Tea and coffee consumption and the risk of digestive tract cancers: data from a comparative case-referent study in Japan

The Association between Tea Consumption and Bladder Cancer Risk Based on the Bladder Cancer Epidemiology and Nutritional Determinants (BLEND) International Consortium

OBJECTIVES

Evidence regarding the association between tea consumption and bladder cancer (BC) risk is inconsistent. This study aimed to increase our knowledge of the association by using international data from the Bladder Cancer Epidemiology and Nutritional Determinants Consortium.

METHODS

Individual data on 2,347 cases and 6,871 controls from 15 case-control studies with information on black, green, herbal, or general tea was pooled. The association was estimated using multilevel multivariable logistic regression analysis adjusted for multiple (non-)dietary factors.

RESULTS

Association between tea consumption and BC risk was observed (odds ratio, OR = 0.72, 95% confidence interval, 95% CI = 0.65-0.80) compared to non-tea drinkers. Stratified analyses based on gender and smoking status yielded similar results. Stratified analysis showed no significant association between black or green tea consumption and BC risk across models, while herbal tea consumption was linked to a reduced BC risk (OR = 0.59, 95% CI = 0.36-0.96). As daily tea consumption increased within a suitable range (<5.67 cups/day), BC risk decreased.

CONCLUSIONS

Camellia sinensis tea showed no association with BC risk, while herbal tea was inversely linked to BC incidence. Despite some significant findings in the selected strata, further studies are required to clarify the underlying mechanisms.

EGCG synergizes the therapeutic effect of irinotecan through enhanced DNA damage in human colorectal cancer cells

Irinotecan is a kind of alkaloid with antitumour activity, but its low solubility and high toxicity limit its application. Epigallocatechin-3-gallate (EGCG) is one of the main bioactive components in tea. The epidemiological investigation and animal and cell experiments show that EGCG has a preventive and therapeutic effect on many kinds of tumours. Here, colorectal cancer cells RKO and HCT116 were employed, and the CCK8 proliferation test was used to screen the appropriate concentration of EGCG and irinotecan, and the effects of single and/or combined drugs on migration, invasion, DNA damage, cell cycle and autophagy of tumour cells were investigated. The results showed that EGCG combined with irinotecan (0.5 μmol L- ) not only had a stronger inhibitory effect on tumour cells than EGCG or irinotecan alone but also prevented tumour cell migration and invasion. EGCG alone did not cause DNA damage in colorectal cancer cells, but its combination with irinotecan could induce S or G2 phase arrest by inhibiting topoisomerase I to cause more extensive DNA damage. EGCG also induced apoptosis by promoting autophagy with irinotecan synergistically. These results indicated that EGCG in combination with irinotecan could be a promising strategy for colorectal cancer.

Chemoprevention Against Gastric Cancer

Gastric cancer is the fifth most common cause of cancer and the third leading cause of cancer-related deaths globally. The number of gastric cancer-related deaths is only projected to increase, attributable primarily to the expanding aging population. Prevention is a mainstay of gastric cancer control programs, particularly in the absence of accurate, noninvasive modalities for screening and early detection, and the absence of an infrastructure for this purpose in the majority of countries worldwide. Herein, we discuss the evidence for several chemopreventive agents, along with putative mechanisms. There remains a clear, unmet need for primary chemoprevention trials for gastric cancer.

Green tea consumption and risk for esophageal cancer: A systematic review and dose-response meta-analysis

OBJECTIVE

Controversial results of the association between green tea consumption and risk for esophageal cancer (EC) were reported by previous meta-analysis. Thus, the aim of this study was to quantitatively investigate the association.

METHODS

The Cochrane Library, PubMed, and EMBASE databases were searched for relevant studies. We used a "one-stage approach" with a restricted cubic spline model to summarize the dose-specific relationships between green tea and risk for EC. Odds ratios (ORs) were used to measure the effects. Fourteen studies were included with a total of 5057 ECs among 493 332 participants.

RESULTS

In the dose-response analysis, the summary OR for a 1 cup/d increase in green tea was 1.00 (95% confidence interval [CI], 0.95-1.04; I² = 77%). No nonlinearity association was observed between tea consumption and risk for EC (P = 0.71 for nonlinearity). In the subgroup of sex, the summary OR for a 1 cup/d increase in green tea was 1.03 (95% CI, 0.95-1.11, I² = 67%) for men and 0.79 (95% CI, 0.68-0.91; I² = 0%) for women.

CONCLUSION

Contrary to previous studies, based on current evidence, the present dose-response study suggested no association between green tea and risk for EC. However, there might be a protective effect of green tea in women. Notably, our conclusion might be influenced by limited studies and potential bias, such as dose of green tea assessment and select bias of case-control studies. Further larger number, prospective, and well-designed larger-scale studies are needed to provide more precise evidence, especially in women and more regions (United States and Europe).

Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain-Gut Axis

Coffee is one of the most popular beverages consumed worldwide. Roasted coffee is a complex mixture of thousands of bioactive compounds, and some of them have numerous potential health-promoting properties that have been extensively studied in the cardiovascular and central nervous systems, with relatively much less attention given to other body systems, such as the gastrointestinal tract and its particular connection with the brain, known as the brain–gut axis. This narrative review provides an overview of the effect of coffee brew; its by-products; and its components on the gastrointestinal mucosa (mainly involved in permeability, secretion, and proliferation), the neural and non-neural components of the gut wall responsible for its motor function, and the brain–gut axis. Despite in vitro, in vivo, and epidemiological studies having shown that coffee may exert multiple effects on the digestive tract, including antioxidant, anti-inflammatory, and antiproliferative effects on the mucosa, and pro-motility effects on the external muscle layers, much is still surprisingly unknown. Further studies are needed to understand the mechanisms of action of certain health-promoting properties of coffee on the gastrointestinal tract and to transfer this knowledge to the industry to develop functional foods to improve the gastrointestinal and brain–gut axis health.

Association of tea consumption and the risk of gastric cancer in Japanese adults: the Japan Collaborative Cohort Study

OBJECTIVE

To examine the possible relationship between tea consumption and risk of gastric cancer (GC) among Japanese men and women included in a large Japanese population-based study titled the Japan Collaborative Cohort (JACC) Study.

DESIGN

Prospective cohort study.

SETTING

A population-based cohort included subjects who were recruited from 24 areas of JACC Study, in which data regarding the incidence of cancer were available.

PARTICIPANTS

63 848 participants (26 025 men and 37 823 women), aged 40-79, were included in the analyses and underwent follow-up (median 13.3 years) prospectively in research on cancer incidence.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome variable was the risk of GC according to the frequency intakes of total tea, green tea, black tea and oolong tea. The adjusted HRs for the risk of GC associated with tea consumption were calculated using the Cox proportional hazards model.

RESULTS

1494 cases of GC were detected (960 men and 534 women) during the follow-up period. The multivariable-adjusted HRs for the risk of GC in the highest versus lowest quintiles of total tea intake were 1.05 (0.83-1.33); p trend=0.50 in men, and 0.82 (0.60-1.12); p trend=0.45 in women. There was no association found between the consumption of green tea, black tea or oolong tea with the risk for GC in either gender.

