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PubMed2004

Protective effect of green tea against prostate cancer: a case-control study in southeast China.

To investigate whether green tea consumption has an etiological association with prostate cancer, a case-control study was conducted in Hangzhou, southeast China during 2001-2002. The cases were 130 incident patients with histologically confirmed adenocarcinoma of the prostate. The controls were 274 hospital inpatients without prostate cancer or any other malignant diseases, and matched to the age of cases. Information on duration, quantity and frequency of usual tea consumption, as well as the number of new batches brewed per day, were collected by face-to-face interview using a structured questionnaire. The risk of prostate cancer for tea consumption was assessed using multivariate logistic regression adjusting for age, locality, education, income, body mass index, physical activity, alcohol consumption, tobacco smoking, total fat intake, marital status, age at marriage, number of children, history of vasectomy and family history of prostate cancer. Among the cases, 55.4% were tea drinkers compared to 79.9% for the controls. Almost all the tea consumed was green tea. The prostate cancer risk declined with increasing frequency, duration and quantity of green tea consumption. The adjusted odds ratio (OR), relative to non-tea drinkers, were 0.28 (95% CI = 0.17-0.47) for tea drinking, 0.12 (95% CI = 0.06-0.26) for drinking tea over 40 years, 0.09 (95% CI = 0.04-0.21) for those consuming more than 1.5 kg of tea leaves yearly, and 0.27 (95% CI = 0.15-0.48) for those drinking more than 3 cups (1 litre) daily. The dose response relationships were also significant, suggesting that green tea is protective against prostate cancer.

Adenocarcinoma↗
PubMed1997

Spontaneous and induced sister chromatid exchanges and delayed cell proliferation in peripheral lymphocytes of Bowen's disease patients and matched controls of arseniasis-hyperendemic villages in Taiwan.

A total of 15 newly-developed Bowen's disease patients and 34 age-sex-residence-matched controls were recruited from three arseniasis-hyperendemic villages in Taiwan to compare spontaneous and arsenic-induced sister chromatid exchanges (SCEs), proportion of cells with high frequencies of SCEs (HFCs), and replication index (RI) in their peripheral lymphocytes. Arsenic-induced Bowen's disease patients were found to have significantly higher spontaneous SCEs and HFCs and a lower spontaneous RI than in matched controls without or with adjustment for age, gender, cigarette smoking, alcohol drinking, tea drinking, status of major diseases, HBsAg carrier status and arsenic exposure indices through multivariate analysis. Sodium arsenite was found to increase SCEs and HFCs and to decrease RI in a dose-response pattern for both cases and controls. The arsenic-induced decrease in RI was significantly greater in arsenic-induced Bowen's disease patients than in matched controls. The arsenic-induced increases in SCEs and HFCs were also consistently, but not statistically significantly, higher in arsenic-induced Bowen's disease patients than in matched controls at all arsenite treatment levels of 0.5, 1.0 and 2.0 microM. The arsenic-induced increase in cytogenetic damages and decrease in cell proliferation among arsenic-induced Bowen's disease patients compared with matched controls may result from their long-term exposure to inorganic arsenic through consumption of high-arsenic artesian well water, elevated individual genetic and acquired susceptibility to arsenic-induced damage, or both.

Arsenic↗
PubMed1998

Tea and coffee consumption and risk of colon and rectal cancer in middle-aged Finnish men.

The association between coffee and black tea consumption and the subsequent risk of colon and rectal cancer was investigated within a Finnish clinical trial cohort. One hundred eleven cases of colon cancer and 83 cases of rectal cancer were diagnosed over a median of 9.0 years of follow-up. Proportional hazards regression models were used to derive adjusted relative risk (RR) and 95% confidence intervals (CI) for the association between coffee and tea consumption and cancer incidence. After controlling for confounders, coffee was not significantly associated with colon or rectal cancer. A positive association was seen for increased consumption of tea drinking and colon cancer. Compared with persons who did not drink tea, those who consumed <1 cup/day had an RR of 1.40 (95% CI = 0.84 - 2.33) and those who consumed > or = 1 cup/day had an RR of 2.09 (95% CI = 1.34-3.26, p for trend = 0.001). In contrast, tea consumption had little effect on rectal cancer incidence. This study does not support the hypothesis that coffee and tea protect against colorectal cancer risk. However, given the strength of the tea-colon cancer association and the significant gradient of risk we observed across level of intake, further epidemiologic research of this relationship in other populations seems warranted.

