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Tanabe H, Suzuki T, Ohishi T, Isemura M, Nakamura Y, Unno K. Effects of Epigallocatechin-3-Gallate on Matrix Metalloproteinases in Terms of Its Anticancer Activity. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020525. [PMID: 36677584 PMCID: PMC9862901 DOI: 10.3390/molecules28020525] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/29/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023]
Abstract
Epidemiological studies have shown that the consumption of green tea has beneficial effects against cancer. Basic studies have provided evidence that epigallocatechin gallate (EGCG) is a major contributor to these effects. Matrix metalloproteinases (MMPs) are zinc-dependent metalloproteinases with the ability to degrade the extracellular matrix proteins and are involved in various diseases including cancer in which MMPs have a critical role in invasion and metastasis. In this review, we discuss the effects of EGCG on several types of MMPs in the context of its anticancer activity. In the promoter region, MMPs have binding sites for at least one transcription factor of AP-1, Sp1, and NF-κB, and EGCG can downregulate these transcription factors through signaling pathways mediated by reactive oxygen species. EGCG can also decrease nuclear ERK, p38, heat shock protein-27 (Hsp27), and β-catenin levels, leading to suppression of MMPs' expression. Other mechanisms by which EGCG inhibits MMPs include direct binding to MMPs to prevent their activation and downregulation of NF-κB to suppress the production of inflammatory cytokines such as TNFα and IL-1β. Findings from studies on EGCG presented here may be useful in the development of more effective anti-MMP agents, which would give beneficial effects on cancer and other diseases.
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Affiliation(s)
- Hiroki Tanabe
- Faculty of Health and Welfare Science, Nayoro City University, Nayoro 096-8641, Hokkaido, Japan
- Correspondence: (H.T.); (T.O.)
| | - Takuji Suzuki
- Department of Food Science and Nutrition, Faculty of Human Life and Science, Doshisha Women’s College of Liberal Arts, Kyoto 602-0893, Japan
| | - Tomokazu Ohishi
- Institute of Microbial Chemistry (BIKAKEN), Numazu, Microbial Chemistry Research Foundation, Numazu 410-0301, Shizuoka, Japan
- Institute of Microbial Chemistry (BIKAKEN), Laboratory of Oncology, Microbial Chemistry Research Foundation, Shinagawa, Tokyo 141-0021, Japan
- Correspondence: (H.T.); (T.O.)
| | - Mamoru Isemura
- Tea Science Center, University of Shizuoka, Suruga-ku, Shizuoka 422-8526, Japan
| | - Yoriyuki Nakamura
- Tea Science Center, University of Shizuoka, Suruga-ku, Shizuoka 422-8526, Japan
| | - Keiko Unno
- Tea Science Center, University of Shizuoka, Suruga-ku, Shizuoka 422-8526, Japan
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Martimianaki G, Alicandro G, Pelucchi C, Bonzi R, Rota M, Hu J, Johnson KC, Rabkin CS, Liao LM, Sinha R, Zhang ZF, Dalmartello M, Lunet N, Morais S, Palli D, Ferraroni M, Yu GP, Tsugane S, Hidaka A, Curado MP, Dias-Neto E, Zaridze D, Maximovitch D, Vioque J, Garcia de la Hera M, López-Carrillo L, Hernández-Ramírez RU, Hamada GS, Ward MH, Mu L, Malekzadeh R, Pourfarzi F, Trichopoulou A, Karakatsani A, Kurtz RC, Lagiou A, Lagiou P, Boccia S, Boffetta P, Camargo MC, Negri E, La Vecchia C. Tea consumption and gastric cancer: a pooled analysis from the Stomach cancer Pooling (StoP) Project consortium. Br J Cancer 2022; 127:726-734. [PMID: 35610368 PMCID: PMC9381730 DOI: 10.1038/s41416-022-01856-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/19/2022] [Accepted: 05/10/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Evidence from epidemiological studies on the role of tea drinking in gastric cancer risk remains inconsistent. We aimed to investigate and quantify the relationship between tea consumption and gastric cancer in the Stomach cancer Pooling (StoP) Project consortium. METHODS A total of 9438 cases and 20,451 controls from 22 studies worldwide were included. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of gastric cancer for regular versus non-regular tea drinkers were estimated by one and two-stage modelling analyses, including terms for sex, age and the main recognised risk factors for gastric cancer. RESULTS Compared to non-regular drinkers, the estimated adjusted pooled OR for regular tea drinkers was 0.91 (95% CI: 0.85-0.97). When the amount of tea consumed was considered, the OR for consumption of 1-2 cups/day was 1.01 (95% CI: 0.94-1.09) and for >3 cups/day was 0.91 (95% CI: 0.80-1.03). Stronger inverse associations emerged among regular drinkers in China and Japan (OR: 0.67, 95% CI: 0.49-0.91) where green tea is consumed, in subjects with H. pylori infection (OR: 0.68, 95% CI: 0.58-0.80), and for gastric cardia cancer (OR: 0.64, 95% CI: 0.49-0.84). CONCLUSION Our results indicate a weak inverse association between tea consumption and gastric cancer.
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Affiliation(s)
- Georgia Martimianaki
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy.
- Hellenic Health Foundation, Athens, Greece.
| | - Gianfranco Alicandro
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Cystic Fibrosis Centre, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Claudio Pelucchi
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
| | - Rossella Bonzi
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
| | - Matteo Rota
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Jinfu Hu
- Harbin Medical University, Harbin, China
| | - Kenneth C Johnson
- School of Epidemiology and Public Health, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Charles S Rabkin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Linda M Liao
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Rashmi Sinha
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Zuo-Feng Zhang
- Department of Epidemiology, UCLA Fielding School of Public Health and Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Michela Dalmartello
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
| | - Nuno Lunet
- EPIUnit-Instituto de Saúde Pública da Universidade do Porto, Porto, Portugal
- Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Laboratório para a Investigação Integrativa e Translacional em Saúde Populacional (ITR), Porto, Portugal
| | - Samantha Morais
- EPIUnit-Instituto de Saúde Pública da Universidade do Porto, Porto, Portugal
- Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Laboratório para a Investigação Integrativa e Translacional em Saúde Populacional (ITR), Porto, Portugal
| | - Domenico Palli
- Cancer Risk Factors and Life-Style Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network, ISPRO, Florence, Italy
| | - Monica Ferraroni
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
| | - Guo-Pei Yu
- Medical Informatics Center, Peking University, Peking, China
| | - Shoichiro Tsugane
- Epidemiology and Prevention Group, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - Akihisa Hidaka
- Epidemiology and Prevention Group, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Maria Paula Curado
- Centro Internacional de Pesquisas, A.C. Camargo Cancer Center, São Paulo, Brazil
| | - Emmanuel Dias-Neto
- Centro Internacional de Pesquisas, A.C. Camargo Cancer Center, São Paulo, Brazil
| | - David Zaridze
- Department of clinical epidemiology, N.N. Blokhin National Medical Research Center for Oncology, Moscow, Russia
| | - Dmitry Maximovitch
- Department of clinical epidemiology, N.N. Blokhin National Medical Research Center for Oncology, Moscow, Russia
| | - Jesus Vioque
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante, Universidad Miguel Hernandez (ISABIAL-UMH), Alicante, Spain
| | - Manoli Garcia de la Hera
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante, Universidad Miguel Hernandez (ISABIAL-UMH), Alicante, Spain
| | | | | | | | - Mary H Ward
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Lina Mu
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Reza Malekzadeh
- Digestive Oncology Research Center, Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Farhad Pourfarzi
- Digestive Disease Research Center, Ardabil University of Medical Sciences, Ardabil, Iran
| | | | - Anna Karakatsani
- Hellenic Health Foundation, Athens, Greece
- 2nd Pulmonary Medicine Department, National and Kapodistrian University of Athens, Medical School, "ATTIKON" University Hospital, Haidari, Greece
| | - Robert C Kurtz
- Department of Medicine, Memorial Sloan Kettering Cancer Centre, New York, NY, USA
| | - Areti Lagiou
- Department of Public and Community Health, School of Public Health, University of West Attica, Athens, Greece
| | - Pagona Lagiou
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Stefania Boccia
- Section of Hygiene, University Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, Roma, Italia
- Department of Woman and Child Health and Public Health-Public Health Area, Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italia
| | - Paolo Boffetta
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY, USA
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - M Constanza Camargo
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Eva Negri
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
- Pegaso Online University, Naples, Italy
| | - Carlo La Vecchia
- Department of Clinical Sciences and Community Health, Branch of Medical Statistics, Biometry and Epidemiology "G.A. Maccacaro", University of Milan, Milan, Italy
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Coe CL, Miyamoto Y, Love GD, Karasawa M, Kawakami N, Kitayama S, Ryff CD. Cultural and life style practices associated with low inflammatory physiology in Japanese adults. Brain Behav Immun 2020; 90:385-392. [PMID: 32805392 PMCID: PMC7544652 DOI: 10.1016/j.bbi.2020.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 07/20/2020] [Accepted: 08/08/2020] [Indexed: 02/05/2023] Open
Abstract
Japan is an exceptionally healthy East Asian country with extended longevity. In addition, the typical levels of several proinflammatory proteins, including both C-reactive protein (CRP) and interleukin-6 (IL-6), are often reported to be low when compared to American and European populations. This analysis determined if blood levels of CRP and IL-6 were associated with 4 cultural practices reflective of Japanese behavior and customs -- drinking tea, eating seafood, consuming vegetables, and partaking in relaxing baths regularly - among 382 adults living in Tokyo. Regression models controlled for demographic factors, adiposity (BMI), physical exercise, smoking, alcohol use, and chronic illness (e.g., diabetes). Consuming a Japanese diet was associated with significantly lower CRP and IL-6 levels. More frequent bathing was associated with lower IL-6, but not specifically predictive of low CRP. This study has confirmed prior evidence for low inflammatory activity in Japanese adults and its association with several behavioral practices common in Japan.