CONCLUSIONS

In this large community-based prospective cohort study, tea consumption was not associated with the risk of GC in either gender.

Association between dietary intake and the prevalence of tumourigenic bacteria in the gut microbiota of middle-aged Japanese adults

The relative contribution of diet to colorectal cancer (CRC) incidence is higher than that for other cancers. Animal models have revealed that Escherichia coli containing polyketide synthase (pks⁺ E. coli) in the gut participates in CRC development. The purpose of this cross-sectional study was to examine the relationship between dietary intake and the prevalence of pks⁺ E. coli isolated from the microbiota in faecal samples of 223 healthy Japanese individuals. Dietary intake was assessed using a previously validated brief-type self-administered diet history questionnaire. The prevalence of pks⁺ E. coli was evaluated using faecal samples collected from participants and specific primers that detected pks⁺ E. coli. The prevalence of pks⁺ E. coli was 26.9%. After adjusting for baseline confounders, the prevalence of pks⁺ E. coli was negatively associated with the intake of green tea (odds ratio [OR], 0.59 [95% confidence interval (CI) 0.30-0.88] per 100 g/1,000 kcal increment) and manganese (OR, 0.43 [95% CI 0.22-0.85] per 1 mg/1,000 kcal increment) and was positively associated with male sex (OR, 2.27 [95% CI 1.05-4.91]). While futher studies are needed to validate these findings, these results provide insight into potential dietary interventions for the prevention of CRC.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan

The aim of our study was to assess the association between green tea consumption and all-cause and cause-specific mortality in a pooled analysis of eight Japanese population-based cohort studies. Pooled hazard ratios (HR) and 95% confidence intervals (CI), derived from random effects models, were used to evaluate the associations between green tea consumption, based on self-report at baseline, and risk of all-cause and cause-specific mortality. During a mean follow-up of 17.3 years, among 313,381 persons, 52,943 deaths occurred. Compared with individuals who consumed < 1 cup/day, those in the highest consumption category (≥ 5 cups/day) had a decreased risk of all-cause mortality [the multivariate-adjusted HR was 0.90 (95% CI 0.87-0.94) for men and 0.82 (0.74-0.90) for women]. A similar inverse association was observed for heart disease mortality [HR 0.82 (0.75-0.90) for men, and 0.75 (0.68-0.84) for women], and cerebrovascular disease mortality [HR 0.76 (0.68-0.85) for men, and 0.78 (0.68-0.89) for women]. Among women, green tea consumption was associated with decreased risk of total cancer mortality: 0.89 (0.83-0.96) for the 1-2 cups/day category and 0.91 (0.85-0.98) for the 3-4 cups/day category. Results for respiratory disease mortality were [HR 0.75 (0.61-0.94)] among 3-4 cup daily consumers and [HR 0.66 (0.55-0.79)] for ≥ 5 cups/day. Higher consumption of green tea is associated with lower risk for all-cause mortality in Japanese, especially for heart and cerebrovascular disease. Moderate consumption decreased the risk of total cancer and respiratory disease mortality in women.

Green Tea Consumption and Esophageal Cancer Risk: A Meta-analysis

Background: The protective role of green tea against cancer is still unknown.Objectives: To investigate the association between green tea consumption and esophageal cancer risk through meta-analysis.Methods: We searched MEDLINE, EMBASE, Web of Science and Cochrane Library for studies on the relationship between green tea and esophageal cancer risk. We assessed heterogeneity (I²) and publication bias (Begg's and Egger's tests). Pooled relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects models.Results: A total of 20 studies were included. The RRs for all studies was 0.65 (95% CI: 0.57-0.73), with I² = 75.3% and P = 0. In the subgroup analysis, the following variables showed marked heterogeneity: Asian (RR: 0.64; 95% CI: 0.56-0.73) and non-Asian countries (RR: 0.74; 95% CI: 0.45-1.03), female (RR: 0.55; 95% CI: 0.39-0.71) and male + female (RR: 0.64; 95% CI: 0.54-0.75), case-control study (RR: 0.62; 95% CI: 0.52-0.71), impact factor >3 (RR: 0.65; 95% CI: 0.56-0.75), impact factor <3 (RR: 0.64; 95% CI: 0.48-0.80), Newcastle-Ottawa Scale >7 (RR: 0.82; 95% CI: 0.66-0.97) and Newcastle-Ottawa Scale ≤7 (RR: 0.59; 95% CI: 0.49-0.68).Conclusion: Green tea consumption could be a protective factor for esophageal cancer.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

A Dose-Response Meta-analysis of Coffee Consumption and Colorectal Cancer Risk in the Japanese Population: Application of a Cubic-Spline Model

BACKGROUND

A recent meta-analysis compared the relative risks of colorectal cancer between the highest and lowest levels of coffee consumption in the Japanese population. However, this analysis did not define the risks with respect to specific exposure values when considering levels of coffee consumption per day in the study population.

METHODS

We conducted a two-stage random-effects dose-response meta-analysis of the association between coffee consumption and colorectal cancer among the Japanese. This was performed by modeling coffee consumption using restricted cubic splines to be able to examine a potential nonlinear relation.

RESULTS

We identified a total of 26 studies from seven articles, which were distributed separately according to sex and colon/rectum cancers. Data from 14 cohort studies showed that the pooled relative risks for colorectal cancers were less than 1.0 in cases with coffee consumption of 1-3 cups/day and 1.0 in cases with consumption of 4 cups/day or more, although these results were not statistically significant. Data from 12 case-control studies showed that the pooled odds ratios for cancer risk were significantly less than 1.0 in cases with coffee consumption of 1-6 cups/day.

CONCLUSIONS

Findings from this meta-analysis indicate that moderate coffee consumption may not be associated or may be weakly inversely associated with the risk of colorectal cancer in the Japanese population.

Coffee consumption and risk of esophageal cancer incidence: A meta-analysis of epidemiologic studies

BACKGROUND

In epidemiologic studies, association between coffee consumption and esophageal cancer risk is inconsistent.

OBJECTIVE

The aim of tjis study was to evaluate the effect of coffee on esophageal cancer by combining several similar studies.

METHODS

We conducted a meta-analysis for association of coffee intake and esophageal cancer incidence. Eleven studies, including 457,010 participants and 2628 incident cases, were identified. A relative risk (RR, for cohort study) or odds ratio (OR, for case-control study) of heavy coffee drinkers was calculated, compared with light coffee drinkers or non-drinkers. The analysis was also stratified by cancer types (esophageal squamous cell carcinoma and esophageal adenocarcinoma), sex, and geographic region.

RESULTS

The summarized OR of having esophageal cancer in heavy coffee drinkers was 0.93 (95% confidence interval [CI]: 0.73-1.12), compared with light coffee drinkers. When stratified by sex, pathologic type of esophageal cancer, and type of epidemiologic study, we did not find any association of coffee consumption and esophageal cancer incidence. However, an inverse association between coffee consumption and incidence of esophageal cancer was found in East Asia participants with OR of 0.64 (95% CI: 0.44-0.83), but not in Euro-America participants (OR = 1.05; 95% CI: 0.81-1.29).

