Japanese green tea contains many ingredients such as theanine and catechin as you may have heard before. Recently, a component called polysaccharide has also been attracting as one of the health benefits.
You already know that tea can be expected to have a number of health benefits that make us happy. Today, I would like to introduce the health benefits of Japanese green tea.
- What’s Theanine And What’s You Can Expect
- What’s Catechin And What’s You Can Expect
- Health Benefits of Polysaccharides
- Caffeine In Japanese Green Tea
- The Bottom Line
What’s Theanine And What’s You Can Expect
Theanine is a type of amino acid discovered in Gyokuro by Japanese researchers in 1950 and is known as a component peculiar to tea.
The Main Component Of Umami And Sweetness In Tea
The taste of tea is determined by the balance of four elements: astringency, bitterness, umami, and sweetness.
The ingredient that brings umami and sweetness is theanine. Amino acids are thought to have an umami effect, and Japanese green tea contains about half of all amino acids, theanine.
Theanine contained in tea leaves is composed of the roots of tea trees, transfer to sprouts in early spring, and changes to catechin when exposed to sunlight.
The Relaxation Effect
The human brain produces alpha waves when you’re calm and relaxed.
Studies have shown that theanine stimulates the production of alpha brain waves directly, creating a state of deep relaxation. In short, theanine can be expected its relaxing effect.
A cup of Japanese green tea contains approximately 15 to 30 mg of caffeine.
Despite this caffeine level should have a strong stimulant effect, drinking Japanese green tea remains a mild stimulant effect. This is because theanine has a caffeine excitatory-inhibitory effect.
Other Amino Acids In Green Tea
Other amino acids contained in green tea leaves include glutamic acid, aspartic acid, arginine, and serine. In addition to these amino acids, multiple components such as organic acids and polyphenols contribute comprehensively to the green tea flavor.
Glutamic acid and arginine are the second most abundant amino acids in green tea leaves after theanine. Glutamic acid is known as a strong umami taste to the tea. Arginine has a vasodilatory effect and an effect of excreting ammonia in the body and has been shown to enhance the body’s immunity.
Green tea can be expected to improve athletic performance (endurance) by the action of caffeine. On the other hand, since ammonia, which is a waste product, increases during exercise, Research is being conducted on the combination of arginine, which promotes the metabolism of ammonia, and theanine, which has a relaxing effect and effectively reduces fatigue.
What’s Catechin And What’s You Can Expect
The second ingredient to introduce is catechin. Catechin is a type of polyphenol contained in tea. This is also known as an ingredient peculiar to tea.
The Main Component Of Astringency And Bitterness
Catechin is also one of the ingredients that impact the taste of green tea and brings astringency and bitterness.
Astringency/ bitterness sounds negative, but the four elements of green tea taste, well-balanced both astringency and bitterness are indispensable.
As I said, the theanine changes to catechin when exposed to sunlight while tea trees are growing. Therefore, Sencha tea grown in plenty of sunlight is rich in catechin.
In particular, Niban-cha, which grows for a long time in the sunlight, has a high catechin content. At the catechin level, Nibancha has a high health effect.
Catechin can be expected to have these health effects.
- Antioxidant effect
- Sterilization / disinfection action
- Antiviral effect
- Fat absorption inhibitory effect
- Deodorant effect
The Antioxidant Effect Of Catechin
Among these health benefits, the antioxidant effect is the most powerful effect of catechin. The antioxidant effect is the function of protecting the cells of the body from active oxygen.
The Active Oxygen
The body cells use the oxygen you intake to get energy. At the same time, active oxygen generated as using oxygen oxidizes and damages cells. This causes factors such as aging, cancer, and lifestyle-related diseases.
By intaking catechin, which has a strong antioxidant effect, it can be expected to be effective in preventing those factors.
Catechin Effect Is Expected For Bactericidal And Antiviral
Secondly, let’s focus on the bactericidal/antiseptic and antiviral.
As for bactericidal and disinfecting action, catechin works effectively against food poisoning bacteria attached to food.
Food poisoning bacteria can be mainly categorized into “poisoning”, which causes abnormalities in the body bacteria or chemical toxins, and “infection”, which causes abnormalities when bacteria themselves adhere to the intestinal tract.
Catechin exerts a detoxifying action against the poisoning and also a bactericidal action that destroys the cell membrane of bacteria against the infection.
Catechins also have a strong antibacterial effect against O-157. Besides, it has been clarified its proactivity for a growth-inhibitory effect on food poisoning bacteria such as Shigella infection and Vibrio cholerae, and Helicobacter pylori.
