loftfield et al., 2015). Again, these studies were large cohort studies including several thousand participants (ranging from approximately 6400 to 402,000 in number), with mean follow-up periods ranging from approximately 5 to 19 years and with a wide variation of coffee and tea consumption levels (<45 to 475 mg/caffeine a day). ...
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This report evaluates the scientific literature on caffeine with respect to potential cardiovascular outcomes, specifically relative risks of total cardiovascular disease (CVD), coronary heart disease (CHD) and acute myocardial infarction (AMI), effects on arrhythmia, heart failure, sudden cardiac arrest, stroke, blood pressure, hypertension, and other biomarkers of effect, including heart rate, cerebral blood flow, cardiac output, plasma homocysteine levels, serum cholesterol levels, electrocardiogram (EKG) parameters, heart rate variability, endothelial/platelet function and plasma/urine catecholamine levels. Caffeine intake has been associated with a range of reversible and transient physiological effects broadly and cardiovascular effects specifically. This report attempts to understand where the delineations exist in caffeine intake and corresponding cardiovascular effects among various subpopulations. The available literature suggests that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect. The point at which caffeine intake may cause harm to the cardiovascular system is not readily identifiable in part because data on the effects of daily intakes greater than 600 mg is limited. However, the evidence considered within this review suggests that typical moderate caffeine intake is not associated with increased risks of total cardiovascular disease; arrhythmia; heart failure; blood pressure changes among regular coffee drinkers; or hypertension in baseline populations.
... Two studies on the consumption of green tea reported reduced mortality from intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), and one cohort study reported a reduced risk of ICH [8][9][10] . However, studies in non-Asian populations could not report a meaningful protective effect of tea against the risk of hemorrhagic stroke; it seems that these populations have lower levels of consumption of green tea than black tea and have a low incidence rate of hemorrhagic stroke [3,11,12] . A recent meta-analysis suggested that consumption of tea, including both green tea and black tea, is associated with a reduced risk of ischemic stroke but is not significantly related to ICH or SAH [13] . ...
... green tea once or more per day reduced the risk of SAH by 44% compared with non-daily consumption and a recent cohort study suggested that greater green tea consumption reduced the risk of ICH [9,10] , but 2 other cohort studies failed to prove a statistically significant association [18,19] . Also, 2 cohort studies and 1 case-control study of black tea in a non-Asian population could not suggest meaningful findings on the risk of hemorrhagic stroke [3,11,12] . Several human, animal, and in vitro studies have suggested that green tea has the potential to reduce the incidence of hypertension, atherosclerosis, and thrombogenesis, which are known to be major risk factors for stroke [1,20,21] . ...
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Different types of tea may have varying effects on the risk of hemorrhagic stroke, but previous studies have generated inconsistent results. We performed a nationwide, multi-center, case-control study to evaluate the association between the consumption of tea and the risk of hemorrhagic stroke. This study included 940 patients aged 30 to 84 with non-traumatic acute hemorrhagic stroke who did not have a history of stroke or hemorrhage-prone brain lesions, as well as 940 community controls and 940 hospital controls matched to each patient by age and gender. Pre-trained interviewers obtained information on potential confounders. Consumption of tea was assessed by using a food frequency questionnaire. Participants were asked to indicate the number of cups of tea (green, black, and oolong tea) they consumed per day or per week during the preceding year. The adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated by conditional logistic regression. The adjusted ORs of hemorrhagic stroke were 0.71 (95% CI: 0.59-0.87), 0.86 (95% CI: 0.55-1.37), and 1.34 (95% CI: 0.91-1.98) for consumption of green, oolong, and black tea, respectively, compared with no consumption. There was no significant linear trend for green tea consumption. Consumption of green tea may protect against hemorrhagic stroke, whereas consumption of black tea may have no meaningful effect on risk. © 2015 S. Karger AG, Basel.
... [18] Several studies have reported 26-808 mg/kg fluoride in teas processed from young leaves. [19][20][21][22] The popularity of tea may be attributed to the systemic health benefits reported from its consumption. In agreement with the growing health and wellness trend in Malaysia, an increasing number of consumers are consuming tea for its health benefits. ...
... This result is in agreement with other studies reported worldwide. [13][14][15][17][18][19][20][21][22] The uptake of fluoride from the soil and air occurs via the tea bush, Camellia sinensis; thereafter, fluoride is stored as ions in tea leaves. [19,20,34,35] Tea leaves that are used for brewing release fluoride into the surrounding solution. ...
Article
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Background: Tea ranks first as the most-enjoyed beverage worldwide. Nevertheless, tea is rich in fluoride due to its uptake and storage from the soil by tea plants. Moreover, limited information is available regarding the fluoride content of Malaysian teas. Objective: This study aims to quantify the amount of fluoride present in teas available in the Malaysian market. Methods: An exploratory research was conducted on commercially available infusion teas from Peninsular Malaysia between November 2016 and December 2017. The fluoride content of 106 tea samples from three groups, viz., black, green, and other tea types, respectively, was measured using ultraviolet–visible spectrophotometry. The results were analyzed by one-way analysis of variance and independent t-test. Results: All of the tea leaf samples contained fluoride content between 0.01 and 1.08 mg/L. Black, green, and red tea exhibited significantly different contents of fluoride (P = 0.028). Conclusion: Significant amounts of fluoride were present in teas found in Malaysian markets. Our study provides Malaysian consumers key information regarding the amount of fluoride present in their teas.
... Moreover, it was also suggested that a Mediterranean diet is associated with a lower progression of atherosclerosis, in particular with carotid intima media thickness (IMT) [76], which is considered to be a well-established risk for diabetes mellitus and for IS rather than haemorrhagic stroke [76,77]. In a prospective study conducted on 74,961 Swedish women and men, the effects of black tea on stroke risk was evaluated [78]. The collected results highlighted that 4 or more cups of black tea daily were inversely correlated with stroke risk [78]. ...
... In a prospective study conducted on 74,961 Swedish women and men, the effects of black tea on stroke risk was evaluated [78]. The collected results highlighted that 4 or more cups of black tea daily were inversely correlated with stroke risk [78]. ...
Article
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Ischemic stroke (IS) is still among the leading causes of death and disability worldwide. The pathogenic mechanisms beyond its development are several and are complex and this is the main reason why a functional therapy is still missed. The beneficial effects of natural compounds against cardiovascular diseases and IS have been investigated for a long time. In this article, we reviewed the association between the most studied polyphenols and stroke protection in terms of prevention, effect on acute phase, and rehabilitation. We described experimental and epidemiological studies reporting the role of flavonols, phenolic acid, and stilbens on ischemic mechanisms leading to stroke. We analyzed the principal animal models used to evaluate the impact of these micronutrients to cerebral blood flow and to molecular pathways involved in oxidative stress and inflammation modulation, such as sirtuins. We reported the most significant clinical trials demonstrated as the persistent use of polyphenols is clinically relevant in terms of the reduction of vascular risk factors for IS, such as Atrial Fibrillation. Interestingly, different kinds of polyphenols provide brain protection by activating different pathways and mechanisms, like inducing antithrombotic effect, such as Honokiol. For this reason, we discussed an appropriate integrative use of them as a possible therapeutic alternative against stroke.
... Tea varieties have been studied independently, including green tea (Tanabe et al. 2008) or black tea (Gans et al. 2010). More recent studies have looked at total tea intake (Lopez-Garcia et al. 2009;Larsson, Virtamo, and Wolk 2013;Leurs et al. 2010). The Tokamachi-Nakasato study focused specifically on several levels of green tea intake in Japan (n = 6,358) (Tanabe et al. 2008). ...
... A more recent Finnish study with a great number of stroke occurrences also found an inverse correlation between tea intake and total stroke (Larsson, Virtamo, and Wolk 2013). Consumption of more than four cups of tea per day showed had a statistically significant impact (RR = 0.77, 0.61-0.98) ...
... [19,20] Besides these, regular drinking of black tea also reduces the risk for stroke. [21,22] Larsson et al. performed an extensively study on 74,961 stroke patients during the course of 10.2 years and concluded that drinking four or more cups of black tea on a daily basis inhibited the risk associated with stroke. [21] Not only this, Arab et al. performed a meta-analysis on black tea intake and risk of stroke. ...