CONCLUSION

There is a protective role of coffee consumption against esophageal cancer in East Asians, but not in Euro-Americans.

An inverse association between tea consumption and colorectal cancer risk

It is well known that the tea extracts, mainly polyphenols as chemo-preventive elements, could act as cancer progression blockers. Although the association between tea consumption and colorectal cancer risk has been widely investigated, the results still remain inconsistent. We conducted a dose-response meta-analysis to evaluate their relationships by enrolling qualified 29 literatures. The summary odds ratio (OR) of colorectal cancer for the highest vs. lowest tea consumption was 0.93 with 0.87–1.00 of 95% confidence intervals (CIs) among all studies with modest heterogeneity (P = 0.001, I² = 43.4%). Stratified analysis revealed that tea, especially green tea, had a protective effect among female and rectal cancer patients. Particularly, the dose-response analysis showed that there was a significant inverse association between an increment of 1 cup/day of tea consumption and colorectal cancer risk in the subgroup of the green tea drinking (OR = 0.98, 95% CI = 0.96–1.01, P_nonlinear = 0.003) and female (OR = 0.68, 95% CI = 0.56-0.81, P_nonlinear < 0.001). Our findings indicate that tea consumption has an inverse impact on colorectal cancer risk, which may have significant public health implications in the prevention of colorectal cancer and further similar researches.

Antioxidant Activity of Different Forms of Green Tea: Loose Leaf, Bagged and Matcha

Green tea is commercially available in three forms: loose leaf, bagged and powdered. The objective of this study was to compare the radical scavenging capacity of different forms of green tea like loose leaf (3), bagged (2) and powdered matcha (2) of various brands. The green tea forms were prepared at 95-100°C for 5 min., to mimic conditions usually used for tea preparations at home. The comparison of combined IC50 values of different green tea forms (loose leaf, bagged and matcha) showed no significant difference in their radical scavenging activity except bagged tea that exhibited slightly more DPPH radical scavenging potential as compared to matcha. Individually, the Bud white loose leaf demonstrated highest antioxidant activity followed by Laplant bag, Lipton bag, Laplant loose, Gourmet matcha, Wow matcha and Lipton loose. These findings revealed that on the basis of form, it may not be possible to generalize which form of tea whether loose leaf, bagged or matcha, is more effective in scavenging free radicals.

Association between green tea intake and risk of gastric cancer: a systematic review and dose-response meta-analysis of observational studies

OBJECTIVE

To examine and quantify the potential dose-response relationship between green tea intake and the risk of gastric cancer.

DESIGN

We searched PubMed, EMBASE, Web of Science, CBM, CNKI and VIP up to December 2015 without language restrictions.

SETTING

A systematic review and dose-response meta-analysis of observational studies.

SUBJECTS

Five cohort studies and eight case-control studies.

RESULTS

Compared with the lowest level of green tea intake, the pooled relative risk (95 % CI) of gastric cancer was 1·05 (0·90, 1·21, I 2=20·3 %) for the cohort studies and the pooled OR (95 % CI) was 0·84 (0·74, 0·95, I 2=48·3 %) for the case-control studies. The pooled relative risk of gastric cancer was 0·79 (0·63, 0·97, I 2=63·8 %) for intake of 6 cups green tea/d, 0·59 (0·42, 0·82, I 2=1·0 %) for 25 years of green tea intake and 7·60 (1·67, 34·60, I 2=86·5 %) for drinking very hot green tea.

CONCLUSIONS

Drinking green tea has a certain preventive effect on reducing the risk of gastric cancer, particularly for long-term and high-dose consumption. Drinking too high-temperature green tea may increase the risk of gastric cancer, but it is still unclear whether high-temperature green tea is a risk factor for gastric cancer. Further studies should be performed to obtain more detailed results, including other gastric cancer risk factors such as smoking and alcohol consumption and the dose of the effective components in green tea, to provide more reliable evidence-based medical references for the relationship between green tea and gastric cancer.

Prevention of Gastric Cancer: Eradication of Helicobacter Pylori and Beyond

Although its prevalence is declining, gastric cancer remains a significant public health issue. The bacterium Helicobacter pylori is known to colonize the human stomach and induce chronic atrophic gastritis, intestinal metaplasia, and gastric cancer. Results using a Mongolian gerbil model revealed that H. pylori infection increased the incidence of carcinogen-induced adenocarcinoma, whereas curative treatment of H. pylori significantly lowered cancer incidence. Furthermore, some epidemiological studies have shown that eradication of H. pylori reduces the development of metachronous cancer in humans. However, other reports have warned that human cases of atrophic metaplastic gastritis are already at risk for gastric cancer development, even after eradication of these bacteria. In this article, we discuss the effectiveness of H. pylori eradication and the morphological changes that occur in gastric dysplasia/cancer lesions. We further assess the control of gastric cancer using various chemopreventive agents.

Effect of decaffeinated coffee on function and nucleotide metabolism in kidney

Little is known about the effects of coffee that are not related to the presence of caffeine. The aim of the study was to analyse changes in kidney function and nucleotide metabolism related to high intake of decaffeinated coffee. Mice consumed decaffeinated coffee extract for two weeks. Activities of AMP deaminase, ecto5′-nucleotidase, adenosine deaminase, purine nucleoside phosphorylase were measured in kidney cortex and medulla by analysis of conversion of substrates into products using HPLC. Concentration of nucleotides in kidney cortex, kidney medulla and serum were estimated by HPLC. Activity of ecto5′-nucleotidase increased from 0.032 ± 0.006 to 0.049 ± 0.014 nmol/mg tissue/min in kidney cortex of mice administered high-dose decaffeinated coffee (HDC) together with increase in cortex adenosine concentration and decrease in plasma creatinine concentration. HDC leads to increased activity of ecto5′-nucleotidase in kidney cortex that translates to increase in concentration of adenosine. Surprisingly this caused improved kidney excretion function.

The risk of cancer as a result of elevated levels of nitrate in drinking water and vegetables in Central India

The objective of the present study was to determine the effect of nitrates on the incidence of gastrointestinal (GI) cancer development. Nitrate converted to nitrite under reducing conditions of gut results in the formation of N-nitrosamines which are linked to an increased gastric cancer risk. A population of 234 individuals with 78 cases of GI cancer and 156 controls residing at urban and rural settings in Nagpur and Bhandara districts of India were studied for 2 years using a case-control study. A detailed survey of 16 predictor variables using Formhub software was carried out. Nitrate concentrations in vegetables and primary drinking water supplies were measured. The logistic regression model showed that nitrate was statistically significant in predicting increasing risk of cancer when potential confounders were kept at base level (P value of 0.001 nitrate in drinking water; 0.003 for nitrate in vegetable) at P < 0.01. Exposure to nitrate in drinking water at >45 mg/L level of nitrate was associated with a higher risk of GI cancers. Analysis suggests that nitrate concentration in drinking water was found statistically significant in predicting cancer risk with an odds ratio of 1.20.

