Tea and cancer prevention: An evaluation of the epidemiologic literature

Kohlmeier, Lenore; Weterings, K.; Steck, Susan E.; Kok, F.J.

doi:10.1080/01635589709514494

Cited by 185 publications

(93 citation statements)

References 22 publications

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“…It was suggested that the protective effect of tea may depend on the different etiological factors involved in different cancer types and even for the same cancer types in different geographical areas. Similar conclusions have been reached in subsequent reviews [59][60][61][62].…”

Section: Studies On Tea and Human Cancersupporting

confidence: 74%

Inhibition of carcinogenesis by tea constituents

Lǚ

Lambert

et al. 2007

Seminars in Cancer Biology

130

104

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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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Section: Studies On Tea and Human Cancersupporting

confidence: 74%

Inhibition of carcinogenesis by tea constituents

Lǚ

Lambert

et al. 2007

Seminars in Cancer Biology

130

104

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“…Red wine is one of the best known such drinks (Maxwell et al, 1994;Whitehead et al, 1995), and the green tea favored by Orientals also contains high level of antioxidants. A few epidemiologic studies have reported that the incidence of coronary heart disease and cancer decreased with intake of green tea (Bushman, 1998;Kohlmeier et al, 1997;Stoner & Mukhtar, 1995) and that the oxidation of low density lipoprotein was suppressed with green tea in vitro (Luo et al, 1997). However, the studies dealing with in vivo increase of antioxidant effects of green tea are rare (Benzie et al, 1999;Pietta et al, 1998;Sera®ni et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

In vivo antioxidant effect of green tea

et al. 2000

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Objective: The object of this study was to investigate the in vivo antioxidant effect of green tea and dosage effect of green tea on antioxidant effect. Design: We tested 10 healthy subjects (aged 23 ± 25 y, ®ve women and ®ve men) with overnight fasting. The total antioxidant capacity of plasma was measured at baseline and 60 min and 120 min after ingestion of 150 ml green tea. Green tea was prepared by infusing 2.5 g of dried green tea leaves for 2 min at 80 C in 150 ml of water. In the second week, they took 300 ml of tea (5.0 g of green tea leaves) and, in the third week, 450 ml of tea (7.5 g of green tea leaves). The total antioxidant capacities of plasma were determined with a Total Antioxidant Kit (Randox Laboratories Ltd, UK) using a Cobas Mira analyser (Roche Diagnostic Systems Inc., Switzerland). The mean intra-assay coef®cient of variation was 1.2%. Results: The total antioxidant capacity of plasma increased by 1.1% at 60 min and 2.1% at 120 min over baseline value in subjects consuming 150 ml of green tea, which was statistically not signi®cant. However, total antioxidant capacity of plasma after consuming 300 ml of green tea showed a signi®cant increase of 7.0% after 60 min and 6.2% after 120 min (P`0.0001), and after consuming 450 ml 12.0% after 60 min and 12.7% after 120 min over baseline value (P`0.0001). Conclusions: Total antioxidant capacity of plasma was signi®cantly increased after taking green tea in amounts of 300 and 450 ml. A positive increment according to green tea dosage was also observed. Sponsorship: This work was funded by the Paci®c Corporation (Korea).

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“…The relationship between tea consumption and colorectal risk has been studied by many investigators, but no clear-cut conclusions can be drawn (reviewed in (Blot et al, 1996;Kohlmeier et al, 1997;Bushman, 1998;Landau et al, 2005). Sun et al recently conducted a meta-analysis on 21 relevant papers published up to January 2005 (Sun et al, 2006b).…”

Section: Human Studiesmentioning

confidence: 99%

Tea and cancer prevention: Molecular mechanisms and human relevance

Yang

Lambert

et al. 2007

Toxicology and Applied Pharmacology

238

169

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Tea made from the leaves of the plant Camellia sinensis is a popular beverage. The possible cancer preventive activity of tea and tea polyphenols has been studied extensively. This article briefly reviews studies in animal models, cell lines, and possible relevance of these studies to the prevention of human cancer. The cancer preventive activity of tea constituents have been demonstrated in many animal models including cancer of the skin, lung, oral cavity, esophagus, stomach, liver, pancreas, small intestine, colon, bladder, prostate, and mammary gland. The major active constituents are polyphenols, of which (-)-epigallocatechin-3-gallate (EGCG) is most abundant, most active, and most studied, and caffeine. The molecular mechanisms of the cancer preventive action, however, are just beginning to be understood. Studies in cell lines led to the proposal of many mechanisms on the action of EGCG. However, mechanisms based on studies with very high concentrations of EGCG may not be relevant to cancer prevention in vivo. The autooxidation of EGCG in cell culture may also produce activities that do not occur in many internal organs. In contrast to the cancer prevention activity demonstrated in different animal models, no such conclusion can be convincingly drawn from epidemiological studies on tea consumption and human cancers. Even though the human data are inconclusive, tea constituents may still be used for the prevention of cancer at selected organ sites if sufficient concentrations of the agent can be delivered to these organs. Some interesting examples in this area are discussed.

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Tea and cancer prevention: An evaluation of the epidemiologic literature

Cited by 185 publications

References 22 publications

Inhibition of carcinogenesis by tea constituents

Inhibition of carcinogenesis by tea constituents

In vivo antioxidant effect of green tea

Tea and cancer prevention: Molecular mechanisms and human relevance

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