Traditionally, research on the health benefits of tea focuses on heart diseases and cancers. A new medical study found some compelling evidence that green tea can boost up the immune system after immune system crashes due to infection or other diseases.
White Tea
White tea is known to have a delicate flavor. It comes from the Camellia Sinensis plant that is native to China and India. It is also the least processed tea variety. From fresh leaves, it only goes through withering and drying. A 2010 study from the journal of food science found that white tea is positively associated with immune-boosting properties (Unachukwu et al., 2010). This study is based on assessing the active chemicals inside tea that is known to have immune-boosting effects. The result of the 2010 study has shown that white tea has comparable levels of catechins with potential health-promoting qualities. The study also notes that the quantity and presence of catechins can vary by tea subtypes and sources. Many studies in China have also found that older white tea growing in higher elevation terms to have more of those properties. Although some research suggests that white tea offers the least amount of caffeine, it depends on the subtype. For instance, silver needle white tea, which uses only the tip of the cultivate has a much higher content than caffeine than Shou Mei White tea that uses the bigger leaves. Caffeine serves as a self-defense mechanism for Camellia Sinensis (tea) plant and is often concentrated on the tips.
Green Tea
Green tea originates from China. Different from white tea, green tea is stirred in 185F hot pan to stop the oxidation. Green tea has a possible impact on the liver, breast, prostate, and colorectal cancers. This tea variety has also shown to be anti-inflammatory, which helps keep your skin clear and glowing (Yang et al., 2009). Using a meta-analysis method, the European Journal of Nutrition published an article in 2014 that concluded the top health benefits of green teas. Green tea is high in flavonoids, which can help lowering bad cholesterol and reducing blood clotting (Khalesi et al., 2014). A recent study in 2018 has also found preliminary evidence that green tea’s immune-boosting effect also works on immunocompromised conditions caused by infections (Rahayu et al., 2018).
Black Tea
Black tea is made from the same leaves of the Camellia Sinensis plant as green tea. However, the leaves are fully-fermented, giving black tea its rich flavor. Similar to green and white tea, black tea contains flavonoids that fight inflammation and support healthy immune function.
Oolong Tea
Oolong tea is a traditional Chinese tea variety made from the same plant as green and black tea. While green tea is not oxidized and black tea being fully-fermented, oolong tea sits in-between. The leaves are partially oxidized. Since this is a very delicate process, minor changes in tea cultivation and making process can all make or break the final product. This is also why oolong tea is one of the tea that Chinese tea drinkers chase after tea masters and competition-grade products. Oolong tea is notable for containing l-theanine, an amino acid that reduces anxiety and increases alertness and attention. Polito et al., (2018) published an article in Nutrients, where they found people with tea drinking habits have less likelihood of developing neurodegenerative diseases such as Alzheimer’s disease (AD). Oolong tea is also high in polyphenols, which are linked to lowering inflammation, preventing the growth of cancers, and decreasing type 2 diabetes risk.
Reference
Khalesi, S., Sun, J., Buys, N., Jamshidi, A., Nikbakht-Nasrabadi, E., & Khosravi-Boroujeni, H. (2014). Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials. European journal of nutrition, 53(6), 1299-1311.
Polito, C. A., Cai, Z. Y., Shi, Y. L., Li, X. M., Yang, R., Shi, M., … & Ye, J. H. (2018). association of tea consumption with risk of Alzheimer’s disease and anti-beta-amyloid effects of tea. Nutrients, 10(5), 655.
Rahayu, R. P., Prasetyo, R. A., Purwanto, D. A., Kresnoadi, U., Iskandar, R. P., & Rubianto, M. (2018). The immunomodulatory effect of green tea (Camellia sinensis) leaves extract on immunocompromised Wistar rats infected by Candida albicans. Veterinary world, 11(6), 765.
Unachukwu, U. J., Ahmed, S., Kavalier, A., Lyles, J. T., & Kennelly, E. J. (2010). White and green teas (Camellia sinensis var. sinensis): variation in phenolic, methylxanthine, and antioxidant profiles. Journal of food science, 75(6), C541-C548.
Yang, C. S., Lambert, J. D., & Sang, S. (2009). Antioxidative and anti-carcinogenic activities of tea polyphenols. Archives of toxicology, 83(1), 11-21.