Coffee consumption and the risk of colorectal cancer by anatomical subsite in Japan: Results from the HERPACC studies

Consumption of coffee, a popular beverage worldwide, has been associated with lower colorectal cancer (CRC) risk. Although CRC exhibits different biological characteristics by anatomical subsite, the possibly heterogeneous impact of coffee on CRC by anatomical subsite has remained unclear. Here, we conducted two case-control studies to examine the association between coffee consumption and CRC risk as well as risk by anatomic subsite among Japanese using data from the Hospital-based Epidemiological Research Program at Aichi Cancer Center I and II (HERPACC-I and II). Subjects were enrolled in HERPACC-I between 1988 and 2000 and in HERPACC-II between 2001 and 2005. Coffee consumption was measured with a self-administered questionnaire. A conditional logistic regression model was used to calculate odds ratios (ORs) of CRC with coffee consumption, adjusted for potential confounders of age, smoking, alcohol drinking, red meat intake, BMI, exercise, family history of CRC, and diabetes mellitus history. We estimated summary ORs by pooling study-specific ORs with a fixed effects model. In total, 2,696 CRC cases and 13,480 non-cancer outpatients as controls were included. Overall, compared to non-drinkers, ORs of less than 1 cup/day, 1-2 cups/day and 3 or more cups/day for CRC were 0.88 (95% CI: 0.77-1.00), 0.90 (95% CI: 0.80-1.01) and 0.78 (95% CI: 0.65-0.92), respectively (trend-p = 0.009). Subsite-specific analysis revealed a significant inverse linear trend between coffee consumption and distal colon cancer (p-trend = 0.048), and a tendency toward a lower risk of rectal cancer (p-trend = 0.068). These findings suggest that coffee consumption might impact the prevention of CRC, especially distal colon cancer.

Pharmacological Intervention through Dietary Nutraceuticals in Gastrointestinal Neoplasia

Neoplastic conditions associated with gastrointestinal (GI) tract are common worldwide with colorectal cancer alone accounting for the third leading rate of cancer incidence. Other GI malignancies such as esophageal carcinoma have shown an increasing trend in the last few years. The poor survival statistics of these fatal cancer diseases highlight the need for multiple alternative treatment options along with effective prophylactic strategies. Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high intake of certain dietary agents in their regular meals have lower cancer rates. Thus, an impressive embodiment of evidence supports the concept that dietary factors are key modulators of cancer including those of GI origin. Preclinical studies on animal models of carcinogenesis have reflected the pharmacological significance of certain dietary agents called as nutraceuticals in the chemoprevention of GI neoplasia. These include stilbenes (from red grapes and red wine), isoflavones (from soy), carotenoids (from tomatoes), curcuminoids (from spice turmeric), catechins (from green tea), and various other small plant metabolites (from fruits, vegetables, and cereals). Pleiotropic action mechanisms have been reported for these diet-derived chemopreventive agents to retard, block, or reverse carcinogenesis. This review presents a prophylactic approach to primary prevention of GI cancers by highlighting the translational potential of plant-derived nutraceuticals from epidemiological, laboratory, and clinical studies, for the better management of these cancers through consumption of nutraceutical rich diets and their intervention in cancer therapeutics.

Effect of green tea catechins on gastric mucosal dysplasia in insulin-gastrin mice

Green tea catechins (GTCs) have been implicated in various physiological effects, including anti-carcinogenic activities. In the present study, we evaluated the effects of GTCs specifically on the development of gastritis and pre-malignant lesions in insulin-gastrin mice. Nine-week-old male INS-GAS mice (n=38) were supplemented with GTCs for 4 and 28 weeks, and their body weights, serum gastrin levels, histopathology and pro-inflammatory cytokine levels in gastric tissue and mucosal cell proliferation were monitored. Body weights of the GTC-treated mice were significantly lower than those of the untreated controls (P≤0.05). Serum gastrin levels were suppressed at the age of 37-weeks (P≤0.05). The histopathological scores indicated that the extent of dysplasia was significantly diminished (P≤0.05), although GTC supplementation did not affect the inflammation scores. The messenger RNA levels of interferon (IFN)-γ were significantly reduced at the age of 13 weeks (P≤0.05), although the changes did not reach statistical significance at the age of 37 weeks (P=0.056). The labeling index of Ki-67 immunohistochemistry was significantly decreased (P≤0.05). These results demonstrated that GTCs may play a protective role in the development of gastritis and pre-malignant lesions via an IFN-γ, gastrin, and mucosal cell proliferation-dependent mechanism in this rodent model and potentially in humans.

Tea and human health: biomedical functions of tea active components and current issues

Originating in China, tea and tea planting have spread throughout the world since the middle of the Tang dynasty. Now people from 160 countries in the world are accustomed to tea drinking. A brief history of tea's medicinal role in China and its spread to the world are introduced. The effectiveness of tea active components and tea drinking on major human diseases, including cancer, metabolic syndrome, cardiovascular disease, and neurodegenerative diseases, is discussed. Also presented are some related issues, such as the bioavailability of tea active components, the new formulations of tea polyphenols, and the safety for consumers of dietary supplements containing tea polyphenols.

Combination of siRNA-directed gene silencing with epigallocatechin-3-gallate (EGCG) reverses drug resistance in human breast cancer cells

Elevated expression of NF-E2-related factor 2 (Nrf2), a nuclear transcription factor, is a frequent genetic abnormality seen in this malignancy and is an important contributor to chemoresistance in cancer therapy. In the present study, we investigated if Nrf2 was associated with drug resistance in tamoxifen-resistant MCF-7 (MCF-7/TAM) cells, and whether EGCG, major flavonoid isolated from green tea, could reverse drug resistance in MCF-7/TAM cells. Our results showed that the endogenous expression of Nrf2 as well as its target proteins heme oxygenase-1, NADP (H):quinone oxidoreductase in MCF-7/TAM cells was higher than that in MCF-7 cells. Epicatechin gallate (EGCG) significantly sensitizes MCF-7/TAM cells to tamoxifen and dramatically reduced Nrf2 expression at both the messenger RNA and protein, leading to a reduction of Nrf2-downstream genes. In addition, using siRNA technique, we found that the intracellular Nrf2 protein level was significantly decreased in MCF-7/TAM cells and tamoxifen resistance was partially reversed by Nrf2 siRNA. Combination of siRNA-directed gene silencing with EGCG downregulated the Nrf2-dependent response and partly reversed tamoxifen resistance in MCF-7/TAM cells in a synergic manner. These results suggested that combining the chemotherapeutic effect of EGCG with siRNA-mediated Nrf2 knock-down results in the feasibility of using Nrf2 inhibitors to increase efficacy of chemotherapeutic drugs.

A case-control study of stomach cancer in relation to Camellia sinensis in China

OBJECTIVE

The purpose of our study was to investigate the association between green tea (Camellia sinensis) drinking habits and risk of stomach cancer in China.

