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PubMed1999

Tea consumption: fluid intake and bladder cancer risk in Southern Taiwan.

OBJECTIVES: To determine whether tea consumption and intake of other beverages increases bladder cancer risk. METHODS: A case-control study was conducted in Kaohsiung, Taiwan between August 1996 and June 1997. Index patients studied were consecutive patients with histologically confirmed, newly diagnosed bladder cancer in two major hospitals. For each patient, 4 controls were selected from patients with non-neoplastic and nonurologic diseases undergoing surgical operations in the same hospital and individually matched by sex, age, and date of admission. Using a structured questionnaire, a trained interviewer interviewed 40 patients and 160 controls. Conditional logistic regression analysis adjusting for ethnicity, family history, and smoking status and matching variables were used to estimate the odds ratio (OR) and 95% confidence interval (CI). RESULTS: Tea consumption overall was associated with increased bladder cancer risk (OR 3.29, 95% CI 1.34 to 8.05). Compared with non-tea drinkers, the odds ratios of bladder cancer for oolong tea drinkers was 3.00 (95% CI 1.20 to 7.47); for non-oolong tea drinkers (black and/or other green tea), it was 14.86 (95% CI 2.13 to 103.83). The risk was greater among those who began to drink tea before age 40 (OR 9.50, 95% CI 2.39 to 37.75) and those who had been drinking tea for more than 30 years (OR 17.75, 95% CI 3.00 to 105.17). Coffee, tap water, and alcohol consumption were associated with a slightly increased risk, and both soy juice and rice juice consumption were associated with reduced risk; none of these odds ratio estimates were statistically significant, however. CONCLUSIONS: Our results suggest that tea consumption is associated with an increased risk of bladder cancer.

Aged↗
PubMedDate not supplied

[The Tuaregs addiction to tea, to smokeless tobacco and to milk: ethnological and clinical approach].

Some rituals about a regular consumption of tea, smokeless tobacco (chewing) and milk are described by one of the authors at the time of his anthropological investigation among the Tuaregs of Timbuktu's region (Mali). He carries out some ethnographical and clinical materials which highlight the dependence to these substances and the role of their psychostimulant and anorexigene effects in a society much ritualised. The subject of this article appears original in the literature which approaches more the dependence to coffee than tea, to cigarettes than to chewing tobacco. The observation of daily life of a tuareg encampment shows a ritual consumption of tea at four time a day. The motivations of the Tuaregs are the increase of vigilance and performance with that psychostimulant substance. They describe an intoxication syndrome related to caffeineism, observed among European tourists. The Tuaregs are aware of their addiction to tea and distinguish psychological dependence from physical dependence. The psychological dependence corresponds to a powerful desire to drink tea at ritual moments, while the physical dependence appears at waking-up and when the time of preparing this beverage is too late. The Tuaregs describe also a phenomenon of loss tolerance after an abstinence period. In spite of the maraboutic prohibition to drink tea, which diverts Tuaregs of their religious practice, they defy this ban from the waking-up to take that infusion before the matinal prayer. That addiction appears also in the identity of the Tuaregs who are called "the sons of tea". The consumption of chewing tobacco, mixed with ash, rhythms the daily life. The mean number of chewing is about fifteen by day; every chewing last 30 minutes. The first chewing of the day occurs 15 minutes after waking-up. The Tuaregs use tobacco in order to get relaxation and vigilance. They suggest intoxication symptoms and especially a withdrawal syndrome which appears at the waking-up or after an important interval between chewing. The authors raise the idea about the dependence to this type of tobacco, consistent with the Anglo-Saxon literature of the 80th which tried to implement scales and criteria as to assess the dependence to smokeless tobacco. The Tuaregs could be more addicted than American consumers in regard to american studies: they use more chewing a day and they can't refrain from chewing at the waking-up. Empirical addition of plant ash, made up of hydroxide of calcium, may act a role in pharmacokinetic by alkalinising the pH. It could increase the absorption of nicotine through the mouth mucus membrane. The authors raise the idea about the dependence to the milk, much consumed and ritualised among those nomadic breeders. They rely on the observation of a withdrawal syndrome clearly identified in the tuareg medical nosography. These regular consumptions integrate the daily life within other rituals. Tea and tobacco facilitate certain motor stimulation, a struggle against hunger and some relaxation regarding an hostile environment over climatological, ecological and economical plan. The brutal and unexpected occurring of one of those rituals disrupt, indeed invert, the usual order of social rituals. Those social and religious disruptions materialise the pathological effect of that double dependence to nicotine and caffeine. That one is called by a term which translate its subjective and social appearance, reflecting so the interaction between man, environment and psychoactive substance. This article highlight the importance of cultural factors in the etiopathogeny of poly-dependence among Tuareg subjects. The question about the diagnostic of the dependence in the DSM IV and the CIM-10 is raised. The DSM IV could be completed because it doesn't evoke addiction to caffeine of tea such like it is consumed in West actually. That hermeneutic approach, including anthropological observations and clinical investigations, allow to understand that addiction to psychoactive substances among Tuareg subjects is consistent with their survival in hostile environments.

