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PubMed1998

Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: a pilot study.

Apolipoprotein E (ApoE) genotype was determined in sixty-five subjects who had taken part in a 4-week randomized crossover trial to compare the effect of six mugs of black tea per day v. placebo on blood lipids and blood coagulation factors. Four ApoE genotype variants (seven E2/E3, forty-five E3/E3, twelve E3/E4 and one E4/E4) were found. ApoE allele frequency was within the range typical for Caucasian populations (ApoE-E2 5.4%; ApoE-E3 83.8%; ApoE-E4 10.8%). Individuals bearing at least one E4 allele had substantially higher levels of serum total cholesterol, LDL cholesterol and triacylglycerols. Mean plasminogen activator inhibitor (PAI-1) activity was higher in ApoE-E4 allele-bearing individuals (E3/E4 + E4/E4, 11.89 (SE 1.27) U/ml; E3/E3, 9.19 (SE 0.80) U/ml; E2/E3, 7.21 (SE 1.04) U/ml, P values of E4-group v. E3 and E2 being respectively 0.093 and 0.030). These unexpected findings imply that elevated PAI-1 activity may be a hitherto unrecognized additional factor involved in the increased cardiovascular disease risk associated with apoE-E4 allele. The interactions between tea drinking and genotype were also examined. In the E3/E3 homozygotes, HDL-cholesterol was significantly reduced in the tea period (mean placebo 1.54 mmol/l v. mean tea 1.50 mmol/l, P = 0.027). In the E2/E3 group, triacylglycerol concentration was significantly reduced (mean placebo 1.18 mmol/l v. mean tea 1.09 mmol/l, P = 0.039). Tea also caused a significant decrease of PAI-1 activity in the subjects with E2/E3 genotype (mean placebo 7.21 U/ml v. mean tea 5.88 U/ml, P = 0.007). In the other two genotype groups, there was no significant effect of tea. The results indicate that tea drinking has a beneficial effect on some cardiovascular disease risk-associated factors, especially in E2 allele-bearing individuals. Dietary intervention may be particularly effective in population groups with certain genetic characteristics.

Adult↗
PubMed2004

The effect of drinking tea at high altitude on hydration status and mood.

The effect of drinking tea on hydration status and mood was studied in nine male and four female members of expeditions based at Mt. Everest base camp at an altitude of 5,345 m. Whilst exposed to altitude-cold diuresis, participants were subjected to a crossover experimental design comprising two 24-h dietary interventions. In the "tea" condition, hot brewed tea formed a major part of fluid intake, whereas in the "no-tea" condition tea was excluded from the diet. Subjects were prohibited in both cases from consuming other caffeinated beverages, caffeinated foods, and alcoholic drinks. Mean fluids ingested [mean (SE); tea=3,193 (259) ml versus no tea=3,108 (269) ml] and urine volume (tea=2,686 (276) ml versus no tea=2,625 (342) ml] were similar under both conditions. Statistical analysis found no difference in urine stimulated as a result of the tea intervention (P=0.81). Several markers of hydration status were also taken immediately pre and post each condition, including measures of urine specific gravity, urine electrolyte balance (K+, Na+), and urine colour. None of these measures indicated a difference in hydration status as a result of the dietary intervention in either the control or tea condition. A difference was, however, found in mood, with subjects reporting reduced fatigue when tea was included in the diet (P=0.005). The study shows therefore that even when drunk at high altitude where fluid balance is stressed, there is no evidence that tea acts as a diuretic when consumed through natural routes of ingestion by regular tea drinkers, but that it does have a positive effect on mood.

Adaptation, Physiological↗
PubMedDate not supplied

Tea drinking and haemostasis: a randomized, placebo-controlled, crossover study in free-living subjects.

The hypothesis that tea drinking may protect against coronary heart disease (CHD) through effects on clotting as measured by plasma fibrinogen, tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) was tested in 65 healthy volunteers (31 men and 34 women; aged 20-74 years) in a randomized, blind, placebo-controlled, crossover study lasting 10 weeks (run-in phase 2 weeks, tea and placebo phases 4 weeks). During the placebo phase, intakes of milk, sugar, water and caffeine were matched to those in the tea phase during which 6 mugs of tea were drunk daily. Compliance with tea intake was measured by marking tea bags with p-aminobenzoic acid and measuring recovery in 24-hour urine collections. The mean +/- SD fibrinogen level, PAI-1 activity and tPA antigen level at baseline of 2.91 +/- 0.81 g/l, 7.9 +/- 5.3 U/ml and 4.76 +/- 2.17 ng/ml, respectively, were in the normal range. No significant differences in these variables between the run-in, tea or placebo phases were observed. The putative protective effect of tea against development of CHD is not mediated through effects of black tea on fibrinogen, tPA or PAI-1.