... [21,22] Larsson et al. performed an extensively study on 74,961 stroke patients during the course of 10.2 years and concluded that drinking four or more cups of black tea on a daily basis inhibited the risk associated with stroke. [21] Not only this, Arab et al. performed a meta-analysis on black tea intake and risk of stroke. By pooling the data from nine studies on 194,965 adults including 4378 stroke patients, concluded that drinking three cups of black tea on a daily basis reduced the ...
... Similar to coffee, teas are very rich in polyphenols, mainly flavonoids. It is known that tea flavonoids improve endothelial function, BP, cholesterol levels, and blood glucose concentrations [91,92]. The results of a meta-analysis of 14 prospective studies showed that the increment of 3 cups/day in green or black tea consumption decreased the relative risk by 13% (95% confidence interval (CI), 0.81-0.94). ...
... The association did not depend on gender but was slightly higher for green tea. Other results from two large prospective studies of green and black tea were in line with these findings [90,92]. ...
Article
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Polyphenols have an important protective role against a number of diseases, such as atherosclerosis, brain dysfunction, stroke, cardiovascular diseases, and cancer. Cardiovascular diseases are the number one cause of death worldwide: more people die annually from cardiovascular diseases than from any other cause. The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use, and excess alcohol intake. The dietary consumption of polyphenols has shown to be inversely associated with morbidity and mortality by cardio- and cerebrovascular diseases. It is well-known that the protective effects of polyphenols in vivo depend on the grade how they are extracted from food and on their intestinal absorption, metabolism, and biological action with target tissues. The aim of this review was to summarise the relation between polyphenols of different plant sources and stroke in human intervention studies, animal models, and in vitro studies.
... Tea contains many of bioactive compounds, including amino acids, caffeine, lignins, proteins, xanthines and flavonoids (2). Tea consumption reduces the risk of heart disease and stroke (3,4). Tea compounds by many mechanisms such as reducing free radical and DNA damage, inhibiting uncontrolled cell growth, and boosting the immune system help stave off the development of cancer cells and provide chemo-protection for our body (5). ...
... However some side effects have been reported when green tea is consumed regularly and at regular intervals 7. The researches have proven that black tea consumption reduces heart diseases and stroke risks when consumed three or more cups regularly. [8][9][10][11][12] As the cultivation of tea requires humid climate provinces like southern part of China mainland, Northern India slopes, Sri Lanka, Tibet are ideal growing area of tea. ...
... Black tea has been shown to have anticancer activity in different types of cancers (oral, esophageal and gastric, intestinal, prostrate, lung, breast, skin, liver, urinary tract) (Bhattacharya et al., 2004;Sharma et al., 2007;Sharma and Rao, 2009). It has also been reported that the regular consumption of three or more cups of black tea per day reduces the risk of heart disease and stroke (Larsson et al., 2013). Black tea improves oral health by inhibiting the growth of bacteria and reducing the incidence of dental cavities. ...
Article
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Background: The same plant, Camellia sinensis, is used to produce all types of tea, and the differences among the various types arise from the different processing steps that are used. Based on the degree of fermentation, tea can be classified as black, green, white, or oolong tea. Of these, black tea is the most or fully fermented tea. The oxidized polyphenolic compounds such as theaflavins (TF) and thearubigins (TR) formed during fermentation are responsible for the color, taste, flavor, and aroma of black tea. Results: Research indicates that an optimum ratio of TF and TR (1:10) is required to ensure a quality cup of tea. The concentrations of TF and TR as well as desirable quality characteristics increase as fermentation time increases, reaching optimum levels and then degrading if the fermentation time is prolonged. It is also necessary to control the environment for oxidation. There are no established environment conditions that must be maintained during the fermentation of the ruptured tea leaves. However, in most cases, the process is performed at a temperature of 24-29^{\circ}C for 2-4 h or 55-110 min for orthodox tea or crush, tear, and curl (CTC) black tea, respectively, under a high relative humidity of 95-98% with an adequate amount of oxygen. Conclusion: The polyphenolic compounds in black tea such as TF and TR as well as un-oxidized catechins are responsible for the health benefits of tea consumption. Tea is rich in natural antioxidant activities and is reported to have great potential for the management of various types of cancers, oral health problems, heart disease and stroke, and diabetes and to have other health benefits such as the ability to detoxify, improve urine and blood flow, stimulate, and improve the immune system.
... In fact, data from the Prospective Studies Collaboration indicate that a 2 mmHg lower SBP is associated with a 10% lower stroke mortality and about 7% lower mortality from ischemic heart disease or other vascular causes in middle age subjects [3]. Therefore, our findings provide a possible explanation for the reductions in risk for stroke observed in epidemiological studies on tea consumption [36][37][38]. ...
Article
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Objective Epidemiological evidence has linked consumption of black tea, produced from Camellia sinensis, with a reduced risk of cardiovascular diseases. However, intervention studies on the effects of tea consumption on blood pressure (BP) have reported inconsistent results. Our objective was to conduct a systematic literature review with meta-analysis of controlled human intervention studies examining the effect of tea consumption on BP. Methods We systematically searched Medline, Biosis, Chemical Abstracts and EMBASE databases through July 2013. For inclusion, studies had to meet the following pre-defined criteria: 1) placebo controlled design in human adults, 2) minimum of 1 week black tea consumption as the sole intervention, 3) reported effects on systolic BP (SBP) or diastolic BP (DBP) or both. A random effects model was used to calculate the pooled overall effect of black tea on BP. Results Eleven studies (12 intervention arms, 378 subjects, dose of 4–5 cups of tea) met our inclusion criteria. The pooled mean effect of regular tea ingestion was −1.8 mmHg (95% CI: −2.8, −0.7; P = 0.0013) for SBP and −1.3 mmHg (95% CI: −1.8, −0.8; P<0.0001) for DBP. In covariate analyses, we found that the method of tea preparation (tea extract powders versus leaf tea), baseline SBP and DBP, and the quality score of the study affected the effect size of the tea intervention (all P<0.05). No evidence of publication bias could be detected. Conclusions Our meta-analysis indicates that regular consumption of black tea can reduce BP. Although the effect is small, such effects could be important for cardiovascular health at population level.
... Moderate strength green tea or Oolong tea consumption (120 mL/d or more for 1 year) reported lower risk of developing hypertension in a Chinese population of 1,507 subjects (711 men and 796 women) [83]. Further studies, revealed that the daily consumption of four or more cups of black tea or moderate consumption of coffee and tea were inversely associated with risk of stroke [84,85]. A meta-analysis suggested that daily consumption of either green or black tea equaling 3 cups per day could lower the risk of stroke by 21% compared to those consuming <1 cup per day [86]. ...
... 15 Also, noteworthy were 3 reports showing a significant decrease in the risk of stroke incidence associated with increases in coffee or tea consumption. [16][17][18] Selected dietary flavonoids, specifically flavones and flavanones, that are contained, for example, in citrus fruits, were also shown to provide protection from stroke for women; however, replication of these observations is important as total flavonoids and other specific subclasses showed no association. 19 Meta-analyses showed 19% (10%-27%) decreased stroke risk with higher chocolate consumption, 20 an 11% (3%-20%) increase with higher levels of red meat, 21 and a 12% (3%-20%) decrease in the lowest quintile of low-fat dairy intake. ...
