Tea is the hot drink of choice for many. In fact, for some, it is the only way to start the day. But could it also help to prevent COVID-19? A new study from the University of Georgia suggests the answer is yes.
Could a cup of tea help to prevent COVID?
Tea has been lauded for its health benefits for many hundreds of years. According to healthcare provider UCLA Health, tea is a power antioxidant, promotes heart health, reduces the risk of stroke, improves focus, lowers blood sugar levels and decreases the risk of developing some cancers. It is perhaps unsurprising then that it is now being studied for potential anti-viral effects.
Malak Esseili, a virologist with the University of Georgia Center for Food Safety in the College of Agricultural and Environmental Sciences, decided to look further into the health benefits of tea to see if they extend to potentially impacting the effects of SARS-CoV-2.
Esseili first began her research into the potential anti-viral effects of tea at the outbreak of the COVID 19 pandemic, as she looked for ways to help protect herself and her family. She worked on the basis that she needed to find something that was easily accessible and palatable. With that in mind, the researcher looked to foods and beverages she already owned or could buy easily from the local shop, and found tea.
“Having something that is accessible, easily prepared, and suitable for all the family would be ideal,” said Esseili, who was also inspired by her tea-loving kids.
The findings, which were researched and analysed in conjunction with fellow researchers at the University of Georgia, have been published in the journal Food and Environmental Virology. They demonstrate how certain teas “inactivate” SARS-CoV-2 in saliva – in some instances by up to 99.9%.
These findings are significant as the virus itself infects and replicates inside the oral cavity, passing through the oropharynx before reaching the lungs.
“Inactivating SARS-CoV-2 in the mouth and the throat matters because that potentially reduces the introduction of the virus to the lower respiratory system,” says Esseili.
Esseili and then-graduate student Julianna Morris, who graduated with her master’s degree in food science in 2023, studied 24 different types of commercially available teas, some of which claim to aid in respiratory health. Of those, they found five that significantly reduced the virus in saliva: raspberry zinger, eucalyptus mint, mint medley, green tea and black tea. Of those five, black tea resulted in the greatest reduction.
All testing was done in the laboratory under simulated conditions.
What is SARS-CoV-2?
SARS-CoV-2 is the virus which causes a respiratory disease called coronavirus disease 19, or COVID-19. SARS-CoV-2 is a member of a large family of viruses called coronaviruses. These viruses can infect people and some animals. SARS-CoV-2 was first known to infect people in 2019.
How to consume tea as a medicine?
The team tested the efficacy of tea, both as a drink and as a gargle, to understand the efficacy of both approaches and to provide an option for those do not want to drink tea.
Researchers prepared a drinkable infusion concentration, using one tea bag per cup, and steeped for 10 minutes. No additions, such as milk, sugar or lemon, were included. All five teas reduced the virus by at least 96% within 10 seconds in the mouth. Black tea was the most effective, reducing the virus by 99.9%.
When tested as a gargle, they brewed the tea at four times the concentration of the drinkable infusion, finding that all five varieties of tea reduced the virus by 99.9% within 10 seconds.
Further research into the effect of tea on COVID
The team has said that further clinical trials are required to better understand what effect these results may have on a patient who is already ill with COVID-19.
They are also quick to emphasise that tea is not to be considered as a replacement for medical care. However, they consider these initial results as “promising and exciting” for those looking to supplement their medical care.
“At this stage, we are not suggesting tea as a stand-alone intervention against SARS-CoV-2, because the virus also replicates in the nose and may have already reached the lung by the time a person tests positive,” Esseili said. “But tea can be an additional layer of intervention that the patients and their families can easily adopt on a routine basis.”
Source: Screening Commercial Tea for Rapid Inactivation of Infectious SARS-CoV-2 in Saliva
Published online: 31 January 2024
DOI: https://link.springer.com/article/10.1007/s12560-023-09581-0
Authors: Julianna N. Morris & Malak A. Esseili