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Affiliation(s)
- Christopher L Coe
- Harlow Center for Biological Psychology, University of Wisconsin, Madison, WI, United States.
| | - Yuri Miyamoto
- Department of Psychology, University of Wisconsin, Madison, WI, United States
| | - Gayle D Love
- Institute on Aging, University of Wisconsin, Madison, WI, United States
| | - Mayumi Karasawa
- Department of Comparative Psychology, Tokyo Woman's Christian University, Tokyo, Japan
| | - Norito Kawakami
- Department of Mental Health, University of Tokyo, Tokyo, Japan
| | - Shinobu Kitayama
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States
| | - Carol D Ryff
- Department of Psychology, University of Wisconsin, Madison, WI, United States; Institute on Aging, University of Wisconsin, Madison, WI, United States
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Sheerah H, Keyang L, Eshak ES, Cui R, Shirai K, Muraki I, Iso H, Tamakoshi A. Association of tea consumption and the risk of gastric cancer in Japanese adults: the Japan Collaborative Cohort Study. BMJ Open 2020; 10:e038243. [PMID: 33028558 PMCID: PMC7539605 DOI: 10.1136/bmjopen-2020-038243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
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.
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Affiliation(s)
- Haytham Sheerah
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Liu Keyang
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Ehab Salah Eshak
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
- Public Health and Preventive Medicine, Faculty of Medicine, Minia University, Minia, Minia, Egypt
| | - Renzhe Cui
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Kokoro Shirai
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Isao Muraki
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Hiroyasu Iso
- Public Health, Department of Socia Medicine, Osaka University Graduate School of Medicine, Suita-shi, Osaka-fu, Japan
| | - Akiko Tamakoshi
- Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
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Filippini T, Malavolti M, Borrelli F, Izzo AA, Fairweather-Tait SJ, Horneber M, Vinceti M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev 2020; 3:CD005004. [PMID: 32118296 PMCID: PMC7059963 DOI: 10.1002/14651858.cd005004.pub3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
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.
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Affiliation(s)
- Tommaso Filippini
- University of Modena and Reggio Emilia, Research Center in Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Via Campi 287, Modena, Italy, 41125
| | - Marcella Malavolti
- University of Modena and Reggio Emilia, Research Center in Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Via Campi 287, Modena, Italy, 41125
| | - Francesca Borrelli
- University of Naples 'Federico II', Department of Pharmacy, School of Medicine and Surgery, Via D Montesano 49, Naples, Italy, 80131
| | - Angelo A Izzo
- University of Naples 'Federico II', Department of Pharmacy, School of Medicine and Surgery, Via D Montesano 49, Naples, Italy, 80131
| | | | - Markus Horneber
- Paracelsus Medical University, Klinikum Nuremberg, Department of Internal Medicine, Division of Oncology and Hematology, Prof.-Ernst-Nathan-Str. 1, Nuremberg, Germany, D-90419
| | - Marco Vinceti
- University of Modena and Reggio Emilia, Research Center in Environmental, Nutritional and Genetic Epidemiology (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Via Campi 287, Modena, Italy, 41125
- Boston University School of Public Health, Department of Epidemiology, 715 Albany Street, Boston, USA, MA 02118
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Li X, Yu C, Guo Y, Bian Z, Shen Z, Yang L, Chen Y, Wei Y, Zhang H, Qiu Z, Chen J, Chen F, Chen Z, Lv J, Li L. Association between tea consumption and risk of cancer: a prospective cohort study of 0.5 million Chinese adults. Eur J Epidemiol 2019; 34:753-763. [PMID: 31152367 PMCID: PMC6602977 DOI: 10.1007/s10654-019-00530-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/24/2019] [Indexed: 12/14/2022]
Abstract
Current experimental and epidemiological studies provide inconsistent evidence toward the association between tea consumption and cancer incidence. We investigated whether tea consumption was associated with the incidence of all cancers and six leading types of cancer (lung cancer, stomach cancer, colorectal cancer, liver cancer, female breast cancer and cervix uteri cancer) among 455,981 participants aged 30-79 years in the prospective cohort China Kadoorie Biobank. Tea consumption was assessed at baseline (2004-2008) with an interviewer-administered questionnaire. Cancer cases were identified by linkage to the national health insurance system. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). In the present population, daily tea consumers were more likely to be current smokers and daily alcohol consumers. 22,652 incident cancers occurred during 10.1 years follow-up (5.04 cases/1000 person-years). When we restricted analyses to non-smokers and non-excessive alcohol consumers to minimize confounding, tea consumption was not associated with all cancers (daily consumers who added tea leaves > 4.0 g/day vs. less-than-weekly consumers: HR, 1.03; 95%CI, 0.93-1.13), lung cancer (HR, 1.08; CI, 0.84-1.40), colorectal cancer (HR, 1.08; CI, 0.81-1.45) and liver cancer (HR, 1.08; CI, 0.75-1.55), yet might be associated with increased risk of stomach cancer (HR, 1.46; CI, 1.07-1.99). In both less-than-daily and daily tea consumers, all cancer risk increased with the amount of tobacco smoked or alcohol consumed. Our findings suggest tea consumption may not provide preventive effect against cancer incidence.
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Affiliation(s)
- Xinyi Li
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100191, China
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Canqing Yu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100191, China
| | - Yu Guo
- Chinese Academy of Medical Sciences, Beijing, China
| | - Zheng Bian
- Chinese Academy of Medical Sciences, Beijing, China
| | - Zewei Shen
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100191, China
| | - Ling Yang
- Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Yiping Chen
- Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Yongyue Wei
- Department of Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Hao Zhang
- Liuyang Center for Disease Control and Prevention, Liuyang, Hunan, China
| | - Zhe Qiu
- Liuyang Center for Disease Control and Prevention, Liuyang, Hunan, China
| | - Junshi Chen
- China National Center for Food Safety Risk Assessment, Beijing, China
| | - Feng Chen
- Department of Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Zhengming Chen
- Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Jun Lv
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100191, China.
- Key Laboratory of Molecular Cardiovascular Sciences (Peking University), Ministry of Education, Beijing, China.
- Peking University Institute of Environmental Medicine, Beijing, China.
| | - Liming Li
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, 38 Xueyuan Road, Beijing, 100191, China.
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Zhang L, He Y, Wu X, Zhao G, Zhang K, Yang CS, Reiter RJ, Zhang J. Melatonin and (-)-Epigallocatechin-3-Gallate: Partners in Fighting Cancer. Cells 2019; 8:cells8070745. [PMID: 31331008 PMCID: PMC6678710 DOI: 10.3390/cells8070745] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 07/11/2019] [Accepted: 07/16/2019] [Indexed: 12/24/2022] Open
Abstract
We have demonstrated previously that melatonin attenuates hepatotoxicity triggered by high doses of (−)-epigallocatechin-3-gallate (EGCG) in mice. The current work investigated the influence of melatonin on the oncostatic activity of EGCG in two cancer cell lines, wherein melatonin induced an opposite response of p21. In human tongue cancer TCA8113 cells, melatonin-induced p21 and EGCG-mediated formation of quinoproteins were positively associated with the oncostatic effects of melatonin and EGCG. Melatonin-stimulated an increase in p21 which was correlated with a pronounced nuclear translocation of thioredoxin 1 and thioredoxin reductase 1, both of which are known to induce p21 via promoting p53 trans-activation. Melatonin did not influence the EGCG-mediated increase of quinoprotein formation nor did EGCG impair melatonin-induced p21 up-regulation. Co-treatment with both agents enhanced the cell-killing effect as well as the inhibitory activities against cell migration and colony formation. It is known that p21 also plays a powerful anti-apoptotic role in some cancer cells and confers these cells with a survival advantage, making it a target for therapeutic suppression. In human hepatocellular carcinoma HepG2 cells, melatonin suppressed p21 along with the induction of pro-survival proteins, PI3K and COX-2. However, EGCG prevented against melatonin-induced PI3K and COX-2, and melatonin probably sensitized HepG2 cells to EGCG cytotoxicity via down-regulating p21, Moreover, COX-2 and HO-1 were significantly reduced only by the co-treatment, and melatonin aided EGCG to achieve an increased inhibition on Bcl2 and NFκB. These events occurring in the co-treatment collectively resulted in an enhanced cytotoxicity. In addition, the co-treatment also enhanced the inhibitory activities against cell migration and colony formation. Overall, the results gathered from these two cancer cell lines with a divergent p21 response to melatonin show that the various oncostatic activities of melatonin and EGCG together are more robust than each agent alone, suggesting that they may be useful partners in fighting cancer.
