COVID-19 : There is no evidence that tannins fight COVID in people

You have asked us through our WhatsApp verification service (+34 627 28 08 15) for a text stating that “the tannins in wine prevent and control the COVID-19”.

“An investigation led by the Taiwanese-born American molecular biologist, Mien-Chie Hung, concluded that tannins from grapes and also other vegetables such as bananas, sorghum and soybeans can help fight COVID-19 by effectively inhibiting the activity of two key enzymes within the virus ”, is stated in the content you asked us about, published on a website about wines.

In recent days, other messages citing the same research and talking about the supposed benefits of wine against the disease caused by the coronavirus have also been disseminated on social networks. In one of them it is stated that “a study reveals that the tannins in wine help to combat COVID-19”.

However, the aforementioned study has only been carried out ‘in vitro’ and even no scientific evidence that prove that tannins or foods rich in this substance are effective against COVID-19 in people. We explain it to you.

Covid and tannins: What are they?

The professor of the Department of Biology and Geology of the University of Almería Tomás Francisco Martínez Moya, who carried out his doctoral thesis on tannins, explains to that these are “a complex group of chemical substances of plant origin whose main function in the plants that synthesize it is to act as a chemical defense against herbivores and phytophagous insects”. Some foods like grapes and, by extension, wine, “are rich in tannins”, adds the researcher.

Martínez Moya also specifies that tannic acid is “a type of tannins”. In the research referred to in the content we are verifying, published last December in the ‘American Journal of Cancer Research’, it is analyzed ‘in vitro’ if tannic acid “suppresses the entry of the virus into cells”.

The researchers point out that, according to their results, “tannic acid has a high potential for the development of anti-COVID-19 therapies as a powerful inhibitor of two independent enzymes essential for SARS-CoV-2 infection.”

However, these results have been obtained in laboratory experiments and not in people. I mean, still there is no evidence that tannins or products containing them are effective against COVID-19 in humans.

Martínez Moya emphasizes that we must be “prudent in the face of these laboratory results”, because we are still “light years away” from knowing if they really have effects against the coronavirus in people. “The process from an ‘in vitro’ discovery to a possible clinical use in people is arduous and lengthy and there are no guarantees that it will be effective,” he says.

Alcohol is not good for your health, according to health authorities

On various web pages on wine, content about this research has been published in which an alleged relationship between wine and the prevention or cure of the effects of COVID-19 has been published.

But since the World Health Organization (WHO) recall that “no food prevents contracting COVID-19.” In addition, a report published by this international body on COVID-19 denies that “alcohol (beer, wine, distilled spirits or herbal alcohol) stimulates immunity and resistance to the virus” and highlights that “alcohol have a harmful effect on the immune system and it does not stimulate immunity or resistance to viruses ”.

Martínez Moya also recalls that it is not necessary to take “the whole for the part”. In other words, “a substance is not a specific molecule, so when we think of wine, we must not only assess its tannins but also the other components, some of which, like alcohol, they are not beneficial to the body”.

From we have already spoken before about false beliefs about the effects of wine on health. Although new articles are published from time to time stating, for example, that drinking one drink a day is healthy, from the WHO they recall that “alcohol consumption is a causal factor in more than 200 diseases and disorders ”.

The supposed benefits of wine are associated with one of its components, polyphenols, to which resveratrol belongs. “In principle, resveratrol is a healthy substance that has been associated with a reduction in inflammation related to atherosclerosis”, explains to Dr. Alfonso Valle, member of the Section of Vascular Risk and Cardiac Rehabilitation of the Spanish Society of Cardiology (SEC), who insists that we must differentiate between resveratrol, a single substance, and wine, a product with more components.

The nutritionist and scientific communicator Beatriz Robles also recalls that “in view of the potential beneficial effects, on which there is no scientific evidence, we are certain that alcohol consumption is harmfull “. The European Union also warns that “moderate alcohol consumption increases the long-term risk of heart disease, liver disease and cancer ”.

From the WHO they recommend “be careful with false and misleading claims, especially in relation to the effects of alcohol on health and immunity. Such claims should be categorically ruled out as a source of health information, since there is no evidence that alcohol use offers any protection against COVID-19 or have a positive effect on the course and outcomes of any infectious disease ”.


The professor of the Department of Biology and Geology of the University of Almería Tomás Francisco Martínez Moya. The nutritionist and scientific communicator Beatriz Robles. Dr. Alfonso Valle, member of the Vascular Risk and Cardiac Rehabilitation Section of the Spanish Society of Cardiology (SEC).