Aged↗
PubMed1975

Coffee drinking and cancer of the lower urinary tract.

The relationship between coffee drinking and cancer of the lower urinary tract (LUT) was investigated by a case-control study of white women identified from hospitals in urban areas of Massachusetts and Rhode Island. Data on coffee drinking, tea drinking, use of coffee additives, and cigarette smoking were obtained by mail questionnaire. Information was available for 135 women with LUT cancer and 390 controls. For women who usually drank 1+ cups of coffee per day, the risk ratio of having LUT cancer was 2.1 (95 percent confidence limits, 1.1-4.3), compared to a risk of 1 for women who drank less or not at all. However, no dose-response relationship was demonstrated between LUT cancer and usual daily coffee consumption or "cup-years" of coffee drinking. The association of coffee with disease was no different, whether decaffeinated, nondecaffeinated, regular, or instant coffee had been drunk, or whether the coffee was brewed strong or weak. Use of nondairy creamers, saccharin, or cyclamates was not associated with increased risk of disease. The risk of LUT cancer for cigarette smokers relative to nonsmokers was 1.6 (1.0-2.4). The attendant dose-response relationship was statistically significant. The absence of a dose-response relationship between coffee drinking and LUT cancer suggested that the association observed was noncasual.

Aged↗
PubMed2006

[A matched case-control study of papillary thyroid carcinoma].

OBJECTIVE: In order to explore the risk factors of the papillary thyroid carcinoma(PTC), a hospital-based matched case-control study was carried out in Shanghai. METHODS: Matched by gender, age (+/- 3 years old) and native place,205 pairs of cases and controls were recruited and studied. Database was established with Epi Info 6.0 software. Univariate and multivariate conditional logistic regression analysis were carried out with SPSS 11.5 software. RESULTS: Data from multivariate conditional logistic regression analysis showed that often drinking tea and having better economic living standard 20 years ago were protective factors of PTC, with ORs of 0.456 and 0.221 respectively. Personal history of CT examination, familial history of cancer and the mother's age was older than 22 years when the research subject was delivered, were risk factors of PTC, with ORs of 12.935, 7.027 and 3.729 respectively. Results data from multivariate analysis on female subjects showed that the history of CT examination, mother's age was older than 22 (when the subject was delivered) and the history of gynecological disease were the risk factors of PTC,with ORs of 107.453,29.246 and 59.521 respectively. Taking bean products frequently and having higher standard of living 20 years ago were the protective factors of PTC,with ORs of 0.025 and 0. 144 respectively. CONCLUSION: History of CT examination, familial history of cancer and the mother's age(older than 22 when the subject was delivered) were the risk factors of PTC. Frequent tea drinking habit and having higher standard of living 20 years ago were the protective factors of PTC. History of CT examination,mother's age (older than 22 when the subject was delivered) and the history of gynecological disease appeared the risk factors of PTC for women. Habit on frequent bean products taking and had higher standard of living 20 years ago were the protective factors of PTC to women.

Carcinoma, Papillary↗
PubMed1988

Risk factors in renal cell carcinoma: I. Methodology, demographics, tobacco, beverage use, and obesity.

Potential risk factors in renal cell carcinoma (RCC) were studied in a case-control study of 315 RCC cases, 313 hospital and 336 population controls. Risk factors included body mass index, education, smoking, beverage use, and artificial sweeteners. High body mass index, when present at age 20 and maintained, was a significant risk factor in both men and women. The lower the educational levels attained, the higher the risk. There was a weak positive association with cigarette smoking, coffee drinking, tea drinking, and decaffeinated coffee. A strong negative association was found with ever use of alcohol and it was strongest for wine. A positive association was found with use of artificial sweeteners in men. These findings have increased our understanding of the etiology of this rare but increasingly important neoplastic disease in humans.

Adult↗
PubMed1998

Mortality risks of oesophageal cancer associated with hot tea, alcohol, tobacco and diet in Japan.