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Affiliation(s)
- Lingyun Zhang
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China
| | - Yufeng He
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China
| | - Ximing Wu
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China
| | - Guangshan Zhao
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China
| | - Ke Zhang
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China
| | - Chung S Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX 78229, USA
| | - Jinsong Zhang
- Laboratory of Redox Biology, State Key Laboratory of Tea Plant Biology and Resources Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230000, China.
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Association between green tea intake and risk of gastric cancer: a systematic review and dose-response meta-analysis of observational studies. Public Health Nutr 2017; 20:3183-3192. [PMID: 28980522 DOI: 10.1017/s1368980017002208] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
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.
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Kim S, Woo M, Kim M, Noh JS, Song YO. Hot water extracts of pressure-roasted dried radish attenuates hepatic oxidative stress via Nrf2 up-regulation in mice fed high-fat diet. Food Sci Biotechnol 2017; 26:1063-1069. [PMID: 30263637 PMCID: PMC6049537 DOI: 10.1007/s10068-017-0135-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/15/2017] [Accepted: 04/07/2017] [Indexed: 11/30/2022] Open
Abstract
This study investigated the effect of pressure-roasted dried radish (PRDR) against oxidative stress. To prepare PRDR extract, dried radish (DR) was pressure-roasted, boiled, and then freeze-dried. Mice fed a chow diet with oral administration of distilled water (DW) (normal group) or a high-fat diet with DW (control, CON group), DR (DR group, 237 mg/kg bw/day), or PRDR (PRDR group, 237 mg/kg bw/day) (n = 8 each group) for 12 weeks. Hepatic lipid peroxidation level in the DR and PRDR groups was lower than that in the CON group, whereas hepatic glutathione level in these groups was higher (p < 0.05). Hepatic expression of nuclear factor (erythroid-derived 2)-like 2 and its related antioxidant enzymes such as catalase, glutathione S-transferase, and peroxidases was the highest in the PRDR group (p < 0.05). It is apparent that radish attenuate oxidative stress and the process of pressure roasting might contribute positively to this effect.
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Affiliation(s)
- Seulki Kim
- Department of Food Science and Nutrition, Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63 Beon-gil, Geumjeong-gu, Busan, 46241 Republic of Korea
- Food Processing Research Center, Korean Food Research Institute, Seongnam, 13539 Republic of Korea
| | - Minji Woo
- Department of Food Science and Nutrition, Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63 Beon-gil, Geumjeong-gu, Busan, 46241 Republic of Korea
| | - Mijeong Kim
- Department of Food Science and Nutrition, Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63 Beon-gil, Geumjeong-gu, Busan, 46241 Republic of Korea
| | - Jeong Sook Noh
- Department of Food Science and Nutrition, Tongmyong University, Busan, 48520 Republic of Korea
| | - Yeong Ok Song
- Department of Food Science and Nutrition, Kimchi Research Institute, Pusan National University, 2, Busandaehak-ro 63 Beon-gil, Geumjeong-gu, Busan, 46241 Republic of Korea
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Prevention of abdominal aortic aneurysm progression by oral administration of green tea polyphenol in a rat model. J Vasc Surg 2016; 65:1803-1812.e2. [PMID: 27473778 DOI: 10.1016/j.jvs.2016.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/05/2016] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Inflammation-mediated elastin destruction in the aortic medial layer is related to progression of abdominal aortic aneurysm (AAA). Epigallocatechin-3-gallate (EGCG), a major component of green tea polyphenols, reportedly increases elastin synthesis in vitro and may possess anti-inflammatory effects. We used a rat model to investigate whether EGCG could prevent AAA progression. METHODS AAA was induced with administration of intraluminal elastase and extraluminal CaCl2 in male rats. Rats were randomly divided into a control group (n = 30) and an EGCG group (n = 30). In the EGCG group, an EGCG solution (20 mg/d) was administered orally to each rat from 2 weeks before AAA induction and continued 4 weeks beyond induction. RESULTS The abdominal aortic diameter was significantly smaller in the EGCG group than in the control group on day 28 (2.9 ± 0.2 vs 2.3 ± 0.1 mm; P < .0001). The medial layer wall thickness and elastin content were significantly greater in the EGCG group than in the control group on day 28 (68.4 ± 13.6 vs 46.7 ± 13.4 μm [P < .001] and 20.3 ± 4.6 vs 9.5 ± 3.6% [P < .0001], respectively). Gene expression levels of tropoelastin and lysyl oxidase were significantly higher in the EGCG group immediately before AAA induction, indicating promoted elastoregeneration by EGCG administration (tropoelastin: 0.59 ± 0.36 control vs 1.24 ± 0.36 EGCG [P < .05], lysyl oxidase: 0.77 ± 0.45 control vs 1.34 ± 0.4 EGCG [P < .05]) (fold increase). Gene expression levels of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, were significantly downregulated in the EGCG group (1.82 ± 0.71 vs 0.97 ± 0.59 [P < .05] and 3.91 ± 3.24 vs 0.89 ± 0.59 [P < .05], respectively). On day 7, gene expression levels and gelatinolytic activity of matrix metalloproteinase 9 were significantly lower in the EGCG group (1.41 ± 0.86 vs 0.51 ± 0.42 [P < .05] and 1.00 ± 0.17 vs 0.29 ± 0.12 [P < .0001], respectively), whereas gene expression levels of tissue inhibitors of metalloproteinase-1 were significantly higher in the EGCG group (0.96 ± 0.11 vs 1.14 ± 0.09; P < .05). CONCLUSIONS EGCG attenuated AAA progression in a rat model by preserving the aortic thickness and elastin content of the medial layer through regeneration of elastin, as mediated by anti-inflammatory effects, and subsequent reduction of matrix metalloproteinase activity.
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Affiliation(s)
- P Correa
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-0252, USA.
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Granja A, Pinheiro M, Reis S. Epigallocatechin Gallate Nanodelivery Systems for Cancer Therapy. Nutrients 2016; 8:307. [PMID: 27213442 PMCID: PMC4882719 DOI: 10.3390/nu8050307] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 12/31/2022] Open
Abstract
Cancer is one of the leading causes of morbidity and mortality all over the world. Conventional treatments, such as chemotherapy, are generally expensive, highly toxic and lack efficiency. Cancer chemoprevention using phytochemicals is emerging as a promising approach for the treatment of early carcinogenic processes. (-)-Epigallocatechin-3-gallate (EGCG) is the major bioactive constituent in green tea with numerous health benefits including anti-cancer activity, which has been intensively studied. Besides its potential for chemoprevention, EGCG has also been shown to synergize with common anti-cancer agents, which makes it a suitable adjuvant in chemotherapy. However, limitations in terms of stability and bioavailability have hampered its application in clinical settings. Nanotechnology may have an important role in improving the pharmacokinetic and pharmacodynamics of EGCG. Indeed, several studies have already reported the use of nanoparticles as delivery vehicles of EGCG for cancer therapy. The aim of this article is to discuss the EGCG molecule and its associated health benefits, particularly its anti-cancer activity and provide an overview of the studies that have employed nanotechnology strategies to enhance EGCG's properties and potentiate its anti-tumoral activity.
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Affiliation(s)
- Andreia Granja
- UCIBIO/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Marina Pinheiro
- UCIBIO/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
| | - Salette Reis
- UCIBIO/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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Amitani M, Amitani H, Sloan RA, Suzuki H, Sameshima N, Asakawa A, Nerome Y, Owaki T, Inui A, Hoshino E. The translational aspect of complementary and alternative medicine for cancer with particular emphasis on Kampo. Front Pharmacol 2015; 6:150. [PMID: 26300773 PMCID: PMC4527580 DOI: 10.3389/fphar.2015.00150] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/09/2015] [Indexed: 12/17/2022] Open
Abstract
Complementary and alternative medicine (CAM) including Japanese Kampo is known to have anticancer potential. An increasing number of cancer survivors are using CAM for disease prevention, immune system enhancement, and symptom control. Although there have been abundant previous clinical reports regarding CAM, scientific investigations aimed at acquiring quantifiable results in clinical trials, as well as basic research regarding CAM, have only recently been undertaken. Recent studies suggest that CAM enhancement of immune function is related to cytokines. This review provides a translational aspect of CAM, particularly Hozai in Kampo from both scientific and clinical points of view for further development of CAM for cancer treatment.
