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Why some people are saying that tea is good against virus ?

Dernière mise à jour : 16 avr. 2020

Coronavirus is unfortunately here, some people are trying to find alternative solutions to increase their viral resistance or even better : to destroy them. Some people say that hot tea can kill coronavirus. But is it really the case ?


Currently, we’re facing a problematic contagion as it was also the case in 2002-2003 with SARS plague in China. Thanks to internet and the easy access to many information, we’re more concerned about our health and we know natural products that can help improving our health, for example tea. However, there is a risk of spreading wrong information or worse : fake news.


But what is exactly a virus ?


The actual consensus is that virus isn’t classified as plants, animals or shrooms. Virus are 200 to 1000 times smaller than our cells and are described as non-living infectious agent : Encapsulated genetic material. There are two main components in a virus :


- One or two DNA or RNA molecules. DNA is the support of genetic information, what makes what we are. Sometimes, we can read genetic code because DNA is a precise association of molecules that formulates an information. For example, a sequence of molecules will give the specific colour to our hair. RNA is the information of DNA that has been copied and traduced to form our proteins. For example, RNA that has the information of hair colour will be read and interpreted by complex molecules to produce hair pigments.


- A capsule of viral proteins that we call capside. This capside protects the viral genetics and will help the virus to penetrate our cells.


It is important to know that contrary to our cells which can self-multiply, virus need living organism to multiply.


The virus, professional cheater since the beginning of life


If we take the example of the coronavirus, the virus enters in our organism through our respiratory entries (throat, mouth, noise, etc). The virus can be present in air or can be transmitted by a person who has the virus (contact skin-skin, saliva, etc).


To face it, our immune system stops the progression of the virus before his multiplication and spreading. When our immune system isn’t capable to stop the virus, it fixates to the receptors at the surface of our cells, thanks to the viral proteins of the capside. This process is called adsorption. The cells will recognize the viral proteins as human proteins and will let the virus enter in the cells. The capside will vanish in the cells which liberates the viral genetics. It will reach the nucleus of the cells that contains our DNA. The viral DNA or RNA will use our DNA and the proteins that allow the copy of our DNA during cell multiplication. At this stage, the viral DNA/RNA will multiply, which is called viral replication.


When viral genetics is sufficiently replicated, it will leave the nucleus and will use the proteins in our cells that are necessary to read our RNA to produce proteins. The virus will produce the viral proteins that are necessary to reform their capside. The new virus will leave the cells to contaminate the other cells of our organism (1)


The consequence of the virus multiplication isn’t immediate. The immune system will destroy contagious cells. Or, our cells can have trouble to multiply as virus are known to perturbate the human DNA multiplication because of the use of our DNA/proteins necessary for this. In long term the consequences are dramatic as we know hepatite B virus can lead to liver destruction.


How can we stop a virus ?

The most efficient way to kill a virus is our immune system as it can recognize and destroy a virus or contagious cells. But our organism is smart as he has other defensive mechanism : the fever. In fact, the protein that allow the viral DNA/RNA to multiply are sensible to heat variation. The corporal temperature will increase in response to a contamination to slow the viral multiplication (2). However, the increase of temperature, even if it’s two degrees, is bad for the human cells (which lead to take anti-inflammatory drugs or drugs that help to decrease the fever).


This is where the hypothesis of “destroying virus with hot tea” came from. But, the World Health Organisation (WHO) published (3) that coronavirus dies at 70°C in cooking condition. We also know tthat the virus of coronavirus family die in 15min at 56°C (4)


We never drink high temperature tea (60 to 70°C in general). The temperature of our organism is approximately 37°C. When a hottest fluid touches a colder fluid, the temperature of the hottest fluid decrease. More importantly, when we drink tea, it passes directly in the stomach and not in our lungs. Regarding this information, neither the necessary temperature nor time of exposure to heat is validated to kill virus with hot tea.


We can say that this is a fake news !


The response is in the virus itself


As I previously said in my article about tea and immune system, it seems that a daily consumption of green tea and gargles with green tea decrease the risk of flu infection. A scientific review published in 2018 (5) has recapitulated the major findings (experiments and clinical trials) about tea and virus.


Polyphenol, catechin, EGCG : again, green tea !


Experimental studies have demonstrated that polyphenol of tea, specially catechin, accumulate in the cells and block not only the virus fixation to the cells but also prevent the viral multiplication. In fact, the 2018 review is based on a previous work published in 2013 (6) that compiled more than twenty publications about in vitro effects of catechins to different virus (influenza or flu, enterovirus, HIV, adenovirus, Epstein-Barr, Herpes, hepatite).


One of the most powerful catechin, EGCG, seems to act directly to the viral capside. It fixates to the viral proteins that can link to the cell surface receptors which prevent the entry of the virus. Moreover, it seems that green tea extracts can decrease the proportion of viral proteins of the capside which can impact the integrity of the virus.


In the 2013 review, it was also been reported that polyphenol of the tea limit or more, block the multplication of the viral genetics. The catechin in green tea inhibit the action of the integrase, a molecule that is necessary for viral DNA/RNA replication. Other proteins necessary for the viral replication could also be inhibited by catechin such as reverse transcriptase. In 2011, a Japanese study has demonstrated that the RNA replication of VIH virus is diminished in presence to the association of EGCG and the most used drug to treat VIH, AZT (7)


Inside the cell, the antioxidant potential of polyphenol from green tea is potentially protector for cells. In fact, it seems that the penetration and the multiplication of the virus generates oxidative stress that is toxic for cells (8). Green tea could be protective against secondary effects generated by viral replication.


But there isn’t only green tea !


The catechin that are more concentrated in green tea compared to other tea family aren’t the only polyphenol to have an action against virus. It seems that theaflavins, polyphenol that are produced in black tea, also inhibit the viral penetration of hepatite C in cells (9) and prevent the multiplication of viral RNA of the coronavirus responsible of SARS plague of 2002-2003 (10).


We clearly can expect other similar results with anthocyanins from purple tea or other polyphenol from oolong tea, white tea and Pu’Erh tea.


Virus and tea, a successful team ?


The studies of daily consumption of tea and the experimental data are very interesting as they seem to show that tea is protector against virus. However, it is important to note that effects of the tea depend on the type of virus studied. Moreover, most of the time the pure extract of tea is used against cells and the dose could be 10 to 1000 times superior than a classic tea infusion. It’s also not currently known what is the best way to extract polyphenol (gong fu cha or occidental infusion method).


These considerations are very interesting to highlight, not only for virus studies but for any pathology that involves the use of tea.

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