Adult↗
PubMed2006

Beneficial effects of tea and its polyphenols against prostate cancer.

Tea, next to water, is the most widely consumed beverage in the world. Depending upon the level of fermentation, tea can be categorized into three types: green (unfermented), oolong (partially fermented), and black (highly to fully fermented). In general, green tea has been found to be superior to black and oolong tea in terms of antioxidant and health promoting benefits owing to the higher content of (-)-epigallocatechin-3-gallate. Tea polyphenols comprise about one-third of the weight of the dried leaf, and they exhibit biochemical and pharmacological activities including antioxidant activities, inhibition of cell proliferation, induction of apoptosis, cell cycle arrest and modulation of carcinogen metabolism. Several studies demonstrate that most tea polyphenols exert their effects by scavenging reactive oxygen species (ROS) since excessive production of ROS has been implicated in the development of a variety of ailments including cancer of the prostate gland (CaP). Using cell culture and animal model systems, molecular targets for these remarkable beneficial effects of green tea drinking on CaP prevention and therapy have been defined. Geographical and case-control studies are showing that green tea drinking could afford CaP chemopreventive effects in human population. In this review we attempt to summarize the experimental as well as the epidemiological basis for the possible role of tea and its polyphenols for chemoprevention and chemotherapy of CaP.

Androgens↗
PubMed1996

Tea and cancer: a review of the epidemiological evidence.

Numerous recent reports of inhibition of carcinogenesis in experimental animals by tea or tea compounds raise the possibility that tea drinking may lower cancer risk in humans. Thus, studies around the world were reviewed to evaluate whether there is a consensus of epidemiologic evidence on the relation of tea drinking to cancer overall or to specific cancers. Ecological data suggest at most a modest benefit, since there is considerable international variation in tea consumption but generally small differences in cancer rates. More relevant case-control and cohort studies show mixed results. Detailed data from these studies on cancer risks according to amount and duration of tea intake are quite limited, and consistent dose-related patterns. have yet to emerge. Nevertheless, several investigations point to the possibility of lowered risks of digestive tract cancers among tea drinkers, especially those consuming green tea. Further research, particularly in population with wide ranges of tea consumption, is needed before definitive conclusions on tea's impact upon cancer risk can be reached.

Case-Control Studies↗
PubMed2003

[A case-control study on the risk factors of leukemia in mining areas of rare-earth in South Jiangxi].

OBJECTIVE: In order to explore the correlation on radioactive contamination of lanthanon to leukemia, and provide clues for the causes and prevention of leukemia in mining areas of rare-earth elements. METHODS: 1:1 matched case-control study was used. A total of 51 clinically confirmed leukemia cases, individually matched with controls from general population, were interviewed in mining areas of rare-earth in South Jiangxi from November to December, 2001. Data were analyzed, using conditional logistic regression. RESULTS: The main risk factors would include frequently drinking water from river (OR = 5.543), distance from residence to rare-earth mine and years for living in the area (OR = 3.308), exposure to organophosphorus pesticide (OR = 3.014). Tea drinking habit appeared to be a protective factor. CONCLUSIONS: Leukemia seemed to be related to environmental pollution with rare-earth elements around the residential areas and organophosphorus pesticide exposure. The protective factor of tea drinking habit seemed to be unique in this study, which called for further studies.