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Affiliation(s)
- Marie Amitani
- Education Center for Doctors in Remote Islands and Rural Areas, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan ; Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Haruka Amitani
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Robert A Sloan
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Hajime Suzuki
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Nanami Sameshima
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Akihiro Asakawa
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Yasuhito Nerome
- Education Center for Doctors in Remote Islands and Rural Areas, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Tetsuhiro Owaki
- Education Center for Doctors in Remote Islands and Rural Areas, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Akio Inui
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima, Japan
| | - Etsuo Hoshino
- Division of Kampo Support, Cancer Institute Hospital Tokyo, Japan
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Tsugane S, Sawada N. The JPHC Study: Design and Some Findings on the Typical Japanese Diet. Jpn J Clin Oncol 2014; 44:777-82. [DOI: 10.1093/jjco/hyu096] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim J, Cho YA, Choi WJ, Jeong SH. Gene-diet interactions in gastric cancer risk: A systematic review. World J Gastroenterol 2014; 20:9600-9610. [PMID: 25071358 PMCID: PMC4110595 DOI: 10.3748/wjg.v20.i28.9600] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/17/2014] [Accepted: 05/26/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To conduct a systematic review of the published epidemiological studies investigating the association of the interactions between gene variants and dietary intake with gastric cancer risk.
METHODS: A literature search was conducted in PubMed, EMBASE, and MEDLINE for articles published between January 2000 and July 2013, and 38 studies were identified. Previous studies included various dietary factors (e.g., fruits and vegetables, soybean products, salt, meat, and alcohol) and genetic variants that are involved in various metabolic pathways.
RESULTS: Studies suggest that individuals who carry high-risk genetic variants and demonstrate particular dietary habits may have an increased risk of gastric cancer compared with those who do not carry high-risk genetic variants. Distinctive dietary patterns and variations in the frequency of genetic variants may explain the higher incidence of gastric cancer in a particular region. However, most previous studies have limitations, such as a small sample size and a retrospective case-control design. In addition, past studies have been unable to elucidate the specific mechanism in gene-diet interaction associated with gastric carcinogenesis.
CONCLUSION: Additional large prospective epidemiological and experimental studies are required to identify the gene-diet metabolic pathways related to gastric cancer susceptibility.
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Sang LX, Chang B, Li XH, Jiang M. Green tea consumption and risk of esophageal cancer: a meta-analysis of published epidemiological studies. Nutr Cancer 2014; 65:802-12. [PMID: 23909723 DOI: 10.1080/01635581.2013.805423] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
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.
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Affiliation(s)
- Li-Xuan Sang
- Department of Cadre Ward II, First Affiliated Hospital of China Medical University, Shenyang, China
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Kokubo Y, Iso H, Saito I, Yamagishi K, Yatsuya H, Ishihara J, Inoue M, Tsugane S. The impact of green tea and coffee consumption on the reduced risk of stroke incidence in Japanese population: the Japan public health center-based study cohort. Stroke 2013; 44:1369-74. [PMID: 23493733 DOI: 10.1161/strokeaha.111.677500] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND PURPOSE Few prospective studies have examined the impact of both green tea and coffee consumption on strokes. We investigated the association of the combination of those consumption with stroke incidence in a general population. METHODS We studied 82 369 Japanese (aged 45-74 years; without cardiovascular disease [CVD] or cancer in 1995 and 1998 for Cohort I and II, respectively) who received 13 years of mean follow-up through the end of 2007. Green tea and coffee consumption was assessed by self-administered food frequency questionnaire at baseline. RESULTS In the 1 066 718 person-years of follow-up, we documented the incidence of strokes (n=3425) and coronary heart disease (n=910). Compared with seldom drinking green tea, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.86 (0.78-0.95) and 0.80 (0.73-0.89) in green tea 2 to 3 and ≥ 4 cups/d, respectively. Higher green tea consumption was associated with inverse risks of CVD and strokes subtypes. Compared with seldom drinking coffee, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.89 (0.80-0.99), 0.80 (0.72-0.90), and 0.81 (0.72-0.91) for coffee 3 to 6 times/week and 1 and ≥ 2 times/day, respectively. Coffee consumption was associated with an inverse risk of CVD and cerebral infarction. Higher green tea or coffee consumption reduced the risks of CVD and stroke subtypes (especially in intracerebral hemorrhage, P for interaction between green tea and coffee=0.04). None of the significant association was observed in coronary heart disease. CONCLUSIONS Higher green tea and coffee consumption were inversely associated with risk of CVD and stroke in general population.
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Affiliation(s)
- Yoshihiro Kokubo
- Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, 5-7-1, Fujishiro-dai, Suita, Osaka, 565-8565 Japan.
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Johnson R, Bryant S, Huntley AL. Green tea and green tea catechin extracts: An overview of the clinical evidence. Maturitas 2012; 73:280-7. [DOI: 10.1016/j.maturitas.2012.08.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 01/08/2023]
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Sasazuki S, Tamakoshi A, Matsuo K, Ito H, Wakai K, Nagata C, Mizoue T, Tanaka K, Tsuji I, Inoue M, Tsugane S. Green tea consumption and gastric cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Jpn J Clin Oncol 2012; 42:335-46. [PMID: 22371426 DOI: 10.1093/jjco/hys009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
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.
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Affiliation(s)
- Shizuka Sasazuki
- Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji Chuo-ku, Tokyo 104-0045 Japan.
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Associations between frequency of tea consumption and health and mortality: evidence from old Chinese. Br J Nutr 2012; 108:1686-97. [PMID: 22243697 DOI: 10.1017/s0007114511007173] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
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.
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SUZUKI Y, MIYOSHI N, ISEMURA M. Health-promoting effects of green tea. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2012; 88:88-101. [PMID: 22450537 PMCID: PMC3365247 DOI: 10.2183/pjab.88.88] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Green tea is manufactured from the leaves of the plant Camellia sinensis Theaceae and has been regarded to possess anti-cancer, anti-obesity, anti-atherosclerotic, anti-diabetic, anti-bacterial, and anti-viral effects. Many of the beneficial effects of green tea are related to the activities of (-)-epigallocatechin gallate (EGCG), a major component of green tea catechins. For about 20 years, we have engaged in studies to reveal the biological activities and action mechanisms of green tea and EGCG. This review summarizes several lines of evidence to indicate the health-promoting properties of green tea mainly based on our own experimental findings.
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Affiliation(s)
- Yasuo SUZUKI
- Faculty of Human Life Sciences, Nagoya Keizai University, Inuyama, Japan
| | - Noriyuki MIYOSHI
- Graduate School of Nutritional and Environmental Sciences and Global COE Program, University of Shizuoka, Shizuoka, Japan
| | - Mamoru ISEMURA
- Graduate School of Nutritional and Environmental Sciences and Global COE Program, University of Shizuoka, Shizuoka, Japan
- Correspondence should be addressed: M. Isemura, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Shizuoka, Suruga-ku, Shizuoka 422-8526, Japan (e-mail: )
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Oka Y, Iwai S, Amano H, Irie Y, Yatomi K, Ryu K, Yamada S, Inagaki K, Oguchi K. Tea polyphenols inhibit rat osteoclast formation and differentiation. J Pharmacol Sci 2011; 118:55-64. [PMID: 22186621 DOI: 10.1254/jphs.11082fp] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 11/07/2011] [Indexed: 10/14/2022] Open
Abstract
Matrix metalloproteinases (MMPs) play an important role in degeneration of the matrix associated with bone and cartilage. Regulation of osteoclast activity is essential in the treatment of bone disease, including osteoporosis and rheumatoid arthritis. Polyphenols in green tea, particularly epigallocatechin-3-gallate (EGCG), inhibit MMPs expression and activity. However, the effects of the black tea polyphenol, theaflavin-3,3'-digallate (TFDG), on osteoclast and MMP activity are unknown. Therefore, we examined whether TFDG and EGCG affect MMP activity and osteoclast formation and differentiation in vitro. TFDG or EGCG (10 and 100 µM) was added to cultures of rat osteoclast precursors cells and mature osteoclasts. Numbers of multinucleated osteoclasts and actin rings decreased in polyphenol-treated cultures relative to control cultures. MMP-2 and MMP-9 activities were lower in TFDG- and EGCG-treated rat osteoclast precursor cells than in control cultures. MMP-9 mRNA levels declined significantly in TFDG-treated osteoclasts in comparison to control osteoclasts. TFDG and EGCG inhibited the formation and differentiation of osteoclasts via inhibition of MMPs. TFDG may suppress actin ring formation more effectively than EGCG. Thus, TFDG and EGCG may be suitable agents or lead compounds for the treatment of bone resorption diseases.
