Green Tea

Many, many years ago, in one of those uncomfortable instances of workplace TMI, a colleague told me that he drank green tea because it helped him with his bad breath, he was a cigar smoker, you see. (Still, how is one supposed to respond to that?)

And although I am not, nor have I ever been a cigar smoker, it was around that time that I started drinking green tea. This was partly due to circumstance: sushi had become all the rage, and green tea was the only thing on the menu I could stomach; and partly because, well, one can never be too careful about bad breath, right?

Through the years I’ve heard and read a constant stream of studies and reports on the health benefits of green tea. From head to toe, it has been consistently reported to remedy &/or prevent all many of disease states. So, perhaps I owe a debt of gratitude to my former colleague; the one who smoked cigars, and who, for reasons unknown decided one day to tell me about both his bad breath and its remedy.

Camellia sinensis is a species of evergreen shrub whose leaves and leaf buds are used to produce green tea.[1][2]

Green tea fields in Portugal

Demonstrated properties of green tea extracts include: antioxidant, anti-carcinogen, anti-inflammatory, and anti-radiation.[3][4][5][6]

A catechin is a type of natural phenol and antioxidant.[7]

Catechins make up roughly 30 to 40% of green tea.[8]

Processing green tea

The ability of catechins in green tea extracts to eliminate lipid-derived free radicals is ~ 50 times stronger than that of ginkgo biloba extracts.[3][5]

Epigallocatechin gallate

Of the eight catechins in green tea, epigallocatechin-3-gallate, or EGCG, is the most active.[8][9]

THE RESEARCH


GREEN TEA & CANCER 

EGCG (as contained in green tea) has been found to:[8, 10-14, 15]

• cause cell death in experimental prostate cancer
• inhibit the growth of squamous cell carcinomas of the head and neck 
• inhibit the production and limit the invasion of experimentally induced breast cancers 
• reduce the incidence of carcinogen-induced lung cancers
• sensitize melanoma cells to growth inhibition by other agents

• Recent studies have suggested that a topical cream based on green tea may help in the prevention of skin cancer.[20]

Researchers at the Arizona Cancer Center performed a randomized, controlled study of the effects of tea drinking among heavy smokers.

• The team determined that the smokers who drank green tea had a 31% decrease in their levels of urinary 8-hydroxydeoxyguanosine (OhdG)—the presence of OhdG is associated oxidative stress.

• This suggests that the smokers who drank green tea were less susceptible to oxidative DNA damage than were smokers who drank black tea or members of the control group.[20][21]

Scientists from the Los Angeles Biomedical Research Institute recently discovered EGCG’s ability to prevent and slow the growth of pancreatic cancer by interfering with one of the key enzymes in pancreatic cancer cells known as LDHA (Lactate dehydrogenase A).[22][23]

A recent study from Penn State University suggests that it is through the destruction of mitochondria, that EGCG helps kill oral cancer cells.[22][24] 

Moreover, EGCG may trigger this destruction while leaving healthy cells alone.[25]

"EGCG is doing something to damage the mitochondria and that mitochondrial damage sets up a cycle causing more damage and it spirals out, until the cell undergoes programmed cell death," said Joshua  Lambert, associate professor of food science and co-director of Penn State's Center for Plant and Mushroom Foods for Health.[25]

GREEN TEA AND DEMENTIA & ALZHEIMER'S

Green tea consumption is associated with a 54% reduction in the risk of developing cognitive decline.[8][16]

GREEN TEA & RHEUMATOID ARTHRITIS

Researchers at the University of Michigan have demonstrated that EGCG reduces the production of specific molecules that contribute to inflammation and joint damage in people with rheumatoid arthritis.[17][18]


GREEN TEA & DIABETES

Researchers at Karolinska Institute in Sweden compared the effects of EGCG with an anti-diabetes drug in rats, and found EGCG improved the animals' glucose levels, as well as the amount of insulin they made in response to a glucose load.[17][19] 

EGCG wasn’t as potent as the drug, but it did have some of the same beneficial effects.[17][19]

UPDATES

Apple A Day And Cup Of Green Tea Benefits The Heart And Slows Down Cancer Progression Medical Daily, April 13, 2015