Article
With ischemic heart disease (IHD) and stroke sharing many risk factors, one could presume a similar geographic pattern of stroke and IHD; however, Kim and Johnston described remarkable worldwide variations in disability-adjusted life-years (DALY) loss for both diseases.1 For stroke, much of Asia, eastern Europe, and Africa had DALY loss of ≥120/100 000 in contrast to North America, western Europe, and Australia having DALY loss rates ≤60/100 000. Eastern Europe and northern Asia also had strikingly high DALY loss (≥240/100 000) from IHD. Overall, there were 62 of 192 countries with higher DALY loss from stroke than for IHD, particularly for China, but also in many countries in Africa and South America. There were only marginally more countries (74 of 192) with higher DALY loss from IHD, particularly the Middle East, but also North America, Australia, and western Europe. Countries with lower national income, lower prevalence of diabetes, higher average alcohol intake, and less obesity tended to have higher DALY loss from stroke than IHD.1 The contributors to the substantial variations in stroke incidence within countries have been examined by reports including that by Grimaud and colleagues, who showed stroke incidence was as much as one third higher in regions of France with lower levels of socioeconomic status and/or higher levels of income inequality.2 A similar one third difference (32%) in stroke risk was observed between high socioeconomic status and low socioeconomic status neighborhoods in the United States.3 Attenuation of these neighborhood differences was larger with adjustment for biological risk factors (mediated to a 16% excess) than for behavioral risk factors (mediated to a 30% excess), suggesting that biological risk factors …
... We examined potential confounding from dietary intakes of vitamin C, folate, b-carotene, magnesium, and potassium and from foods that are associated with risk of stroke in this study population, including processed and nonprocessed red meat (13,14), fish (15), low-fat dairy (16), coffee (17), and tea (18). Tests for linear trend were conducted by assigning the median value to each quintile and by modeling this variable as a continuous variable in the model. ...
Article
Prospective studies of dietary fiber intake in relation to stroke risk have reported inconsistent results. This study assessed the association between intake of total fiber and fiber sources and stroke incidence in healthy Swedish adults. The analysis was based on 69,677 participants (aged 45-83 y) from the Swedish Mammography Cohort and the Cohort of Swedish Men who were free from cancer, cardiovascular disease, and diabetes at baseline (1 January 1998). Diet was assessed with a food-frequency questionnaire. Cases of stroke were ascertained through linkage to the Swedish Inpatient Register and the Swedish Cause of Death Register. Cox proportional hazards regression model was used to calculate RRs, adjusted for potential confounders. During 10.3 y of follow-up, 3680 incident stroke cases, including 2722 cerebral infarctions, 363 intracerebral hemorrhages, 160 subarachnoid hemorrhages, and 435 unspecified strokes, were ascertained. High intakes of total fiber and fiber from fruits and vegetables but not from cereals were inversely associated with risk of stroke. After adjustment for other risk factors for stroke, the multivariable RRs of total stroke for the highest vs. lowest quintile of intake were 0.90 (95% CI: 0.81, 0.99) for total fiber, 0.85 (95% CI: 0.77, 0.95) for fruit fiber, 0.90 (95% CI: 0.82, 1.00) for vegetable fiber, and 0.94 (95% CI: 0.84, 1.04) for cereal fiber. These findings indicate that intake of dietary fiber, especially fruit and vegetable fibers, is inversely associated with risk of stroke. © 2014 American Society for Nutrition.
... Нещодавно опубліковані результати проведеного в Швеції дослідження показали, що споживання чотирьох або більше чашок чорного чаю щоденно обернено пропорційно пов'язане з ризиком інсульту (S. C. Larsson et. al., 2013 р.) [306]. Висока прихильність до середземноморської дієти (поєднання оливкової олії, риби, овочів і сухофруктів) також асоціюється зі [327]. ...
Book
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The book is devoted to transient ischemic attacks (TIA) – one of the most common clinical types of acute cerebrovascular disease, which are considered as an important risk factor for ischemic stroke. Based on a large number of examined patients, four pathogenic subtypes of TIA have been distinguished and the peculiarities of clinical features of their course analyzed. The risk and frequency of the recurrent TIA / ischemic stroke with regard to the pathogenic subtype, carotid artery intima media thickness and possible structural changes in the brain tissue have been analyzed and identified for the first time. A strategy of prevention and treatment of recurrent transient ischemic attacks and strokes is particularly highlighted. This work is recommended for neurologists, neurosurgeons, physicians, family doctors, first aid doctors, occupational pathologists and interns.
... mg CE/L) ( The functionality of herbal teas is largely due to the high levels of phenolic compounds present in the different species (Table 4). Larsson et al. [26] asserted that their subjects who consumed a mean of four cups of black tea per day had 21% lower risk of stroke compared with non-drinkers. In another study, The InterAct Consortium [27] reported that tea consumption in Europe of at least four cups per day may result in a 16% lower risk of type 2 diabetes. ...
Article
Background The consumption of herbal teas has gained much attention due to its healthpromoting benefits, including antioxidant, neuroprotective, antimicrobial, antitumor, and antiinflammatory effects. These biological activities are associated in part to the antioxidant activity of chemical compounds present in teas, especially flavonoids and phenolic acids. Objective The aim of this study was to evaluate a total of 17 different botanical herbal infusions consumed in Brazil in terms of their phenolic antioxidants. Methods The analysis performed were total phenolic compounds, total flavonoids, total flavonols, tannin content and in vitro antioxidant activity (DPPH, ABTS, CUPRAC, FRAP, and ORAC assays). Data were processed using univariate, bivariate and multivariate analysis (hierarchical cluster analysis). Results The use of Hierarchical Cluster Analysis (HCA) suggested an unsupervised classification relationship based on level of functionality of the herbal teas. Higher levels of total phenolics, total flavonoids and antioxidant activity were found in Anemopaegma mirandum while higher values of tannin content and total flavonols were found in Peumus boldus. All antioxidant activity assays showed significant correlations among each other (r > 0.84, p < 0.001), and with total phenolic and flavonoids (r> 0.83, p < 0.001). Using HCA, three clusters were suggested and cluster 1 showed the highest functionality. Conclusion The herbal infusions evaluated can be a good resource of bioactive compounds to consume and supplementing food products. Nevertheless, future studies should focus on the evaluation of these herbal teas using in vivo systems to understand the mechanisms of action when these different herbal infusions are used as beverages.
... Moreover, higher green tea consumption was associated with inverse risks of cardiovascular disease and stroke subtypes (28). Consistent with this finding, a recent study performed in Sweden (29), after a mean follow-up of 10.2 y, reported that high tea consumption was associated with a significantly lower risk of total stroke, without observing a doseresponse relation. Compared with no tea consumption, the multivariable RR for $4 cups/d was 0.79 (95% CI: 0.62, 0.998). ...
Article
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Several studies have suggested that tea consumption might protect against the development and progression of cardiovascular disease, one of the leading causes of morbidity and mortality worldwide. The endothelium plays a pivotal role in arterial homeostasis. Reduced nitric oxide (NO) bioavailability with endothelial dysfunction is considered the earliest step in the pathogenesis of atherosclerosis. Endothelial dysfunction has been considered an important and independent predictor of future development of cardiovascular risk and events. The association between brachial NO-dependent flow-mediated dilation (FMD) and cardiovascular disease risk has been investigated in several prospective studies, suggesting that FMD is inversely associated with future cardiovascular events. Dietary flavonoids and tea consumption have been described to improve endothelial function and FMD. A proposed mechanism by which dietary flavonoids could affect FMD is that they improve the bioactivity of the endothelium-derived vasodilator NO by enhancing NO synthesis or by decreasing superoxide-mediated NO breakdown. This could be of clinical relevance and may suggest a mechanistic explanation for the reduced risk of cardiovascular events and stroke observed among tea drinkers in the different studies.The purpose of this article is to provide an overview of the relation between tea consumption and cardiovascular disease, with a focus on clinical implications resulting from the beneficial effects of tea consumption on endothelial function.
... In the Netherland EPIC_NL cohort of 37,514 Netherlands, high tea consumption was not associated with risk of stroke [5]. However, in another cohort of 74,961 Swedish adults, high tea consumption (!4 cups/day) was significant associated with a reduced risk of total stroke [25]. Recently, a large meta-analysis of 6 cohorts study based in European ancestry (country including the Netherland, Finland, and Sweden) did not find significant association between tea consumption and risk of stroke (Pooled adjusted relative ratio, 0.971; 95% CI, 0.922e1.023; ...