Adult↗
PubMed2006

Influence of tea drinking on manganese intake, manganese status and leucocyte expression of MnSOD and cytosolic aminopeptidase P.

OBJECTIVE: Since black tea contains high levels of manganese (Mn), we investigated the relationship between dietary Mn intake, circulating Mn levels and leucocyte expression of two Mn-dependent enzymes in tea drinkers and non-tea drinkers. DESIGN: We assessed Mn intakes (food frequency questionnaire), fasting whole blood and plasma Mn levels, and quantitative expression of peripheral blood mononuclear cell Mn-dependent superoxide dismutase (MnSOD) and cytosolic aminopeptidase-P (cAP-P). SETTING AND SUBJECTS: In total, 24 tea drinkers (> or = 1 l black tea/day) and 28 non-tea drinkers were recruited from the staff and students of King's College London by circular email. RESULTS: Dietary Mn intakes (mean (range)) were significantly lower (P < 0.0001) in non tea drinkers (3.2 mg/day (0.5-6.5)) than tea drinkers (5.5 mg/day (2-12) or 10 mg/day (5-20) depending upon the value used for Mn levels of black tea). Whole blood, plasma Mn levels and expression of MnSOD and cAP-P did not differ between the groups. In a continuous analysis, whole blood Mn levels and expression of MnSOD correlated inversely but no other parameters associated with each other. CONCLUSIONS: Tea drinking is a major source of dietary Mn and intakes commonly exceed proposed adequate intake values of 1.8-2.3 mg Mn/day and, on occasion, exceed upper limits of 10-11 mg/day. Dietary Mn intake has little influence on markers of Mn status or expression of Mn-dependent enzymes. Fasting whole blood Mn levels and leucocyte expression of MnSOD could, together, be further investigated as markers of Mn status.

Adult↗
PubMed1986

The relationship of salt intake and arterial blood pressure in salted-tea drinking Kashmiris.

In this study we attempted to explore the relationship between salt and blood pressure in a salted-tea drinking population of Northern Kashmir which has not been exposed to a Western way of life. All the available family members of randomly selected houses in 14 villages were studied. Dietary intake was documented for the whole month of the study period to estimate the daily salt consumption in 281 subjects (193 males, 88 females), whose ages were reliably known. Their age ranged from 15 to 85 years (median 35) and their mean daily salt intake was 150 +/- 52 mmol (range 80-440). Both the systolic and diastolic blood pressures showed a significant increase with the salt intake and age; multiple regression analysis suggested an independent effect of salt intake on blood pressure after adjusting for age. Twenty-six subjects (9.3%) had hypertension (blood pressure greater than or equal to 160/95 mm Hg); their daily salt intake was significantly higher than that of normotensive subjects (mean 167 +/- SD 53 vs 142 +/- 46 mmol; P less than 0.001). These studies suggest a relationship between habitual high salt intake and blood pressure.

Adolescent↗
PubMedDate not supplied

Effect of coffee and tea drinking on postprandial hypotension in older men and women.