***

FIN

REFERENCES

[1] http://en.wikipedia.org/wiki/Green_tea
[2] http://en.wikipedia.org/wiki/Camellia_sinensis
[3] http://en.wikipedia.org/wiki/Green_tea_extract
[4] I.T. Johnson & G. Williamson, Phytochemical functional foods, Cambridge, UK: Woodhead Publishing, 2003, pp. 135-145
[5] Y.S. Zhen, Z.M. Chen, S.J. Cheng & M.L. Chen, Tea: bioactivity and therapeutic potential, London, UK: New York Taylor & Francis, 2002, pp. 121–225.
[6] F. Murray, 100 super supplements for a longer life, Los Angeles: CA McGraw-Hill Professional, 2000, pp. 181–182.
[7] http://en.wikipedia.org/wiki/Catechin
[8] http://www.lef.org/Magazine/2014/8/How-Green-Tea-Protects-Against-Alzheimers-Disease/Page-01
[9] Sutherland BA, Rahman RMA, Appleton I. Mechanisms of action of green tea catechins, with a focus on ischemia-induced neurodegeneration. The Journal of Nutritional Biochemistry.2006;17, 291–306.
[10] Siddiqui IA, Shukla Y, Adhami VM, et al. Suppression of NFkappaB and its regulated gene products by oral administration of green tea polyphenols in an autochthonous mouse prostate cancer model. Pharm Res. 2008 Sep; 25(9):2135-42.
[11] Amin AR, Khuri FR, Chen ZG, Shin DM. Synergistic growth inhibition of squamous cell carcinoma of the head and neck by erlotinib and epigallocatechin-3-gallate: the role of p53-dependent inhibition of nuclear factor-kappaB. Cancer Prev Res (Phila). 2009 Jun; 2(6):538-45.
[12] Nihal M, Ahsan H, Siddiqui IA, Mukhtar H, Ahmad N, Wood GS. (-)-Epigallocatechin-3-gallate (EGCG) sensitizes melanoma cells to interferon induced growth inhibition in a mouse model of human melanoma. Cell Cycle. 2009 Jul 1; 8(13):2057-63.
[13] Sen T, Moulik S, Dutta A, et al. Multifunctional effect of epigallocatechin-3-gallate (EGCG) in downregulation of gelatinase-A (MMP-2) in human breast cancer cell line MCF-7. Life Sci. 2009 Feb 13; 84(7-8):194-204.
[14] Roy P, Nigam N, Singh M, et al. Tea polyphenols inhibit cyclooxygenase-2 expression and block activation of nuclear factor-kappa B and Akt in diethylnitrosoamine induced lung tumors in Swiss mice. Invest New Drugs. 2010 Aug; 28(4):466-71.
[15] Yang CS, Wang X. Green tea and cancer prevention. Nutr Cancer. 2010;62(7):931-7.
[16] Kuriyama S, Hozawa A, Ohmori K, Shimazu T, Matsui T, Ebihara S, Awata S, Nagatomi R, Arai H, Tsuji I. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 1. Am J Clin Nutr. 2006 Feb;83(2):355-61.
[17] http://discovermagazine.com/2007/oct/the-legend-of-green-tea-keeps-a-growin
[18] http://www.med.umich.edu/opm/newspage/2007/greentea.htm
[19] http://www.chinapost.com.tw/health/2007/09/21/123432/Green-tea.htm 

Reporting on:

• European Association for the Study of Diabetes meeting in Amsterdam, Netherlands September 19, 2007

[20] http://www.scientificamerican.com/article/green-tea-and-ginger-show/
[21] http://www.ncbi.nlm.nih.gov/pubmed/14973088
[22] http://www.medicaldaily.com/green-tea-polyphenol-helps-kill-oral-cancer-cells-destroying-mitochondria-320730
[23] http://labiomed.org/2014/05/30/study-explains-how-green-tea-could-reduce-pancreatic-cancer-risk-findings-open-a-new-area-for-research-into-cancer-prevention/
[24] http://onlinelibrary.wiley.com/doi/10.1002/mnfr.201400485/abstract
[25] http://www.sciencedaily.com/releases/2015/01/150128152209.htm
Penn State. "Green tea ingredient may target protein to kill oral cancer cells." ScienceDaily. ScienceDaily, 28 January 2015. <www.sciencedaily.com/releases/2015/01/150128152209.htm>.

From Journal Reference:

Ling Tao, Jong-Yung Park, Joshua D. Lambert. Differential prooxidative effects of the green tea polyphenol, (-)-epigallocatechin-3-gallate, in normal and oral cancer cells are related to differences in sirtuin 3 signaling. Molecular Nutrition & Food Research, 2014; DOI: 10.1002/mnfr.201400485


IMAGE CREDITS

"Tea leaves steeping in a zhong čaj 05" by Wikimol - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Tea_leaves_steeping_in_a_zhong_%C4%8Daj_05.jpg#mediaviewer/File:Tea_leaves_steeping_in_a_zhong_%C4%8Daj_05.jpg

"Camellia sinensis - Köhler–s Medizinal-Pflanzen-025" by Franz Eugen Köhler, Köhler's Medizinal-Pflanzen - List of Koehler Images. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Camellia_sinensis_-_K%C3%B6hler%E2%80%93s_Medizinal-Pflanzen-025.jpg#mediaviewer/File:Camellia_sinensis_-_K%C3%B6hler%E2%80%93s_Medizinal-Pflanzen-025.jpg

"Plantação de Chá Gorreana, Camellia sinensis, Ribeira Grande, ilha de São Miguel, Açores" by José Luís Ávila Silveira/Pedro Noronha e Costa - Own work. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Planta%C3%A7%C3%A3o_de_Ch%C3%A1_Gorreana,_Camellia_sinensis,_Ribeira_Grande,_ilha_de_S%C3%A3o_Miguel,_A%C3%A7ores.JPG#mediaviewer/File:Planta%C3%A7%C3%A3o_de_Ch%C3%A1_Gorreana,_Camellia_sinensis,_Ribeira_Grande,_ilha_de_S%C3%A3o_Miguel,_A%C3%A7ores.JPG

"Processing green tea" by Spinster cardigan - Own work. Licensed under CC BY 1.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Processing_green_tea.jpg#mediaviewer/File:Processing_green_tea.jpg

"(+)-Catechin" by Edgar181 - Own work. Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:(%2B)-Catechin.png#mediaviewer/File:(%2B)-Catechin.png

"Epigallocatechin gallate3Dan2" by Fuse809 at English Wikipedia. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Epigallocatechin_gallate3Dan2.gif#mediaviewer/File:Epigallocatechin_gallate3Dan2.gif

"Knightni" by screenshot from the film Monty Python and the Holy Grail. Via Wikipedia - http://en.wikipedia.org/wiki/File:Knightni.jpg#mediaviewer/File:Knightni.jpg