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Affiliation(s)
- Yoshiomi Oka
- Department of Pharmacology, Showa University School of Medicine, Japan
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Iwasaki M, Inoue M, Sasazuki S, Sawada N, Yamaji T, Shimazu T, Willett WC, Tsugane S. Green tea drinking and subsequent risk of breast cancer in a population-based cohort of Japanese women. Breast Cancer Res 2010; 12:R88. [PMID: 22889409 PMCID: PMC3096981 DOI: 10.1186/bcr2756] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 10/28/2010] [Indexed: 01/20/2023] Open
Abstract
Introduction Although many in vitro and animal studies have demonstrated a protective effect of green tea against breast cancer, findings from epidemiological studies have been inconsistent, and whether high green tea intake reduces the risk of breast cancer remains unclear. Methods In this Japan Public Health Center-based Prospective Study, 581 cases of breast cancer were newly diagnosed in 53,793 women during 13.6 years' follow-up from the baseline survey in 1990 to 1994. After the five-year follow-up survey in 1995 to 1998, 350 cases were newly diagnosed in 43,639 women during 9.5 years' follow-up. The baseline questionnaire assessed the frequency of total green tea drinking while the five-year follow-up questionnaire assessed that of two types of green tea, Sencha and Bancha/Genmaicha, separately. Results Compared with women who drank less than one cup of green tea per week, the adjusted hazard ratio (HR) for women who drank five or more cups per day was 1.12 (95% confidence interval (CI) 0.81 to 1.56; P for trend = 0.60) in the baseline data. Similarly, compared with women who drank less than one cup of Sencha or Bancha/Genmaicha per week, adjusted HRs for women who drank 10 or more cups per day were 1.02 (95% CI 0.55 to 1.89; P for trend = 0.48) for Sencha and 0.86 (0.34 to 2.17; P for trend = 0.66) for Bancha/Genmaicha. No inverse association was found regardless of hormone receptor-defined subtype or menopausal status. Conclusions In this population-based prospective cohort study in Japan we found no association between green tea drinking and risk of breast cancer.
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Affiliation(s)
- Motoki Iwasaki
- Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Chuo-ku, Tokyo, Japan.
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Kang H, Rha SY, Oh KW, Nam CM. Green tea consumption and stomach cancer risk: a meta-analysis. Epidemiol Health 2010; 32:e2010001. [PMID: 21191454 PMCID: PMC2984861 DOI: 10.4178/epih/e2010001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 01/17/2010] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES Green tea has been suggested to have a chemopreventive effect against various cancers including stomach cancer. The aim of this study is to elucidate the relationship between green tea consumption and stomach cancer risk by meta-analysis. METHODS Eighteen observational studies were identified using MEDLINE, THE COCHRANE LIBRARY, RISS, and a manual search. Summary relative risks/odds ratios (RR/ORs) for the highest versus non/lowest green tea consumption levels were calculated on the basis of fixed and random effect models. Subgroup analyses were used to examine heterogeneity across the studies. RESULTS The combined results indicate a reduced risk of stomach cancer with intake of green tea (RR/OR=0.86, 95% CI=0.74-1.00). Subgroup analysis with six studies that reported differences between the highest and lowest consumption levels equal to or greater than five cups/day revealed a statistically significant protective effect (RR/OR=0.68, 95% CI=0.53-0.87). CONCLUSION Green tea appears to play a protective role against the development of stomach cancer. The results also suggest that a higher level of green tea consumption might be needed for a clear preventive effect to appear. This conclusion, however, should be interpreted with caution because various biases can affect the results of a meta-analysis.
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Affiliation(s)
- Hyunseok Kang
- Department of Epidemiology and Biostatistics, Graduate School of Public Health, Yonsei University, Seoul, Korea
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Is temperature an effect modifier of the association between green tea intake and gastric cancer risk? Eur J Cancer Prev 2010; 19:18-22. [PMID: 19864955 DOI: 10.1097/cej.0b013e328330eb1a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We considered the relationship between green tea and gastric cancer risk in Harbin, Heilongjiang province, Northeast China, an area with high baseline risk of stomach cancer. We used data from a case-control study conducted from 1987 to 1989 among 266 incident cases of stomach cancer and 533 controls admitted to the same hospitals as cases, with non-neoplastic and non-gastric diseases. No association emerged when tea consumption alone was considered: the odds ratio (OR) for green tea consumption was 0.87 (95% CI: 0.60-1.25) for green tea intake > or = 750 g/year versus no intake and 0.99 (95% CI: 0.97-1.02) for an increment of 500 g of tea per year. When tea consumption was classified according to the temperature, however, the OR was 0.19 (95% CI: 0.07-0.49) for lukewarm tea intake > or = 750 g/year and 1.27 (95% CI: 0.85-1.90) for hot tea intake (P value for interaction <0.001) as compared with non-drinkers. The corresponding ORs for an increment of 500 g of tea per year were 0.61 (95% CI: 0.45-0.82) and 1.03 (95% CI: 0.99-1.07) for lukewarm and hot tea, respectively (P value for interaction <0.001). We found an inverse relationship between green tea drinking and gastric cancer risk limited to the intake of lukewarm tea.
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Mahboub FA, Khorshid FA. The Role of Green Tea Extract on the Proliferation of Human Ovarian Cancer Cells (in vitro) Study. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/ijcr.2010.78.88] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sturgeon JL, Williams M, van Servellen G. Efficacy of green tea in the prevention of cancers. Nurs Health Sci 2009; 11:436-46. [DOI: 10.1111/j.1442-2018.2009.00476.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Clement Y. Can green tea do that? A literature review of the clinical evidence. Prev Med 2009; 49:83-7. [PMID: 19465043 DOI: 10.1016/j.ypmed.2009.05.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 05/01/2009] [Accepted: 05/16/2009] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Habitual green tea consumption has long been associated with health benefits including chemoprevention and cardiovascular protection. This non-systematic literature review presents the clinical evidence to date. METHOD A literature review of peer-reviewed articles on observational and interventional studies was conducted to include green tea, its extract or its purified polyphenol (-)-epigallocatechin-3-gallate (EGCG). Electronic databases searched included PubMed (1966-2009) and the Cochrane Library (Issue 4, 2008). RESULTS Observational studies are inconclusive on the benefits of habitual consumption of green tea in the prevention of most cancers. However, there are trends towards prevention in breast and prostate cancers. Interventional studies have demonstrated reduction in relapses following surgical resection in colorectal adenomas and increased survival rates in epithelial ovarian cancer. Observational studies indicate that green tea may provide protection against hypertension and reduce the risk for stroke, and interventional studies are providing biochemical and physiological evidence. CONCLUSION Although the overall clinical evidence is inconclusive, habitual green tea consumption may be providing some level of chemoprevention in prostate and breast cancer. Green tea may also attenuate the risk factors association with the development of atherosclerosis thus reducing the incidence of cardiovascular events and stoke.
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Affiliation(s)
- Yuri Clement
- Pharmacology Unit, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago.
