Boosting Immunity with Japanese Green Tea

Back to Health Benefits of Japanese Green Tea

This article was last modified December 11th, 2022. by Yuki

Green Tea Catechins are nutrients found in green tea that contain several important health benefits for humans.

EGC, one of the critical Catechins found in Japanese green tea, plays a crucial role in boosting the effectiveness of our body's immune system.

First, let's talk briefly about how our immune system works.

Our immune system fights off sickness by making antibodies. An antibody called IgA is one of the key antibodies that the body produces to do so.

EGC improves the amount of IgA in the body.

This happens as EGC improves the functions of macrophage and dendritic cells, which are vital functions in our immune system, by removing microorganisms and dead cells in the intestinal tract.

It allows for more IgA to be produced efficiently without obstruction.

The interesting thing is that while the EGC helps immunity, another key tea catechin found in green tea called the EGCG has an effect of canceling the immunity effects of EGC.

EGCG is also a powerful compound with incredible health benefits in its own right. However, when it comes to immunity, the EGCG works negatively.

Since all Japanese green tea have both EGC and EGCG, achieving a high EGC: EGCG ratio is important to strengthen your immunity.

We can easily achieve this with a simple trick; cold-brewing green tea. [1]

Although EGCG and EGC are green tea catechins, they dissolve in water at different temperatures.

EGC can be extracted at room temperature, while EGCG requires more than 80 degrees Celsius water to be effectively extracted into the tea.

Studies show that the continued consumption of cold brew Japanese green tea of 2 cups a day increases the levels of IgA, which protects against the invasion of diseases. [1]

By cold-brewing your Japanese tea, you can achieve a high EGC ratio, which will help strengthen your immunity.

When looking for tea types with the highest amount of green tea catechin, it's best to go with the most standard Japanese green tea. These are the Sencha and the Tamaryokucha.

The Sencha is the most standard type of Japanese Green tea. It is an "unoxidized tea," where the loose leaf maintains its natural green colors. It is also cultivated and manufactured in the most standard way.

Other types of Japanese green tea can be considered alterations of the Sencha, intended to enhance the taste of the tea. Here are some examples below.

• A Gyokuro or Matcha shades the leaves from the sun to reduce the amount of Catechins. This leads to a delicious tea. However, it reduces the number of catechins in the leaves.
• A Genmaicha is a flavored green tea with roasted brown rice kernels. While the tea leaf contains similar amounts of catechin to a Sencha, the additional brown rice dilutes the amount of Catechins in the tea.
• A Houjicha is Sencha roasted after the initial process to give a light and heartwarming taste. The roasting significantly reduces the number of catechins, hence not suitable for enhancing immunity.

Sencha is the most basic form of Japanese green tea and contains the most amount of green tea catechins. Therefore we recommend you stick with Sencha.

While relatively rare, the Tamaryokucha is a basic form of Japanese green tea with similar levels of tea catechin. If you can find Tamaryokucha near you, it's certainly an option to help take green tea catechins.

Different cultivars have different levels of EGC and EGCG. So if you want to be extremely picky and have the luxury of available choices, you can also check the different types of cultivars that make green tea.

Regarding a high EGC/EGCG ratio, the "Yutakamidori" cultivar comes out extremely high with a 0.69. Saemidori follows this with 0.66, and Kanayamidori with 0.61.
The most common Yabukita cultivar is 0.55, which is practical as well. So if you don't have a choice, you can go with the most common cultivar in the Japanese green tea market. [3]