Adolescent↗
PubMed2003

[Interactions between lifestyle, methylanetetrahydrofolate reductase gene and polymorphisms in thymidylate synthase gene with risk of stomach cancer].

OBJECTIVE: To evaluate interactions between lifestyle, methylanetetrahydrofolate reductase gene (MTHFR) and polymorphisms in the 3'-untranslated region (3'-UTR) of the thymidylate synthase gene (TS) with reference to development of stomach cancer (SC). METHODS: We conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. TS genotypes were identified by polymerase chain reaction. RESULTS: (1) The frequencies of TS genotypes (+6 bp/+6 bp, +6 bp/-6 bp and -6 bp/-6 bp) among the cases were 5.6%, 47.7% and 46.7% and among the controls were 9.0%, 54.0% and 37.0%, respectively. Individuals identified as -6 bp/-6 bp genotype had a slightly higher risk for SC than those individuals with +6 bp alleles (the crude OR = 1.49, 95% CI: 0.90 - 2.47; adjusted OR = 1.36, 95% CI: 1.00 - 1.78, P = 0.047). (2) Individuals having TS -6 bp/-6 bp genotype and having smoking habit were at a significantly higher risk of developing SC (adjusted OR = 2.79, 95% CI: 1.51 - 5.18) compared with those who had +6 bp alleles with no smoking habit. Individuals having TS -6 bp/-6 bp genotype and habit of frequent alcohol drinking were at an increased risk of developing SC (adjusted OR = 1.76, 95% CI: 1.07 - 2.90) compared with those with +6 bp alleles and low consumption of alcohol. As compared with individuals with +6 bp alleles and who had habit of tea drinking, individuals who had TS -6 bp/-6 bp genotype and but without habit of tea drinking had an increased risk of developing SC (adjusted OR = 2.34, 95% CI: 1.43 - 3.82). (3) Individuals with TS -6 bp/-6 bp genotype and with MTHFR T alleles had an increased risk of developing SC (adjusted OR = 2.67, 95% CI: 1.07 - 6.70) compared with those with +6 bp alleles and with MTHRF C/C genotype. CONCLUSION: Results in the present study suggested that there was a combined effect between lifestyle, MTHFR C/T or T/T genotype and TS -6 bp/-6 bp genotype in the development of SC.

Alcohol Drinking↗
PubMed2005

[Green tea consumption and the risk of endometrial cancer: a population-based case-control study in urban Shanghai].

OBJECTIVE: To assess the effect of tea consumption on the risk of endometrial cancer. METHODS: In a population based case-control study conducted in urban Shanghai, face-to-face interviews were completed for 995 incidence cases aged 30 - 69 from January 1997 to December 2002 and 1087 controls that frequency-matched to cases on age. Unconditional logistic model was used for analysis. RESULTS: An inverse association was observed in tea drinking and endometrial cancer risk. Compared to non-tea drinkers, regular tea drinkers had reduced risk of endometrial cancer (OR = 0.74; 95% CI: 0.54 - 1.01) in premenopausal women. Green tea had a protective effect on endometrial cancer among non-smoking or non-alcohol drinking women (OR = 0.77, P = 0.0199) and the ORs reduced with the increasing concentration of tea being served (P for trend = 0.0493). The multivariate ORs for drinking green tea < 7 times/week and >or= 7 times/week were 0.90 (95% CI: 0.53 - 1.54) and 0.76 (95% CI: 0.60 - 0.95) with the trend test of P = 0.0163. CONCLUSION: Tea drinking, with green tea in particurlar, seemed to have weak but inverse association with endometrial cancer risk, but this effect of protection might only limit to premenopausal women.

Adult↗
PubMed1997

Green tea consumption and the risk of pancreatic and colorectal cancers.

