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PubMed2006

Smoking, alcohol drinking, green tea consumption and the risk of esophageal cancer in Japanese men.

BACKGROUND: Although smoking and alcohol drinking are established risk factors of esophageal cancer, their public health impact is unclear. Furthermore, the effect of green tea is controversial. METHODS: The present study was based on a pooled analysis of two prospective cohort studies. A self-administered questionnaire about health habits was distributed to 9,008 men in Cohort 1 and 17,715 men in Cohort 2, aged 40 years or older, with no previous history of cancer. We identified 38 and 40 patient cases with esophageal cancer among the subjects in Cohort 1 (9.0 years of follow-up) and Cohort 2 (7.6 years of follow-up), respectively. Cox proportional hazards regression was used to estimate hazard ratios (HRs) of the risk of esophageal cancer incidence. RESULTS: Cigarette smoking, alcohol drinking and green tea consumption were significantly associated with an increased risk of esophageal cancer. Compared with men who had never smoked, never drunk alcohol or green tea, the pooled multivariate HRs (95% confidence intervals) were 5.09 (1.80-14.40) (p for trend <0.0001), 2.73 (1.55-4.81) (p for trend=0.0002), or 1.67 (0.89-3.16) (P for trend=0.04) for men who were currently smoking > or =20 cigarettes/day, drinking alcohol daily, or drinking > or =5 cups green tea/day, respectively. The population attributable fractions of esophageal cancer incidence that was attributable to smoking, alcohol drinking and green tea consumption were 72.0%, 48.6%, and 22.1%, respectively. CONCLUSIONS: Among the variables studied, smoking has the largest public health impact on esophageal cancer incidence in Japanese men, followed by alcohol drinking and green tea drinking.

Adult↗
PubMed1981

Comparison of the bisbiguanide antiseptics alexidine and chlorhexidine. II. Clinical and in vitro staining properties.

A blind cross-over trial was carried out to compare the tooth and tongue staining associated with the use of a 0.035% alexidine and a 0.2% chlorhexidine mouthrinse. Twenty-two volunteers were divided into two groups termed "tea drinkers" and "non-tea drinkers". All volunteers were requested to refrain from oral hygiene measures throughout two 10-day periods when they rinsed twice a day with the preparation randomly allocated for the respective period. During both periods the members of the groups excluded coffee, red wine and port from their diet. The tea drinking group consumed seven cups of tea per day. Tooth and tongue staining was recorded for extent and severity at the end of each period. The amount of stain accumulating in the two groups was similar following the use of chlorhexidine and alexidine. However, for both chlorhexidine and alexidine the extent and severity of tooth and tongue staining were significantly increased in the tea drinking group. An in vitro study of tea staining of perspex blocks exposed twice a day to 0.035% solutions of alexidine or chlorhexidine throughout a 5-day period demonstrated significantly more staining with alexidine when measured spectrophotometrically. Visually however, the differences in the specimens were minimal. Saliva treatment of the perspex did not significantly alter the staining by alexidine or chlorhexidine. The results provide further evidence for a dietary aetiology to the staining associated with cationic antiseptics. However, alexidine at the concentration used offered no advantage in reducing the side effect of staining when compared with chlorhexidine.

Biguanides↗
PubMed1997

[The method to remove nitrite from tap water by tea].

Drinking water (tap water) is polluted in pipelines by bacteria after long distance transportation. The water contains nitrite (NO2-) which is potentially harmful to human health. The nitrite concentrations range from 0.10 to 2.0 mg/L. Our experiment proved that NO2- could not be removed by boiling, but could be removed by tea. As a natural antioxidant, tea contains several antioxidants, such as ascorbic acid and catechins, which removed NO2- from tap water effectively.

Antioxidants↗
PubMed1997

Tea and cancer prevention: an evaluation of the epidemiologic literature.

