Tea consumption

Green tea, consumed hot or cold, is most common in Japan and China and is growing rapidly in the United States owing to the numerous reports of health benefits. The market has doubled from about 110 metric tons in 1993 to just over 227 t in 1996. Green tea consumption in the United States remains a small segment (less than 2%) of the total tea market. 

Tea flavonoids, or tea extracts, have been linked to benefits in reducing the risk of certain cancers and cardiovascular diseases in experimental animals. However, epidemiological studies have produced inconsistent evidence in the relationship between tea drinking and cancer (Blot et a/., 1997 Goldbohm etal, 1996 Hertog eta/., 1997 Yang eta/., 1996). Therefore, further research is needed before definitive conclusions on the impact of tea consumption upon the cancer risk in humans can be reached. The metabolites of catechins and flavonols after consumption of tea infusions have scarcely been investigated, and thus more research is needed as to the role of those compounds in the reported health benefits of tea consumption. 

GABRiELLi G B and DE SANDRE G (1995) Excessive tea consumption can inhibit the efficacy of oral iron treatment in iron-deficiency anemia , Haematologica, 80(6), 518-20. 

Green tea consumption and the risk of pancreatic and colorectal cancers , Int J Cancer, 70, 255-8. 

SOUTH p K, HOUSE w A and MILLER D (1997) Tea consumption does not affect iron consumption in rats unless tea and iron are consumed together , Nutr Res, 17, 1303-10. 

VAN HET HOF K H, WISEMAN s A, YANG c s, TiJBURG L B M (1999) Plasma and lipoprotein levels of tea catechins following repeated tea consumption, Proceedings of the Society for Experimental Biology and Medicine, 220, 203-9. 

The spread of tea to Japan probably occurred during the introduction of Buddhism in the seventh century. Tea cultivation began in the eighth century, but tea consumption did not become a perma-... 

Although earlier work had showed a positive association between coffee consumption and pancreatic cancer rates across countries,2 it was the much-publicized case-control study of MacMahon et al.3 in 1981 that attracted widespread attention to the question of a possible link. In that study, which was designed primarily to investigate the role of smoking and alcohol in pancreatic cancer, 369 pancreatic cancer patients prior to diagnosis and 644 hospital controls reported their typical daily coffee and tea consumption. Unexpectedly, the authors found a significantly increased risk of pancreatic cancer associated with coffee consumption (overall rela-... 

In 1981, Lawson et al.,87 for example, compared a group of 210 women hospitalized for fibrocystic disease with 241 women who had breast cancer and were drawn from two ongoing studies in different countries. They matched each case to three female control patients on age, current smoking habits, country, and study. Recent coffee and tea consumption in cases and controls were compared and were shown to have a modest positive association with hot beverage consumption for both fibrocystic disease and breast cancer, but there was no dose-response relationship. The risk of fibrocystic disease associated with heavy consumption of hot beverages (7+ cups per day) vs. none was elevated but not statistically significant. 

Yu, G., Hsieh, C., Wang, L., Yu, S., Li, X., et al, Green-tea consumption of risk of stomach cancer A population-based case-control study in Shanghai, China, Cancer Causes Control, 6, 532, 1995. 

Zheng, W., Tea consumption and cancer incidence in a prospective cohort study of postmenopausal women, Am J Epidemiol, 144, 175, 1996. 

Duffy SJ, Keaney JF Jr, Holbrook M, Gokce N, Swerdloff PL, Frei B and Vita JA. 2001. Short- and longterm black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. Circulation 104(2) 151-156. 

Hakim IA, Alsaif MA, Alduwaihy M, Al-Rubeaan K, Al-Nuaim AR and Al-Attas OS. 2003. Tea consumption and the prevalence of coronary heart disease in Saudi adults results from a Saudi national study. Prev Med 36 64-70. 

Klaunig JE, Xu Y, Han C, Kamendulis LM, Chen J, Heiser C, Gordon MS and Mohler ER. 1999. The effect of tea consumption on oxidative stress in smokers and nonsmokers. Proc Soc Exp Biol Med 220 249-254. 

Kuriyama S, Shimazu T, Ohmori K, Kikuchi N, Nakaya N, Nishino Y, Tsubono Y and Tsuji I. 2006. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan the Ohsaki study. JAMA 296 1255-1265. 

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