Health Benefits of Tea
It is of no surprise to a tsaiophilist
that the letters; "t, e, and a" are found inside of and comprise one half of the word health
According to the online Cambridge Dictionary
The Way of Tea
- Health - the condition of the body and the degree to which it is free from illness, or the state of being well.
- Nutrition - the process of taking in and using food, or the scientific study of this.
"Before tea was a practice of Zen it was influenced in China by both Taoism and Confucianism. We can
read something of both in the inscription left by the twelfth-century Japanese
priest Myoe on his favorite kettle. He outlined the ten virtues of tea
in these words:
Tea has the blessings of all the deities,
promotes filial piety,
drives away the devil,
keeps the five viscera in harmony,
wards off disease,
disciplines body and mind,
destroys the passions,
gives peaceful death."
Tea and Health
The health benefits of tea have been receiving attention in the media. Tea's ability to promote good health has long been promoted and believed in China. Recent research has been able to identify the components in tea that appear to be directly related to tea's health promoting benefits.
Several substances, classified as antioxidants
(also referred to as polyphenols), are found in tea and these are the components that are able to combine with unstable positively charged oxygen molecules, otherwise known as 'free radicals'. The 'free radicals
' have been shown to cause not only cellular damage but also can damage DNA. As a consequence to the damage, various health problems develop.
Therefore, the antioxidants that are naturally occurring in tea, help remove the "free radicals" which helps promote better health. Other well known antioxidants are vitamins C and E. Some of the antioxidants that are found in tea are much more powerful than these two vitamins.
Research has shown that non-oxidized tea, (white, green, yellow), contains the highest amounts of antioxidants. Green tea, which is high in antioxidants, has received the most attention about its health benefits because it is the most commonly drunk tea in the China and Japan. Yet another non-oxidized tea which is much less common, namely white tea, is also high in antioxidants. One of the teas that is available here is a white (whyte) tea, Darjeeling White tea
More recent studies indicate that oxidized tea (pouchong, oolong, black) contains levels of antioxidants comparable to the non-oxidized teas. As a result of being oxidized during their processing, these teas, have other related antioxidants, theaflavins, that are only found in oxidized tea. Therefore, oxidized tea also has health promoting benefits. The other teas that are available, namely First Flush Darjeeling Tea
, Second Flush Darjeeling Teas
, Autumnal Flush Darjeeling Tea
, and the Darjeeling Oolong Tea
, are all oxidized tea.
Both of the Darjeeling White tea and the Darjeeling Oolong tea are very unusual in that they are Indian teas that are processed following Chinese methods. Darjeeling tea is traditionally prepared via the orthodox method by hand and is oxidized to a black tea level. So again, both the Darjeeling Oolong tea and the Darjeeling White tea promote health and are very unusual, especially the Darjeeling White tea.
Ancient Tea Health
As long as four thousand years ago, the ancient Chinese were praising the healthful attributes tea (primarily green, probably because it was / is the
most consumed tea in China ). The legendary Emperor Shen Nong in addition to being attributed to as being 'The Father of Tea', is known to have instructed people to boil water before drinking it, as a health measure and to prevent sickness. He is also known as the founder of agriculture and herbal medicine.
Since boiled water is sterile, this advice still holds true. Sterile water is the foundation upon which tea is made. In addition, boiling water (or that which has been allowed to cool just a bit for Jasmine tea) has sufficient heat to dissolve out all of the healthful components that are in the tea leaves.
It is also said that the leaves were added at some point in time to give some flavor to the rather flat tasting water that had been boiled. In the mid-1600's an early English tea merchant, Thomas Garway, claimed that some of the benefits of drinking tea included curing headache, dropsy, scurvy, sleepiness, loss of memory, looseness of the guts, heavy dreams, and collick proceeding from the wind! The human condition hasn't changed much over time.
Tea's Health Promoting
Components and Properties
Modern science has confirmed, to various degrees, the effects of tea drinking as a contributor to good health. It contains a variety of components that are beneficial to one's health. These include theanine
(an amino acid unique to tea), polyphenols, vitamins, minerals, and methylxanthines. These are the components that are the source of the healthful properties of tea.
These components impart a wide variety of beneficial effects under categories such as antimutagenic, anticarcinogenic, antioxidant, antihypertensive, stimulate the immune system, anticholesterolemic, platelet aggregation inhibition, anti-inflammatory, antibacterial, antiviral, diuretic, astringent, anticariogenic, and a mild stimulating effect.
Please visit the topics in the table above. The various effects are discussed in conjunction with the various components of tea.
From the lead article in the Health / Science section of the Boston Globe, 13 June '00, entitled; "The Tao of Tea". According to Dr. Hasan Mukhtar, a dermatologist at Case Western Reserve University, there is "convincing evidence" that the antioxidants in green tea can keep cancer from developing or slow its progress.
Dr. Yihai Cao, of the Karolinska Institute in Sweden, has found that green tea also has the property of blocking or interfering with the development of new blood vessels. The reason this may be important, is that for tumors to grow they need new blood vessels to "fuel their expansion". These and other researchers admit that conclusive evidence is still being sought, yet many of them do drink green tea.
Tea Health References
As a concise, single source this book is focused on green tea's health benefits.
In support of the above components and properties, this is but a sample of some of the research, involving the health benefits of tea, that has been recently conducted around the world.
- Bushman JL. Green tea and cancer in humans: a review of the literature. Nutr Cancer 1998;31(3):151-9.
- Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693-96.
- Yamaguchi Y, Hayashi M, Yamazoe H, et al. Preventive effects of green tea extract on lipid abnormalities in serum, liver, and aorta of mice fed an atherogenic diet. Nip Yak Zas 1991;97(6):329-37.
