Discovering green tea, a drink with multiple benefits

Did you know that tea is the most consumed drink in the world after water? Learn more about this beverage that has been around for thousands of years…

Tea, the second most popular drink in the world

What are the origins of green tea?

A little history...

Historically, the first appearance of tea dates to the second century BC. There are different types of teas like green tea that interest us here, but also black teas, oolong teas, and many others. All teas come from the Camellia sinensis shrub. The differences between green tea, black tea, and oolong tea come from the different maturation processes. Green tea represents 18% of the world’s consumption. 

The tea plant, an emblematic plant

The tea plant is naturally almost 10 meters high. However, growers prune it to a height of 1 meter to facilitate harvesting in the plantations. This shrub grows mainly on acidic and loose soils. Concerning the climate, the tea plant likes sunny environments as well as cool and rainy nights necessary for the maturation of the aromas of its leaves. 

A demanding harvest

The harvest of tea leaves is done up to 4 times a year depending on the region. Even today, the harvest is still done by hand and the leaves are collected one by one. The youngest leaves are richer in beneficial compounds such as tannins. In addition, these are the leaves that give off the most flavor. Also, an early harvest guarantees a better-quality tea due to the richness of polyphenols.

How to obtain a tea fit for consumption?

Once picked, the tea leaves must be processed through various stages to obtain the much-appreciated beverage. The first one is called “withering”. The objective is to reduce the water content in the leaves, either with the help of a blower or directly in the open air. Once this stage is completed, the time comes for rolling, which marks the beginning of the oxidation process. This is the third stage and is carried out in a particularly humid environment. In the case of green teas, this stage is short-lived. Finally comes the last stage of drying. The objective is to stop the oxidation process to preserve a maximum of aromatic substances while ensuring that the leaves do not become moldy. 

Did you know that? It takes no less than 5 kg of fresh tea leaves to obtain 1 kg of tea to brew!

How many varieties of tea are there?

Concerning the number of tea varieties, there are countless of them coming mainly from China, Japan, and India. Among the most famous varieties, concerning Japan, we can mention names like matcha tea or bancha tea. On the Chinese side, gunpower tea or long jing tea remains very well known. Finally, on Indian soil, green Darjeeling tea is still making a name for itself. 

A drink with multiple benefits

Tea is renowned for its high content of compounds known for their benefits to the body.

Tea is an antioxidant drink

Tea is defined as a natural antioxidant drink. Indeed, tea leaves contain numerous polyphenols. These polyphenols help protect cells against oxidative stress and thus against cell aging. It should be noted that the richness of antioxidant substances increases with low oxidation times, as in the case of green teas. The most active polyphenol with the most beneficial effects on the body is called epigallocatechin, which is present in green teas up to 70%. Note that one cup contains an average of 400 mg of polyphenols, which is twice as much as in a glass of orange juice. Finally, note that the polyphenol content varies greatly depending on the quality of the harvest, the harvest season, and the infusion time. 

Relaxing effects of tea on the nervous system

The compound responsible for the relaxing effects of tea on the nervous system is called L-theanine. It is an amino acid present in 1 to 2% of tea leaves. Being picked young and with a low rate of oxidation, green tea leaves are the best source of L-theanine among the different types of tea. Also, the longer the tea is brewed, the higher the L-theanine content. Regarding the action of L-theanine on the brain, scientists have shown that this amino acid significantly increases activity in the alpha frequency zone. Thus, it relaxes the mind without causing drowsiness.

Caffeine or theine?

It is common to hear that the caffeine contained in coffee excites, unlike tea. But did you know that theine in tea is the same molecule as caffeine? This molecule is found in about 6% of teas, depending on their origin.  In the tea plant, this molecule offers a natural defense. It is therefore found in large quantities in the young shoots, hence its high presence in green teas.

Thanks to the tannins present in the tea leaves, theine is released over the long term. This results in a stimulating effect, but without irritation. Conversely, in coffee, the absence of tannin leads to a sudden release of caffeine, resulting in an irritating effect. In addition, the theanine mentioned above balances the effects of theine and contributes to the calming effect.

Beware of harmful associations

Tea and iron do not mix well...

Iron exists in heme and non-heme form. When tea and non-heme iron are taken simultaneously, the absorption of the latter decreases by about 70%. This is due to the association of the tannins present in the tea with the iron molecules. Therefore, to guarantee a good absorption of iron in your body, you just must space your meals from your tea breaks by 2 hours!  


The second most-consumed drink after water, tea has its origins in Asia. Its harvest and its work result from centuries of transmission of ancestral knowledge. Recognized for its multiple benefits, green tea contains many antioxidants that protect cells against oxidative stress. In addition, its theanine content has a relaxing and calming effect on the nervous system. To benefit from all its advantages, be sure to space your tea from your meals for at least two hours so as not to complicate the absorption of iron from your food. 


Key take-home messages

  • Green tea accounts for 18% of global consumption
  • Tea leaves are harvested up to 4 times a year depending on the region
  • 5 kg of fresh tea leaves are needed to obtain 1 kg of tea for brewing
  • A cup of green tea contains an average of 400 mg of polyphenols, twice as much as in a glass of orange juice
  • The theanine present in green tea leaves plays a relaxing role in the nervous system


  • Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail, Sécurité à l’emploi des préparations de thé vert, 2012
  • Dhenin, Théine et caféine, quels effets, quelles différences ?, 2020
  • Kimura et al., L-theanine reduces psychological and physiological stress responses, 2006
  • Kusmitea, les différentes variétés et types de thé vert
  • National center for complementary and integrative health, Green tea, 2020
  • Nobre et al., L-theanine, a natural constituent in tea, and its effect on mental stage, 2008
  • Tea photo created by zirconicusso <>
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