Furthermore, as an antiviral effect, gargling with tea is expected to be effective in preventing influenza.
Green tea mainly contains the following four types of catechins.
- Epicatechin (EC)
- Epigallocatechin (EGC)
- Epigallocatechin gallate (ECG)
- Epigallocatechin gallate (EGCG)
Among these four catechins, epigallocatechin gallate was found to its powerful health effects such as antioxidant power and cholesterol level control- known as effects of catechin.
The highest content is epigallocatechin gallate (EGCG), which accounts for about half of the total amount of catechin in tea and acts inactivation of the virus. Many research suggests that EGCG can be expected in protecting your cells from damage and preventing disease with its powerful antioxidant effect.
How To Take EGCG Effectively
This component is abundant in Sencha and Kamairicha, and also cold-brewing is most likely the best way to extract EGCG.
Yet, EGCG undergoes structural changes from 82 ° C in water and also is extracted less at low temperatures of 20 ° C and lower. Therefore, the best temperature to extract is preferably 70 ° C or higher and 80 ° C or lower.
Also, epigallocatechin gallate is easy to take with supplements.
If you are pregnant, nursing, or taking any medication, consult your doctor before use. Discontinue use and consult your doctor if any adverse reactions occur.
Antibacterial Action; Prevention Of Tooth Decay
Cavities are caused by the main causative bacterium, Streptococcus mutans, adhering to the tooth surface- the plaque is formed and the acid produced by the attached causative bacterium dissolves the enamel on the tooth surface.
Catechin is effective in preventing tooth decay because it suppresses the growth of mutant bacteria and the formation of plaque.
The Effect Of Weight Loss
Green tea also contains gallate-type catechins (ECG and EGCG) that are expected to work to suppress fat absorption and prevents metabolic.
Lipase is an enzyme the body uses to break down fats so they can be absorbed, and ester-type catechin suppresses the action of lipase.
Since fat is not easily absorbed by the body due to the action of catechin, it can be expected to prevent metabolic syndrome.
Continuous intake of catechin can also be expected to increase fat consumption. Since it also acts on the mitochondria of the liver and muscles that produce energy, it activates internal enzymes (β-oxidation-related enzymes) that act on fat consumption.
Health Benefits of Polysaccharides
Polysaccharides (long-chain polymeric carbohydrates) are extracted by cold-brewed tea.
Polysaccharides are a tea component that has been attracting attention in recent years, which leads to a decrease in the blood sugar level and has been expected to be effective in preventing diabetes.
Polysaccharides take time to break down and digest in the body, so they allow the blood sugar levels to rise slowly.
At the same time, insulin, a hormone that suppresses the blood sugar level, is sufficiently secreted, and hyperglycemia can be suppressed.
Polysaccharides are abundant in “Shutou Bancha“, which is harvested from autumn to winter.
Caffeine In Japanese Green Tea
Caffeine contributes to the bitterness of Japanese green tea.
Caffeine levels are not so much different depends on the harvest season. Yet, because the caffeine level is abundant in young leaves, Tencha (Matcha) and Gyokuro made by picking young leaves contain high caffeine levels.
Caffeine includes increased arousal, vigilance, locomotor activity, and diuresis effects– acts excitably on the central nerves of the brain (awakening action), which has the effect of preventing drowsiness, improving intellectual workability, and improving athletic ability.
In addition, it helps to boost endurance using fat as an energy source (glucose- glycogen) in the muscle when you take caffeine before a workout.
Green tea is expected to be effective hangover prevention, also because the action of caffeine enhances alcohol metabolism.
The Bottom Line
Today, I mainly introduced the health benefits of theanine, catechin, and polysaccharides contained in Japanese green tea.
These effects here are only a part of many other health benefits of it. Why not incorporate Japanese green tea, the “natural healthy supplement”, into your daily life.
Although Japanese green tea is considered the daily healthy drink and has been cleared its powerful health benefits as I told here, in some people can have dark sides of green tea.
I explain three ingredients that can work negatively on your health. Read here next as well.
- A Review of the Antiviral Role of Green Tea Catechins
- Inhibiting Effects of Theanine on Caffeine Stimulation Evaluated by EEG in the Rat
- Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men
- The protective activity of tea catechins against experimental infection by Vibrio cholerae O1
- Inhibitory Activity of Green Tea (Camellia sinensis) Extract on Some Clinically Isolated Cariogenic and Periodontopathic Bacteria
- In Vitro and In Vivo Activities of Tea Catechins against Helicobacter pylori
- Antibacterial and anti-hemolysin activities of tea catechins and their structural relatives. [in Japanese]