Article
Background & aim: Observational studies have reported that tea consumption is associated with risk of stroke. However, this observed association is inconsistent, and whether this observed association is due to confounding factors or reverse causation remains unclear. Thus, we applied a two-sample mendelian randomization (MR) approach to determine whether genetically predicted tea consumption is causally associated with risk of stroke, ischemic stroke (IS), and IS subtypes. Methods: UK Biobank available data (349,376 samples of European ancestry) was used to identify single nucleotide polymorphisms associated with tea consumption (cups/day). The summary statistics for stroke, IS, and IS subtypes were obtained from the MEGASTROKE consortium with 40,585 stroke cases and 406,111 controls. Results: We found that genetically predicted an extra daily cup of tea consumption was casually associated with a reduced risk of small vessel stroke (odds ratio (OR), 0.79; 95% confidence interval (CI), 0.69-0.91; P = 0.001), but not with cardioembolic stroke (OR, 0.97; 95% CI, 0.86-1.09; P = 0.582), large artery stroke (OR, 0.95; 95% CI, 0.82-1.10; P = 0.506), stroke (OR, 1.00; 95% CI, 0.95-1.06; P = 0.889) or IS (OR, 0.95; 95% CI, 0.89-1.01; P = 0.083). Conclusions: Our study provided evidence that genetically predicted an extra daily cup of tea consumption is causally associated with a reduced risk of small vessel stroke.
... Black, white, green and oolong teas are the major tea types (5)(6)(7). The nutritional value of tea is mostly from the tea catechins and condensed tannins, which are reported to possess a broad spectrum of biological activities, including antioxidant and antimicrobial properties, reduction of various cancers and protective effects against diabetes, cardiovascular diseases, hyperlipidemia and obesity (8)(9)(10)(11). ...
Article
A high-performance liquid chromatography method employing diode array detection was developed to determine levels of the major catechins, proanthocyanidin, procyanidin B2, caffeine, thymoquinone and carvacrol and its isomer, thymol, which are present in different natural complex matrices found in commercial products of Camellia sinensis L. and/or Nigella sativa L. Reversed-phase separation was performed on a C18 column by using gradient elution by varying the proportions of solvent A (distilled water containing 0.05% orthophosphoric acid) and solvent B (acetonitrile), with a flow rate of 1.5 mL/min and duration of 31 min. Excellent linearity was observed for all standard calibration curves, and correlation coefficients were above 0.9996. The developed method is efficient, with high reproducibility and sensitivity, and is ideally suited for rapid and routine analysis of principal components in these promising medicinal plants.
... This hypothesis was also supported by the very limited proportion of patients that did fill in all the variables (2.6%). Moreover, based on statistics for Swedish consumption of tea, we expected around 50% of non-tea consumers in our population [26], a percentage even higher than what we obtained after imputing all non-entries as zero (42%). To overcome this ascertainment limitation, we instead used irregular tea consumption as a reference. ...
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Background: Tea is a popular beverage around the world and has properties that can affect the immune system. The association between tea consumption and the risk of rheumatoid arthritis (RA), a chronic autoimmune disease primarily affecting the joints, is not well studied and results are conflicting. Methods: We collected data on tea consumption for 2237 incident RA cases diagnosed 2005-2018 and 4661 controls matched on age, sex, and residential area. Tea consumption was classified into no (0 cups/day), irregular (< 1 cup/day), regular (1-2 cups/day), and high (≥ 2 cups/day) consumption, and irregular consumption was used as the reference category. Missing data on tea consumption was classified as no consumers, and sensitivity analyses were performed to test this assumption. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression, adjusting for smoking, coffee, alcohol, educational level, and body mass index. We also performed stratified analysis on sex, anti-citrullinated autoantibody (ACPA) status, and smoking habits. Results: Among the cases, we found 57.3% to be ever consumers of tea with 19.7 having a high tea consumption. Corresponding figures for the controls were 58.4% ever drinkers with 22.1% high tea consumers. High tea consumption had an inverse association to the risk of RA compared to irregular consumption [OR = 0.78 (95% CI 0.66-0.92)], but the association lost statistical significance in the adjusted model [adjusted OR (adjOR) = 0.85 (95% CI 0.71-1.01)]. Among non-tea consumers, a protective effect was also observed compared to irregular consumers [adjOR = 0.82 (95% CI 0.70-0.88)], but this association did not withstand sensitivity analysis, possibly due to bias. In the ACPA-positive group and among current smokers, a protective effect of tea consumption was observed among the high tea consumers [adjOR = 0.76 (95% CI 0.62-0.94) and adjOR = 0.60 (95% CI 0.38-0.95), respectively]. Conclusions: This study suggests a protective effect of high consumption of tea, among smokers and for ACPA-positive RA. Trial registration: Not applicable.
... While they found that white tea consumption increased the total antioxidant capacity in heart, other organs such as the liver, brain, or kidney showed no increase in antioxidant capacity. Although the studies are contradictory in this respect, our hypothesis that polyphenols remain in the cell background is supported by the fact that the polyphenols were absorbed due to their bioavailability in white tea [26]. Furthermore, they are stored or located in the cell in the membrane cytosol [44], a target very susceptible to the first attack by the oxidative ADR, as the results we previously published suggested [13][14][15]. ...
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The infusion tea extracted from the leaves of the plant Camellia sinensis can be used in the prevention of cancer, cardiovascular and neurodegenerative diseases and aging, while adriamycin (ADR) is an anticancer drug that increases oxidative stress in cells. The present study evaluated the protective effect of the long term consumption of white tea used at two different doses against the oxidative stress produced by: aging and acute oxidation caused ADR treatment. At wearing, rats received distilled water (control), or 0.15 mg (Dose 1) or 0.45 mg (Dose 2) of solid tea extract/kg body weight in their drink. At 12 months, about half of the rats of each group were injected with a bolus of ADR, and six rats of the control group with an injection of saline solution and sacrificed. The rest of the animals continued in their cages until 24 months of age, when they were sacrificed. Lipid and protein oxidation of liver and brain microsomes was analysed by measuring hydroperoxide and carbonyl levels. White tea consumption for 12 months at a non-pharmacological dose was seen to reverse the oxidative damage caused by ADR in both liver and brain, while the consumption of white tea for 20 months at a non-pharmacological dose had no effect on carbonyl or hydroperoxides in these tissues. The long term ingestion of white tea protected tissues from acute oxidative stress but did not affect chronic oxidative agents such aging.
Article
Coffee, tea, and cocoa are important dietary sources of polyphenols and have received much attention during the past years because of their potential beneficial effects on cardiovascular health. The polyphenols in these beverages and cocoa may reduce the risk of stroke through multiple mechanisms, including antihypertensive, hypocholesterolemic, antioxidant, and anti-inflammatory effects as well as through improvements of vascular endothelial function and insulin sensitivity. This review summarizes the available evidence from experimental studies, prospective studies, and metaanalyses of the potential role of coffee, tea, and cocoa in the prevention of stroke.
Article
The consumption of sweetened beverages such as soft drinks has been associated with adverse effects on markers of cardiovascular risk. We examined the hypothesis that high consumption of sweetened beverages increases the risk of stroke. We followed 32,575 women aged 49-83 y and 35,884 men aged 45-79 y without cardiovascular disease, cancer, or diabetes at baseline. The consumption of sweetened beverages, including sugar-sweetened and artificially sweetened soft drinks and juice drinks, was assessed by using a food-frequency questionnaire. Stroke cases were ascertained by linkage to the Swedish Inpatient Register and the Swedish Cause of Death Register. The data were analyzed by using a Cox proportional hazards regression model. We ascertained 3510 incident cases of stroke, including 2588 cerebral infarctions, 349 intracerebral hemorrhages, 156 subarachnoid hemorrhages, and 417 unspecified strokes, during a mean follow-up of 10.3 y. Sweetened beverage consumption was significantly positively associated with risk of total stroke and cerebral infarction but not with hemorrhagic stroke. The multivariable RRs comparing ≥2 (median: 2.1) servings/d (200 mL/serving) with 0.1 to <0.5 (median: 0.3) servings/d were 1.19 (95% CI: 1.04, 1.36) for total stroke and 1.22 (95% CI: 1.04, 1.42) for cerebral infarction. These findings suggest that sweetened beverage consumption is positively associated with the risk of stroke.