Animal and in vitro studies provide evidence of an anticarcinogenic potential of active ingredients in teas. This review encompasses epidemiologic studies of stomach, colon, and lung cancer as well as the evidence of a relationship between tea drinking and cancer at large in humans. Cohort studies do not suggest a protective role for tea drinking in the total risk of cancer. Site-specific studies reveal a more complex picture. The epidemiologic studies on tea drinking and stomach cancer do not justify claims of a cancer-protective effect. A protective effect of green tea on the development of colon cancer is suggested. The evidence regarding black tea is less clear, with some indication of a risk of colon or rectal cancer associated with regular use of black tea. The studies on tea and lung cancer also suggest an increased risk with increased tea consumption. The range and crude categorization of tea consumption, choice of control groups, and inadequate control for confounding might have obscured possible relationships. From the limited studies that suggest a favorable effect from tea, it is likely that benefits are restricted to high intakes in high-risk populations.

Antineoplastic Agents↗
PubMed2002

Effect of drinking green tea on age-associated accumulation of Maillard-type fluorescence and carbonyl groups in rat aortic and skin collagen.

Tea catechins and other flavonoids have been shown to potentially protect against chronic cardiovascular diseases such as coronary heart disease and atherosclerosis. In this study, 6-month-old female Sprague-Dawley rats were fed green tea extract (50 mg/100 ml in drinking water) up to the age of 22 months, and the age-associated changes in Maillard-type fluorescence and carbonyl groups in the aortic and skin collagen were compared with those occurring in the water-fed control animals. Collagen-linked Maillard-type fluorescence was found to increase in both the aortic and skin tissues as animals aged. The age-associated increase in the fluorescence in the aortic collagen was remarkably inhibited by the green tea extract treatment, while that occurring in the skin collagen was not significantly inhibited by the treatment. The collagen carbonyl content also increased in both the aortic and skin tissues as animals aged. In contrast with the case of Maillard-type fluorescence, however, the age-associated increase in the carbonyl content was not inhibited by the green tea extract treatment either in the aortic or skin collagen. These results suggest that the inhibition of AGE formation in collagen is an important mechanism for the protective effects of tea catechins against cardiovascular diseases.

Aging↗
PubMed2000

[Staining of complete denture: a preliminary clinical study]

OBJECTIVE:To study the relation between staining of complete denture and drinking tea, coffee and smoking, and to evaluate the result of denture cleaning agent on removing stain of complete denture.METHODS:A survey of 176 patients with complete dentures were carried out, which included the history of drinking tea, coffee and smoking, the use of denture-cleaning agent and the times of daily use. Statistical analysis was performed to determine the relationship between staining of denture and the above factors. RESULTS:The results showed (1)The longer the complete denture was weared, the more serious the staining. (2)Drinking tea and smoking were the main causes for denture staining. (3)Daily use of cleaning agent can effictively remove stain of denture. CONCLUSION:Change of life habit(drinking less tea and stop of smoking) and daily use of cleaning agent can reduce denture staining.

Journal Article↗
PubMed1996

Tea consumption and cancer incidence in a prospective cohort study of postmenopausal women.

Tea has consistently been shown to inhibit the occurrence of tumors in experimental animals. The evidence for such a beneficial effect in humans, however, is limited. The authors examined the association between non-herbal tea consumption and cancer incidence in a prospective cohort study of 35,369 postmenopausal Iowa women. In this cohort, information on the frequency of tea drinking and other dietary and lifestyle factors was collected by mailed survey in 1986. After 8 years of follow-up, 2,936 incident non-skin cancer cases were ascertained in this cohort through the State Health Registry of Iowa. Proportional hazards regressions were used to derive adjusted relative risks and 95% confidence intervals for the association between tea consumption and cancer incidence. After controlling for confounding factors, the authors found that regular tea consumption was related to a slight, but not statistically significant, reduced incidence of all cancers combined. Inverse associations with increasing frequency of tea drinking were seen for cancers of the digestive tract (p for trend, 0.04) and the urinary tract (p for trend, 0.02). For women who reported drinking > or = 2 cups (474 ml) of tea per day, compared with those who never or occasionally drank tea, the relative risk for digestive tract cancers was 0.68 (95% confidence interval (CI) 0.47-0.98) and for urinary tract cancers, 0.40 (95% CI 0.16-0.98). Similar inverse associations were seen for specific digestive and urinary tract cancers, although site-specific analyses were not statistically significant. No appreciable association of tea drinking was found with melanoma, non-Hodgkin's lymphoma, or cancers of the pancreas, lung, breast, uterine corpus, or ovary. This study suggests that tea, one of the most popular beverages consumed worldwide, may protect against some cancers in postmenopausal women.