The effect of green tea drinking in reducing human cancer risk is unclear, though a protective effect has been reported in numerous animal studies and several epidemiologic investigations. Herein the hypothesis that green tea consumption may reduce the risk of cancers of the colon, rectum and pancreas is examined in a large population-based case-control study conducted in Shanghai, China. Newly diagnosed cancer cases (931 colon, 884 rectum and 451 pancreas) during 1990-1993 among residents 30-74 years of age were included. Controls (n = 1,552) were selected among Shanghai residents and frequency-matched to cases by gender and age. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of each cancer associated with green tea consumption were derived after adjustment for age, income, education and cigarette smoking. Additional adjustment for dietary items and body size was found to have minimal impact. An inverse association with each cancer was observed with increasing amount of green tea consumption, with the strongest trends for rectal and pancreatic cancers. For men, compared with non-regular tea drinkers, ORs among those in the highest tea consumption category (> or = 300 g/month) were 0.82 for colon cancer, 0.72 for rectal cancer and 0.63 for pancreatic cancer, with p values for trend being 0.38, 0.04 and 0.04, respectively. For women, the respective ORs for the highest consumption category (> or = 200 g/month) were 0.67, 0.57 and 0.53, with the respective p values for trend being 0.07, 0.001 and 0.008. Our findings provide further evidence that green tea drinking may lower the risk of colorectal and pancreatic cancers.

Adult↗
PubMed2006

Drinking of Salvia officinalis tea increases CCl(4)-induced hepatotoxicity in mice.

In a previous study, the drinking of a Salvia officinalis tea (prepared as an infusion) for 14 days improved liver antioxidant status in mice and rats where, among other factors, an enhancement of glutathione-S-transferase (GST) activity was observed. Taking in consideration these effects, in the present study the potential protective effects of sage tea drinking against a situation of hepatotoxicity due to free radical formation, such as that caused by carbon tetrachloride (CCl(4)), were evaluated in mice of both genders. Contrary to what was expected, sage tea drinking significantly increased the CCl(4)-induced liver injury, as seen by increased plasma transaminase levels and histology liver damage. In accordance with the previous study, sage tea drinking enhanced significantly GST activity. Additionally, glutathione peroxidase was also significantly increased by sage tea drinking. Since CCl(4) toxicity results from its bioactivation mainly by cytochrome P450 (CYP) 2E1, the expression level of this protein was measured by Western Blot. An increase in CYP 2E1 protein was observed which may explain, at least in part, the potentiation of CCl(4)-induced hepatotoxicity conferred by sage tea drinking. The CCl(4)-induced hepatotoxicity was higher in females than males. In conclusion, our results indicate that, although sage tea did not have toxic effects of its own, herb-drug interactions are possible and may affect the efficacy and safety of concurrent medical therapy with drugs that are metabolized by phase I enzymes.

Animals↗
PubMed1985

Coffee, tea, and plasma cholesterol: the Jerusalem Lipid Research Clinic prevalence study.

The association of intake of coffee and tea, assessed by 24 hour dietary recall, with plasma cholesterol and its lipoprotein fractions was studied in a sample of 1007 men and 589 women aged 35-64 resident in Jerusalem. These cross sectional data showed a significant linear association (p less than 0.001) between consumption of coffee in men and plasma cholesterol and low density lipoprotein cholesterol concentrations. Men who drank five cups of coffee or more had plasma cholesterol concentrations about 0.5 mmol/l (20 mg/100 ml) higher than non-drinkers after controlling for age, ethnicity, body mass, education, season of year, smoking, tea drinking, and dietary intake of fat and carbohydrates. In women adjusted mean plasma cholesterol concentration was 0.34 mmol/l (13 mg/100 ml) higher in coffee drinkers grouped together (p less than 0.01). The test for a linear trend was not significant. The association in both sexes was largely with the low density lipoprotein cholesterol fraction. High density lipoprotein cholesterol concentrations were somewhat increased in women who drank coffee (p less than 0.01 for a linear trend) but not in men. Tea drinking was not associated with unadjusted plasma cholesterol concentrations in either sex. Male tea drinkers, but not female, had slightly higher adjusted plasma cholesterol concentrations than non-drinkers (0.15 mmol/l (6 mg/100 ml), p = 0.04). No dose response relation was evident. In this population, characterised by a low intake of saturated fatty acids and relatively low mean plasma cholesterol concentrations, coffee drinking may be a determinant of low density lipoprotein cholesterol concentrations.

Adult↗
PubMed1994

Reduced risk of esophageal cancer associated with green tea consumption.