To clarify mortality risks of oesophageal cancer associated with hot tea, alcohol, tobacco and diet, further analyses on the data from a large prospective cohort study in Japan were conducted. The subjects for analysis were 220,272 men and women aged 40 to 69 at the baseline of 1965. There were 440 oesophageal cancer deaths during the period from January 1966 to December 1981. Person-years at risk were 3,065,182 in total. Rate ratio and 95% confidence interval adjusted for attained age, prefecture, occupation and sex were (RR (95% CI)): 1.6 (1.2-2.0) for hot tea (drinking green tea at high temperatures) in comparison with not-hot tea (drinking green tea at moderate temperatures); 2.4 (1.8-3.1) for daily (4 times/week or more) alcohol drinking in comparison with non-drinking; and 2.3 (1.7-3.1) for heavy smoking (15 cigarettes/day or more) in comparison with non-smoking. Dose-response relationships were found in alcohol drinking and smoking among men and women (p for trend; p < 0.001). The rate ratios were not significantly associated with the dietary factors except for green-yellow vegetables (1-3 times/month or less in comparison with daily; RR = 2.0, 95% CI: 1.2-3.1), where a no dose-response trend was observed (p = 0.45). In comparison based on the binary variables, the RR for the subjects with daily alcohol drinking and current smoking was 3.9 with 95% CI of 2.7 to 5.4, relative to those exposed to neither habit. The joint effect of alcohol drinking (A) and smoking (S) was more than additive (A*S > A + S: 3.9 > 1 + (1.0-1) + (1.6-1)). Further sub-analysis showed that the RR for the subjects with daily alcohol drinking, current smoking and hot tea was 5.7 with 95% CI of 3.7 to 8.9, when the reference was the subjects with not-daily alcohol drinking, non-smoking and not-hot tea. Similar results were obtained from further adjustment of green-yellow vegetables. It is concluded that mortality risks of oesophageal cancer in the present cohort were substantially associated with thermal effect of hot tea, alcohol drinking, smoking and lower consumption of green-yellow vegetables. This finding suggests that life-style modification for smoking and dietary habits is essential to reduce the risks of oesophageal cancer in Japan.

Adult↗
PubMed2001

Catechins are bioavailable in men and women drinking black tea throughout the day.

Tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. This study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. After 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, and 31.14 mg of (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG), respectively, at four time points (0, 2, 4 and 6 h). Blood, urine and fecal specimens were collected over a 24- to 72-h period and catechins were quantified by HPLC with coularray detection. Plasma concentrations of EGC, EC and EGCG increased significantly relative to baseline (P < 0.05). Plasma EGC, EC and EGCG peaked after 5 h, whereas ECG peaked at 24 h. Urinary excretion of EGC and EC, which peaked at 5 h, was increased relative to baseline amounts (P < 0.05) and fecal excretion of all four catechins was increased relative to baseline (P < 0.05). Approximately 1.68% of ingested catechins were present in the plasma, urine and feces, and the apparent bioavailability of the gallated catechins was lower than the nongallated forms. Thus, catechins were bioavailable. However, unless they are rapidly metabolized or sequestered, the catechins appeared to be absorbed in amounts that were small relative to intake.

Adult↗
PubMed2026

Genetic and Environmental Influences on Caffeine Intake in Korean Twins.

Caffeine intake may be influenced by both genetic and environmental factors. This study aimed to examine the genetic contribution to variation in coffee and tea drinking, as well as total caffeine intake. A total of 1,106 Korean twins, comprising 456 monozygotic and 97 dizygotic twin pairs aged 30 years or older, from the Healthy Twin Study were included. Structural equation models were used to assess heritability estimates and their 95% confidence intervals (CIs). Heritability (95% CI) was estimated at 0.29 (0.21, 0.37) for coffee drinking, 0.11 (0.02, 0.20) for tea drinking, and 0.27 (0.16, 0.38) for total caffeine intake, with the remaining variance in each trait attributed to unique environmental factors. The unique environmental factors contributed more substantially to coffee drinking than genetic factors during early adulthood, while the genetic contribution to tea drinking remained consistently low across all ages. In conclusion, coffee drinking, tea drinking, and total caffeine intake were partly heritable, with unique environmental factors playing a predominant role.