Article
Stroke is an important cerebrovascular disease which causes chronic disability and death in patients. Despite to its high morbidity and mortality, there are limited available effective neuroprotecitve agents for stroke. In recent years, the research aimed at finding novel neuroprotective agents from natural origins has been intensified. Camellia sinensis L. (tea) is the second most consumed beverage worldwide, after water. It is classified into green and white, oolong, black and red, and Pu-erh tea based on the manufacturing process. Catechins are the main phytochemical constituents of Camellia sinensis which are known for their high antioxidant capacity. On other hand, it is well known that oxidative stress plays an important role in the initiation and progression of different cardiovascular diseases such as stroke. Therefore, the present article is aimed to review scientific studies that show the protective effects of tea consumption against ischemic stroke.
Book
Antioxidants in Food, Vitamins and Supplements bridges the gap between books aimed at consumers and technical volumes written for investigators in antioxidant research. It explores the role of oxidative stress in the pathophysiology of various diseases as well as antioxidant foods, vitamins, and all antioxidant supplements, including herbal supplements. It offers healthcare professionals a rich resource of key clinical information and basic scientific explanations relevant to the development and prevention of specific diseases. The book is written at an intermediate level, and can be easily understood by readers with a college level chemistry and biology background.
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Studies that investigated the association between tea consumption and the risk of major cardiovascular events have reported inconsistent results. We conducted a meta-analysis of prospective observational studies in order to summarize the evidence regarding the association between tea consumption and major cardiovascular outcomes or total mortality. In July 2014, we performed electronic searches in PubMed, EmBase, and the Cochrane Library, followed by manual searches of reference lists from the resulting articles to identify other relevant studies. Prospective observational studies that reported effect estimates, with 95 % confidence intervals (CIs), for coronary heart disease (CHD), stroke, cardiac death, stroke death, or total mortality for more than two dosages of tea consumption were included. A random-effects meta-analysis was performed to determine the risk of major cardiovascular outcomes associated with an increase in tea consumption by 3 cups per day. Of the 736 citations identified from database searches, we included 22 prospective studies from 24 articles reporting data on 856,206 individuals, and including 8,459 cases of CHD, 10,572 of stroke, 5,798 cardiac deaths, 2,350 stroke deaths, and 13,722 total deaths. Overall, an increase in tea consumption by 3 cups per day was associated with a reduced risk of CHD (relative risk [RR], 0.73; 95 % CI: 0.53-0.99; P = 0.045), cardiac death (RR, 0.74; 95 % CI: 0.63-0.86; P < 0.001), stroke (RR, 0.82; 95 % CI: 0.73-0.92; P = 0.001), total mortality (RR, 0.76; 95 % CI: 0.63-0.91; P = 0.003), cerebral infarction (RR, 0.84; 95 % CI: 0.72-0.98; P = 0.023), and intracerebral hemorrhage (RR, 0.79; 95 % CI: 0.72-0.87; P < 0.001), but had little or no effect on stroke mortality (RR, 0.93; 95 % CI: 0.83-1.05; P = 0.260). The findings from this meta-analysis indicate that increased tea consumption is associated with a reduced risk of CHD, cardiac death, stroke, cerebral infarction, and intracerebral hemorrhage, as well as total mortality.
Article
Background: Tea contains many polyphenols with biological properties such as antithrombosis and antioxidation. Recent observational studies on tea consumption concerning cerebral hemorrhage risk have reported inconsistent results. This meta-analysis aimed to summarize the accumulated evidence on the association between tea consumption and cerebral hemorrhage risk. Methods: Web of Science, PubMed, Embase, and Scopus databases were searched to identify relevant studies through December 2021. Relative risks (RRs) or odds ratios (ORs) from observational studies were synthesized. Results: Ten studies involving over 721,827 participants were included. Higher tea consumption was correlated with a 23% (RR = 0.77; 95% CI 0.66-0.89) lower risk of cerebral hemorrhage. Subgroup meta-analyses indicated higher tea consumption was beneficial in preventing cerebral hemorrhage risk for green tea, alcohol-adjusted, fruit/vegetables-adjusted, and physical activity-adjusted subgroups, respectively (P < 0.01). Dose-response analysis indicated each one-cup (120 ml/cup) increment in tea or green tea intake/day was correlated with an average of 2% (RR = 0.98, 95% CI 0.976-0.990), or 6% (RR = 0.94; 95% CI 0.92-0.97) lower cerebral hemorrhage risk. Conclusions: This study suggests that daily tea consumption is related to a lower risk of cerebral hemorrhage among adults. Green tea consumption appears to be more beneficial in preventing cerebral hemorrhage. Physical activity, fruit/vegetables, and alcohol may affect the relationship between tea consumption and hemorrhagic stroke. Future studies should investigate the interplay of tea with these factors.
Article
Aluminium is reported to play an important role in the aetiology, pathogenesis and development of Alzheimer's disease (AD). Black tea (BT, Camellia sinensis, family - Theaceae) represents approximately 78% of total consumed tea in the world and possesses neuroprotective properties under conditions like hypoxia, ischaemia and Parkinson's disease. This research aimed to evaluate neuroprotective effect of black tea extract (BTE) on the cognitive deficits, activity of acetylcholinesterase (AChE), levels and activities of oxidant-antioxidant indices (thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx)), expressions of β amyloid 1-42 (Aβ1-42) synthesis related (amyloid precursor protein (APP), β and γ secretases) and apoptotic markers (Bax, Bcl-2, cyto c, caspases 3, 8 and 9) in hippocampus and cortex of aluminium chloride (AlCl3) induced AD rats. Chronic AlCl3 administration (100 mg/kg body weight i.p.) in Wistar rats for 60 days significantly enhanced the AChE activity, memory impairment, oxidative damage, Aβ burden and apoptosis markers. Co-administration of BTE to AlCl3 rats for 60 days significantly ameliorated the aluminium induced pathological changes. Thus, it is suggested that the anti-Alzheimer role of BTE may be attributed mainly to the active components present in black tea.
Chapter
Large numbers of plants and phytochemicals with potential effects that reduce inflammatory responses or stimulate antioxidant defenses in neural cells have been discovered across the world. They act via downregulation of proinflammatory enzymes through activation of PPARγ; inhibition of PI3K, tyrosine kinases, NF-κB, and c-Jun; modulation of cell survival/cell-cycle genes; and stimulation of antioxidant response-element pathways. Phytochemicals disrupt the Nrf2-Keap1 association, thereby releasing Nrf2, which translocates to the nucleus and upregulates the expression of phase II detoxifying enzymes, such as HO-1 and glutathione S-transferases, which have a protective effect on cells. On compiling the classification of plants that have been reported in the literature to have antineuroinflammatory properties, we discovered that those that have been reported to be effective in antineuroinflammation are not randomly distributed throughout the plant kingdom but are concentrated in a small number of orders, especially Fabales, Lamiales, Rosales, Apiales, and Sapindales. These are the same orders associated with food allergy. We hypothesize that plants that are useful against neuroinflammation are those that are mildly proinflammatory or immunogenic (triggering a host anti-inflammatory response). Knowledge of the orders of plants that are more likely to be effective against neuroinflammation may help in the future discovery of novel phytochemicals. This chapter presents the mechanisms of action, bioavailabilities, and plant orders of origin of phytochemicals, as well as their effects on neuroinflammation, stroke, and Alzheimer's disease.
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Black tea consumption has been proven to improve endothelial function and to lower the risk of stroke and cognitive impairment. Several effects of black tea on cardiovascular system had been surveyed. However, the black tea effect on pressure pulse spectrum remains unknown. The study was aimed to investigate the influence of black tea on radial blood pressure and Pulse Spectrum. Fourteen healthy subjects received water and single doses of black tea (0.05 g/Kg) in separate weeks. The radial blood pressure and pulse wave were measured and the pressure pulses were evaluated using harmonic analysis. This report confirmed that black tea consumption (dose = 0.05 g/Kg) significantly increased third, fifth, (P < 0.1), sixth, seventh, and eighth harmonics (p < 0.05) of radial pressure wave comparing to water control. We proposed that black tea may increase cerebral blood flow (CBF), which was deduced from the results and from the conclusions of previous studies. The results also showed that the harmonic components of pressure pulse could be the vascular kinetic index that assessed the hemodynamic status in each time frame before and after consumption of black tea.