1. A postprandial fall in blood pressure (BP) in older men and women increases the risks of falls and impaired cerebral perfusion. Postprandial hypotension has been suggested to be greater in hypertensive subjects, particularly in those on antihypertensive medication. 2. Caffeine, given as tablets or as strong coffee, may attenuate postprandial falls in BP in older subjects, but findings are not consistent. 3. In a randomized controlled intervention in 171 healthy non-smokers over the age of 50 years, we compared the effects of coffee-drinking with abstaining from caffeine in normotensives (NT), untreated hypertensives (UNHT) and subjects on drug treatment for hypertension (TRHT). Tea drinking was a third intervention used only in TRHT. 4. After adjustment for the effects of the initial value on changes in BP, there were no significant differences related to hypertension or to hypertensive agents in the magnitude of postprandial falls in BP. 5. After the intervention, changes in fasting supine and standing systolic BP and heart rate (HR) were not significantly different from controls in NT, UNHT and TRHT, but fasting supine and standing diastolic BP were significantly higher in coffee drinkers in the UNHT group. 6. In normotensive coffee drinkers there was a significant reduction in the postprandial fall in supine systolic BP of 4.1 mmHg (+/- s.e.m. 1.1) and in standing systolic BP of 5.2 +/- 1.6 mmHg. Among untreated hypertensives, abstainers showed a significant attenuation of the postprandial fall in supine, but not standing, systolic BP. Among treated hypertensives who were tea drinkers the postprandial fall decreased for supine systolic BP by 3.8 +/- 1.2 mmHg (P = 0.029) and for standing systolic BP by 5.2 +/- 2.1 mmHg. 7. Both tea and coffee were potentially beneficial in decreasing postprandial falls in systolic BP, but coffee drinking may increase fasting diastolic pressures in untreated hypertensives.

Aged↗
PubMed1997

Effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit.

Thirty-one men (47 (SD 14) years) and thirty-four women (35 (SD 13) years) took part in a 4-week randomized cross-over trial to compare the effect of six mugs of black tea daily v. placebo (water, caffeine, milk and sugar) on blood lipids, bowel habit and blood pressure, measured during a run-in period and at the end of weeks 2, 3 and 4 of the test periods. Compliance was established by adding a known amount of p-aminobenzoic acid (PABA) to selected tea bags, and then measuring its excretion in urine. Mean serum cholesterol values during run-in, placebo and on tea drinking were 5.67 (SD 1.05), 5.76 (SD 1.11) and 5.69 (SD 1.09) mmol/l (P = 0.16). There were also no significant changes in diet, LDL-cholesterol, HDL-cholesterol, triacylglycerols, and blood pressure in the tea intervention period compared with placebo. Compared with placebo, stool consistency was softened with tea (P = 0.04), and no other differences were found in bowel habit. Results were unchanged when fifteen 'non-compliers', whose PABA excretion indicated that fewer than six tea bags had been used, were excluded from the analysis, and when differences between run-in and tea periods were considered separately for those who were given tea first or second.

4-Aminobenzoic Acid↗
PubMed2006

Stress proteins (Hsp72/73, Grp94) expression pattern in rat organs following metavanadate administration. Effect of green tea drinking.

Expression pattern of heat shock proteins (Hsp) 72/73 and glucose regulated protein (Grp) 94 was studied in liver, kidney and testis of rats injected with sublethal doses of ammonium metavanadate (5 mg/kg/day). In addition, some batches of animals were given green tea decoction, known to be rich in anti-oxidative compounds, as sole beverage in order to evaluate its protective properties. In control animals, the stress proteins expression was found to be organ-dependent: anti-Grp94 antibody revealed two bands at 96 and 98 kDa in kidney and liver whereas the 98 kDa band only was found in testis; anti-Hsp72/73 antibody revealed that the constitutive Hsp73 was present in all organs whereas the inducible Hsp72 was only present in kidney and testis. In kidney of vanadium-treated rats, Hsp73 was over-expressed by about 50% whereas Hsp72 was down-regulated by 50-80%. No such effects were observed in liver and testis. In liver and kidney of vanadium-treated rats, Grp94 was over-expressed by 50% and 150% respectively whereas no change was found in testis. In rats given green tea as sole beverage, the 96 kDa protein expression level in liver was reduced both in controls and in vanadium-treated animals. However, green tea drinking failed to prevent the vanadium-induced Hsp72 under-expression in kidney of vanadium-treated rats.

Animals↗
PubMed1989

Possible contribution of green tea drinking habits to the prevention of stroke.

Among 5910 nondrinking and nonsmoking women (of greater than or equal to 40 years of age) in a prefectural city of Sendai, and two villages of Taijiri and Wakuya in Miyagi prefecture, Japan, medical history of stroke was less frequently observed among those who took more green tea in daily life. No relation with tea drinking was observed for hypertension history. The uneven distribution of stroke history was detectable even after the effects of age, location of residence, and high salt intake were ruled out. The incidence of stroke and cerebral hemorrhage during a 4-year follow-up of the study population was twice or more times higher in those who took less green tea (less than 5 cups a day) than in those who took more (greater than or equal to 5 cups daily).