Humans↗
PubMed2001

Protective effect of green tea on the risks of chronic gastritis and stomach cancer.

Despite the declining trend, stomach cancer remains the second most common cancer worldwide. We examined the role of green tea consumption on chronic gastritis and stomach cancer risks. A population-based case-control study was conducted in Yangzhong, China, with 133 stomach cancer cases, 166 chronic gastritis cases, and 433 healthy controls. Epidemiologic data were collected by standard questionnaire and odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models in SAS. Inverse association was observed between green tea drinking and chronic gastritis and stomach cancer risks. After adjusting for age, gender, education, body mass index, pack-years of smoking and alcohol drinking, ORs of green tea drinking were 0.52 (95% CI: 0.29-0.94) and 0.49 (95% CI: 0.31-0.77) for stomach cancer and chronic gastritis, respectively. In addition, dose-response relationships were observed with years of green tea drinking in both diseases. The results provide further support on the protective effect of green tea against stomach cancer. This is the first time that green tea drinking was found to be protective against chronic gastritis, which may be of importance when designing intervention strategies for stomach cancer and its pre-malignant lesions in the high-risk population.

Adult↗
PubMed1996

Antimutagenicity of Tochu tea (an aqueous extract of Eucommia ulmoides leaves): 2. Suppressing effect of Tochu tea on the urine mutagenicity after ingestion of raw fish and cooked beef.

The effect of Tochu tea, which is an aqueous extract of Eucommia ulmoides leaves and a popular-beverage in Japan, on the urine mutagenicity before and after ingestion of raw fish and cooked beef was studied using Salmonella typhimurium YG1024. Urines were collected from seven healthy, non-smoking Japanese women before and after ingestion of raw fish and cooked beef. In experiment 1,3 were in a control group and 4 were in a Tochu tea-drinking group (2000 ml per day). The mutagenicity of urine from the Tochu tea-drinking group was much lower. In experiment 2 the 7 women switched groups; the tea-drinking group became the control group, and the control group became the Tochu tea-drinking group. Again, the mutagenicity of urine collected from the Tochu tea-drinking group was much lower. These results suggest that the decrease in the mutagenicity of the urine from the Tochu tea-drinking group was due to the intake of Tochu tea, but not to individual differences. Thus, the ingestion of Tochu tea may reduce human exposure to dietary mutagens.

Adult↗
PubMed2003

Dose-dependent protective effect of coffee, tea, and smoking in Parkinson's disease: a study in ethnic Chinese.

INTRODUCTION: Few studies have examined the relationship of coffee and tea in Parkinson's disease (PD). The potential protective effect of coffee intake and risk of PD has not been studied in a Chinese population. There is a high prevalence of caffeine takers among Chinese in our population. OBJECTIVE: We undertook a case control study to examine the relationship between coffee and tea drinking, cigarette smoking, and other enviromental factors and risk of PD among ethnic Chinese in our population. METHODS AND RESULTS: 300 PD and 500 population controls were initially screened. Two hundred case control pairs matched for age, gender, and race were finally included in the analysis. Univariate analysis revealed significant association of PD with coffee drinking (p<0.0005), tea drinking (p=0.019), alcohol drinking (p=0.001), cigarette smoking (p<0.0005), and exposure to heavy metals (p=0.006). Conditional logistic regression analysis demonstrated that amount of coffee drunk (OR 0.787, 95%CI 0.664-0.932, p=0.006), amount of tea drunk (OR 0.724, 95%CI 0.559-0.937, p=0.014), number of cigarettes smoked (OR 0.384, 95%CI 0.204-0.722, p=0.003), history of heavy metal and toxin exposure (OR 11.837, 95%CI 1.075-130.366, p=0.044), and heart disease (OR 5.518, 95%CI 1.377-22.116, p=0.016) to be significant factors associated with PD. One unit of coffee and tea (3 cups/day for 10 years) would lead to a 22% and 28% risk reduction of PD. One unit of cigarette smoke (3 packs/day for 10 years) reduced the risk of PD by 62%. CONCLUSIONS: We demonstrated a dose-dependent protective effect of PD in coffee and tea drinkers and smokers in an ethnic Chinese population. A history of exposure to heavy metals increased the risk of PD, supporting the multifactorial etiologies of the disease.