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Crush–tear–curl (CTC) black tea is a popular beverage, owing to its unique taste characteristics and health benefits. However, differences in the taste quality and chemical profiles of CTC black tea from different geographical regions remain unclear. In this study, 28 CTC black tea samples were collected from six geographical regions and analyzed using electronic tongue and ultrahigh performance liquid chromatography-Orbitrap-mass spectroscopy. The e-tongue analysis indicated that each region's CTC black tea has its own relatively prominent taste characteristics: Sri Lanka (more umami and astringent), North India (more umami), China (more sweetness and astringent), South India (moderate umami and sweetness), and Kenya (moderate umami and astringent). Based on multivariate statistical analysis, 78 metabolites were tentatively identified and used as potential markers for CTC black tea of different origins, mainly including amino acids, flavone/flavonol glycosides, and pigments. Different metabolites, which contributed to the taste characteristics of CTC black tea, were clarified by partial least squares regression correlation analysis. Our findings may serve as useful references for future studies on origin traceability and quality characteristic determination of CTC black teas. Practical Application This study provides useful references for future studies on the origin traceability and taste characteristic determination of CTC black teas from different geographical regions.
Chapter
Tea, a product of the leaves and buds of the Camellia sinensis (Theaceae) plant, is one of the world’s most popular beverages. Tea can be broadly classified according to the production method as unfermented (green tea), half-fermented (oolong tea), fully fermented (black tea), or post-fermented (pu-erh tea). Green tea is mainly consumed in Japan and China, whereas black tea is primarily consumed in Western countries, India, and other parts of the world. The global production of green tea accounts for only 20 % of the total amount of tea produced, which is approximately one fourth of that of black tea [1]. However, green tea has been the primary target for investigations on health and nutrition among the various teas as indicated by a search conducted in the PubMed database in January 2015, which showed approximately 6020, 3340, 330, and 100 publications for the keywords “green tea,” “black tea,” “oolong tea,” and “pu-erh tea,” respectively. When combined with cancer, for example, the corresponding numbers of publications were approximately 2000, 670, 40, and 10, respectively.
Article
Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer's disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, considered the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer's disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-β plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer's disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.
Article
Tea flavonoids have been suggested to offer potential benefits to cardiovascular health. This review synthesized the evidence on the relation between tea consumption and risks of cardiovascular disease (CVD) and all-cause mortality among generally healthy adults. PubMed, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials, Food Science and Technology Abstracts, and Ovid CAB Abstract databases were searched to identify English-language publications through 1 November 2019, including randomized trials, prospective cohort studies, and nested case-control (or case-cohort) studies with data on tea consumption and risk of incident cardiovascular events (cardiac or peripheral vascular events), stroke events (including mortality), CVD-specific mortality, or all-cause mortality. Data from 39 prospective cohort publications were synthesized. Linear meta-regression showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with an average 4% lower risk of CVD mortality, a 2% lower risk of CVD events, a 4% lower risk of stroke, and a 1.5% lower risk of all-cause mortality. Subgroup meta-analysis results showed that the magnitude of association was larger in elderly individuals for both CVD mortality (n = 4; pooled adjusted RR: 0.89; 95% CI: 0.83, 0.96; P = 0.001), with large heterogeneity (I2 = 72.4%), and all-cause mortality (n = 3; pooled adjusted RR: 0.92; 95% CI: 0.90, 0.94; P < 0.0001; I2 = 0.3%). Generally, studies with higher risk of bias appeared to show larger magnitudes of associations than studies with lower risk of bias. Strength of evidence was rated as low and moderate (depending on study population age group) for CVD-specific mortality outcome and was rated as low for CVD events, stroke, and all-cause mortality outcomes. Daily tea intake as part of a healthy habitual dietary pattern may be associated with lower risks of CVD and all-cause mortality among adults.
Technical Report
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Ce travail se situe dans le cadre d’un travail global relatif à la mise à jour des repères de consommations alimentaires, présidé par M. Jean-Louis BRESSON.
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Red and processed meat consumption has been implicated in several diseases. However, data on meat consumption in relation to stroke incidence are sparse. Our objective was to examine the associations of red meat and processed meat consumption with stroke incidence in men. We prospectively followed 40,291 men aged 45-79 y who had no history of cardiovascular disease or cancer at baseline. Meat consumption was assessed with a self-administered questionnaire in 1997. During a mean follow-up of 10.1 y, 2409 incident casesof stroke (1849 cerebral infarctions, 350 hemorrhagic strokes, and 210 unspecified strokes) were identified from the Swedish Hospital Discharge Registry. Consumption of processed meat, but not of fresh red meat, was positively associated with risk of stroke. The multivariable relative risks (RRs) of total stroke for the highest compared with the lowest quintiles of consumption were 1.23 (95% CI: 1.07, 1.40; P for trend = 0.004) for processed meat and 1.07 (95% CI: 0.93, 1.24; P for trend = 0.77) for fresh red meat. Processed meat consumption was also positively associated with risk of cerebral infarction in a comparison of the highest with the lowest quintile (RR: 1.18; 95% CI: 1.01, 1.38; P for trend = 0.03). The findings from this prospective cohort of men indicate that processed meat consumption is positively associated with risk of stroke. The Cohort of Swedish Men is registered at clinicaltrials.gov as NCT01127711.
Article
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Tea consumption is associated with a lower risk of cardiovascular disease including stroke. Direct effects of tea components on the vasculature, particularly the endothelium, may partly explain this association. We performed a meta-analysis of controlled human intervention studies on the effect of tea on flow-mediated dilation (FMD) of the brachial artery, a measurement of endothelial function, which is suggested to be associated with cardiovascular risk. Human intervention studies were identified by systematic search of the databases Medline, Embase, Chemical Abstracts and Biosis through March 2009 and by hand-searching related articles. Studies were selected based on predefined criteria: intervention with tea as the sole experimental variable, placebo-controlled design, and no missing data on FMD outcome or its variability. A random effects model was used to calculate the pooled overall effect on FMD due to the intake of tea. The impact of various subject and treatment characteristics was investigated in the presence of heterogeneity. In total, 9 studies from different research groups were included with 15 relevant study arms. The overall absolute increase in FMD of tea vs. placebo was 2.6% of the arterial diameter (95% CI: 1.8-3.3%; P-value <0.001) for a median daily dose of 500 mL of tea (2-3 cups). This is a relative increase of approximately 40% compared to the average FMD of 6.3% measured under placebo or baseline conditions. There was significant heterogeneity between studies (P-value <0.001) that might partly be explained by the cuff position either distal or proximal to the area of FMD measurement. No indication for publication bias was found. Moderate consumption of tea substantially enhances endothelial-dependent vasodilation. This may provide a mechanistic explanation for the reduced risk of cardiovascular events and stroke observed among tea drinkers.
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Chronic mild dehydration has been associated with several diseases, including fatal IHD and stroke. It has been suggested that hydration through total fluid intake (or water) is inversely associated with IHD or stroke mortality. The objective of the present study was to evaluate the relationship between total fluid (and specific beverage) intake and IHD or stroke mortality in the Netherlands Cohort Study (NLCS). In 1986, 120,852 participants aged 55-69 years were enrolled into the NLCS. Mortality data were collected over a 10-year follow-up period. Analysis was done through a case-cohort approach, and it was based on the subjects without a history of heart disease, stroke or diabetes at baseline. A total of 1789 IHD mortality cases and 708 stroke mortality cases occurred during the follow-up. Higher total fluid consumption was not associated with either IHD mortality or stroke mortality in men or women. When analysing specific beverages, a positive association between coffee consumption (increment 270 ml/d) and IHD mortality was observed in men (hazard ratio (HR) 1.09, 95% CI 1.00, 1.18), while an inverse relationship was observed in women (HR: 0.88, 95% CI 0.78, 1.00). For tea consumption (increment of 253 ml/d), an inverse relationship with IHD mortality was observed in men (HR: 0.91, 95% CI 0.83, 1.00). No association with water intake was observed. In the study population, fresh water consumption was very low. In conclusion, total fluid intake was not associated with IHD or stroke mortality in either men or women. Coffee consumption was inversely associated with IHD mortality in women only, while a higher tea intake was associated with lower IHD mortality in men only.
