health benefits

green tea & health

How it works

All various kinds of tea come from the leaves of the same plant, Camellia sinensis. The three main types of tea are green tea, oolong tea, and black tea.

The difference between them is the fermentation degree of the leaves. Fermentation, in turn,  influences their oxidation levels. When tea leaves are steamed (like with sencha, tamaryokucha or gyokuro), baked, or pan fried (like with kamairicha), there is no oxidation and therefore the leaves remain green. Oolong tea is partially fermented, and black tea is fully fermented.

In this sense, Japanese white tea is a kind of green tea; its pale color comes from the shading process used by the producers. Sunlight exposure is completely blocked, so there is no chlorophylle production. The same process boosts the levels of amino acids in the leaves, making Japanese white tea an extra healthy kind of green tea.

Green tea has gained a lot of attention from scientists because a specific and powerful antioxidant (epigallocatechin-3 gallate (EGCG)) found in tea leaves is preserved thanks to their lack of oxidation. On the opposite, when there is a degree of fermentation, this antioxidant is lost.

Studies have shown that antioxidants help the body fight against free radicals, that cause cellular damage leading to various health issues, from cancer to heart diseases and premature aging.

Research has pointed out that the EGCG found in green tea is a very powerful antioxidant, 100 times more effective than Vitamin C for example. So, ready to see what green tea can do for you? Read on, the list is long!
Green tea leaf detail in Yame, Fukuoka prefecture
A.Bloise 2016
1.   Focus & Concentration : L-theanine (here referred to as theanine) is an amino acid that has a relaxing, but not sedating, effect. It is renowned for its ability to put you in the ideal state of “calm attentiveness.” It can sharpen focus and concentration, while reducing stress and enhancing overall well-being.

Theanine can interact with caffeine, allowing a smaller dose of caffeine to have a stronger effect in terms of boosting concentration and alertness. This may explain why tea seems to provide a stronger boost in alertness for some people than one would expect from its caffeine content alone.

2.  Prevents tooth decay and bad breath  Catechin  and fluorine limits the growth of the bacteria causing tooth decay and  freshens the mouth. This effect is best achieved by drinking it after meals.  

3.  Effectively burns body fat  Caffeine  promotes the metabolism of fat. Drinking green tea and engaging in physical activity 20-30 minutes afterwards burns up body fat but also acts as a muscle  stimulant.

4.  Beautifies the skin  Drinking  tea maintains the skin’s elasticity, and the vitamin C strengthens the  capillaries. It also improves the skin’s ability to retain warmth.

5.  Prevents hardening of the arteries and high blood pressure  Tea with  high catechin contents increase the levels of HLD (good cholesterol) in the  blood. Gamma-aminobutyric acid inhibits high blood pressure. 

6.  Protects against colds. Due to catechins, green tea strengthens the body’s defenses against infection, so  using it as a gargle protects against viruses, regardless of the type of  influenza.

7.  Antibacterial properties and acidification balance  Tea’s  strong antibacterial properties limit oxidation in the body and maintains a  good pH balance by promoting the body’s alkalinity, therefore helping fight against inflammations and pain due to body acidification.

8.  Prevents food poisoning  Catechin  has a powerful effect on bacteria causing food poisoning. It also regulates  intestinal functions.

9. Lower  blood glucose levels.  The  conjugated polysaccharide found in green tea helps to prevent diabetes.  

10.  Prevent aging  Green  tea suppress the production of free radicals and lipid peroxide, and  therefore prevents aging. Green tea has anti-oxidative effects.
Tea Master explaining the Tea ceremony gestures. Note the tea cup, an invaluable Kakiemon teaware. Iriki, Satsumasendai
A.Bloise 2015

green tea & health

components of green tea

Tea has both soluble and insoluble components. The latter can only be ingested when drinking matcha, and this is why matcha is so good for your health. The first category is found in all kinds of tea, at various levels depending on the cultivar, the type of tea, its quality and the temperature used to brew it. For more information about the components of Green Tea, please feel free to download our infographic.

insoluble components

  • Dietary  fibers
  • Protein
  • Provitamin A
  • Vitamin E
  • Chlorophyll
  • Minerals

soluble components

  • Catechin (antioxidant)
  • Tannin (antioxidant)
  • Flavonoid (antioxidant)
  • Caffein (central nervous  system stimulant)
  • Conjugated polysaccharide (hypertension inhibitor)
  • Vitamin C (antioxidant, antiallergic, immune system booster)
  • Vitamin B2 (antioxidant)
  • Theanin (hypotension)
  • Gamma-aminobutyric acid  (hypotension)
  • Saponin (anti-asthma, anti-bacterial, hypotension)
  • Pectin  (soluble dietary fiber, lower blood cholesterol)
  • Minerals (fluorine, zinc,  manganese, copper, selenium).
A small tea break during the first green tea harvest...and photo shooting. Sweets are on the way. Ei, Kagoshima
A.Bloise 2014

green tea & health

influence of components On the taste of green tea

There is a direct link between the components of green tea and its taste. Some cultivars and some tea types have more or less umami, astringency or bitterness. Even more importantly, water temperature has a direct impact on how those components are released. Therefore, by controlling water temperature, you can adjust the tea taste to your preference.

1) Amino acids release the umami taste and are easily dissolved regardless of the  temperature.

2) Astringency and bitterness are linked with caffein and catechin (tannin). Those are released at higher temperatures. Therefore, high quality tea should be prepared with a lower temperature.

Note that catechin and caffeine have both positive health impact, so they should not be avoided at all costs. Depending on your personal preferences, however,  you may want to make sure that not too much of them is released.

some tips

Should I drink green tea before going to bed? What about pregnant women or infants?Green tea contains caffeine but not all kinds have the same amounts. It is recommended to choose a kind of tea with low caffeine levels (like Shira-ore), or simply use about half the amount of leaves. In Japan, in the tea farming areas, babies are given watered down green tea to drink as soon as they start eating solid foods (6-8 months).

Green tea on an empty stomach
Green tea is rich in caffeine and catechin and so may be tough on an empty stomach. We recommend to drink weakly brewed teas in this case.

For more information, you can have look at our FAQ page or simply ask us by e-mail.
Close up of Gyokuro leaves during one of our tasting session at Yorozu. Fukuoka
A.Bloise 2016


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