Adult↗
PubMed2006

The effect of green tea in oxidative stress.

BACKGROUND & AIMS: Green tea, an infusion prepared with the leaves of Camellia sinensis is particularly rich in flavonoids, which are strong antioxidants. Tea drinking, by providing antioxidants, may become valuable in several oxidative stress conditions. Our aim was to evaluate the effect of green tea drinking on some factors reflecting the development of oxidative stress in plasma and in erythrocytes. METHODS: The study was performed in 34 Portuguese subjects. We evaluated the total antioxidant status (TAS), the lipid peroxidation products-malonyldialdehyde (MDA) and malonyldialdehyde+4-hydroxy-2(E)-nonenal (MDA+4-HNE)-and the oxidative changes in erythrocyte membrane, namely membrane bound haemoglobin (MBH) and the band 3 profile. Analytical evaluations were performed after 3 weeks drinking 1l of water daily, and after 4 weeks drinking 1l of green tea daily. Tea was prepared daily at the same conditions of temperature, time of infusion and concentration. RESULTS: After green tea drinking, we found a significant reduction in serum levels of MDA and MDA+4-HNE and in the oxidative stress within the erythrocyte, as suggested by a significantly lower value of MBH and by changes in band 3 profile towards a normal mean profile, namely an increase in the band 3 monomer. A rise in the antioxidant capacity was also observed. CONCLUSIONS: Our data suggest for green tea drinking a beneficial effect, by reducing the development or the enhancement of oxidative stress and, therefore, protecting the individual for oxidative stress diseases. Moreover, we propose further studies about the value of band 3 profile and of MBH in providing a cumulative measurement of the effect of green tea drinking upon the oxidative stress in cells. Moreover, further studies are also needed, to clarify the effect of green tea consumption, the value of regular green tea consumption and the way it should be prepared to reach a healthy effect.

Adult↗
PubMed2002

Tea consumption and ovarian cancer risk: a case-control study in China.

To investigate whether tea consumption has an etiological association with ovarian cancer, a case-control study was conducted in China during 1999-2000. The cases were 254 patients with histologically confirmed epithelial ovarian cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplasm hospital outpatients, and 51 women recruited from the community. Information on the frequency, type, and duration of tea consumption was collected by personal interview using a validated questionnaire. The risk of ovarian cancer for tea consumption was assessed using adjusted odds ratios based on multivariate logistic regression analysis, accounting for confounding demographic, lifestyle, and familial factors including hormonal status and family ovarian cancer. The ovarian cancer risk declined with increasing frequency and duration of overall tea consumption. The adjusted odds ratio was 0.39 for those drinking tea daily and 0.23 for those drinking tea for >30 years, compared with nontea drinkers. The dose response relationships were significant, and the inverse association with ovarian cancer was observed for green tea consumption. We concluded that increasing frequency and duration of tea drinking, especially green tea, can reduce the risk of ovarian cancer. However, the protective effects of black tea and Oolong tea need to be additionally investigated.

Adult↗
PubMed2004

[A study on the association between tea consumption and stroke].

OBJECTIVE: The aim of the study was to investigate the association between tea consumption and stroke. METHODS: A cross sectional study was conducted in autumn, 1998. The subjects were from 12 provinces in China. 15 groups of populations were selected by cluster randomized sampling and each group had about 1000 persons, aged from 35 to 60 years old. 14 212 subjects had complete data for analysis. Data regarding tea drinking would include drinking status, dose and type of teas. Logistic regression was used to analyze the association between tea consumption and stroke. RESULTS: There was a strong inverse correlation between tea drinking and stroke after adjusting other risk factors of stroke (P < 0.05). The odds ratio (OR) of stroke was 0.60 [95% confidence interval (CI): 0.42 - 0.85] for subjects who drank tea compared to those who did not. Increased amount of tea consumption per month was associated with decreased stroke prevalence. The association for tea consumption over 150 gram per month and stroke was statistically significant (P < 0.05) with an OR value of 0.56 (95% CI: 0.36 - 0.89). Analytical results indicated that the OR value was 0.24 (95% CI: 0.06 - 1.01) for black tea and other tea (P = 0.05). The OR value was 0.35 (95% CI: 0.18 - 0.72) for green tea (P < 0.01), and 0.75 (95% CI: 0.51 - 1.11) for jasmine tea (P > 0.05). CONCLUSION: Tea drinking was independently associated with prevalence of stroke which might play a role in the prevention of the disease.