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Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M. Green tea (Camellia sinensis) for the prevention of cancer. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2009. [PMID: 19588362 DOI: 10.1002/14651858.cd005004.pub2.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND 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. Cross-culturally tea drinking habits vary. Camellia sinensis contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants. It has been suggested that green tea polyphenol may inhibit cell proliferation and observational studies have suggested that green tea may have cancer-preventative effects. OBJECTIVES To critically assess any associations between green tea consumption and the risk of cancer incidence and mortality. SEARCH STRATEGY We searched eligible studies up to January 2009 in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Amed, CancerLit, Psych INFO and Phytobase and reference lists of previous reviews and included studies. SELECTION CRITERIA We included all prospective, controlled interventional studies and observational studies, which either assessed the associations between green tea consumption and risk of cancer incidence or that reported on cancer mortality. DATA COLLECTION AND ANALYSIS At least two review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. Due to the nature of included studies, which were mainly epidemiological, results were summarised descriptively according to cancer diagnosis. MAIN RESULTS Fifty-one studies with more than 1.6 million participants were included. Twenty-seven of them were case-control studies, 23 cohort studies and one randomised controlled trial (RCT).Twenty-seven studies tried to establish an association between green tea consumption and cancer of the digestive tract, mainly of the upper gastrointestinal tract, five with breast cancer, five with prostate cancer, three with lung cancer, two with ovarian cancer, two with urinary bladder cancer one with oral cancer, three further studies included patients with various cancer diagnoses.The methodological quality was measured with the Newcastle-Ottawa scale (NOS). The 9 nested case-control studies within prospective cohorts were of high methodological quality, 13 of medium, and 1 of low. One retrospective case-control study was of high methodological quality and 21 of medium and 5 of low.Results from studies assessing associations between green tea and risk of digestive tract cancer incidence were highly contradictory. There was limited evidence that green tea could reduce the incidence of liver cancer. The evidence for esophageal, gastric, colon, rectum, and pancreatic cancer was conflicting. In prostate cancer, observational studies with higher methodological quality and the only included RCT suggested a decreased risk in men consuming higher quantities green tea or green tea extracts. However, there was limited to moderate evidence that the consumption of green tea reduced the risk of lung cancer, especially in men, and urinary bladder cancer or that it could even increase the risk of the latter. There was moderate to strong evidence that green tea consumption does not decrease the risk of dying from gastric cancer. There was limited moderate to strong evidence for lung, pancreatic and colorectal cancer. AUTHORS' CONCLUSIONS There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention. The results of this review, including its trends of associations, need to be interpreted with caution and their generalisability is questionable, as the majority of included studies were carried out in Asia (n = 47) where the tea drinking culture is pronounced. Desirable green tea intake is 3 to 5 cups per day (up to 1200 ml/day), providing a minimum of 250 mg/day catechins. If not exceeding the daily recommended allowance, those who enjoy a cup of green tea should continue its consumption. Drinking green tea appears to be safe at moderate, regular and habitual use.
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Affiliation(s)
- Katja Boehm
- Medizinische Klinik 5-Schwerpunkt Onkologie / Haematologie, Klinikum Nord, Prof.-Ernst-Nathan-Str. 1, Nuernberg, Germany, D-90419
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Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev 2009; 2009:CD005004. [PMID: 19588362 PMCID: PMC6457677 DOI: 10.1002/14651858.cd005004.pub2] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND 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. Cross-culturally tea drinking habits vary. Camellia sinensis contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants. It has been suggested that green tea polyphenol may inhibit cell proliferation and observational studies have suggested that green tea may have cancer-preventative effects. OBJECTIVES To critically assess any associations between green tea consumption and the risk of cancer incidence and mortality. SEARCH STRATEGY We searched eligible studies up to January 2009 in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Amed, CancerLit, Psych INFO and Phytobase and reference lists of previous reviews and included studies. SELECTION CRITERIA We included all prospective, controlled interventional studies and observational studies, which either assessed the associations between green tea consumption and risk of cancer incidence or that reported on cancer mortality. DATA COLLECTION AND ANALYSIS At least two review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. Due to the nature of included studies, which were mainly epidemiological, results were summarised descriptively according to cancer diagnosis. MAIN RESULTS Fifty-one studies with more than 1.6 million participants were included. Twenty-seven of them were case-control studies, 23 cohort studies and one randomised controlled trial (RCT).Twenty-seven studies tried to establish an association between green tea consumption and cancer of the digestive tract, mainly of the upper gastrointestinal tract, five with breast cancer, five with prostate cancer, three with lung cancer, two with ovarian cancer, two with urinary bladder cancer one with oral cancer, three further studies included patients with various cancer diagnoses.The methodological quality was measured with the Newcastle-Ottawa scale (NOS). The 9 nested case-control studies within prospective cohorts were of high methodological quality, 13 of medium, and 1 of low. One retrospective case-control study was of high methodological quality and 21 of medium and 5 of low.Results from studies assessing associations between green tea and risk of digestive tract cancer incidence were highly contradictory. There was limited evidence that green tea could reduce the incidence of liver cancer. The evidence for esophageal, gastric, colon, rectum, and pancreatic cancer was conflicting. In prostate cancer, observational studies with higher methodological quality and the only included RCT suggested a decreased risk in men consuming higher quantities green tea or green tea extracts. However, there was limited to moderate evidence that the consumption of green tea reduced the risk of lung cancer, especially in men, and urinary bladder cancer or that it could even increase the risk of the latter. There was moderate to strong evidence that green tea consumption does not decrease the risk of dying from gastric cancer. There was limited moderate to strong evidence for lung, pancreatic and colorectal cancer. AUTHORS' CONCLUSIONS There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention. The results of this review, including its trends of associations, need to be interpreted with caution and their generalisability is questionable, as the majority of included studies were carried out in Asia (n = 47) where the tea drinking culture is pronounced. Desirable green tea intake is 3 to 5 cups per day (up to 1200 ml/day), providing a minimum of 250 mg/day catechins. If not exceeding the daily recommended allowance, those who enjoy a cup of green tea should continue its consumption. Drinking green tea appears to be safe at moderate, regular and habitual use.
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Affiliation(s)
- Katja Boehm
- Klinikum NordMedizinische Klinik 5‐Schwerpunkt Onkologie/HaematologieProf.‐Ernst‐Nathan‐Str. 1NuernbergGermanyD‐90419
| | - Francesca Borrelli
- University of Naples 'Federico II'Department of Experimental PharmacologyVia D Montesano 49NaplesItaly80131
| | - Edzard Ernst
- Peninsula Medical School, University of ExeterComplementary Medicine DepartmentExeterUK
| | - Gabi Habacher
- Small Animal HospitalFeline CentreDepartment of Veterinary Clinical SciencesUniversity of BristolLangfordUK
| | - Shao Kang Hung
- Peninsula Medical School, Universities of Exeter and PlymouthComplementary Medicine25 Victoria Park RoadExeterUKEX2 4NT
| | - Stefania Milazzo
- Paracelsus Medical University, Klinikum NuernbergDepartment of Internal Medicine, Division of Oncology and HematologyProf.‐Ernst‐Nathan‐Str. 1NuernbergGermanyD‐90419
| | - Markus Horneber
- Paracelsus Medical University, Klinikum NurembergDepartment of Internal Medicine, Division of Oncology and HematologyProf.‐Ernst‐Nathan‐Str. 1NurembergGermanyD‐90419
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Yuasa Y, Nagasaki H, Akiyama Y, Hashimoto Y, Takizawa T, Kojima K, Kawano T, Sugihara K, Imai K, Nakachi K. DNA methylation status is inversely correlated with green tea intake and physical activity in gastric cancer patients. Int J Cancer 2009; 124:2677-82. [PMID: 19170207 DOI: 10.1002/ijc.24231] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epigenetic silencing of genes by aberrant DNA methylation is recognized as a crucial component of the mechanism underlying tumorigenesis. However, the relationship between DNA methylation and the past lifestyle in cancer patients remains largely unknown. We examined the methylation statuses of 6 tumor-related genes, CDX2 (homeobox transcription factor), BMP-2 (bone morphogenetic protein 2), p16 (INK4A), CACNA2D3 (calcium channel-related), GATA-5 (transcription factor) and ER (estrogen receptor), in 106 primary gastric carcinomas by methylation-specific PCR and compared them with the past lifestyles of the patients. The methylation frequencies of the genes were 23.6, 21.7, 9.4, 32.4, 40.8 and 59.1%, respectively. Significant association was found between a decreased intake of green tea and methylation of CDX2 and BMP-2. More physical activity was correlated with a lower methylation frequency of CACNA2D3. Of these 6 genes, the methylation statuses of CDX2, BMP-2 and p16 revealed a significant interrelationship and those of CACNA2D3, GATA-5 and ER did likewise. Thus, some epidemiological factors, such as green tea intake, could be important as to determination of the methylation statuses of selected genes and may influence the development of cancer, including that of the stomach.
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Affiliation(s)
- Yasuhito Yuasa
- Department of Molecular Oncology, Tokyo Medical and Dental University, Tokyo, Japan.
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Chon SU, Heo BG, Park YS, Kim DK, Gorinstein S. Total phenolics level, antioxidant activities and cytotoxicity of young sprouts of some traditional Korean salad plants. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2009; 64:25-31. [PMID: 19016328 DOI: 10.1007/s11130-008-0092-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
UNLABELLED The aim of this investigation was to study the antioxidant and anticancer activities of young sprouts of some traditional Korean salad plants. Total phenolics, antioxidant and anticancer activities of the methanol extracts from young sprouts of 11 salad plants were determined. The highest amount of phenolics was found in methanol extracts of Euonymus alatus (235.7 mg kg(-1)), followed by Hypericum ascyron (197.1 mg kg(-1)), Zanthoxylum piperitum (194.1 mg kg(-1)) and Zanthoxylum schinifolium (142.5 mg kg(-1)). Methanol extracts of E. alatus, H. ascyron, and Z. piperitum at 63 mg kg(-1) exhibited the highest dose-depend DPPH radical scavenging activity by 91.2, 91.2 and 83.9%, respectively. According to the MTT results, the methanol extracts from Stellaria aquatica, Eleutherococcus sessilifolrus and Z. schinifolium showed the highest anticancer activities against Calu-6 (IC50<25.0 microg ml(-1)) and from S. aquatica-the highest anticancer activities against SNU-601 (153.3 microg ml(-1)), following by E. sessilifolrus (196.7 microg ml(-1)) and Amaranthus mangostanus (303.1 microg ml(-1)). Total phenolics were highly correlated with the DPPH, suggesting that they contribute to the antioxidant properties of the studied plants. IN CONCLUSION young sprouts of Korean salad possess antioxidant and anticancer properties and could be used as a supplement to proper drugs.