BACKGROUND: Studies in laboratory animals have suggested inhibitory effects of green tea on the induction of some cancers, notably, esophageal cancer. However, only a few epidemiologic studies have evaluated green tea as a potential inhibitor of human esophageal cancer. PURPOSE: Our purpose was to evaluate the relationship between green tea consumption and the risk of esophageal cancer. METHODS: This esophageal cancer study was part of a larger multicenter, case-control study that included three other gastrointestinal sites (pancreas, colon, and rectum). Medical records of patients aged 30-74 years old who were diagnosed with esophageal cancer from October 1, 1990, through January 31, 1993, were identified from the Shanghai Cancer Registry, which covers 6.8 million people in the urban area of Shanghai, People's Republic of China. During the ascertainment period, records of 1016 eligible cases of esophageal cancer were identified. Control subject records were selected by frequency matching in accordance with the age-sex distribution of the four gastrointestinal cancers ascertained by the cancer registry during 1986-1987. Patient interviews were then conducted using a structured, standardized questionnaire to obtain information on demographic characteristics, residential history, height and weight, diet, smoking, alcohol and tea drinking, medical history, family history of cancer, occupation, physical activity, and reproductive history. RESULTS: Of the 902 patients interviewed, 734 (81.4%) had their disease pathologically confirmed. There were 1552 control subjects interviewed, including 240 alternates. All analyses of tea effects were conducted separately among men and women and all were adjusted for age. After further adjustment for other known confounders, a protective effect of green tea drinking on esophageal cancer was observed among women (odds ratio [OR] = 0.50; 95% confidence interval [CI] = 0.30-0.83), and this risk decreased (P for trend < or = .01) as tea consumption increased. Among men, the ORs were also below 1.00, although not statistically significant. ORs for green tea intake were estimated among those persons who neither smoked nor drank alcohol. In this subset, statistically significant decreases in risk among tea drinkers were observed for both men (OR = 0.43; 95% CI = 0.22-0.86; P for trend = .05) and women (OR = 0.40; 95% CI = 0.20-0.77; P for trend < .001). CONCLUSIONS: This population-based, case-control study of esophageal cancer in urban Shanghai suggests a protective effect of green tea consumption. Although these findings are consistent with studies in laboratory animals, indicating that green tea can inhibit esophageal carcinogenesis, further investigations are definitely needed.

Adult↗
PubMed1998

Influence of drinking green tea on breast cancer malignancy among Japanese patients.

Inhibitory effects of green tea on carcinogenesis have been investigated in numerous laboratory studies using (-)-epigallocatechin gallate (EGCG) or crude green tea extract, and there is also some epidemiologic evidence. Further, EGCG has been reported to inhibit the growth of cancer cells, lung metastasis in an animal model, and urokinase activity. In this study, we first examined the association between consumption of green tea prior to clinical cancer onset and various clinical parameters assessed at surgery among 472 patients with stage I, II, and III breast cancer. We found that increased consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal patients with stage I and II breast cancer and with increased expression of progesterone receptor (PgR) and estrogen receptor (ER) among postmenopausal ones. Since these are potential prognostic factors, we then investigated the prognosis of breast cancer with special reference to consumption of green tea, in a follow-up study of these patients. We found that increased consumption of green tea was correlated with decreased recurrence of stage I and II breast cancer (P < 0.05 for crude disease-free survival); the recurrence rate was 16.7 or 24.3% among those consuming > or = 5 cups or < or = 4 cups per day, respectively, in a seven-year follow-up of stage I and II breast cancer, and the relative risk of recurrence was 0.564 (95% confidence interval, 0.350-0.911) after adjustment for other lifestyle factors. However, no improvement in prognosis was observed in stage III breast cancer. Our results indicate that increased consumption of green tea prior to clinical cancer onset is significantly associated with improved prognosis of stage I and II breast cancer, and this association may be related to a modifying effect of green tea on the clinical characteristics of the cancer.

Adult↗
PubMed1995

Inhibition of oncogene expression by green tea and (-)-epigallocatechin gallate in mice.