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Physical activity is hypothesized to reduce the risk of obesity and several other chronic diseases and enhance longevity. However, most of the questionnaires used measure only part of total physical activity, occupational and/or leisure-time activity, which might lead to misclassification of total physical activity level and to dilution of risk estimates. We evaluated the validity and reproducibility of a short self-administered physical activity questionnaire, intended to measure long-term total daily 24 h physical activity. The questionnaire included questions on level of physical activity at work, hours per day of walking/bicycling, home/household work, leisure-time activity/inactivity and sleeping and was sent twice during one year (winter/spring and late summer). Two 7-day activity records, performed 6 months apart, were used as the reference method. One-hundred and eleven men, aged 44-78, completed the questionnaire and one or two activity records. The physical activity levels were measured as metabolic equivalents (MET)xh/day. Spearman correlation coefficient between total daily activity score estimated from the first questionnaire and the records (validity) was 0.56 (deattenuated) and between the first and the second questionnaire (reproducibility) 0.65. Significantly higher validity correlations were observed in men with self-reported body mass index below 26 kg/m(2) than in heavier men (r=0.73 vs r=0.39). This study indicates that the average total daily physical activity scores can be estimated satisfactorily in men using this simple self-administered questionnaire.
Article
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Tea remains the most consumed drink in the world after water, well ahead of coffee, beer, wine and carbonated soft drinks. An accumulated number of population studies suggests that consumption of green and black tea beverages may bring positive health effects (1). One hypothesis explaining such effects is that the high levels of flavonoids in tea can protect cells and tissues from oxidative damage by scavenging oxygen-free radicals. Chemically, the flavonoids found in green and black tea are very effective radical scavengers. The tea flavonoids may therefore be active as antioxidants in the digestive tract or in other tissues after uptake. A substantial number of human intervention studies with green and black tea demonstrates a significant increase in plasma antioxidant capacity in humans approximately 1 h after consumption of moderate amounts of tea (1-6 cups/d). There are initial indications that the enhanced blood antioxidant potential leads to reduced oxidative damage to macromolecules such as DNA and lipids. However, the measurement of oxidative damage through biomarkers needs to be further established. In conclusion, tea flavonoids are potent antioxidants that are absorbed from the gut after consumption. Tea consumption consistently leads to a significant increase in the antioxidant capacity of the blood. Beneficial effects of increased antioxidant capacity in the body may be the reduction of oxidative damage to important biomolecules. The scientific support is strongest for the protection of DNA from oxidative damage after black or green tea consumption. However, the quality of the studies now available is insufficient to draw firm conclusions. Therefore, further evidence from human intervention studies is required.
Article
Background: Epidemiological studies suggested that consumption of fruit and vegetables may protect against stroke. The hypothesis that dietary antioxidant vitamins and flavonoids account for this observation is investigated in a prospective study. Methods: A cohort of 552 men aged 50 to 69 years was examined in 1970 and followed up for 15 years. Mean nutrient and food intake was calculated from crosscheck dietary histories taken in 1960, 1965, and 1970. The association between antioxidants, selected foods, and stroke incidence was assessed by Cox proportional hazards regression analysis. Adjustment was made for confounding by age, systolic blood pressure, serum cholesterol, cigarette smoking, energy intake, and consumption of fish and alcohol. Results: Forty-two cases of first fatal or nonfatal stroke were documented Dietary flavonoids (mainly quercetin) were inversely associated with stroke incidence after adjustment for potential confounders, including antioxidant vitamins. The relative risk (RR) of the highest vs the lowest quartile of flavonoid intake (greater than or equal to 28.6 mg/d vs <18.3 mg/d) was 0.27 (95% confidence interval [CI], 0.11 to 0.70). A lower stroke risk was also observed for the highest quartile of beta-carotene intake (RR, 0.54; 95% CI, 0.22 to 1.33). The intake of vitamin C and vitamin E was not associated with stroke risk. Black tea contributed about 70% to flavonoid intake. The RR for a daily consumption of 4.7 cups or more of tea vs less than 2.6 cups of tea was 0.31 (95% CI, 0.12 to 0.84). Conclusions: The habitual intake of flavonoids and their major source (tea) may protect against stroke.
Article
High red meat consumption has been associated with increased risk of some cancers and may also be a risk factor for cardiovascular diseases. However, epidemiological studies of red meat consumption in relation to risk of stroke are very limited. Our objective was to examine the association between red meat consumption and stroke incidence in the Swedish Mammography Cohort. We prospectively followed 34 670 women without cardiovascular disease and cancer at baseline. Participants completed a self-administered questionnaire on diet and other risk factors for cardiovascular diseases in 1997. Cox proportional hazards models were used to estimate multivariable-adjusted relative risks (RR) and 95% CI. During a mean follow-up of 10.4 years, we ascertained 1680 incident cases of stroke, comprising 1310 cerebral infarction, 154 intracerebral hemorrhage, 79 subarachnoid hemorrhage, and 137 unspecified stroke. Total red meat and processed meat consumption was associated with a statistically significant increased risk of cerebral infarction, but not of total stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. The multivariable RR of cerebral infarction for the highest versus the lowest quintile of consumption were 1.22 (95% CI, 1.01-1.46) for red meat and 1.24 (95% CI, 1.04-1.49) for processed meat. Fresh (unprocessed) meat consumption was not associated with total stroke or with any stroke subtype. Findings from this study suggest that red and processed meat consumption may increase the risk of cerebral infarction in women.
Article
The two main types of tea are green and black. Both green and black teas are rich dietary sources of flavonoids. Available evidence suggests that regular tea consumption may reduce the risk of cardiovascular disease. The cardiovascular health benefits of drinking tea are thought to be largely due to flavonoids. Tea intake and intake of flavonoids found in tea have been associated with reduced risk of cardiovascular disease in cross-sectional and prospective population studies. Isolated flavonoids found in tea have also been consistently shown to inhibit the development of atherosclerosis in animal models. A number of possible pathways and mechanisms have been investigated. There is now consistent data indicating that tea and tea flavonoids can enhance nitric oxide status and improve endothelial function, which may be at least partly responsible for benefits on cardiovascular health. There is also evidence, although limited, to suggest benefits of green tea (flavonoids) on body weight and body fatness. Data supporting reduced oxidative damage, inflammation, platelet activation, blood pressure, and risk of type 2 diabetes with tea (flavonoids) remains inadequate to draw any conclusions.
Article
To examine the associations of coffee and tea consumption with risk of morbidity and mortality of stroke and coronary heart disease (CHD) and with all-cause mortality. Coffee and tea consumption were assessed with a validated food-frequency questionnaire, and 37 514 participants were observed for 13 years for the occurrence of cardiovascular morbidity and mortality. A U-shaped association between coffee and CHD was found, with the lowest hazard ratio (HR [95% CI]) for 2.1 to 3.0 cups per day (0.79 [0.65 to 0.96]; P(trend)=0.01). Tea was inversely associated with CHD, with the lowest HR (95% CI) for more than 6.0 cups per day (0.64 [0.46 to 0.90]; P(trend)=0.02). No associations between tea or coffee and stroke were found (P(trend)=0.63 and P(trend)=0.32, respectively). Although not significant, coffee slightly reduced the risk for CHD mortality (HR, 0.64; 95% CI, 0.37 to 1.11; P(trend)=0.12) for 3.1 to 6.0 cups per day. A U-shaped association between tea and CHD mortality was observed, with an HR of 0.55 (95% CI, 0.31 to 0.97; P(trend)=0.03) for 3.1 to 6.0 cups per day. Neither coffee nor tea was associated with stroke (P(trend)=0.22 and P(trend)=0.74, respectively) and all-cause mortality (P(trend)=0.33 and P(trend)=0.43, respectively). High tea consumption is associated with a reduced risk of CHD mortality. Our results suggest a slight risk reduction for CHD mortality with moderate coffee consumption and strengthen the evidence on the lower risk of CHD with coffee and tea consumption.