Adult↗
PubMed2000

Preventive effects of drinking green tea on cancer and cardiovascular disease: epidemiological evidence for multiple targeting prevention.

The significance of drinking green tea in prevention of two of the main lifestyle-related diseases, cancer and cardiovascular disease, was demonstrated in terms of a prospective cohort study on a total of 8,552 general residents in Saitama Prefecture, Japan. On the basis of the follow-up study, we revealed decreased relative risk of cancer incidence for those consuming over 10 cups a day, compared with those consuming below 3 cups: 0.54 (95% confidence interval, 0.22-1.34) for men, 0.57 (0.34-0.98) for women, and 0.59 (0.35-0.98) for both sexes. Furthermore, a significant delay in cancer onset was associated with increased consumption of green tea. Next, decreased relative risk of death from cardiovascular disease was 0.58 (0.34-0.99) for men, 0.82 (0.49-1.38) for women, and 0.72 (0.60-1.04) for members of both sexes consuming over 10 cups a day. Finally, we evaluated the life-prolonging effects of drinking green tea on cumulative survival, using the life table.

Adult↗
PubMedDate not supplied

Epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan.

Both descriptive and analytical studies were carried out to examine epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan. The age-adjusted mortality rate of stomach cancer has been decreasing since the early 1970s for both males and females. The male-to-female ratio of the disease has remained around 2:1 in the past three decades. Comparison of the incidence of stomach cancer among Chinese in different countries showed a much lower incidence among Chinese in the USA than those in southeastern Asia. A hospital-based matched case-control study carried out in Taipei metropolitan areas showed a positive association of stomach cancer with blood type A, chronic gastric diseases, cigarette smoking, alcohol drinking, green tea drinking as well as consumption of salted meat, cured meat, smoked food, fried food and fermented beans. There was also a significant negative association between the disease and the consumption of milk.

Alcohol Drinking↗
PubMed2004

Comparison of antioxidant activity and bioavailability of tea epicatechins with their epimers.

Canned and bottled tea drinks contain not only green tea epicatechins (GTE), namely (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC), but also four GTE epimers, namely (-)-gallocatechin gallate (GCG), (-)-catechin gallate (CG), (-)-gallocatechin (GC) and (-)-catechin (C). In the present study we examined the antioxidant activity and bioavailability of these epimers compared with their corresponding precursors. The epimerisation reaction was induced by autoclaving GTE extract derived from longjing green tea at 120 degrees C for 20 min. Isolation and purification of each GTE and epimer were accomplished by various column chromatographic and semi-preparative HPLC techniques. The antioxidant activity of each epimer with its corresponding GTE precursor was conducted in the three in vitro systems, namely human LDL oxidation, ferric reducing-antioxidant power (FRAP), and anti-2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assays. The results of all three assays demonstrated that CG had similar antioxidant activity with its precursor ECG, while GC was less potent as an antioxidant than its precursor EGC. Regarding EGCG and GCG, the antioxidant potency was similar for both LDL oxidation and DPPH free radical assays, but GCG was statistically less effective than EGCG in the FRAP assay. For EC and C, the latter had less anti-free radical activity in the DPPH assay, but in LDL oxidation and FRAP assays the antioxidant activity was similar. Oral and intravenous dosing of GTE-epimer mixture led to increase in total plasma antioxidant capacity in rats. In general, both epicatechins and epimers had low bioavailability (0.08-0.31) and most of the observed differences between epicatechins and their corresponding epimers were small, even if they were statistically significant in some cases. It was concluded that the epimerisation reaction occurring in manufacturing canned and bottled tea drinks would not significantly affect antioxidant activity and bioavailability of total tea polyphenols.

Animals↗