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Affiliation(s)
- Sang-Uk Chon
- EFARINET Co. Ltd., BI Center, Chosun University, Gwangju, 501-759, South Korea
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Myung SK, Bae WK, Oh SM, Kim Y, Ju W, Sung J, Lee YJ, Ko JA, Song JI, Choi HJ. Green tea consumption and risk of stomach cancer: a meta-analysis of epidemiologic studies. Int J Cancer 2008; 124:670-7. [PMID: 18973231 DOI: 10.1002/ijc.23880] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This meta-analysis investigated the quantitative association between the consumption of green tea and the risk of stomach cancer in epidemiologic studies using crude data and adjusted data. We searched MEDLINE, EMBASE and the Cochrane Review in August 2007. All the articles searched were independently reviewed and selected by 3 evaluators according to predetermined criteria. A total of 13 epidemiologic studies were included. When all the case-control and cohort studies were pooled, the odds ratios (OR) [corrected] of stomach cancer for the highest level of green tea consumption when compared with the lowest level of consumption were shown to be 1.10 (95% confidence interval (CI), 0.92-1.32) using the crude data and 0.82 (95% CI, 0.70-0.96) using the adjusted data.In the meta-analyses of case-control studies, no significant association was seen between green tea consumption and stomach cancer using the crude data (odds ratio (OR), 0.79; 95% CI, 0.58-1.07) [corrected], but green tea was shown to have a preventive effect on stomach cancer using the adjusted data (OR, 0.73; 95% CI, 0.64-0.83) [corrected]. In the meta-analyses of the recent cohort studies, the highest green tea consumption was shown to significantly increase stomach cancer risk using the crude data (RR, 1.59; 95% CI, 1.16-2.18), but no significant association between them was seen when using the adjusted data (RR, 1.04; 95% CI, 0.93-1.17). Unlike the case-control studies, no preventive effect on stomach cancer was seen for the highest green tea consumption in the meta-analysis of the recent cohort studies. Further clinical trials are needed.
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Affiliation(s)
- Seung Kwon Myung
- Smoking Cessation Clinic, Center for Cancer Prevention and Detection, National Cancer Center, Goyang, Korea.
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Maruyama K, Iso H, Sasaki S, Fukino Y. The Association between Concentrations of Green Tea and Blood Glucose Levels. J Clin Biochem Nutr 2008; 44:41-5. [PMID: 19177186 PMCID: PMC2613497 DOI: 10.3164/jcbn.08-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 03/11/2008] [Indexed: 02/03/2023] Open
Abstract
Our objective was to examine whether habitual green tea consumption is associated with blood glucose levels and other biomarkers of glucose metabolism. We conducted a cross-sectional study of 35 male volunteers, 23–63 years old and residing in Shizuoka Prefecture in Japan. Biochemical data were measured and we conducted a questionnaire survey on health, lifestyle, and nutrition, as well as frequency of consumption and concentrations (1%, 2%, and 3%) of green tea. Men who consumed a 3% concentration of green tea showed lower mean values of fasting blood glucose and fructosamine than those who consumed a 1% concentration. Fasting blood glucose levels were found to be significantly associated with green tea concentration (β = −0.14, p = 0.03). However, green tea consumption frequency showed no significant differences in mean levels of blood glucose, fructosamine and hemoglobin A1c. In conclusion, our findings suggest that the consumption of green tea at a high concentration has the potential to reduce blood glucose levels.
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Affiliation(s)
- Koutatsu Maruyama
- Department of Food and Nutritional Sciences, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka-shi 422-8526, Japan
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Case–control study of green tea consumption and the risk of endometrial endometrioid adenocarcinoma. Cancer Causes Control 2008; 20:617-24. [DOI: 10.1007/s10552-008-9272-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 11/14/2008] [Indexed: 10/21/2022]
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Pathological features of gastric cancer in Zhuanghe high-risk area in China during 1992–2005. Chin J Cancer Res 2008. [DOI: 10.1007/s11670-008-0262-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Liu J, Xing J, Fei Y. Green tea (Camellia sinensis) and cancer prevention: a systematic review of randomized trials and epidemiological studies. Chin Med 2008; 3:12. [PMID: 18940008 PMCID: PMC2577676 DOI: 10.1186/1749-8546-3-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Accepted: 10/22/2008] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Green tea is one of the most popular beverages worldwide. This review summarizes the beneficial effects of green tea on cancer prevention. METHODS Electronic databases, including PubMed (1966-2008), the Cochrane Library (Issue 1, 2008) and Chinese Biomedical Database (1978-2008) with supplement of relevant websites, were searched. There was no language restriction. The searches ended at March 2008. We included randomized and non-randomized clinical trials, epidemiological studies (cohort and case-control) and a meta-analysis. We excluded case series, case reports, in vitro and animal studies. Outcomes were measured with estimation of relative risk, hazard or odd ratios, with 95% confidence interval. RESULTS Forty-three epidemiological studies, four randomized trials and one meta-analysis were identified. The overall quality of these studies was evaluated as good or moderate. While some evidence suggests that green tea has beneficial effects on gastrointestinal cancers, the findings are not consistent. CONCLUSION Green tea may have beneficial effects on cancer prevention. Further studies such as large and long term cohort studies and clinical trials are warranted.
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Affiliation(s)
- Jianping Liu
- Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, PR China
- National Research Centre in Complementary and Alternative Medicine (NAFKAM), University of Tromso, Norway
- Division of Chinese Medicine, RMIT University, Melbourne, Australia
| | - Jianmin Xing
- Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, PR China
| | - Yutong Fei
- Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, PR China
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Sasazuki S, Inoue M, Miura T, Iwasaki M, Tsugane S. Plasma Tea Polyphenols and Gastric Cancer Risk: A Case-Control Study Nested in a Large Population-Based Prospective Study in Japan. Cancer Epidemiol Biomarkers Prev 2008; 17:343-51. [DOI: 10.1158/1055-9965.epi-07-0428] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Paek YJ. Evidence-based Complementary and Alternative Medicine for Cancer Prevention. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2008. [DOI: 10.5124/jkma.2008.51.5.411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Yu-Jin Paek
- Department of Family Medicine, Hallym University College of Medicine, Korea.
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41
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Green tea and coffee intake and risk of pancreatic cancer in a large-scale, population-based cohort study in Japan (JPHC study). Eur J Cancer Prev 2007; 16:542-8. [DOI: 10.1097/cej.0b013e32809b4d30] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ju J, Lu G, Lambert JD, Yang CS. Inhibition of carcinogenesis by tea constituents. Semin Cancer Biol 2007; 17:395-402. [PMID: 17686632 PMCID: PMC2736048 DOI: 10.1016/j.semcancer.2007.06.013] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 06/21/2007] [Accepted: 06/27/2007] [Indexed: 10/23/2022]
Abstract
The possible cancer preventive activity of tea has received much attention in recent years. The inhibitory activities of tea and tea constituents against carcinogenesis at different organ sites have been demonstrated in many animal models. The effect of tea consumption on human cancers, however, remains inconclusive. The mechanisms of action of tea polyphenols, especially EGCG, the most abundant and active catechin, have been extensively investigated. Most of the studies, however, were based on cell culture systems, and these mechanisms need to be evaluated and verified in animal models or humans in order to gain more understanding on the effect of tea consumption on human cancer. Human intervention trials are warranted to determine the possible prevention of cancer of specific sites by preparation of tea constituents.
