In addition to being full of antioxidants and anti-inflammatory properties and beneficial for overall health, recent studies suggest green tea may also help prevent upper respiratory tract infections, such as the common cold, COVID-19, sinus infections, and influenza.

Results from a recent meta-analysis and several randomized controlled trials suggest that the catechins in green tea may help ward off cold and flu viruses. These findings align with previous studies showing that green tea catechins can help prevent upper respiratory infections. 

Keep reading to find out more about these exciting findings!

What do the studies say?

A meta-analysis published in the European Journal of Nutrition reviewed six random control trials and four prospective cohort studies to determine whether gargling with green tea could help prevent viral upper respiratory infections. The study authors concluded that the catechins in green tea may be an effective way to prevent viral respiratory infections and that the larger the amount of catechins consumed, the stronger the protective effect.

One study published in the Clinical Nutrition Open Science journal looked at the association between green tea consumption in healthcare workers in Japan and severe COVID-19 infections. Participants were asked about their green tea consumption, and COVID-19 cases were determined based on in-house antibody testing. Researchers found that people with higher green tea consumption (more than 4 cups per day) had lower infection rates and that EGCG, a major catechin found in green tea, may prevent disease and/or reduce symptoms. However, it’s important to note that the authors recommend further investigation before concluding about green tea and COVID-19 infection.

A randomized, double-blind study conducted in 2022 published in the journal Nutrients evaluated whether catechin consumption reduced the duration and severity of upper respiratory infections in healthy adults in winter. Researchers found that participants in the catechin group had reduced duration of cold and flu symptoms such as runny nose, nasal congestion, and headaches compared to the control group. They concluded that daily green tea consumption reduced both the duration and severity of infections in healthy men and women. 

What are catechins?

Catechins, found in green tea, berries, and chocolate, are naturally occurring chemical compounds that have been studied for their potential to protect against diseases such as cancer, heart disease, neurodegenerative disorders, and other inflammatory conditions. One crucial role of catechins is antioxidant activity, which help to protect against free radical and cellular damage.

Tea is an excellent source of catechins, with green tea containing the highest amount, giving you one more reason to thoroughly enjoy your cup of matcha each day!

Research shows that catechins have anti-viral, anti-bacterial, and anti-inflammatory properties and that they may form a protective barrier in the pharynx, which can help prevent viruses from spreading in the upper respiratory system.

EGCG, a catechin found in high amounts in green tea and matcha, may inhibit infections such as COVID from binding to our cells.

Role of green tea in immune support

In addition to protecting against respiratory viruses, green tea also supports the immune system in a broader sense. Antioxidants and other bioactive compounds found in green tea and matcha may help to enhance the body’s natural defense mechanism. Research shows that regular consumption of green tea is linked with increased amounts of T-cells. T-cells, a type of white blood cell, play a vital role in the immune system and are essential for keeping us healthy and preventing disease. These immune-boosting effects are especially helpful during cold and flu season.

Ways to incorporate green tea into your diet: 

Researchers suggest drinking green tea regularly to reap these immune-boosting benefits. Here are some ideas for adding more green tea and matcha to your life.

-   Drink it before a workout as a healthier pre-workout alternative

-   Use it in your favorite recipes

-   Switch from coffee to matcha in the morning

-   Mix it with electrolytes as a great way to stay hydrated

-   Learn how to make a traditional cup of matcha

-   Add it to your morning smoothie

The Bottom Line:

Growing evidence shows that green tea may be a cost-effective and delicious way to reduce the prevalence and duration of symptoms from upper respiratory infections.

While researchers suggest more conclusive evidence is still needed, multiple recent studies show that green tea is protective against these types of infections. They also state that the more green tea you drink, the more protected you are.  

Green tea's protective mechanism is likely due to its high catechin quantity, particularly the catechin EGCG. Catechins act as antioxidants in the body and have anti-inflammatory, anti-viral, and anti-bacterial properties. They may also help protect against certain diseases like heart disease, neurodegenerative diseases, and cancer.  

Disclaimer: These statements in this blog post have not been evaluated by the Food and Drug Administration. The information provided here is for educational purposes only and should not be considered medical advice. It's essential to consult with a qualified healthcare professional before making any dietary or lifestyle changes. 

Resources: 

Fan FY, Sang LX, Jiang M. Catechins and Their Therapeutic Benefits to Inflammatory Bowel Disease. Molecules. 2017 Mar 19;22(3):484. doi: 10.3390/molecules22030484. PMID: 28335502; PMCID: PMC6155401.

Liu, J., Bodnar, B.H., Meng, F. et al. Epigallocatechin gallate from green tea effectively blocks infection of SARS-CoV-2 and new variants by inhibiting spike binding to ACE2 receptor. Cell Biosci 11, 168 (2021). https://doi.org/10.1186/s13578-021-00680-8

Matsumoto K, Yamada H, Takuma N, Niino H, Sagesaka YM. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC Complement Altern Med. 2011 Feb 21;11:15. doi: 10.1186/1472-6882-11-15. PMID: 21338496; PMCID: PMC3049752.

Nanri A, Yamamoto S, Konishi M, Ohmagari N, Mizoue T. Green tea consumption and SARS-CoV-2 infection among staff of a referral hospital in Japan. Clin Nutr Open Sci. 2022 Apr;42:1-5. doi: 10.1016/j.nutos.2022.01.002. Epub 2022 Jan 13. PMID: 35039809; PMCID: PMC8755646.

Ozato N, Yamaguchi T, Kusaura T, Kitazawa H, Hibi M, Osaki N, Ono T. Effect of Catechins on Upper Respiratory Tract Infections in Winter: A Randomized, Placebo-Controlled, Double-Blinded Trial. Nutrients. 2022; 14(9):1856. https://doi.org/10.3390/nu14091856

 

Mark P. Mattson, Aiwu Cheng, Neurohormetic phytochemicals: low-dose toxins that induce adaptive neuronal stress responses, Trends in Neurosciences, Volume 29, Issue 11, 2006,Pages   632-639, ISSN 0166-2236, https://doi.org/10.1016/j.tins.2006.09.001.

Wu D. Green tea EGCG, T-cell function, and T-cell-mediated autoimmune encephalomyelitis. J Investig Med. 2016 Dec;64(8):1213-1219. doi: 10.1136/jim-2016-000158. Epub 2016 Aug 16. PMID: 27531904.