Category Archives: Green Tea

Coronavirus: Can Diet Help?

There are a few ways that we can fight the novel coronavirus (SARS-CoV-2). Clinical trials aimed at vaccination have recently begun, and at the earliest, could be available within 6-18 months. Similarly, drugs aimed at inhibiting, blocking, or reducing viral replication, including remdesevir and hydoxychloroquine are entering clinical trials, but large-scale results are also a few months away.

Other alternatives that are rarely discussed are dietary components that can inhibit SARS-CoV-2 replication. Inhibiting replication is important because if the virus continually makes more copies of itself, there will be a systemic viral overload, thereby overwhelming the immune system. Two coronavirus proteins that are important for its replication and binding to cell membranes are its Main protease (Mpro for SARS-CoV-2, 3CLpro for SARS-CoV; X. Liu & Wang, 2020), and its surface Spike glycoprotein (S protein; Song et al. 2018), respectively.

In a recently published (but not peer-reviewed) preprint, Tallei et al. (2020) used a molecular docking approach to predict how SARS-CoV-2’s Mpro and S proteins interact with various drugs and plant-based compounds. A lower molecular docking value is indicative of a potentially better ability to inhibit these proteins. Interestingly, many plant-based metabolites have lower (or equal) molecular docking values when compared with coronavirus-based drugs:

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For example, when compared with the drugs nelfinavir, hyrdroxychloroquine sulfate, and chloroquine, hesperidin (found in citrus fruits and peppermint) and epigallocatechin galleate (found in green tea, apple skin, plums, onions, hazelnut) had equivalent or lower molecular docking scores, evidence that suggests a better ability for the plant-based metabolites to inhibit Mpro and the S protein. Based on this data, incorporation of these foods may be an important strategy for boosting endogenous defense against SARS-CoV-2 infection.

Similarly, a molecular docking approach was used to identify potential inhibitors for Mpro in another recent preprint (Khaerunnisa et al. 2020). When compared with the docking energy for Mpro’s native ligand (-8), the coronavirus drugs nelfinavir and lopinavir had lower docking energies, thereby suggesting that they would be good Mpro inhibitors. Interestingly, kaempferol and quercetin had docking energies that were not as low as the drugs, but were as low as or lower than the docking energy for Mpro’s native ligand, thereby suggesting that they might also act as inhibitors of SARS-CoV-2 replication:

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Kaempferol and quercetin are found in relatively high amounts in dill, lettuce, onions, spinach and other vegetables (for the full list see

It’s important to note that the amount of these foods needed to ingest enough kaempferol, quercetin, or other metabolites that may inhibit SARS-CoV-2 replication or its fusion to cell membranes proteins in vivo is unknown. In addition, with the goal of further boosting endogenous defense, I’d propose including these foods in addition to, but not for the replacement of  a vaccine or FDA approved medicines. Note that clinical trials aimed at direct testing for the ability of these plant-based components to inhibit SARS-CoV-2 replication has yet to be performed, but when consumed as a part of a whole-food diet, may be a low risk, high reward strategy for battling SARS-CoV-2 infection.


Khaerunnisa, S., Kurniawan, H., Awaluddin R., Suhartati S., Soetjipto, S. (2020). Potential Inhibitor of COVID-19 Main Protease (Mpro) from Several Medicinal Plant Compounds by Molecular Docking Study. March 13, Preprint. doi: 10.20944/preprints202003.0226.v1

Liu, X., & Wang, X.-J. (2020). Potential inhibitors for 2019-nCoV coronavirus M protease from clinically approved medicines. BioRxiv, 2020.01.29.924100.

Song, W., Gui, M., Wang, X., & Xiang, Y. (2018). Cryo-EM structure of the SARS coronavirus spike glycoprotein in complex with its host cell receptor ACE2. PLOS Pathogens, 14(8), e1007236.

Tallei, T.E., Tumilaar, S.G., Niode, N.J. , Fatimawali, Kepel4, B.J., Idroes, R., Effendi Y.  (2020). Potential of Plant Bioactive Compounds as SARS-CoV-2 Main Protease (Mpro) and Spike (S) Glycoprotein Inhibitors: A Molecular Docking Study. April 9, Preprint. doi: 10.20944/preprints202004.0102.v2.

Coronavirus isn’t the only virus that negatively affects human health. For more info,



Green Tea and Mortality Risk, Update!

In an earlier post (, I reported that green tea consumption is associated with reduced risk of death for all causes. Now, there’s more recent data! Drinking more than 1 cup of green tea per day is associated with reduced all-cause mortality risk in a pooled analysis of 8 studies that included 313,381 subjects (age range, 40-103y; Abe et al. 2019).

In women (168,631 subjects), risk of death for all causes was reduced by 10%, 6%, and 18% for 1-2, 3-4, and greater than 5 cups/day, when compared with drinking less than 1 cup per day:

gt wom

In men (144,750 subjects), risk of death for all causes was reduced by 5%, 7%, and 10% for 1-2, 3-4, and greater than 5 cups/day, when compared with drinking less than 1 cup per day:

gtea men.png

Cheers to green tea, for health!


Abe SK, Saito E, Sawada N, Tsugane S, Ito H, Lin Y, Tamakoshi A, Sado J, Kitamura Y, Sugawara Y, Tsuji I, Nagata C, Sadakane A, Shimazu T, Mizoue T, Matsuo K, Naito M, Tanaka K, Inoue M; Research Group for the Development and Evaluation of Cancer Prevention Strategies in Japan. Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan. Eur J Epidemiol. 2019 Oct;34(10):917-926. doi: 10.1007/s10654-019-00545-y.

If you’re interested, please have a look at my book!

Drink Green Tea, Reduce All-Cause Mortality Risk?

Is green tea consumption associated with reduced risk of death risk from all causes? To investigate this question, Tang et al. (2015) performed a meta-analysis of 5 studies, including 200,884 subjects. As shown below, drinking 2-3 cups (16-24 oz.) of green tea per day was associated with maximally decreased all-cause mortality risk, ~10%.

green tea

Post update (9/15/2019): Is there new data since this post was first published (2015) for the association between green tea with all-cause mortality risk? Two relatively large studies have been published since then. First, in a study of 164,681 men (average age, ~53y), consuming green tea (~15g/day) was associated with a maximally reduced risk of death from all causes (black lines; Liu et al. 2016). However, note that this data included both smokers and non-smokers. For non-smokers (green lines), all-cause mortality risk was maximally reduced even further at smaller doses, including ~ 6-10g of green tea/day:

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In support of these data, never-smoking men and women (average age, ~52y) that drank more than  8.2g, and 3.3g, respectively, of green tea had an 11% reduced risk of all-cause mortality in Zhao et al. (2017).

The data is clear, drink green tea!

If you’re interested, please have a look at my book!


Liu J, Liu S, Zhou H, Hanson T, Yang L, Chen Z, Zhou M. Association of green tea consumption with mortality from all-cause, cardiovascular disease and cancer in a Chinese cohort of 165,000 adult men. Eur J Epidemiol. 2016 Sep;31(9):853-65.

Tang J, Zheng JS, Fang L, Jin Y, Cai W, Li D. Tea consumption and mortality of all cancers, CVD and all causes: a meta-analysis of eighteen prospective cohort studies. Br J Nutr. 2015 Jul 23:1-11.

Zhao LG, Li HL, Sun JW, Yang Y, Ma X, Shu XO, Zheng W, Xiang YB. Green tea consumption and cause-specific mortalityResults from two prospective cohort studies in ChinaJ Epidemiol. 2017 Jan;27(1):36-41.