The effects of tea drinking on the tobacco-specific nitrosamine 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK)-induced mouse lung oncogene expression and the effect of topical application of the tea polyphenol component (-)-epigallocatechin-3-gallate (EGCG) on 12-O-tedradecanoylphorbol-13-acetate (TPA)-induced mouse skin oncogene expression were investigated. In the first experiment, mice were treated with NNK (1.3 mg/kg body wt ip) once a day for three days and were given 2% tea in drinking water during the whole experimental period. After four or eight weeks, the lung tissue of the mice treated with NNK displayed a significantly high level of expression in c-myc, c-raf, and c-H-ras oncogenes, and they were all inhibited by tea drinking with inhibitory rates of 50%, 20%, and 50%, respectively. In the second experiment, a single application of 10 nmol of TPA to mouse skin led to a marked increase in the transcripts' level of ornithine decarboxylase (ODC) gene, protein kinase C (PKC) gene, and c-myc oncogene at four hours after TPA administration. Topical application of EGCG (1 or 5 mumol) one hour before the application of TPA inhibited all TPA-induced gene expression in a dose-dependent fashion. These results confirm the anticarcinogenic effects of tea and suggest that a possible mechanism is the effect of tea on carcinogen-induced oncogene expression.

Animals↗
PubMed2000

Time for abstention from caffeine before an adenosine myocardial perfusion scan.

Seventy patients undergoing adenosine myocardial perfusion scintigraphy were studied. All patients reported abstention from products containing caffeine in the 12 h prior to the test. Blood samples were drawn prior to initiation of the stress test, and serum caffeine levels were determined using high-performance liquid chromatography. All patients were also asked about their coffee and tea drinking habits. Seventy-four percent of patients had measurable serum caffeine levels (n = 52) ranging from 0.1 to 8.8 mg.l-1. Results were correlated with maximum pulse rate, systolic and diastolic blood pressure changes and clinical symptoms during the test. There was no correlation between coffee or tea drinking habits and serum caffeine levels. A serum caffeine level of 2.9 mg.l-1 was considered a cut-off point for comparing patients. No significant difference was seen in mean maximum change of pulse rate, systolic and diastolic blood pressure between patients with serum caffeine levels > or = 2.9 mg.l-1 and those with lower serum caffeine levels. Of eight patients with serum caffeine levels > or = 2.9 mg.l-1, six had no symptoms (75%). When patients were classified as patients with no symptoms or patients with symptoms (mild, moderate or severe), a significant difference was demonstrated between patients with serum caffeine levels > or = 2.9 mg.l-1 and those with lower levels. This suggests 12 h abstention from caffeine may be insufficient. Whether this translates into false-negative perfusion scans should be the subject of a larger study.

Adenosine↗
PubMed2004

[A case-control study on the polymorphisms of methylenetetrahydrofolate reductase 1298A-->C and susceptibility of esophageal cancer].

OBJECTIVE: To investigate the relationship between polymorphisms of methylenetetra-hydrofolate reductase gene 1298A-->C (MTHFR 1298A-->C) and its susceptibility of esophageal cancer (EC). METHODS: We conducted a case-control study with 141 cases of EC and 228 population-based controls in Huaian city of Jiangsu province, China. Epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects. MTHFR genotypes were identified by polymerase chain reaction. RESULTS: (1) The frequency of MTHFR 1298AA, AC and CC genotype were 63.8%, 34.0% and 2.1% in EC and 71.9%, 28.1% and 0.0% in controls, respectively (chi(2)(MH) = 6.69, P = 0.035). The frequency of the MTHFR 1298C allele was 0.19 for EC and 0.14 for controls. (2) Individuals having MTHFR 1298C allele and smoking habit were at a significantly higher risk of developing EC (adjusted OR = 3.48, 95% CI: 1.57 - 7.71) compared with those who having AA genotype but no smoking habit. Individuals having MTHFR 1298C allele and habit of frequent alcohol drinking were at an increased risk of developing EC (adjusted OR = 2.91, 95% CI: 1.20 - 7.08) compared with those with AA genotype and low consumption of alcohol. Individuals having MTHFR 1298C allele but no habit of tea drinking had a 3.52-fold (95% CI: 1.64 - 7.54) increased risk of developing EC compared with tea drinkers with AA genotype. As compared with subjects having AA genotype, low consumption of alcohol, no smoking habit but having habit of drinking tea, the individuals having 1298C allele, habits of frequent alcohol drinking, smoking but no habit of tea drinking had a 12.64-folds (95% CI: 1.39 - 114.65) increased risk of developing EC. CONCLUSION: Results in the present study suggested that there was a coordinated effect between MTHFR 1298 genotypes and habits of smoking, alcohol drinking and tea consumption in the development of EC.