METHOD

A 1:2 matched hospital-based case-control study including 160 cases and 320 controls was conducted. A self-designed questionnaire was used to collect information on possible risk factors of stomach cancer, and to assess the green tea drinking habit. Conditional logistic regression was used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

RESULT

Our study proposed that green tea was associated with risk of stomach cancer. Regular drinking (OR = 0.72), larger amount of consumption (≥35 g/week) (OR = 0.53) were protective factors. Among regular tea drinkers, lower temperature and longer interval between tea being poured and drunk also reduced the risk. Moreover, a strong agreement was found between temperature at which tea was drunk and tea interval (Correlation coefficient p value = 0.73).

CONCLUSION

Habits of green tea drinking, including regular drinking, larger amount of consumption, lower temperature and longer interval were strongly associated with a lower risk of stomach cancer.

Coffee consumption and risk of colorectal cancer: the Japan Collaborative Cohort Study

BACKGROUND

Epidemiologic studies have reported coffee consumption to be associated with various health conditions. The purpose of this study was to examine the relationship of coffee consumption with colorectal cancer incidence in a large-scale prospective cohort study in Japan.

METHODS

We used data from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study). Here, we analyzed a total of 58 221 persons (23 607 men, 34 614 women) followed from 1988 to the end of 2009. During 738 669 person-years of follow-up for the analysis of colorectal cancer risk with coffee consumption at baseline, we identified 687 cases of colon cancer (355 males and 332 females) and 314 cases of rectal cancer (202 males and 112 females). We used the Cox proportional-hazard regression model to estimate hazard ratio (HR).

RESULTS

Compared to those who consumed less than 1 cup of coffee per day, men who consumed 2-3 cups of coffee per day had an HR of 1.26 (95% confidence interval [CI] 0.93-1.70), and men who consumed more than 4 cups of coffee per day had an HR of 1.79 (95% CI 1.01-3.18). A statistically significant increase in the risk of colon cancer was associated with increasing coffee consumption among men (P for trend = 0.03). On the other hand, coffee consumption in women was not associated with incident risk of colon cancer. Coffee consumption was also not associated with rectal cancer incidence in men or women.

CONCLUSIONS

This large-scale population-based cohort study showed that coffee consumption increases the risk of colon cancer among Japanese men.

Immunomodulatory effect of tea saponin in immune T-cells and T-lymphoma cells via regulation of Th1, Th2 immune response and MAPK/ERK2 signaling pathway

The anti-cancer activity of saponins and phenolic compounds present in green tea was previously reported. However, the immunomodulatory and adjuvanticity activity of tea saponin has never been studied. In this study, we investigated the immunomodulatory effect of tea saponin in T-lymphocytes and EL4 cells via regulation of cytokine response and mitogen-activated protein kinases (MAPK) signaling pathway. Quantitative analysis of mRNA expression level of cytokines were performed by reverse transcription polymerase chain reaction following stimulation with tea saponin, ovalbumin (OVA) alone or tea saponin in combination with OVA. Tea saponin inhibited the proliferation of EL4 cells measured in a dose-dependent manner. No cytotoxicity effect of tea saponin was detected in T-lymphocytes; rather, tea saponin enhanced the proliferation of T-lymphocytes. Tea saponin with OVA increased the expression of interleukin (IL)-1, IL-2, IL-12, interferon-γ and tumor necrosis factor (TNF)-α and decreased the expression level of IL-10 and IL-8 in T-lymphocytes. Furthermore, tea saponin, in the presence of OVA, downregulated the MAPK signaling pathway via inhibition of IL-4, IL-8 and nuclear factor kappaB (NF-κB) in EL4 cells. Th1 cytokines enhancer and Th2 cytokines and NF-κB inhibitor, tea saponin can markedly inhibit the proliferation and invasiveness of T-lymphoma (EL4) cells, possibly due to TNF-α- and NF-κB-mediated regulation of MAPK signaling pathway.

Green tea consumption and risk of esophageal cancer: a meta-analysis of published epidemiological studies

We performed a meta-analysis to analyze the association of various levels of green tea consumption with risk of esophageal cancer. We searched MEDLINE, EMBASE, and the Cochrane Library for studies of green tea consumption and esophageal cancer and identified 12 observational studies. For esophageal cancer, the pooled relative risk (RR) was 1.09 [95% confidence interval (CI), 0.76-1.55] for greatest vs. non/least green tea consumption; however, there was significant heterogeneity across studies (P = 0.00, I(2) = 75.5%). Compared with subjects who drank no/least green tea, the pooled RR was 1.14 (95% CI = 0.97-1.35) for moderate drinkers, 0.94 (95% CI = 0.77-1.13) for those who drank little, and 0.97 (95% CI = 0.77-1.22) for all subjects who had ever drunk green tea. Subgroup analysis showed that the RR was 0.46 (95% CI = 0.29-0.73) for female subjects. The results of the present meta-analysis are that any association between green tea and risk of esophageal cancer remains unclear. Subgroup analyses indicated that greater consumption of green tea might reduce the risk of esophageal cancer in female subjects. However, the results are based on limited research. Further research is needed to confirm the results and clarify the likely biological mechanisms.

Coffee and green tea consumption is associated with upper aerodigestive tract cancer in Japan

The impact of coffee and green tea consumption on upper aerodigestive tract (UADT) cancer risk has not been established. Evaluation of the possible anticarcinogenic properties of their ingredients is confounded by the potential increase in risk owing to the high temperatures at which these beverages are generally consumed. We conducted a case-control study to evaluate the association between coffee and tea consumption and the risk of UADT cancer. The study enrolled 961 patients with UADT cancer and 2,883 noncancer outpatients who visited Aichi Cancer Center between 2001 and 2005. Information on coffee and green tea consumption and other lifestyle factors was collected via a self-administered questionnaire. Consumption of three or more cups of coffee per day had a significant inverse association with UADT cancer [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.55-0.96]. In contrast, consumption of three or more cups of green tea per day had a significant positive association with UADT cancer (OR 1.39, 95% CI 1.13-1.70). These associations were evident for head and neck cancer but not for esophageal cancer. The association of coffee consumption with head and neck cancer was observed only among never smokers and alcohol drinkers. Similarly, the association of green tea consumption was observed among never smokers and never alcohol drinkers. No change in these associations was seen on stratification by each confounding factors. These findings suggest that consumption of coffee might be associated with a decreased risk of UADT cancer, whereas that of green tea might be associated with an increased risk.

Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies

Epidemiological studies regarding the associations of tea and coffee consumption with esophageal cancer (EC) risk are still inconsistent and this meta-analysis was conducted to examine these associations. PubMed, ISI -Web of Science, China National Knowledge Infrastructure (CNKI), and Chinese VIP database up to October 2011 were searched and manual search for reference lists of relevant studies were conducted. Random effects model was used to pool the odds ratios (OR). Twenty-four case-control and cohort studies with 7376 EC cases were included in this meta-analysis. The pooled OR of EC was 0.77 [95% confidence intervals (95% CI): 0.57, 1.04] for highest vs. non/lowest green tea consumption; but it was statistically significant for case-control studies (OR = 0.70; 95% CI: 0.51, 0.96) and for studies conducted in China (OR = 0.64; 95% CI: 0.44, 0.95). No significant association was observed for the highest vs. non/lowest black tea consumption against EC risk (OR = 1.35; 95% CI: 0.86, 2.11). A borderline significantly inverse association of highest vs. non/lowest coffee consumption against EC risk was found (OR = 0.88; 95% CI: 0.76, 1.01). In conclusion, our data showed that both green tea and coffee consumption, but not black tea consumption, have protective effects on EC.

Association between green tea and colorectal cancer risk: a meta-analysis of 13 case-control studies

OBJECTIVE

Experimental studies have suggested green tea to be a chemopreventive agent for colorectal cancer, and many studies have examined possible associations. However, the conclusions were inconsistent or even contradictory, so we performed a meta-analysis based on published case-control studies to explore if green tea is indeed a protective factor.

METHODS

PubMed was searched up to May 10th, 2012 for relevant studies, and references of included studies were manually searched. Finally 13 eligible studies, involving 12,636 cases and 38,419 controls were identified. After data extraction, a meta-analysis was performed using CMA v2 software.

RESULTS

The results indicated there may be a weak but not statistically significant reduced risk of colorectal cancer with high dose of green tea intake (OR=0.95, 95% CI:0.81-1.11, p=0.490.69-0.98). This protective effect was also found in all subgroups, except in American and European populations. Sensitivity analysis indicated the result to be robust. Publication bias was not detected by either funnel plot or Egger tests.

CONCLUSION

The results of this meta-analysis indicate a weak lower tendency for colorectal cancer development with green tea consumption, but available epidemiologic data are insufficient to conclude that green tea may protect against colorectal cancer in humans.

Green tea and incidence of colorectal cancer: evidence from prospective cohort studies

A systematic meta-analysis of prospective cohort studies on green tea consumption and colorectal cancer was performed to determine whether green tea has a chemopreventive effect against colorectal cancer. Six eligible cohort studies involving 352,275 participants and 1675 cases of colorectal cancer were identified. Combined relative risk (RR) ratios for the highest vs. lowest and increment of 1 cup/day green tea consumption levels were calculated. The combined RR of 0.90 (95% CI: 0.72-1.08) was found comparing highest vs. lowest green tea consumption levels for colorectal cancer. No significant differences by cancer-site were found, but an inverse association between green tea and incidence of colorectal cancer (RR: 0.70; 95% CI: 0.55-0.85) and colon cancer (RR: 0.69; 95% CI: 0.48-0.98) was demonstrated in Shanghai population. Singapore men had a higher risk of colorectal cancer (RR: 1.36; 95% CI: 1.06-1.74). Furthermore, an increase in green tea consumption of 1 cup/day was not associated with incidence of colorectal cancer (RR: 0.97; 95% CI: 0.91-1.03). Despite the limited evidence from Shanghai studies in support of green tea as potential chemopreventive agents against colorectal cancer, available data from prospective cohort studies are insufficient to conclude that green tea may protect against colorectal cancer.

PLA2G4A mutants modified protective effect of tea consumption against colorectal cancer

PURPOSE

The primary aim was to respectively evaluate PLA2G4A mutants modifying protective effect of tea consumption against colorectal cancer (CRC), colon and rectal cancer.

METHODS

All participants were recruited from January 2006 to April 2008. The information about tea consumption was collected by a structured questionnaire. CRC patients were diagnosed based on histology. Four single-nuclear polymorphisms (SNPs) in PLA2G4A gene were selected. Multiple logistic regression models were used for assessing the joint effects between tea consumption and SNPs on CRC, colon and rectal cancer.

RESULTS

Three hundred patients with CRC and 296 controls well-matched were used in the final analyses. The significant individual associations between four SNPs (rs6666834, rs10911933, rs4650708 and rs7526089) and CRC were not observed. However, their CTAC haplotype was significantly associated with the increased risk of CRC (OR = 3.06; 95%CI = 1.52-6.19), compared with TCAC haplotype. Drinking tea was correlated with a decreased risk of CRC after adjustment for covariates (OR = 0.61; 95%CI = 0.39-0.97). Meanwhile, compared with no-tea drinkers with TT/CT genotype of rs6666834, tea drinkers with TT/CT or CC had significant lower risk of CRC (OR = 0.6, 95%CI = 0.36-1.00 for TT/CT; 0.38, 0.19-0.74 for CC). The joint effects between the remaining three SNPs and drinking tea on CRC were observed as well. Similar findings were observed on colon and rectal cancers.

CONCLUSIONS

Tea consumption and haplotype of mutants in PLA2G4A gene were respectively associated with the risk of CRC. PLA2G4A mutants modified the protective effect of tea consumption against CRC, colon and rectal cancers in Chinese population.

Coffee induces breast cancer resistance protein expression in Caco-2 cells

Coffee is a beverage that is consumed world-wide on a daily basis and is known to induce a series of metabolic and pharmacological effects, especially in the digestive tract. However, little is known concerning the effects of coffee on transporters in the gastrointestinal tract. To elucidate the effect of coffee on intestinal transporters, we investigated its effect on expression of the breast cancer resistance protein (BCRP/ABCG2) in a human colorectal cancer cell line, Caco-2. Coffee induced BCRP gene expression in Caco-2 cells in a coffee-dose dependent manner. Coffee treatment of Caco-2 cells also increased the level of BCRP protein, which corresponded to induction of gene expression, and also increased cellular efflux activity, as judged by Hoechst33342 accumulation. None of the major constituents of coffee tested could induce BCRP gene expression. The constituent of coffee that mediated this induction was extractable with ethyl acetate and was produced during the roasting process. Dehydromethylepoxyquinomicin (DHMEQ), an inhibitor of nuclear factor (NF)-κB, inhibited coffee-mediated induction of BCRP gene expression, suggesting involvement of NF-κB in this induction. Our data suggest that daily consumption of coffee might induce BCRP expression in the gastrointestinal tract and may affect the bioavailability of BCRP substrates.

Coffee consumption and risk of colorectal cancer: a meta-analysis of observational studies

Objective

Separate meta-analyses based on case–control and cohort studies have reported different results on the relationship between coffee consumption and colorectal cancer risk. To clarify the effect of coffee intake on colorectal cancer risk, we performed a meta-analysis based on both case–control and cohort studies.

Design

Review study.

Setting

We identified case–control and cohort studies related to coffee consumption and colorectal cancer risk listed on MEDLINE, the Cochrane Controlled Trials Register, EMBASE, Science Citation Index and PubMed (until May 2011).

Subjects

Research literature on the relationship between coffee consumption and colorectal cancer risk.

