Regular Consumption Of Black Tea Research Articles

Aged black tea alleviates constipation in mice by modulating intestinal neurotransmitters and decreasing AQP3 and AQP9 expression

Background: Black tea is fully fermented tea with abundant functional components that benefit the gastrointestinal tract. But whether black tea extract relieves constipation is unknown. Therefore, we used loperamide to induce constipation in mice to assess the therapeutical effect of extracts from aged black tea with different storage times.
 Design: Sixty-three C57BL/6J male mice were randomly divided into Control group (Con), Model group (Mod), Positive group (Pos), aged 6 years group (15Y), aged 4 years group (17Y), aged 2 years group (19Y), and unaged group (21Y). Mice were given loperamide (20 mg/kg, twice a day) to induce constipation for 10 days, and black tea extracts (500 mg/kg) were intragastrically given for 7 days while continuing modeling.
 Results: The results showed that black tea extracts relieved constipation symptoms by improving defecation weight, fecal water content, and gastrointestinal transit rate. Black tea extracts can also protect colon tissue, regulate serum neurotransmitters, increase the levels of excitatory neurotransmitters motilin (MTL) and substance P (SP), and decrease the levels of inhibitory neurotransmitters vasoactive intestinal peptide (VIP) and nitric oxide (NO). Immunohistochemistry (IHC) showed that black tea extracts were able to reduce AQP3 and AQP9 expression in the colon of constipated mice. In addition, Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) showed that black tea extracts could decrease AQP3 and AQP9 mRNA expression. The relief effect of aged black tea (15Y) with the longest storage was better than that of other years, which may be due to the role of active ingredients such as thearubigins (TRs), soluble sugar, tea polysaccharide (TPS), gallic acid (GA), and catechin gallate (CG) in aged black tea.
 Conclusions: Based on these results, we believe that regular consumption of black tea is effective in relieving constipation, and that black tea is more effective in relieving constipation as the storage time increases.

Evaluation of the impact of fluoride in drinking water and tea on the enamel of deciduous and permanent teeth

BackgroundSystemic fluoride intake is predominantly derived from drinking water and tea. It’s been noted that water and tea containing fluoride, within the boundaries set by the World Health Organization, can lessen the prevalence of dental caries. A review of the literature did not uncover any study that has examined the impact of fluoride in bottled drinking water and tea on enamel of deciduous and permanent teeth. Thus, we assessed the effects of fluoride present in seven different brands of bottled water from distinct geographical regions of Turkey, and a type of tea produced and packaged in Turkey, on the enamel of deciduous and permanent teeth.Materials and methodsFluoride analysis was performed on drinking water sourced from seven different regions of Turkey and a brand of tea brewed with these waters. The tea was harvested and packaged in Turkey. The analysis was conducted using an ion-selective electrode. In total, 112 tooth enamel samples (56 deciduous molars and 56 permanent molars) were randomly divided into eight distinct groups. These were kept in water for 15 min and tea for 15 min every day for a month. The eighth group was treated with fluoride gel prior to tea and water applications. The amount of fluoride in the tooth enamel structure was evaluated using an SEM EDX device before and after the experiment.ResultsStatistically significant differences were found in fluoride content of enamel between water brands and tooth type (deciduous and permanent teeth). Fluoride levels were higher in the enamel of deciduous teeth than in permanent teeth.ConclusionRegular exposure of enamel samples to black tea and water led to an increase in fluoride levels in the enamel; thus, regular consumption of black tea and fluoride water could help reduce the prevalence of dental caries.

The relationship between regular tea drinking and calcification of the coronary arteries.

Introduction: Coronary Atherosclerosis is the leading cause of death and disability worldwide. Atherosclerosis could be detected noninvasively by coronary calcification, measured by calcium score in CT angiography. Dietary factors are influential in the evolution of coronary plaques, and one of the most prevalent drinks is black tea. We aimed to evaluate the effects of black tea on coronary calcium scores. Methods: This cross-sectional analytical descriptive study was conducted on 200 candidates for CT angiography referred by their physician because their symptoms were suggestive of ischemia. A questionnaire was filled out for every participant, and the habit of tea drinking was asked and marked as none drinker, 1-3 cups per day and >3 cups per day. Results: 89.5% of the participants consumed tea. The mean calcium score in patients who did not drink tea was 674.9±154.74 in those patients who drank 1-3 glasses per day, 269.5±46.9 and in those who drank more than three glasses of tea and was 261.1±45.2. There was a significant statistical relationship between calcium scores and tea intake, independent to other traditional risk factors (P= 0.001). Significant coronary artery plaques were also less prevalent in those who drank tea (36% and 41% in 1-3 and >3 cups, respectively) than non-drinkers (67%). Still, the number of involved vessels was not significantly different. Conclusion: Regular black tea consumption could have protective effects on coronary artery calcification.

