Recent research reveals that something as simple as having a cup of tea could contribute to the fight against COVID-19. Tea is known worldwide for its many health benefits and has been used by various cultures to treat respiratory diseases. This led Malak Esseili, a virologist at the University of Georgia’s Center for Food Safety in the College of Agricultural and Environmental Sciences, to investigate whether regular consumption could have effects on the coronavirus, and to identify what types of commercially available teas can quickly inactivate infectious SARS-CoV-2 in saliva.
At the beginning of the pandemic, given her experience studying viruses, Esseili immediately understood the seriousness of the situation and began looking for ways to protect herself and her family. She was looking for something easy to obtain and palatable, which led her to choose tea leaf. After a quick visit to her local supermarket, she was ready to start researching it. “It would be ideal to have something accessible, easy to prepare and suitable for the whole family,” said Esseili, who was also motivated by the love that her children have for tea.
The results of the work have been published in the journal Food and Environmental Virology and show how certain teas inactivate SARS-CoV-2 in saliva, in some cases up to 99.9%. This is relevant because the virus infects and replicates in the oral cavity, passing through the oropharynx before reaching the lungs. “Inactivating SARS-CoV-2 in the mouth and throat is crucial because that could reduce the introduction of the virus into the lower respiratory system,” Esseili explained.
Five varieties of tea as a drink or rinse against coronavirus
Esseili and Julianna Morris – who was a graduate student and will graduate with a master’s degree in food science in 2023 – examined 24 different types of commercially available teas, some of which are touted as beneficial for respiratory health. Of these, they identified five that significantly reduced the virus in saliva: raspberry zinger, peppermint and eucalyptus tea, mint mix, green tea and black tea, with black tea being the most effective. All tests were performed in the laboratory under simulated conditions.
The team of researchers evaluated the effectiveness of tea both as a drink and in the form of a mouthwash, with the aim of offering an alternative for those who do not wish to drink tea, but want a concentrated mouthwash that provides the same benefits as drinking a cup of tea.
All five teas reduced coronavirus by at least 96% in 10 seconds in the mouth. Black tea was the most effective, reducing the virus by 99.9%
The researchers prepared a drinkable infusion with the concentration of one tea bag per cup, letting it steep for 10 minutes, without adding anything such as milk or sugar. All five teas reduced coronavirus by at least 96% in 10 seconds in the mouth. Black tea was the most effective, reducing the virus by 99.9%. Testing it as a rinse, they brewed the tea with four times the concentration of the drinkable infusion, finding that all five varieties of tea reduced the virus by 99.9% within 10 seconds of gargling.
Clinical trials are needed to better understand the effect these results could have on COVID-19 patients, Esseili said, emphasizing that the tea is not a substitute for medical care. However, the initial results are promising and exciting for those looking to supplement medical care.
“At this stage we are not proposing tea as a stand-alone intervention against SARS-CoV-2, as the virus also replicates in the nose and could have reached the lungs by the time a person tests positive,” Esseili said. “But tea may be an additional intervention measure that patients and their families can easily adopt routinely.”
