In Japanese green tea liquid, 10 – 18% are catechins. EGC is the second most abundant green tea catechin in Japanese tea after EGCG.
(“Standard Tables of Food Composition in Japan”, Ministry of Education, Culture, Sports, Science and Technology in Japan”, 2020, link to this data source)
Scientists confirmed EGC has a positive effect on our immune system. EGC promotes IgA antibodies that work with a pair and prevent microorganisms such as viruses from invasion our body via the nose, mouth, and eyes. EGC supports the activities of the cells that collect information about microorganisms and send messages to IgA antibodies.
(Omori et al. “Tea Health Benefits 20”, Japan Tea Central Public Interest Incorporated Association, 2020 P25, link to this publication)
To take EGC effectively, let us remid the picture below we cited in relaxing effect. Some components of Japanese teas work against each other. EGC and EGCG act antagonistically to each other.
(Unno et al. “Actions of green tea components in the brain”, The journal of Japan Polyphenol Society, Vol.8, No.1, 2019, P22-26)
The following charts are the experiment that compared cold-brewed and ice-brewed teas. It shows for both cold-brewed and ice-brewed, EGC leaching rate is higher than EGCG.
(Monobe et al. “Health Functions of Compounds Extracted in Cold-water brewed Green Tea from Camellia sinensis L.”, JARQ, 2018, No.52, P3, link to this research paper)
And if you drink hot green tea regularly and your salivary sIgA levels are lower than average, we recommend you drink cold-brewed green tea daily, too. Because this preliminary study implies your sIgA antibodies could be increased. It is important to keep drinking cold-brewed tea for at least 2 weeks to get this health benefits.
(Monobe et al. “Effect of Cold Extract Green Tea (Camellia sinensis L.) on Salivary Secretory IgA Levels in Habitual Green Tea Drinker: Preliminary Study”, Tea Research Journal, 2012, No.113, P74, link to this research paper)