Aged↗
PubMed2004

Characterization of corrinoid compounds from a Japanese black tea (Batabata-cha) fermented by bacteria.

A Japanese fermented black tea (Batabata-cha) contained a considerable amount of vitamin B(12) (456 +/- 39 ng per 100 g dry tea leaves and 2.0 +/- 0.3 ng per 100 mL of tea drink). A corrinoid compound was partially purified and characterized from the tea leaves. The patterns of the purified compound by the silica gel 60 thin-layer chromatography and C18 reversed phased high-performance liquid chromatography were identical to those of authentic vitamin B(12). When 20 week old vitamin B(12) deficient rats, which excreted substantial amounts (about 250 mg/day) of methylmalonic acid in urine as an index of vitamin B(12) deficiency, were fed the tea drink (50 mL/day, 1 ng of vitamin B(12)) for 6 weeks, urinary methylmalonic acid excretion (169 +/- 29 mg/day) of the tea drink-supplemented 26 week old rats decreased significantly relative to that (250 +/- 32 mg/day) of the deficient rats. The results indicate that the vitamin B(12) found in the fermented black tea is bioavailable in mammals.

Animals↗
PubMed2006

Epidemiological evidence for an association between habitual tea consumption and markers of chronic inflammation.

BACKGROUND: Tea consumption has been inversely related to the risk of cardiovascular disease, but the mechanism behind this cardioprotective role is not fully understood. In vitro and animal model studies suggest an anti-oxidative and/or anti-inflammatory role. We aimed at investigating the association between tea drinking and indicators of low-grade inflammation in humans. METHODS: We used observational data from 1031 healthy men participating in a larger cross-sectional study (BELSTRESS). Tea consumption was determined according to a semi-quantitative food frequency questionnaire. Blood samples were analysed for C-reactive protein (CRP), serum amyloid A (SAA), serum haptoglobin and plasma fibrinogen. RESULTS: Of all participants, 22% consumed tea regularly while 10% drank more than two cups per day. Tea drinkers were less obese, smoked less and drank less alcohol and coffee. CRP, SAA and haptoglobin were significantly associated with tea consumption, the effect being graded for SAA. Multivariate analysis did confirm the independence of the observed beneficial role of tea drinking. Fibrinogen levels were however not different between habitual tea consumers and non-consumers. Coffee drinking proved unrelated to chronic inflammation. CONCLUSION: Tea drinking might be of interest in reducing the inflammatory process underlying cardiovascular disease. In light of the fact that tea is the most consumed beverage in the world after water, our findings might be of importance from a public health perspective.

Adult↗
PubMedDate not supplied

Lead poisoning from drinking Kombucha tea brewed in a ceramic pot.

Kombucha tea is an alternative therapy that is gaining popularity as a remedy for a diverse range of ailments. We report two cases of symptomatic lead poisoning requiring chelation therapy in a married couple who had been drinking Kombucha tea for six months, brewing the tea in a ceramic pot. We postulate that acids in the tea eluted lead from the glaze pigment used in the ceramic pot, in a manner analogous to elution of lead from crystal decanters by wine and spirits.

Ceramics↗
PubMed2002

A case-control study on risk factors of helicobacter pylori infection in out-patients with stomach diseases.

OBJECTIVE: To investigate the risk factors of Helicobacter Pylori (Hp) infection. METHODS: All cases and controls came from 561 cases of out-patients with stomach diseases seeking gastroscopy in the Zhejiang Province First Hospital between April and July in 2000. The tissue samples of patients were stained for Hp by the improved Warthin-Starry technique and by methylene blue stain for routine histopathology. We classified patients as cases or controls based on the detection of Hp or not. Before gastroscopy, a questionnaire on lifestyle and health condition of was administered to patients by the interviewers. RESULTS: The overall prevalence of Hp infection was 50.21% and the risk factors of Hp infection were significantly different between males and females. As for males, the duration of daily heavy physical activities, numbers of siblings in the household, family history of oliver disease, preference of spicy food and smoking were the risk factors for Hp infection. However, preference of beans and bean products, drinking well water, drinking tea, eating regularly and good education appears to decrease the prevalence of infection. As for females, consumption of caffeine contained beverages seemed to increase risk for infection. By analyzing with unconditional Logistic Regression Model in male and female groups combined, it brought to light that intake of egg and peppery food were the risk factors of infection, and intake of beans and drinking tea were the protective factors. CONCLUSION: Consumption of beans and drinking tea must be advocated and the consumption of spicy food should be discouraged.