Adult↗
PubMedDate not supplied

Inhibition of xanthine oxidase by catechins from tea (Camellia sinensis).

Some epidemiological studies have associated tea drinking with several health benefits, while other such studies have been inconclusive. The liver enzyme, xanthine oxidase (XO) produces uric acid and reactive oxygen species (ROS) during the catabolism of purines. Excess of the former can lead to gout and of the latter to increased oxidative stress, mutagenesis and possibly cancer. Polyphenols are antioxidants, and it has been suggested that they can reduce oxidative stress by their antioxidant properties. We report here on the inhibition of XO by five tea catechins and two flavones. The Ki values (microM) and types of inhibition were catechin (C) (Ki = 303.95, uncompetitive), epicatechin (EC) (Ki = 20.48, mixed), epigallocatechin (EGC) (Ki = 10.66, mixed), epicatechin gallate (ECg) (Ki = 2.86, mixed) and epigallocatechin gallate (EGCg) (Ki = 0.76, competitive). The Ki of EGCg was similar to that of allopurinol (Ki = 0.30, mixed), the drug of choice for inhibition of XO in gout patients. Thus, tea catechins may act at.an earlier stage than has previously been suspected, by inhibiting ROS production, rather than only neutralizing the already formed ROS. This suggests a new mechanism whereby tea drinking may prevent oxidative stress related diseases, e.g. atherosclerosis and cancer.

Antineoplastic Agents↗
PubMed2003

Oral hygiene practices, smoking habit, and self-perceived oral malodor among dental students.

The aims of this study were to determine the prevalence of oral hygiene practices and halitosis among undergraduate students from King Saud University, College of Dentistry. A self-administered questionnaire was distributed among all 481 students; 263 male and 218 female students. A questionnaire was developed to assess the self-reported perception of oral breath, awareness of bad breath, timing of bad breath, treatment received for bad breath, oral hygiene practices, caries and bleeding gums, dryness of the mouth, smoking and tea drinking habits, and tongue coating. The response rate was 77%. Forty four percent of male and 32% of female students reported the self-perception of breath odor. Self-treatment was sought by 12% male and 22% female. Six percent of males and 4% of females experienced bad breath interference at their work. Seventy-eight percent of male and 62% of female students experienced bad breath after waking up. Brushing was prevalent among 81% of male and 99% of female students. Both miswak (chewing sticks) and tooth brushing were used by 53% male and 83% female students. Fifty seven percent of male students and 44% of female students reported caries. Bleeding gingiva was experienced by 26% of males and 14% of females. Dry mouth was common among 14% of males and 17% of females, while smoking was prevalent among 13% of males and 2% of females. Tea drinking was common among 44% of males and 37% of females, while tongue coating was equally common among both males and females (21% and 20%), respectively. The results indicate female students had better oral hygiene practices, significantly less self-reported oral bad breath, and smoked less compared to male students. There was no difference in tongue coating among male and female students. Further research is needed to examine oral malodor clinically and objectively by the standard procedures available. Students should be motivated to be a health symbol and keeping their mouths free from oral malodor.

Adult↗
PubMed1989

Khat chewing spread to the Somali community in Rome.

The habit of chewing Khat (Catha edulis) to experience its euphorizing and psychostimulant effects has prevailed for centuries among the inhabitants of the Horn of Africa and the Arabian peninsula. In recent years, air transport has removed the major obstacle to the diffusion of Khat, its perishableness. Khat is now air-freighted to Europe and we were able to buy some in Rome. We report the results of interviews with 20 members of the Somali community in Rome, who had continued their habit of chewing Khat whilst abroad. They asserted that they gathered together whenever possible, but preferably at weekends, to chew moderate quantities of Khat (one bundle, about 400 g). The customary habit of drinking tea or other soft drinks containing methylxantines during Khat sessions was maintained and very few subjects admitted drinking alcohol. In this small study sample, Khat chewing still seems to be a social event, as it is in Somalia.

Catha↗