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Affiliation(s)
- Jihyeung Ju
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Gang Lu
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Joshua D. Lambert
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Chung S. Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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Tsugane S, Sasazuki S. Diet and the risk of gastric cancer: review of epidemiological evidence. Gastric Cancer 2007; 10:75-83. [PMID: 17577615 DOI: 10.1007/s10120-007-0420-0] [Citation(s) in RCA: 325] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 04/15/2007] [Indexed: 02/06/2023]
Abstract
There are geographic and ethnic differences in the incidence of gastric cancer around the world as well as with its trends for each population over time. The incidence patterns observed among immigrants change according to where they live. All of these factors serve to indicate the close association of gastric cancer with modifiable factors such as diet. This review presents epidemiological evidence on the association between dietary factors and gastric cancer based on previous systematic reviews and subsequent updates. Infection with Helicobacter pylori is a strong and established risk factor of gastric cancer but is not a sufficient cause for its development. Substantial evidence from ecological, case-control, and cohort studies strongly suggests that the risk may be increased with a high intake of various traditional salt-preserved foods and salt per se and decreased with a high intake of fruit and vegetables, particularly fruit. However, it remains unclear which constituents in fruit and vegetables play a significant role in gastric cancer prevention. Among them, vitamin C is a plausible candidate supported by a relatively large body of epidemiological evidence. Consumption of green tea is possibly associated with a decreased risk of gastric cancer, although the protective effects have been, for the most part, identified in Japanese women, most of whom are nonsmokers. In contrast, processed meat and N-nitroso compounds may be positively associated with the risk of gastric cancer. In conclusion, dietary modification by reducing salt and salted food intake, as well as by increasing intake of fruit and vitamin C, represents a practical strategy to prevent gastric cancer.
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Affiliation(s)
- Shoichiro Tsugane
- Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Tokyo, Japan
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Abstract
Ovarian cancer is the leading cause of death from gynecologic cancer. Tea, especially green tea, has shown promise in the prevention of several cancers. Green tea contains a number of compounds, including polyphenols, that have chemopreventive properties. There is much evidence from in vitro and animal studies suggesting that components of tea are associated with decreased risk or progression of ovarian cancer. However, epidemiologic studies have generated inconsistent results. Recent research conducted in China reported reduced risk of ovarian cancer and increased survival post diagnosis with green tea consumption. This review presents emerging evidence and the authors' perspectives on the role of green tea in ovarian cancer prevention.
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Affiliation(s)
- Andy H Lee
- Curtin University of Technology, School of Public Health, Perth, WA, Australia.
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Ide R, Fujino Y, Hoshiyama Y, Mizoue T, Kubo T, Pham TM, Shirane K, Tokui N, Sakata K, Tamakoshi A, Yoshimura T. A prospective study of green tea consumption and oral cancer incidence in Japan. Ann Epidemiol 2007; 17:821-6. [PMID: 17606381 DOI: 10.1016/j.annepidem.2007.04.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 04/06/2007] [Accepted: 04/20/2007] [Indexed: 12/27/2022]
Abstract
PURPOSE To examine the relation of green tea consumption with oral carcinogenesis, we prospectively analyzed data from a nationwide large-scale cohort study in Japan. METHODS A total of 20,550 men and 29,671 women aged 40-79 years, without any history of oral and pharyngeal cancer at baseline survey, were included in the present study. During a mean follow-up period of 10.3 years, 37 oral cancer cases were identified. The Cox proportional hazard model was used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) for oral cancer according to green tea consumption by sex, while adjusting for age, smoking, alcohol drinking, and other dietary factors. RESULTS For women, the HRs of oral cancer for green tea consumption of 1-2, 3-4, and 5 or more cups per day were 0.51 (95% CI: 0.10-2.68), 0.60 (95% CI: 0.17-2.10), and 0.31 (95% CI: 0.09-1.07), respectively, compared with those who drank less than one cup per day (p for trend, 0.08). For men, no such trends were observed. CONCLUSIONS Our findings did not suggest a prominent inverse association of green tea consumption with oral cancer, although there was a tendency for a reduced risk in women.
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Affiliation(s)
- Reiko Ide
- Department of Clinical Epidemiology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyusyu, Japan.
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46
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Rocco A, Nardone G. Diet, H pylori infection and gastric cancer: evidence and controversies. World J Gastroenterol 2007; 13:2901-12. [PMID: 17589938 PMCID: PMC4171140 DOI: 10.3748/wjg.v13.i21.2901] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 12/15/2006] [Accepted: 12/20/2006] [Indexed: 02/06/2023] Open
Abstract
Despite decreasing incidence and mortality rates, gastric cancer (GC) still remains the fourth most common cancer and the second most common cause of cancer-related deaths worldwide. Due to the limited treatment options, at present, prevention is likely to be the only effective means of controlling this disease. The success of a prevention strategy depends upon the understanding of etiological and pathogenic mechanisms underlying gastric carcinogenesis. The etiology of GC is multi-factorial, however, in the recent years, mounting evidence suggests that environmental factors play a key role. The most important environmental factors implicated in the pathogenesis of GC are diet and H pylori infection. Thus, modifications in lifestyle and dietary habit associated with eradication of H pylori infection could hypothetically represent the most promising potential targets for GC prevention. In this review we will address the evidence and the controversies on the role of these agents in non-cardia GC by focusing on retrospective and prospective observational studies and interventional trials.
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Affiliation(s)
- Alba Rocco
- Department of Clinical and Experimental Medicine, Gastroenterology Unit, University Federico II, Naples, Italy
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Carlson JR, Bauer BA, Vincent A, Limburg PJ, Wilson T. Reading the tea leaves: anticarcinogenic properties of (-)-epigallocatechin-3-gallate. Mayo Clin Proc 2007; 82:725-32. [PMID: 17550753 DOI: 10.4065/82.6.725] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Green tea is an extremely popular beverage worldwide. Derivatives of green tea, particularly (-)-epigallocatechin-3-gallate (EGCG), have been proposed to have anticarcinogenic properties based on preclinical, observational, and clinical trial data. To summarize, clarify, and extend current knowledge, we conducted a comprehensive search of the PubMed database and other secondary data sources, as appropriate, regarding the chemopreventive potential of EGCG. Apparently, EGCG functions as an antioxidant, preventing oxidative damage in healthy cells, but also as an antiangiogenic agent, preventing tumors from developing a blood supply needed to grow larger. Furthermore, EGCG may stimulate apoptosis in cancerous cells by negatively regulating the cell cycle to prevent continued division. Finally, EGCG exhibits antibacterial activity, which may be implicated in the prevention of gastric cancer. Although in vitro research of the anticarcinogenic properties of EGCG seems promising, many diverse and unknown factors may influence its in vivo activity in animal and human models. Some epidemiological studies suggest that green tea compounds could protect against cancer, but existing data are inconsistent, and limitations in study design hinder full interpretation and generalizability of the published observational findings. Several clinical trials with green tea derivatives are ongoing, and further research should help to clarify the clinical potential of EGCG for chemoprevention and/or chemotherapy applications.
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Liang W, Binns CW, Jian L, Lee AH. Does the consumption of green tea reduce the risk of lung cancer among smokers? EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2006; 4:17-22. [PMID: 17342237 PMCID: PMC1810371 DOI: 10.1093/ecam/nel066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 08/25/2006] [Indexed: 12/24/2022]
Abstract
Experimental and epidemiological studies were reviewed to assess whether the consumption of green tea could reduce the risk of lung cancer in smokers. Articles published since 1990 were located by searching electronic databases PubMed, Ovid and Science Direct, using keywords 'lung cancer', 'tea' and 'smoking' without any restriction on language. After relevant articles had been located, further papers were obtained from their reference lists. Evidence from experimental studies (in vitro animal and human trials) suggested that regular intake of green tea may be protective against tobacco carcinogens. However, the mechanism behind the protective effect is only partly understood. In most of the epidemiological studies reviewed, the green tea exposure was within 5 years of the interview or follow-up, which would coincide with the induction period and latent period of lung cancer. Longer term studies are thus needed to further quantify the cancer risk. There is some evidence suggesting regular intake of green tea at high level (>3 cups per day) may reduce the risk of smokers developing lung cancer. Improvement in measuring green tea intake is required in order to confirm the evidence from epidemiological studies.
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Affiliation(s)
- Wenbin Liang
- School of Public Health, Curtin University of Technology Perth, Australia
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50
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Abstract
Tea is the most consumed drink in the world after water. Green tea is a 'non-fermented' tea, and contains more catechins, than black tea or oolong tea. Catechins are in vitro and in vivo strong antioxidants. In addition, its content of certain minerals and vitamins increases the antioxidant potential of this type of tea. Since ancient times, green tea has been considered by the traditional Chinese medicine as a healthful beverage. Recent human studies suggest that green tea may contribute to a reduction in the risk of cardiovascular disease and some forms of cancer, as well as to the promotion of oral health and other physiological functions such as anti-hypertensive effect, body weight control, antibacterial and antivirasic activity, solar ultraviolet protection, bone mineral density increase, anti-fibrotic properties, and neuroprotective power. Increasing interest in its health benefits has led to the inclusion of green tea in the group of beverages with functional properties. However, although all the evidence from research on green tea is very promising, future studies are necessary to fully understand its contributions to human health, and advise its regular consumption in Western diets, in which green tea consumption is nowadays limited and sporadic.
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Affiliation(s)
- Carmen Cabrera
- Departamento de Nutrición y Bromatología, Facultad de Farmacia, Campus Universitario de Granada, Granada, Spain.
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