Case-Control Studies↗
PubMedDate not supplied

Cancer-preventive effects of drinking green tea among a Japanese population.

BACKGROUND: Laboratory studies have revealed the cancer preventive effects of green tea, so the association between green tea consumption and cancer was examined in a human population. METHODS: The association between green tea consumption and cancer incidence was studied in our prospective cohort study of a Japanese population. We surveyed 8,552 individuals over 40 years of age living in a town in Saitama prefecture on their living habits, including daily consumption of green tea. During the 9 years of follow-up study (71,248.5 person-years), we identified a total of 384 cases of cancer in all sites. RESULTS: We found a negative association between green tea consumption and cancer incidence, especially among females drinking more than 10 cups a day. The slowdown in increase of cancer incidence with age observed among females who consumed more than 10 cups a day is consistent with the finding that increased consumption of green tea is associated with later onset of cancer. Age-standardized average annual incidence rate was significantly lower among females who consumed large amounts of green tea. Relative risk (RR) of cancer incidence was also lower among both females (RR = 0.57, 95% CI = 0.33-0.98) and males (RR = 0.68, 95% CI = 0.39-1.21) in groups with the highest consumption, although the preventive effects did not achieve statistical significance among males, even when stratified by smoking and adjusted for alcohol and dietary variables. CONCLUSION: Our epidemiological study showed that green tea has a potentially preventive effect against cancer among humans.

Adult↗
PubMed1999

Human salivary tea catechin levels and catechin esterase activities: implication in human cancer prevention studies.

Because of the possible application of tea in the prevention of oral and esophageal cancers, the salivary levels of tea catechins were determined in six human volunteers after drinking tea. Saliva samples were collected after thoroughly rinsing the mouth with water. After drinking green tea preparations equivalent to two to three cups of tea, peak saliva levels of (-)-epigallocatechin (EGC; 11.7-43.9 microg/ml), EGC-3-gallate (EGCG; 4.8-22 microg/ml), and (-)-epicatechin (EC; 1.8-7.5 microg/ml) were observed after a few minutes. These levels were 2 orders of magnitude higher than those in the plasma. The elimination half-life (t(1/2)) of the salivary catechins was 10-20 min, much shorter than that of the plasma. Holding a tea solution in the mouth for a few minutes without swallowing produced even higher salivary catechin levels, but taking tea solids in capsules resulted in no detectable salivary catechin level. Holding an EGCG solution in the mouth resulted in EGCG and EGC in the saliva and, subsequently, EGC in the urine. The results suggest that EGCG was converted to EGC in the oral cavity, and both catechins were absorbed through the oral mucosa. A catechin esterase activity that converts EGCG to EGC was found in the saliva. The enzyme was likely of human origin, but the activity was not inhibited by common human esterase inhibitor. The present results suggest that slowly drinking tea is a very effective way of delivering rather high concentrations of catechins to the oral cavity and then the esophagus.

Absorption↗
PubMed1991

Niacin, thiamin, iron and protein status of humans as affected by the consumption of tea (Camellia sinensis) infusions.

The objective of the project was to determine the effects of tea (Camellia sinensis) leaf beverage consumption on the apparent utilization of niacin, thiamin, and protein in human subjects. During two randomly arranged experimental periods of 14 days each, 10 adult female human subjects were fed a constant (same foods each day), measured, laboratory-controlled diet. Tea was fed during one period while no tea was allowed during the other period. A dehydrated black tea infusion product (instant tea, 8 g/subject/day/dry weight basis) was used which subjects were allowed to dilute in water. Subjects made complete collections of urine and stools. Fasting blood samples were drawn at the end of each experimental period. No effects on protein status were demonstrated. Urinary thiamin losses were depressed with the use of tea but niacin losses were increased. Blood serum concentrations of thiamin diphosphate also were depressed during the tea drinking period as compared to values during the non-tea period. No significant effect on blood serum levels of nicotinaminde or N'-methylnicotinamine were found but values tended to be lower during the tea than the non-tea period. These results suggest that tea consumption inhibits the utilization of thiamin. However, niacin availability was unaffected by tea drinking. Because of the decreased availability of thiamin, the need for niacin was depressed which caused a greater than expected urinary loss of this vitamin.