Black tea and maintenance of normal endothelium-dependent vasodilation: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No1924/2006.

Following an application from Unilever NV, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Ireland, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to black tea and maintenance of normal endothelium‐dependent vasodilation. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The food proposed by the applicant as the subject of the health claim is black tea beverages, either freshly prepared or reconstituted from water extract powders of black tea, characterised by the content of flavanols (expressed as catechins plus theaflavins) of at least 30 mg per 200 mL serving. The Panel considers that black tea characterised by the content of flavanols (expressed as catechins plus theaflavins) is sufficiently characterised. The claimed effect proposed by the applicant is ‘improvement of endothelium‐dependent vasodilation’. The Panel considers that maintenance of normal endothelium‐dependent vasodilation is a beneficial physiological effect. Of the five human intervention studies provided on the chronic effect of black tea consumption on endothelium‐dependent vasodilation, two investigated the effect after regular consumption of black tea for a sufficiently long time period (i.e. at least 4 weeks). These two studies did not allow an effect of black tea on endothelium‐dependent vasodilation to be established. The Panel concludes that a cause and effect relationship has not been established between the consumption of black tea and maintenance of normal endothelium‐dependent vasodilation.

Effects of Black and Green Tea Consumption on Blood Pressure and Liver Enzymes: A Randomized Controlled Trial

Background: The effect on tea consumption on blood pressure and liver enzymes are controversial. The beneficial effects of long-term ingestion of black and green tea on systolic and diastolic blood pressure have been suggested by several studies.Objectives: The overall goal of this study was to determine the effects of high tea consumption on blood pressure and liver enzymes.Design: We completed a 6-month randomized, controlled, double-blinded trial in a group of former and current smokers who were randomized to receive black or green tea preparations or a matching placebo.Results: A total of 146 participants (80 females and 66 males) were enrolled in the study. At the end of the 6-month intervention, women in the black tea group showed a 4 mmHg decrease (p = 0.01) in systolic blood pressure while female in the green tea group showed a 30.1% decrease (p = 0.035) in Alanine transaminase (ALT). No significant changes were observed in men.Conclusion: Our data confirm previous findings related to the beneficial effect of black tea on blood pressure and of green tea on serum liver enzymes especially among females. In addition, our study showed that long-term regular consumption of black tea and green is safe.

GC–MS based metabolite profiling and angiotensin I-converting enzyme inhibitory property of black tea extracts

Angiotensin I-converting enzyme inhibitors are used as therapeutic agents for the treatment of hypertension. Regular consumption of black tea (Camellia sinensis (L.) Kuntze, Theaceae) has been reported to lower blood pressure. The aims of the present work were to compare chemical composition and angiotensin I-converting enzyme inhibitory properties of infusion and decoction of four samples of black tea. GC/MS based metabolomics approach helped in identification of fifty-one metabolites including ten organic acids, one inorganic acid, sixteen amino acids, two sugars, five sugar alcohols, fifteen phenols and flavonoids, two fatty acids from infusions and decoctions of four black tea samples. Partial least squares discriminant analysis and orthogonal partial least squares discriminant analysis models showed good classification among the two groups, diffusion and infusion, based on metabolites. Both infusion and decoction inhibited the enzyme. However, the activity differed with samples. Multivariate analysis also segregated extracts on the basis of activity. Thearubigin, theaflavin, catechin inhibited the enzyme. Epicatechin, epigallocatechin gallate, gallic acid, caffeine showed lower activity.

Black tea lowers blood pressure and wave reflections in fasted and postprandial conditions in hypertensive patients: a randomised study.