Article
Data on the association between coffee consumption and risk of stroke are sparse. We assessed the association between coffee consumption and the risk of stroke over 24 years of follow-up in women. We analyzed data from a prospective cohort of 83,076 women in the Nurses' Health Study without history of stroke, coronary heart disease, diabetes, or cancer at baseline. Coffee consumption was assessed first in 1980 and then repeatedly every 2 to 4 years, with follow-up through 2004. We documented 2280 strokes, of which 426 were hemorrhagic, 1224 were ischemic, and 630 were undetermined. In multivariable Cox regression models with adjustment for age, smoking status, body mass index, physical activity, alcohol intake, menopausal status, hormone replacement therapy, aspirin use, and dietary factors, the relative risks (RRs) of stroke across categories of coffee consumption (<1 cup per month, 1 per month to 4 per week, 5 to 7 per week, 2 to 3 per day, and >or=4 per day) were 1, 0.98 (95% CI, 0.84 to 1.15), 0.88 (95% CI, 0.77 to 1.02), 0.81 (95% CI, 0.70 to 0.95), and 0.80 (95% CI, 0.64 to 0.98) (P for trend=0.003). After further adjustment for high blood pressure, hypercholesterolemia, and type 2 diabetes, the inverse association remained significant. The association was stronger among never and past smokers (RR for >or=4 cups a day versus <1 cup a month, 0.57; 95% CI, 0.39 to 0.84) than among current smokers (RR for >or=4 cups a day versus <1 cup a month, 0.97; 95% CI, 0.63 to 1.48). Other drinks containing caffeine such as tea and caffeinated soft drinks were not associated with stroke. Decaffeinated coffee was associated with a trend toward lower risk of stroke after adjustment for caffeinated coffee consumption (RR for >or=2 cups a day versus <1 cup a month, 0.89; 95% CI, 0.73 to 1.08; P for trend=0.05). Long-term coffee consumption was not associated with an increased risk of stroke in women. In contrast, our data suggest that coffee consumption may modestly reduce risk of stroke.
Article
Except for conflicting evidence about coffee and risk of coronary disease, coffee and tea are not linked to major causes of death. Because of widespread use of both beverages and limitations of prior studies, concern persists. Using Cox models (ten covariates) we studied relations in 128,934 persons to 4501 subsequent deaths. Except for slightly increased risk from acute myocardial infarction among heavier (> or = 4 cups/d) coffee users (relative risk versus nondrinkers = 1.4, 95% confidence interval = 1.0 to 1.9, P = 0.07), there was no increased risk of mortality for all deaths (relative risk per cup of coffee per day = 0.99, 95% confidence interval = 0.97 to 1.01; relative risk per cup of tea per day = 0.98, 95% confidence interval = 0.96 to 1.00) or major causes in adjusted analyses. Coffee was related to lower risk of liver cirrhosis death (relative risk per cup of coffee per day = 0.77, 95% confidence interval = 0.67 to 0.89). Use of both beverages was related to a lower risk of suicide, progressively lower at higher coffee intake (relative risk per cup of coffee per day = 0.87, 95% confidence interval = 0.77 to 0.98). We conclude that coffee and tea have no overall relation to mortality risk. If coffee increases coronary risk, this is balanced by an unexplained lower risk of other conditions, notably cirrhosis and suicide.
Article
Epidemiological studies suggested that consumption of fruit and vegetables may protect against stroke. The hypothesis that dietary antioxidant vitamins and flavonoids account for this observation is investigated in a prospective study. A cohort of 552 men aged 50 to 69 years was examined in 1970 and followed up for 15 years. Mean nutrient and food intake was calculated from cross-check dietary histories taken in 1960, 1965, and 1970. The association between antioxidants, selected foods, and stroke incidence was assessed by Cox proportional hazards regression analysis. Adjustment was made for confounding by age, systolic blood pressure, serum cholesterol, cigarette smoking, energy intake, and consumption of fish and alcohol. Forty-two cases of first fatal or nonfatal stroke were documented. Dietary flavonoids (mainly quercetin) were inversely associated with stroke incidence after adjustment for potential confounders, including antioxidant vitamins. The relative risk (RR) of the highest vs the lowest quartile of flavonoid intake ( > or = 28.6 mg/d vs <18.3 mg/d) was 0.27 (95% confidence interval [CI], 0.11 to 0.70). A lower stroke risk was also observed for the highest quartile of beta-carotene intake (RR, 0.54; 95% CI, 0.22 to 1.33). The intake of vitamin C and vitamin E was not associated with stroke risk. Black tea contributed about 70% to flavonoid intake. The RR for a daily consumption of 4.7 cups or more of tea vs less than 2.6 cups of tea was 0.31 (95% CI, 0.12 to 0.84). The habitual intake of flavonoids and their major source (tea) may protect against stroke.
Article
Flavonoids, a group of phenolic compounds found in fruits and vegetables, are known to have antioxidant properties. They prevent low density lipoprotein oxidation in vitro and thus may play a role in the prevention of coronary heart disease (CHD). In 1986, in a prospective study of 34,492 postmenopausal women in Iowa, the authors examined the association of flavonoid intake with CHD and stroke mortality. Over 10 years of follow-up, 438 deaths from CHD and 131 deaths from stroke were documented. Total flavonoid intake was associated with a decreased risk of CHD death after adjusting for age and energy intake (p for trend = 0.04). This association was attenuated after multivariate adjustment. However, decreased risk was seen in each category of intake compared with the lowest. Relative risks and 95% confidence intervals of CHD death from lowest to highest intake category were 1.0, 0.67 (95% confidence interval (Cl) 0.49–0.92), 0.56 (95% Cl 0.39–0.79), 0.86 (95% Cl 0.63–1.18), and 0.62 (95% Cl 0.44–0.87).There was no association between total flavonoid intake and stroke mortality (p for trend = 0.83). Of the foods that contributed the most to flavonoid intake in this cohort, only broccoli was strongly associated with reduced risk of CHD death. The data of this study suggest that flavonoid intake may reduce risk of death from CHD in postmenopausal women. Am J Epidemiol 1999; 149:943–9.
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Mounting evidence shows that phenol-rich beverages exert strong antioxidant activity. However, in vivo evidence has produced conflicting results. In the present study, we studied the impact of the ingestion of 300 mL of black and green tea, alcohol-free red wine, alcohol-free white wine, or water on plasma total antioxidant capacity in five healthy volunteers. Red wine has the highest content of phenolics (3.63 +/- 0.48 g QE/L), followed by green tea (2.82 +/- 0.07 g QE/L), black tea (1.37 +/- 0.15 g QE/L), and white wine (0.31 +/- 0.01 g QE/L). Plasma total antioxidant capacity values of subjects who drank green tea rose at 30 min (P < 0.05). After black tea and red wine ingestion, the peaks were at 50 min (P < 0.05 and P < 0.01, respectively). No changes were observed in the control and white wine groups. Red wine and green tea were the most efficient in protecting low density lipoprotein from oxidation driven by peroxyl and ferril radicals, respectively. Phenol-rich beverages are a natural source of antioxidants; however, the phenolic content alone cannot be considered an index of their in vivo antioxidant activity.
Article
Coffee and tea consumption could potentially reduce the risk of stroke because these beverages have antioxidant properties, and coffee may improve insulin sensitivity. We examined the associations of coffee and tea consumption with risk of stroke subtypes. We used prospective data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a cohort study of 26 556 male Finnish smokers aged 50 to 69 years without a history of stroke at baseline. Coffee and tea consumption was assessed at baseline using a validated food-frequency questionnaire. During a mean follow-up of 13.6 years, from 1985 through December 2004, 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were ascertained from national registries. After adjustment for age and cardiovascular risk factors, both consumption of coffee and tea was statistically significantly inversely associated with the risk of cerebral infarction but not intracerebral or subarachnoid hemorrhage. The multivariate relative risk of cerebral infarction for men in the highest category of coffee consumption (>/=8 cups/d) was 0.77 (95% CI, 0.66 to 0.90; P for trend <0.001) compared with those in the lowest category (<2 cups/d). The corresponding relative risk comparing men in the highest category of tea consumption (>/=2 cups/d) with those in the lowest category (nondrinkers) was 0.79 (95% CI, 0.68 to 0.92; P for trend=0.002). These results suggest that high consumption of coffee and tea may reduce the risk of cerebral infarction among men, independent of known cardiovascular risk factors.