Adult↗
PubMed2004

Risk of melanoma and vitamin A, coffee and alcohol: a case-control study from Italy.

Limited information is available on the association between the risk of cutaneous malignant melanoma (CMM) and dietary factors. The issue was investigated using data from a case-control study conducted in Italy between 1992 and 1994, including 542 patients with incident, histologically confirmed CMM and 538 controls, admitted to the same hospitals as cases for non-dermatologic and non-neoplastic diseases. We found a significant inverse association between vitamin A intake and CMM risk. The multivariate odds ratio, after allowance for phenotypic characteristics and history of sunburns, for the highest, compared with the lowest, quartile of intake was 0.71 (95% confidence interval (CI) 0.50-1.02) for beta-carotene, 0.57 (95% CI 0.39-0.83) for retinol, and 0.51 (95% CI 0.35-0.74) for total vitamin A. We found no appreciable association of CMM risk with selected food items, including fish, meat, vegetables, fruit, dairy products, wholemeal bread, alcohol, coffee and tea drinking. Consumption of tea appeared to have a protective effect on CMM risk. The relations with measures of dietary vitamin A are, however, moderate compared with the associations between phenotypic characteristics, sun exposure and number of naevi and CMM risk.

Adolescent↗
PubMed1996

Dietary factors and lung cancer among men in west Sweden.

BACKGROUND: Previous studies have reported an association between tea drinking and lung cancer. In view of these data, the relationship between tea drinking as well as other dietary factors and lung cancer was investigated in a case-control study in the west of Sweden. METHODS: Patients with suspected lung cancer were collected from pulmonary units at central hospitals in the area investigated, and population controls were matched for age. The material reported here comprises 308 male cases with a confirmed diagnosis of lung cancer and 504 controls. The participants were interviewed by specially trained nurses, using a questionnaire to assess smoking, dietary habits, occupational exposures and conditions in the residential area (local air pollution). This paper reports the results from dietary factors studied with a food frequency technique. RESULTS: The results demonstrated a strong protective effect of vegetables (odds ratio [OR] = 0.69, 95% confidence interval [CI]: 0.46-1.05, and OR = 0.37, 95% CI: 0.23-0.61 for intermediate and high consumption classes respectively). A low OR was consistent for all histological types of lung cancer. High consumption of fruits did not show any similar protective effect. Drinking milk was associated with a dose-response related risk increase after adjustment for smoking and vegetable consumption (P for trend = 0.07). Odds ratio was 1.73, 95% CI: 1.00-3.01 for high consumption of milk. CONCLUSIONS: High intake of vegetables had a strong protective effect among males. Diet is thus a potential confounding factor in studies on lung cancer and environmental factors and should thus be taken into consideration in the planning of such studies.

Adenocarcinoma↗
PubMed1992

Alcohol, smoking, coffee, and cirrhosis.

Since most heavy drinkers do not develop alcoholic cirrhosis, other causes or predisposing factors are probable. The authors studied traits of 128,934 adults who underwent health examinations at the Oakland and San Francisco, California, facilities of the Kaiser Permanente Medical Care Program from January 1978 to December 1985 in relation to subsequent hospitalization or death from cirrhosis of the liver. In analyses adjusted for nine covariates, past and current alcohol drinking were strongly related to cirrhosis risk, but usual choice of alcoholic beverage had no independent relation. Cigarette smoking was independently related to risk of alcoholic cirrhosis, with cigarette smokers of a pack or more per day at trebled risk compared with lifelong nonsmokers. Coffee drinking, but not tea drinking, was inversely related to alcoholic cirrhosis risk, with persons who drank four or more cups per day at one-fifth the risk of noncoffee drinkers. This inverse relation between coffee consumption and risk of alcoholic cirrhosis was consistent in many subsets, including persons free of gastrointestinal disease and those with 5 or more years before hospitalization or death. Cigarette smoking and coffee consumption were not consistently related to risk of hospitalization or death for nonalcoholic cirrhosis. These data could mean that cigarette smoking promotes alcoholic cirrhosis and that coffee drinking might be protective.

Adult↗