Results

Twenty-five case–control (15 522 cases) and sixteen cohort studies (10 443 cases) were included in the meta-analysis. Comparing the highest v. the lowest/non category of coffee consumption, the combined results from case–control studies showed a significant relationship with colorectal cancer (OR = 0·85, 95 % CI 0·75, 0·97) and colon cancer (OR = 0·79, 95 % CI 0·67, 0·95), but not rectal cancer (OR = 0·95, 95 % CI 0·79, 1·15). For cohort studies, there was a slight suggestion of an inverse association with colorectal cancer (relative ratio = 0·94; 95 % CI 0·88, 1·01) and colon cancer (OR = 0·93, 95 % CI 0·86, 1·01), rather than rectal cancer (OR = 0·98, 95 % CI 0·88, 1·09). In subgroup analyses using case–control studies, significant inverse associations were found in females for colorectal cancer and in Europe for colorectal and colon cancer, while the subgroup analyses of cohort studies found that coffee drinks substantially decreased risk of colon cancer only in Asian women.

Conclusions

Results from case–control studies suggest coffee consumption can significantly decrease the risks of colorectal cancer and colon cancer, especially in Europe and for females.

Green tea consumption and gastric cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population

OBJECTIVE

Numerous in vitro and animal studies have shown that green tea has a protective effect against cancer. However, results from epidemiologic studies are conflicting. We evaluated the association between green tea consumption and risk for gastric cancer risk among the Japanese population based on a systematic review of epidemiologic evidence.

METHODS

Original data were obtained from MEDLINE searches using PubMed or from searches of the Ichushi database, complemented with manual searches. Evaluation of associations was based on the strength of evidence and the magnitude of association, together with biologic plausibility.

RESULTS

Eight cohort studies and three case-control studies were identified. Overall, we found no preventive effect on gastric cancer for green tea intake in cohort studies. However, a small, consistent risk reduction limited to women was observed, which was confirmed by pooling data of six cohort studies (hazard ratio = 0.79, 95% confidence interval 0.65-0.96 with ≥5 cups/day of green tea intake). Case-control studies consistently showed a weak inverse association between green tea intake and gastric cancer risk.

CONCLUSIONS

We conclude that green tea possibly decreases the risk of gastric cancer in women. However, epidemiologic evidence is still insufficient to demonstrate any association in men.

Coffee extract attenuates changes in cardiovascular and hepatic structure and function without decreasing obesity in high-carbohydrate, high-fat diet-fed male rats

Coffee, a rich source of natural products, including caffeine, chlorogenic acid, and diterpenoid alcohols, has been part of the human diet since the 15th century. In this study, we characterized the effects of Colombian coffee extract (CE), which contains high concentrations of caffeine and diterpenoids, on a rat model of human metabolic syndrome. The 8-9 wk old male Wistar rats were divided into four groups. Two groups of rats were fed a corn starch-rich diet whereas the other two groups were given a high-carbohydrate, high-fat diet with 25% fructose in drinking water for 16 wk. One group fed each diet was supplemented with 5% aqueous CE for the final 8 wk of this protocol. The corn starch diet contained ~68% carbohydrates mainly as polysaccharides, whereas the high-carbohydrate, high-fat diet contained ~68% carbohydrates mainly as fructose and sucrose together with 24% fat, mainly as saturated and monounsaturated fat from beef tallow. The high-carbohydrate, high-fat diet-fed rats showed the symptoms of metabolic syndrome leading to cardiovascular remodeling and nonalcoholic fatty liver disease. CE supplementation attenuated impairment in glucose tolerance, hypertension, cardiovascular remodeling, and nonalcoholic fatty liver disease without changing abdominal obesity and dyslipidemia. This study suggests that CE can attenuate diet-induced changes in the structure and function of the heart and the liver without changing the abdominal fat deposition.

Perioperative polyphenon E, a green tea extract, does not affect the wound complication rate in mice after sham laparotomy yet has an inhibitory effect on wound healing

INTRODUCTION

Major surgery is associated with physiologic alterations that may promote tumor growth, and catechins in green tea may inhibit tumor growth. This study's aim was to assess the impact of a green tea extract on laparotomy wound healing in mice.

METHODS

Mice were randomized to daily oral catechins solution (n = 25) or placebo (n = 20), underwent sham laparotomy after 10 days, and were sacrificed on postoperative day 7 or 21. The peak force and total energy required to rupture the abdominal wall wound, wound collagen content, and histology were assessed.

RESULTS

There were no wound complications in either group, and mean peak wound rupture forces and collagen concentration were similar. Mean energy was lower and more fibroblast proliferation was found in the treatment group on postoperative day 21.

CONCLUSIONS

These results suggest that catechins has only mild clinically significant adverse effect on wound healing, and its perioperative use warrants further study.

Associations between frequency of tea consumption and health and mortality: evidence from old Chinese

Tea consumption may be associated with reduced risk of morbidity and mortality; however, this association is not conclusive and has rarely been investigated among very old adults. The present study examines how self-reported frequency of tea consumption in daily life is associated with health and mortality among very old adults in China. The data are from a national longitudinal data set that included 32 606 individuals (13 429 men and 19 177 women) aged 65 years and older: 11 807 respondents aged 65 to 84 years and 20 799 respondents aged 85 years and older. A total of four measurements between 1998 and 2005 resulted in 51 668 observations. Hazard regressions showed that men who drink tea almost every day have a 10-20 % lower risk of death compared to their counterparts who seldom drink tea, after adjusting for numerous confounders including baseline health. This relationship was stronger in younger male elders aged 65 to 84 years than in the oldest-old men aged 85 years and older. However, frequency of tea consumption was not significantly associated with mortality in women. Our analyses further show that high frequency of tea consumption is significantly associated with reduced OR of disability in activities of daily living, cognitive impairment, self-rated poor health, cumulative health deficits and CVD in both young elders and the oldest-old, and in both men and women. These results suggest that the health benefit of drinking tea is universal. We conclude that frequent tea consumption probably helps one achieve healthy longevity and that men benefit more from such lifestyles.

Spatial autocorrelation calculations of the nine malignant neoplasms in Taiwan in 2005-2009: a gender comparison study

Spatial analytical techniques and models are often used in epidemiology to identify spatial anomalies (hotspots) in disease regions. These analytical approaches can be used to identify not only the location of such hotspots, but also their spatial patterns. We used spatial autocorrelation methodologies, including Global Moran's I and Local Getis-Ord statistics, to describe and map spatial clusters and areas in which nine malignant neoplasms are situated in Taiwan. In addition, we used a logistic regression model to test the characteristics of similarity and dissimilarity between males and females and to formulate the common spatial risk. The mean found by local spatial autocorrelation analysis was used to identify spatial cluster patterns. We found a significant relationship between the leading malignant neoplasms and well-documented spatial risk factors. For instance, in Taiwan, the geographic distribution of clusters where oral cavity cancer in males is prevalent was closely correspond to the locations in central Taiwan with serious metal pollution. In females, clusters of oral cavity cancer were closely related with aboriginal townships in eastern Taiwan, where cigarette smoking, alcohol drinking, and betel nut chewing are commonplace. The difference between males and females in the spatial distributions was stark. Furthermore, areas with a high morbidity of gastric cancer were clustered in aboriginal townships where the occurrence of Helicobacter pylori is frequent. Our results revealed a similarity between both males and females in spatial pattern. Cluster mapping clarified the spatial aspects of both internal and external correlations for the nine malignant neoplasms. In addition, using a method of logistic regression also enabled us to find differentiation between gender-specific spatial patterns.