- Segasaka-Mitane Y, Miwa M, Okada S. Platelet aggregation inhibitors in hot water extract of green tea. Chem Pharm Bull (Tokyo). 1990;38:790-793.
- Ali M, Afzal M, Gubler C, Burka J. A potent thromboxane formation inhibitor in green tea leaves. Prostaglandins Leukot Essent Fatty Acids
- Stensvold I, Tverdal A, Solvoll K, et al. Tea consumption. Relationship to cholesterol, blood pressure, and coronary and total mortality. Prev
- Fujiki H, Suganuma M, Okabe S, Sueoka N, Komori A, Sueoka E, Kozu T, Tada Y, Suga K, Imai K, Nakachi K. Cancer inhibition by green tea. Mutat Res 1998 Jun 18;402(1-2):307-10.
- Lotito SB, Fraga CG. (+)-Catechin prevents human plasma oxidation. Free Radic Biol Med 1998 Feb;24(3):435-41.
- Gupta S, Ahmad N, Mukhtar H. Prostate cancer chemoprevention by green tea. Semin Urol Oncol 1999 May;17(2):70-6.
- Chow WH, Blot WJ, McLaughlin JK. Tea drinking and cancer risk: epidemiological evidence. Pros Soc Biol Med 1999 Apr;220(4):197.
- Klaunig JE, Xu Y, Han C, Kamendulis LM, Chen J, Heiser C, Gordon MS, Mohler ER 3rd. The effect of tea consumption on oxidative stress in smokers and nonsmokers. Proc Soc Exp Biol Med 1999 Apr;220(4):249-54.
- Kuroda Y, Hara Y. Antimutagenic and anticarcinogenic activity of tea polyphenols. Mutat Res 1999 Jan;436(1):69-97.
- Halder J, Bhaduri AN. Protective role of black tea against oxidative damage of human red blood cells. Biochem Biophys Res Commun
1998 Mar 27;244(3):903-7.
- Weisburger JH. Tea and health: a historical perspective. Cancer Lett 1997 Mar 19:114(1-2):315-7.
- Dreosti IE, Wargovich MJ, Yang CS. Inhibition of carcinogenesis by tea: the evidence from experimental studies. Crit Rev Food Sci Nutr
- Han C. Screening of anticarcinogenic ingredients in tea polyphenols. Cancer Lett 1997 Mar 19;114(1-2):153-8.
- Yang CS, Lee MJ, Chen L, Yang GY. Polyphenols as inhibitors of carcinogenesis. Environ Health Perspect 1997 Jun;105 Suppl 4:971-6.
- Shiraki M, Hara Y, Osawa T, Kumon H, Nakayama T, Kawakishi S. Antioxidative and antimutagenic effects of theaflavins from black tea. Mutat
Res 1994 Jan-Feb;323(1-2):29-34.
- Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med 1992 May;21(3):334-50.
- Komori A, Yatsunami J, Okabe S, Abe S, Hara K, Suganuma M, Kim SJ, Fujiki H. Anticarcinogenic activity of green tea polyphenols. Jpn J Clin Oncol 1993 Jun;23(3):186-90.
- Bronner WE, Beecher GR. Method for determining the content of catechins in tea infusions by high-performance liquid chromatography. J Chromatogr A 1998 May 1;805(1-2):137-42.
- Zhang A, Zhu QY, Luk YS, Ho KY, Fung KP, Chen Zy. Inhibitory effects of jasmine green tea epicatechin isomers on free radical-induced lysis of red blood cells. Life Sci 1997;61(4):383-94.
- Wei H, Zhang X, Zhao JF, Wang ZY, Bickers D, Lebwohl M. Scavenging of hydrogen peroxide and inhibition of ultraviolet light-induced oxidative
DNA damage by aqueous extracts from green and black teas. Free Radic Biol Med 1999 Jun;26(11-12):1427-35.
- Matsumoto N, Kohri T, Okushio K, Hara Y. Inhibitory effects of tea catechins, black tea extract and oolong tea extract on hepatocarcinogenesis in rat. Jpn J Cancer Res 1996 Oct;87(10):1034-8.
- Chung FL. The prevention of lung cancer induced by a tobacco-specific carcinogen in rodents by green and black tea. Proc Soc Exp Biol Med
- Katiyar SK, Mukhtar H. Tea antioxidants in cancer chemoprevention. J Cell Biochem Suppl 1997;27:59-67;
- Hibasami H, Komiya T, Achiwa Y, Ohnishi K, Kojima T, Nakanishi K, Sugimoto Y, Hasegawa M, Akatsuka R, Hara Y. Black tea theaflavins induce programmed cell death in cultured human stomach cancer cells. Int J Mol Med 1998 Apr;1(4):725-7.
- Yang GY, Liao J, Kim K, Yurkow EJ, Yang CS. Inhibition of growth and induction of apoptosis in human cancer cell lines by tea polyphenols.
Carcinogenesis 1998 Apr;19(4):611-6.
- Weisburger JH. Tea and health: the underlying mechanisma. Proc Soc Exp Biol Med 1999 Apr;220(4):271-5.
- Yam TS, Shah S, Hamilton-Miller Jm. Microbiological activity of whole and fractionated crude extracts of tea (Camellia sinensis), and
of tea components. FEMS Microbiol Lett 1997 Jul;152(1):169-74.
- Yen GC, Chen HY. Relationship between antimutgenic activity and major components of various teas. Mutagenesis 1996 Jan;11(1):37-41.
- Shen X, Lu R, Wu m. Effects of tea polyphenol on blood lipid and antioxidation in vivo in aged rats. Chung Hua Yu Fang I Hsueh Tsa Chih 1998 Jan;32(1):34-6.
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