Letter
The Relationship Between Tea Consumption and Cancer
Salman Khazaei 1, Hamid Salehiniya 2,3 * , Mohammad Keshvari Delavar 4, Abdollah ; Abdollah Mohammadian Hafshejani 5
1 Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, IR Iran
2 Minimally Invasive Surgery Research Center, Iran University of Medical Sciences, Tehran, IR Iran
3 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
4 Hamadan University of Medical Sciences, Hamadan, IR Iran
5 Department of Epidemiology and Biostatistics, School of Public Health, Isfahan University of Medical Sciences, Isfahan, IR Iran
IR
Iran *Corresponding author: Hamid Salehiniya, Department of Epidemiology
and Biostatistics, School of Public Health, Tehran University of
Medical Sciences, Tehran, IR Iran. Email: alesaleh70@yahoo.com
Dear Editor,
Tea is the most
commonly consumed beverage in the world after water. Black tea accounts
for about 75% of the world’s tea consumption, while green tea is the
most popular tea in Japan and China (1). Tea contains many of bioactive compounds, including amino acids, caffeine, lignins, proteins, xanthines and flavonoids (2). Tea consumption reduces the risk of heart disease and stroke (3, 4).
Tea compounds by many mechanisms such as reducing free radical and DNA
damage, inhibiting uncontrolled cell growth, and boosting the immune
system help stave off the development of cancer cells and provide
chemo-protection for our body (5).
Although many of the potential beneficial effects of tea have been
attributed to the strong antioxidant activity of tea polyphenols, the
precise mechanism by which tea might help prevent cancer has not been
established (6).
The results of one study showed that green tea was effective in the initial stages of colon carcinogenesis (7). Another study showed that drinking iced black tea and citrus peel was associated 42% reduction in the risk of skin cancer (8). Tea compounds can influence genetic alteration to reduce the grown and survival of human lung cancer cells (9). The protective effect of tea consumption on ovarian (10), breast (11) and prostate cancer (12)
has been shown in some studies. In contrast, the results of another
study showed that drinking tea at a temperature of 70 -79°C and above is
related to highly elevated risk of esophageal cancer (13).
Conclusions from the results of these studies should be cautious
because some variables such as differences in tea preparation and
consumption, the types of tea studied (green or black), the ways of tea
production, genetic diversity, the concomitant use of tobacco and
alcohol, and lifestyle factors such as physical activity may affect the
risk of developing cancer. Therefore more evidence is needed before
definitive conclusions can be drawn.
References
-
1.
Seeram NP, Henning SM, Niu Y, Lee R, Scheuller HS, Heber D. Catechin and
caffeine content of green tea dietary supplements and correlation with
antioxidant capacity. J Agric Food Chem. 2006;54(5):1599-603. [DOI] [PubMed]
-
2.
Balentine DA, Wiseman SA, Bouwens LC. The chemistry of tea flavonoids. Crit Rev Food Sci Nutr. 1997;37(8):693-704. [DOI] [PubMed]
-
3.
Peters U, Poole C, Arab L. Does tea affect cardiovascular disease? A
meta-analysis. Am J Epidemiol. 2001;154(6):495-503. [PubMed]
-
4.
Larsson SC, Virtamo J, Wolk A. Black tea consumption and risk of stroke
in women and men. Ann Epidemiol. 2013;23(3):157-60. [DOI] [PubMed]
-
5.
Bhattacharyya A, Mandal D, Lahiry L, Sa G, Das T. Black tea protects
immunocytes from tumor-induced apoptosis by changing Bcl-2/Bax ratio. Cancer Lett. 2004;209(2):147-54. [DOI] [PubMed]
-
6.
Lambert JD, Yang CS. Mechanisms of cancer prevention by tea
constituents. J Nutr. 2003;133(10):3262S-7S. [PubMed]
-
7.
Issa
AY, Volate SR, Muga SJ, Nitcheva D, Smith T, Wargovich MJ. Green tea
selectively targets initial stages of intestinal carcinogenesis in the
AOM-ApcMin mouse model. Carcinogenesis. 2007;28(9):1978-84. [DOI] [PubMed]
-
8.
Hakim IA, Harris RB. Joint effects of citrus peel use and black tea
intake on the risk of squamous cell carcinoma of the skin. BMC Dermatology. 2001;1(1):3. [DOI]
-
9.
Kr
CGPSC, Das PS. Inhibition of growth, induction of apoptosis and
alteration of gene expression by tea polyphenols in the highly
metastatic human lung cancer cell line NCI-H460. Asia Pac J Cancer Prev. 2005;6:326-31.
-
10.
Baker JA, Boakye K, McCann SE, Beehler GP, Rodabaugh KJ, Villella JA, et
al. Consumption of black tea or coffee and risk of ovarian cancer. Int J Gynecol Cancer. 2007;17(1):50-4. [PubMed]
-
11.
Zhang M, Holman CD, Huang JP, Xie X. Green tea and the prevention of
breast cancer: a case-control study in Southeast China. Carcinogenesis. 2007;28(5):1074-8. [DOI] [PubMed]
-
12.
Jian
L, Lee AH, Binns CW. Tea and lycopene protect against prostate cancer. Asia Pac J Clin Nutr. 2007;16 Suppl 1:453-7. [PubMed]
-
13.
Chen
Z, Chen Q, Xia H, Lin J. Green tea drinking habits and esophageal
cancer in southern China: a case-control study. Asian Pac J Cancer Prev. 2011;12(1):229-33. [PubMed]