Hypertension and arterial stiffening are independent predictors of cardiovascular mortality. Flavonoids may exert some vascular protection. We investigated the effects of black tea on blood pressure (BP) and wave reflections before and after fat load in hypertensives. According to a randomized, double-blind, controlled, cross-over design, 19 patients were assigned to consume black tea (129 mg flavonoids) or placebo twice a day for eight days (13 day wash-out period). Digital volume pulse and BP were measured before and 1, 2, 3 and 4 h after tea consumption. Measurements were performed in a fasted state and after a fat load. Compared to placebo, reflection index and stiffness index decreased after tea consumption (p < 0.0001). Fat challenge increased wave reflection, which was counteracted by tea consumption (p < 0.0001). Black tea decreased systolic and diastolic BP (−3.2 mmHg, p < 0.005 and −2.6 mmHg, p < 0.0001; respectively) and prevented BP increase after a fat load (p < 0.0001). Black tea consumption lowers wave reflections and BP in the fasting state, and during the challenging haemodynamic conditions after a fat load in hypertensives. Considering lipemia-induced impairment of arterial function may occur frequently during the day, our findings suggest regular consumption of black tea may be relevant for cardiovascular protection.

Regular consumption of black tea increases circulating kynurenine concentrations: A randomized controlled trial

BackgroundCirculating neopterin and the ratio of kynurenine to tryptophan (KYN/TRP) concentrations are biomarkers of immune activation that have been linked to cardiovascular and total mortality. Several in vitro studies indicated that tea flavonoids and other antioxidants can modulate tryptophan breakdown rates and neopterin production in immune cells. We aimed to assess the effects of regular black tea consumption on tryptophan and neopterin metabolisms in vivo. MethodsParticipants were healthy individuals, with no major illnesses and having normal to mildly elevated systolic blood pressure. They were randomly assigned to consume 3cups/day of either powdered black tea solids (tea; n=45) or a flavonoid-free caffeine-matched beverage (control; n=49). Serum concentrations of tryptophan, kynurenine and neopterin were assessed at baseline and again at 3 and 6months after daily ingestion of the respective beverage. ResultsRegular consumption of tea over 6months, compared to control, did not significantly alter neopterin (p=0.13) or tryptophan (p=0.85) concentrations, but did result in significantly higher kynurenine (p=0.016) and KYN/TRP (p=0.012). Relative to the control group, in the tea group kynurenine and KYN/TRP increased during the treatment period by 0.28μmol/L (95% CI: −0.04, 0.60) and 3.2μmol/mmol (95% CI: −1.6, 8.0), respectively at 3months, and by 0.48μmol/L (95% CI: 0.16, 0.80) and 7.5μmol/mmol (95% CI: 2.5, 12.5), respectively at 6months. ConclusionsIncreased circulation of kynurenine and KYN/TRP following regular black tea consumption may indicate enhanced tryptophan breakdown, possibly due to immune activation-induced tryptophan degrading enzyme indoleamine 2,3-dioxygenase. General significanceThe influence of black tea consumption on biomarkers of immune system activation could relate to its general health benefits. Data suggests that the net effect strongly depends on the individual immune state, being stimulatory in healthy individuals, while acting more immune dampening in situations with an inflammatory background.

J13 The Role Of Natural Products On Huntington Disease: A Sri Lankan Perspective

Background The prevalence of Huntington Disease (HD) in Europeans are 10 times higher than Asian populations. The domestic per capita tea consumption is higher in Sri Lanka compared to the West. We hypothesise that, the frequency of natural product consumption and environmental factors that are unique to this part of the world may contribute to the disparity in phenoconversion in HD. Method Sociodemographic data, dietary history, clinical and genotyping of CAG repeats followed by a detailed haplotype analysis was performed in HD patients and controls. Results Pilot data of HD 16 patients: [Adult onset n = 14 (85%), Juvenile onset n = 2 (15%), Male n = 9(56%), Female n = 7(44%)], age of onset: 16–60yrs (mean = 42.9 ± 14.1). The CAG repeats on normal alleles (n = 11) range: 16–22 (mean =18.3 ± 2), abnormal allele (n = 11) range: 41–66 (mean = 46 ± 7). A significant inverse correlation exists between the age of onset and CAG repeat length (r = 0.897, p Discussion The data suggest that, regular consumption of black tea was associated with a lower risk of cognitive impairment. We propose future studies with a larger sample size to improve statistical power.

The effect of black tea on blood pressure: a systematic review with meta-analysis of randomized controlled trials.

ObjectiveEpidemiological 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.MethodsWe systematically searched Medline, Biosis, Chemical s 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.ResultsEleven 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.ConclusionsOur 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.