Adult↗
PubMed2004

HTLV-1 provirus load in peripheral blood lymphocytes of HTLV-1 carriers is diminished by green tea drinking.

Human T-cell lymphotropic virus type 1 (HTLV-1) is causatively associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Since a high level of HTLV-1 provirus load in circulating lymphocytes is thought to be a risk for ATL and HAM/TSP, diminution of HTLV-1 provirus load in the circulation may prevent these intractable diseases. Our previous study (Jpn J Cancer Res 2000; 91: 34-40) demonstrated that green tea polyphenols inhibit in vitro growth of ATL cells, as well as HTLV-1-infected T-cells. The present study aimed to investigate the in vivo effect of green tea polyphenols on HTLV-1 provirus load in peripheral blood lymphocytes on HTLV-1 carriers. We recruited 83 asymptomatic HTLV-1 carriers to examine HTLV-1 provirus DNA with or without administration of capsulated green tea extract powder. Thirty-seven subjects were followed up for 5 months by measuring HTLV-1 provirus load after daily intake of 9 capsules of green tea extract powder per day (equivalent to 10 cups of regular green tea), and 46 subjects lived ad libitum without intake of any green tea capsule. The real-time PCR quantification of HTLV-1 DNA revealed a wide range of variation of HTLV-1 provirus load among asymptomatic HTLV-1 carriers (0.2-200.2 copies of HTLV-1 provirus load per 1000 peripheral blood lymphocytes). Daily intake of the capsulated green tea for 5 months significantly diminished the HTLV-1 provirus load as compared with the controls (P = 0.031). These results suggest that green tea drinking suppresses proliferation of HTLV-1-infected lymphocytes in vivo.

Administration, Oral↗
PubMed2003

Catalytic spectrophotometric determination of ascorbic acid in tea drink with 1,5-bis(p-hydroxybenzaldene)thiocarbohydrazone as the substrate for horseradish peroxidase.

1,5-bis(p-Hydroxybenzaldene)thiocarbohydrazone (BHBTZ) had been synthesized and used as a new kind of substrate for horseradish peroxidase (HRP). The experiment results showed that ascorbic acid (AsA) had strongly inhibiting effect on the BHBTZ-H(2)O(2)-HRP reaction system, so AsA had been spectrophotomericly determined as the inhibitor by enzymatic inhibition method. Under experimental conditions, the linear relationship between DeltaA(386) and AsA concentration was in the range of 0.82-18.0 microg ml(-1) with a detection limit of 0.245 microg ml(-1). The effect of interferences on AsA determination was investigated. The proposed method was successfully applied to the determination of AsA in tea drink.

Ascorbic Acid↗
PubMed2001

Change in the flavor of black tea drink during heat processing.

Heat processing during canning is responsible for the change in flavor of black tea infusion. The quantitative change in the volatile components of the black tea infusion during heat processing is not sufficient for explaining the sensory evaluation. In this study, application of aroma extract dilution analysis using the volatile fraction before and after black tea (Darjeeling) samples were heat processed resulted in the detection of 10 odor-active peaks for which flavor dilution (FD) factors changed. Seven potent odorants were identified from these peaks by gas chromatography-mass spectrometry. Among these components, 3-methylbutanal (stimulus), methional (potato-like), beta-damascenone (sweet), dimethyl trisulfide (putrid), and 2-methoxy-4-vinylphenol (clove-like) showed the highest FD factors after heat processing of the black tea sample. Therefore, these odorants were the most important components involved in changing the black tea odor during heat processing. In addition, the precursor of beta-damascenone in black tea infusion was investigated, and 3-hydroxy-7,8-didehydro-beta-ionol was determined to be one of the beta-damascenone-generating compounds for the first time.

Food Packaging↗
PubMed2005

[China-home of the tea drinking custom].

This paper summarizes how Gambir entered China. While the author attempts to explain how Gambir was replaced by tea in the area, there still appear to be many missing links, to which the author would like to welcome constructive criticism. Lao-cai on the China-Vietnam border, where Acacia pads were produced up to the 16th century, can be read as Rakuju . A tribe that belongs to Hani in northern Laos also consumes these Acacia pads. It was Li Jichin who called tea Lau-nu. This was based on a historical fact that Oh Shuku pointed out to Emperor Kobun in the 5th century in Northern Wei that calling tea a slave of lactic products could not be considered appropriate.

Beverages↗