Dietary soy and tea mitigate chronic inflammation and prostate cancer via NFκB pathway in the Noble rat model

Chronic inflammation and nuclear factor-kappa B (NFκB) have been implicated in prostate cancer development; thus, dietary factors that inhibit NFκB may serve as effective chemo-preventative agents. Prostate cancer risk is significantly lower in Asian countries compared to the United States, which has prompted interest in the potential chemopreventative action of Asian dietary components such as soy and green tea. This study examined the effects of dietary soy and tea on NFκB activation and inflammation in vivo using a hormone-induced rat model for prostate cancer. Male Noble rats implanted with estradiol and testosterone were divided into 4 dietary groups: control, soy, tea, or soy+tea. NFκB activation and inflammatory cytokines were measured post implantation. The combination of soy and tea suppressed NFκB p50 binding activity and protein levels via induction of IκBα. Soy and tea also decreased prostate inflammatory infiltration, increased Bax/BcL2 ratio and decreased protein expression of tumor necrosis factor-alpha, interleukin (IL)-6 and IL-1β compared to control. Soy and tea attenuated prostate malignancy by decreasing prostate hyperplasia. These effects were not apparent in groups treated with soy or tea alone. The ongoing in vivo studies thus far suggest that combination of foods, such as soy and tea, may inhibit hormone-induced proinflammatory NFκB signals that contribute to prostate cancer development.

Green tea and prevention of esophageal and lung cancers

Green tea contains high concentrations of tea polyphenols that have shown inhibitory effects against the development, progress, and growth of carcinogen-induced tumors in animal models at different organ sites, including the esophagus and lung. Green tea polyphenols also have shown to suppress cell proliferation and induce apoptosis. Besides antioxidative property, green tea polyphenols have pro-oxidative activities under certain conditions and modulate phase II metabolic enzymes that can enhance the detoxification pathway of environmental toxicants and carcinogens. Although epidemiological studies have provided inconclusive results on the effect of green tea consumption against the development of esophageal and lung cancers in humans overall, the inverse association between green tea intake and risk of esophageal cancer risk is more consistently observed in studies with adequate control for potential confounders. Epidemiological studies also have demonstrated an inverse, albeit moderate, association between green tea consumption and lung cancer, especially in non-smokers. This article reviews data on the cancer-preventive activities of green tea extract and green tea polyphenols and possible mechanisms against the esophageal and lung carcinogenesis in experimental animals, and summarizes the current knowledge from epidemiological studies on the relationship between green tea consumption and esophageal and lung cancer risk in humans.

Coffee and cancers of the upper digestive and respiratory tracts: meta-analyses of observational studies

BACKGROUND

Data of epidemiological studies on the relation between coffee drinking and upper aerodigestive tract cancer risk are scattered and inconclusive. We therefore conducted systematic meta-analyses of observational studies published before October 2009.

MATERIALS AND METHODS

We combined relative risks (RR) with 95% confidence intervals (CI) for cancers of the oral cavity/pharynx (OP) and larynx, esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC), comparing the highest versus the lowest categories of coffee consumption, using random-effects models.

RESULTS

For OP cancer, the pooled RR was 0.64 (95% CI 0.51-0.80) for highest versus lowest coffee drinking, based on a total of 2633 cases from one cohort and eight case-control studies, with no significant heterogeneity across studies. The RRs were 0.61 (95% CI 0.41-0.89) for European, 0.58 (95% CI 0.36-0.94) for American and 0.74 (95% CI 0.48-1.15) for Asian studies, where coffee consumption is lower. The corresponding RRs were 1.56 (95% CI 0.60-4.02) for laryngeal cancer (732 cases from three case-control studies), 0.87 (95% CI 0.65-1.17) for ESCC (2115 cases from one cohort and six case-control studies) and 1.18 (95% CI 0.81-1.71) for EAC (415 cases from three case-control studies).

CONCLUSION

Coffee drinking is inversely related to OP cancer risk, while there is no relation with laryngeal cancer, ESCC and EAC.

Coffee consumption and risk of colorectal cancer: a meta-analysis of case-control studies

A meta-analysis of case-control studies on coffee consumption and colorectal cancer risk was conducted. Twenty-four eligible studies published before May 2010 were identified, including a total of 14,846 cases of colorectal, colon or rectal cancer. Compared to non/occasional drinkers, the odds ratios (OR) for drinkers were 0.83 (95% CI 0.73-0.95) for colorectal, 0.93 (95% CI 0.81-1.07) for colon and 0.98 (95% CI 0.85-1.13) for rectal cancer, with significant heterogeneity among studies; the corresponding ORs for the increment of 1 cup/day were 0.94 (95% CI 0.91-0.98), 0.95 (95% CI 0.92-0.98), and 0.97 (95% CI 0.95-0.99). For the highest coffee drinkers, the ORs were 0.70 (95% CI 0.60-0.81) for colorectal cancer, 0.75 (95% CI 0.64-0.88) for colon cancer and 0.87 (95% CI 0.75-1.00) for rectal cancer, when compared to non/low drinkers. The results of this meta-analysis of case-control studies suggest a moderate favorable effect of coffee consumption on colorectal cancer risk. The reduced risk was consistent across study design (hospital vs. population based), geographic area, and various confounding factors considered. It may reflect a real protection but also partly or largely be due to reverse causation, i.e. decreased coffee consumption among cases following the onset of bowel symptoms.

Targeting of histamine producing cells by EGCG: a green dart against inflammation?

The human body is made of some 250 different cell types. From them, only a small subset of cell types is able to produce histamine. They include some neurons, enterochromaffin-like cells, gastrin-containing cells, mast cells, basophils, and monocytes/macrophages, among others. In spite of the reduced number of these histamine-producing cell types, they are involved in very different physiological processes. Their deregulation is related with many highly prevalent, as well as emergent and rare diseases, mainly those described as inflammation-dependent pathologies, including mastocytosis, basophilic leukemia, gastric ulcer, Crohn disease, and other inflammatory bowel diseases. Furthermore, oncogenic transformation switches some non-histamine-producing cells to a histamine producing phenotype. This is the case of melanoma, small cell lung carcinoma, and several types of neuroendocrine tumors. The bioactive compound epigallocatechin-3-gallate (EGCG), a major component of green tea, has been shown to target histamine-producing cells producing great alterations in their behavior, with relevant effects on their proliferative potential, as well as their adhesion, migration, and invasion potentials. In fact, EGCG has been shown to have potent anti-inflammatory, anti-tumoral, and anti-angiogenic effects and to be a potent inhibitor of the histamine-producing enzyme, histidine decarboxylase. Herein, we review the many specific effects of EGCG on concrete molecular targets of histamine-producing cells and discuss the relevance of these data to support the potential therapeutic interest of this compound to treat inflammation-dependent diseases.