Black tea lowers the rate of blood pressure variation: a randomized controlled trial

Measures of blood pressure variation have been associated with cardiovascular disease and related outcomes. The regular consumption of black tea can lower blood pressure, but its effects on blood pressure variation have yet to be investigated. We aimed to assess the effects of black tea consumption on the rate of ambulatory blood pressure variation. Men and women (n = 111) with systolic blood pressure between 115 and 150 mm Hg at screening were recruited in a randomized, controlled, double-blind, 6-mo parallel-designed trial designed primarily to assess effects on blood pressure. Participants consumed 3 cups/d of either powdered black tea solids (tea) or a flavonoid-free caffeine-matched beverage (control). The 24-h ambulatory blood pressure level and rate of measurement-to-measurement blood pressure variation were assessed at baseline, day 1, and 3 and 6 mo. Across the 3 time points, tea, compared with the control, resulted in lower rates of systolic (P = 0.0045) and diastolic (P = 0.016) blood pressure variation by ~10% during nighttime (2200-0600). These effects, which were immediate at day 1 and sustained over 6 mo, were independent of the level of blood pressure and heart rate. The rate of blood pressure variation was not significantly altered during daytime (0800-2000). These findings indicate that a component of black tea solids, other than caffeine, can influence the rate of blood pressure variation during nighttime. Thus, small dietary changes have the potential to significantly influence the rate of blood pressure variation. This trial was registered at the Australian New Zealand Clinical Trials Registry as ACTR12607000543482.

Is black tea consumption associated with a lower risk of cardiovascular disease and type 2 diabetes?

SummaryType 2 diabetes mellitus and cardiovascular disease represent major causes of morbidity, which impact greatly on healthcare expenditure. Clinical studies suggest that ingestion of black tea, which contains a range of bioactive compounds, can inhibit oxidative damage and improve endothelial function. The objectives of this review are to: (1) evaluate observational evidence linking black tea consumption with the prevalence of cardiovascular diseases and type 2 diabetes; (2) consider the mechanisms by which black tea may have a protective effect; and (3) examine the potential role of tea drinking in relation to public health.The findings from epidemiological studies suggested a significant association between regular black tea consumption and a reduced risk of coronary heart disease at around three or more cups per day. For diabetes risk, the data are restricted to a few large cohort studies that suggested a beneficial association at one to four cups daily. These findings need to be confirmed by intervention trials. While some studies suggest that drinking black tea may reduce the risk of stroke, likely mechanisms remain unclear, highlighting the need for more human intervention studies. Disparities found involving studies may have been influenced by variations in reported tea intakes, limited sample sizes in intervention trials and inadequate control of confounders. In conclusion, drinking black tea may have a role in lowering the risk of coronary heart disease and type 2 diabetes. Future research should focus on controlled trials and studies to elucidate likely mechanisms of action.

Associations Between Black Tea and Coffee Consumption and Risk of Lung Cancer Among Current and Former Smokers

Although cigarette smoking is a clear risk factor for lung cancer, the other determinants of lung cancer risk among smokers are less clear. Tea and coffee contain catechins and flavonoids, which have been shown to exhibit anticarcinogenic properties. Conversely, caffeine may elevate cancer risk through a variety of mechanisms. The current study investigated the effects of regular consumption of black tea and coffee on lung cancer risk among 993 current and former smokers with primary incident lung cancer and 986 age-, sex-, and smoking-matched hospital controls with non-neoplastic conditions. Results indicated that lung cancer risk was not different for those with the highest black tea consumption (≥2 cups/day) compared with nondrinkers of tea [adjusted odds ratio (aOR) = 0.90; 95% confidence interval (CI) = 0.66–1.24]. However, elevated lung cancer risk was observed for participants who consumed 2-3 cups of regular coffee daily (aOR = 1.34; 95% CI = 0.99–1.82) or ≥4 cups of regular coffee daily (aOR = 1.51, 95% CI = 1.11–2.05). In contrast, decaffeinated coffee drinking was associated with decreased lung cancer risk for both participants who consumed ≤1 cup/day (aOR = 0.67; 95% CI = 0.54–0.84) and those who consumed ≥2 cups/day (aOR = 0.64; 95% CI = 0.51–0.80). These results suggest that any chemoprotective effects of phytochemicals in coffee and tea may be overshadowed by the elevated risk associated with caffeine in these beverages.