The Washington Post noted in May:
It is one of the many mysteries of the coronavirus pandemic: Why has the death toll from covid-19 apparently been lower in Asia than in Western Europe and North America?
Even allowing for different testing policies and counting methods, and questions over full disclosure of cases, stark differences in mortality across the world have caught the attention of researchers trying to crack the coronavirus code.
The BBC pointed out last month that Japan has a mysteriously low death rate from Covid.
Voice of America News asked in June: How Did Vietnam Become Biggest Nation Without Coronavirus Deaths?
And even though China is ground zero, it has experienced very low mortality compared to many Western nations.
Why are these Asian countries experiencing such low Covid mortality rates?
Correlation is obviously not causation. But as discussed below, there is some evidence that these Asian countries' green tea consumption may be part of what is helping to prevent higher mortality (as it may also be doing with cancer and heart disease).
According to the World Green Tea Association, the biggest green tea drinkers are as follows:
Green Tea Consumption
Annual Consumption Per Person
Annual Consumption Nationwide
Other countries drink a fraction as much green tea (all other countries combined drink approximately 170,000 tons a year).
An admitted problem with the theory is that Indonesia's mortality rate from Covid is actually higher than the global average.
One possible explanation: Indonesia has a substantially higher zinc deficiency than Japan, Vietnam of China. Specifically, as of 2005, Indonesia had almost twice as much zinc deficiency as Japan, almost 3 times as much as Vietnam, and over 4 times as much as China:
Zinc Deficiency by Country (2005):
Percentage of Population with Zinc Deficiency
Indeed, Indonesia has the 10th highest zinc deficiency in the world, out of 173 countries studied.
As I noted last week, zinc has strong antiviral properties, but zinc cannot easily get into your cells without hitching a ride with a "zinc ionophore". And I pointed out that the active ingredient in green tea (EGCG) is a powerful zinc ionophore which helps get zinc into the cells.
Interestingly, green tea itself may have powerful Covid-fighting properties in its own right. And - coming full circle - zinc may help EGCG get into our cells.
Green Tea May Fight Covid
A group of Indian scientists have shown that - at least in a petri dish - EGCG can powerfully target numerous key structures in this coronavirus:
Various studies have been done for discovering the antiviral activity of tea polyphenols, especially EGCG.
As evident from the mechanisms of action of EGCG in various viruses, it is a wide spectrum antiviral agent with its mechanism differing from infection to infection.
In a study investigating phytochemical mediated inhibition of SARS-CoV 3CLpro, molecular docking and in vitro studies were performed to screen different naturally obtained flavonoids. It was observed that EGCG with a docking score of −11.7, showed the best in silico activity among all the compounds tested. In vitro studies showed that EGCG exhibited 85% inhibition of 3CLpro at a concentration of 200 μM and had an IC50 value of 73 ± 2 μM (Thi Thanh Hanh et al., 2012).
Tahir ul Qamar et al. showed that the 3CLpro structure of SARS-CoV-2 is highly similar to that of SARS-CoV, suggesting the validity of earlier studies in the present outbreak (Tahir Ul Qamar et al., 2020). Recently, another study recommended EGCG as one of the most potential inhibitor of 3CLpro among the phytochemicals found in nature on basis of molecular docking studies (Khaerunnisa et al., 2020). Hence on these foundations, we can expect EGCG to be a potential inhibitor of 3CLpro for the treatment of COVID-19.
EGCG showed a very high binding affinity and a low inhibition constant among all the phytoconstituents screened, especially in the case of 6vw1, which is a potential target of SARS-CoV-2.
EGCG exhibited better binding with the viral proteins and hence, is expected to show better antiviral activity than the reference drugs, remdesivir and chloroquine (Mf et al., 2020).
EGCG was found to inhibit the ATPase activity of GRP78, thus making it less flexible (Ibrahim et al., 2019). Inferring from the studies by Ibrahim et al. and Bhattacharjee et al., we can expect EGCG to be a potential inhibitor of COVID-19 S protein-GRP78 binding site (Bhattacharjee et al., 2015).
The Indian paper also documents that theanine - another abundant substance in tea - targets many key structural sites in Covid. The following graphic summarizes these concepts:
Fig. 2 shows possible mechanism of actions for tea polyphenols on different active sites:
Depiction of role of tea polyphenols on druggable targets of COVID-19.
("TF" refers to theanine compounds).
However, the authors note:
EGCG is unstable and when consumed orally has low bioavailability.
In other words, EGCG cannot easily be transported into your cells by itself.
Back to Zinc
Fortunately, there is some evidence that zinc can help make EGCG bioavailable, and transport it into your cells.
For example, Japanese scientists report:
UV-VIS spectrometry revealed that the absorption of EGCG increased and its peak became large by adding zinc.
Zinc enhances the hepatoprotective [i.e. liver-protecting] activity of EGCG.
A team of Chinese scientists note:
Zn 2+ enhanced the growth inhibitory effects of EGCG on [prostate cancer] cells ....
EGCG permeated [cells] more easily in the presence of Zn2+ [a zinc cation]. These results imply that Zn2+ enhanced the influx of EGCG.
Another paper notes:
The amount of EGCG incorporated into the liposomes was increased in the presence of Zn2+ (Fig.(Fig.5b),5b), reflecting the balance of the affinity of these compounds for lipid bilayers of liposomes. We tested the effect of different ratios of EGCG to Zn2+ (2:1, 1:1, 1:2) on the amount of EGCG incorporated in the liposomes. It was noted that in the presence of Zn2+, the amount of EGCG incorporated into the lipid bilayers of the liposomes was significantly increased compared with EGCG alone (Fig.(Fig.5b).5b). Treatment of 1:1 or 1:2 of EGCG to Zn2+ did not display any significant difference in the amount of EGCG incorporated into the lipid bilayers of the liposomes, but a ratio of 1:1 of EGCG to Zn2+ gave the best results.
Indeed, some of these studies show little to no effect from EGCG in the absence of zinc. This may lend some weight to the theory that Indonesia is suffering higher Covid mortality than the other green tea drinking nations because zinc deficiency is so widespread.
And Professor Juan Bautista Fernández Larrea - a professor in the Department of Biochemistry and Biotechnology at the Universitat Rovira i Virgili, whose team showed that EGCG is a powerful zinc ionophore - told me:
We did not try to visualize or measure the entrance of EGCG into the liposome, helped by zinc ... although it is obvious that EGCG must enter the liposome together with Zinc, or together with another metal, never alone by itself. Thus, if zinc enters the liposome, if follows that EGCG has also entered the liposome.
Zinc also has antioxidant properties. Therefore, zinc may help reduce the oxidation of EGCG before it is transported into the cells.
Therefore, there are several lines of evidence indicating that taking EGCG together with zinc may be a powerful combination.
The bottom line is that it is worth conducting bigger, better in vivo studies to determine the potential of EGCG and zinc in protecting against the worst symptoms of Covid.
Note: I am not a health professional and this article is solely general information, and not intended to diagnose or treat. Please see your doctor before deciding to change anything you're doing.