Tea isn’t just for scones and English breakfasts. This beverage, steeped in history and ritual (pun intended) is the subject of daily consumption not only in American and European nations, but also in Asia. Although tea does not get its own pillar in the five pillars of Chinese Medicine, it is included in the first pillar of Diet. You could make the argument that it also belongs in the fourth pillar of Herbal Medicine because it functions not just a dietary beverage but a medicinal compound as well.
Many patients inquire about the health benefits of various supplements and teas, and about green tea specifically. So here’s an abbreviated look at some recent studies on the effects of green tea on various conditions:
• A study published this month concludes that “long-term dietary intake of Artemisia extracts and/or green tea extracts can be an effective strategy either to rejuvenate H. pylori atrophic gastritis or to suppress tumorigenesis” helping to heal the digestive tract. (1)
• A paper published last month found “the 10-year prospective cohort study by Drs. K. Nakachi and K. Imai revealed that drinking 10 Japanese-size cups (120 mL/cup) of green tea per day delayed cancer onset in humans by 7.3 years among females and by 3.2 years among males.” (2)
• In January, a results from a study on melanoma “suggest(ed) that green tea polyphenols (GTPs) induce a marked disruption of the uncontrolled cell cycle progression, and that may be a mechanism by which GTPs inhibit the proliferation or suppress the cell viability of melanoma cells.” (3)
• Another study published in January comparing irradiation verses green tea polyphenols “indicate that nerve allografts pretreated by green tea polyphenols are equivalent to transplanting autologous nerves in the repair of sciatic nerve defects, and promote nerve regeneration. Pretreatment using green tea polyphenols is better than pretreatment with irradiation.” (4)
• An abstract released in February concluded that “experimental data indicated that EGCG (the bioactive component of green tea) treatment suppresses cell proliferation of SSC-4 human oral squamous cell carcinoma (OSCC).” (5)
• Last February, a study of elderly rats that had a hind limb immobilized for two weeks had better muscle recovery of the plantaris, a fast muscle, although it didn’t help the soleus, a slow muscle. (6)
• Results from a study last October found “long-term administration of cigarette smoke altered the cellular antioxidant defense system, induced apoptosis in lung tissue, inflammation and damage in liver, lung, and kidney. All these pathophysiological and biochemical events were significantly improved when the cigarette smoke-exposed albino rats were given Chinese green tea (CGT) infusion as a drink instead of water.” The specific green tea variety used in this study is Lung Chen. (7)
• A study published back in 2011 found “epigallocatechin gallate (EGCG, 0·05 % in drinking-water), the primary polyphenolic component in green tea, effectively delayed the onset of Type 1 diabetes in non-obese diabetic (NOD) mice.” (8)
Most of these studies were done on rats and mice, but it provides a broad spectrum of potential health benefits of humans. At the very least, moderate daily consumption of green tea won’t hurt. The biggest concern with green tea intake seem to be too much. Here’s what rxdrugs.com has to say about possible side effects:
“Green tea is safe for most adults. Green tea extract seems to be safe for most people for short-term use. In some people, green tea can cause stomach upset and constipation. Green tea extracts have been reported to cause liver problems.
“Too much green tea, such as more than five cups per day, can cause side effects because of the caffeine. These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion. Green tea seems to reduce the absorption of iron from food.” (http://www.rxlist.com/green_tea/supplements.htm)
Like any change in your diet, talk to your health professionals to see if green tea consumption is appropriate for you. But it is generally regarded as safe. Moderation and proper preparation are the keys to getting health benefits from green tea.
My fiance, who is a smoker, frequently brewed Lung Ching green tea to give out as samples when he sold loose tea at the local farmers markets. Clearly that was a good choice for him as well. Since we are both serious about tea quality, we always recommend loose tea infused in a strainer that allows the individual leaves to unfurl and steep properly. When brewed at the range of 122 to 180 degrees for a minute, a good quality green tea can be brewed multiple times from the same serving. Preparing green tea in the traditional Chinese way ensures a good tasting tea that isn’t bitter. Steeping a green tea for too long or too hot ruins the tea and isn’t worth drinking. If caffeine is a concern, we recommend discarding the first brew and drinking the subsequent brews. This works for any caffeinated tea, by the way.
With dozens of varieties of green tea available, good health is just a cup away.
Pubmed studies on the benefits of green tea
1. Helicobacter. 2015 Apr 10: Dietary Intervention of Artemisia and Green Tea Extracts to Rejuvenate Helicobacter pylori-Associated Chronic Atrophic Gastritis and to Prevent Tumorigenesis.
2. J Cancer Prev. 2015 Mar: Primary cancer prevention by green tea, and tertiary cancer prevention by the combination of green tea catechins and anticancer compounds.
3. Genes Cancer. 2015 Jan: Polyphenols from green tea inhibit the growth of melanoma cells through inhibition of class I histone deacetylases and induction of DNA damage.
4. Neural Regen Res. 2015 Jan: Allograft pretreatment for the repair of sciatic nerve defects: green tea polyphenols versus radiation.
5. Onco Targets Ther. 2015 Feb 20: Epigallocatechin-3-gallate suppresses cell proliferation and promotes apoptosis and autophagy in oral cancer SSC-4 cells.
6. Exp Gerontol. 2014 Feb: Epigallocatechin-3-gallate improves plantaris muscle recovery after disuse in aged rats.
7. Iran J Basic Med Sci. 2014 Oct: Chinese green tea consumption reduces oxidative stress, inflammation and tissues damage in smoke exposed rats.
8. Br J Nutr. 2011 Apr: Epigallocatechin gallate delays the onset of type 1 diabetes in spontaneous non-obese diabetic mice.