A recent study conducted in Japan has unveiled intriguing findings regarding the potential of certain teas to combat specific Omicron subvariants of COVID-19. While the virus continues to evolve, scientists are diligently exploring various avenues to mitigate its spread.

The study, led by Professor Osam Mazda and his research team at Kyoto Prefectural University of Medicine, delved into the potential of teas like green tea, matcha, and black tea to effectively neutralize select Omicron subvariants. Given that COVID-19 is primarily transmitted through the saliva of infected individuals, including asymptomatic carriers, inactivating the virus within saliva has been identified as a crucial step in preventing its spread.

Previous research by the same team had already demonstrated the virus-inactivating properties of polyphenols found in green tea and black tea. These polyphenols have the remarkable ability to bind to the spike protein of the virus, rendering it incapable of infecting human cells.

The latest study, published in Scientific Reports, enlisted seven healthy volunteers who consumed candies containing green tea, black tea, or no tea components. Saliva samples collected immediately after consumption exhibited high concentrations of tea polyphenols, including epigallocatechin gallate (EGCG) and theaflavin digallate. When these saliva samples were mixed with the early Omicron virus strain BA.1, rapid inactivation of the virus was observed. However, this virus-inactivating effect gradually waned between 5 and 15 minutes after candy consumption ceased.

The implications of this research are intriguing. It suggests that individuals infected with COVID-19 could potentially reduce their virus load in the oral and gastrointestinal tracts by consuming candies containing green tea or black tea, thereby limiting the risk of transmitting the virus to others.

Further experiments involved steeping black tea, green tea, or matcha in hot water and then mixing the resulting tea beverages with the virus suspension. The results were striking, as they revealed a reduction in the infectivity of the BA.1 and other Omicron subvariants to less than one percent.

Interestingly, bottled green tea beverages from grocery stores were also found to significantly reduce the infectivity of specific Omicron subvariants, such as BA.1, BA.5, and BQ.1.1, although their efficacy against BA.2.75 was limited.

It’s important to note that different Omicron subvariants displayed varying sensitivity to tea polyphenols. For instance, a concentration of 1000 μM of EGCG could inactivate more than 99 percent of the BA.1 and BA.5 viruses. However, BA.2, BA.2.75, XBB.1, and BQ.1.1 viruses remained infectious at the same EGCG concentration.

Additionally, black tea, which results from the oxidation of green tea leaves, showed promise in reducing the virulence of several Omicron viruses, including BA.1, XE, BA.5, XBB.1, and BQ.1.1. However, it had limited impact on BA.2 and BA.2.75.

The antiviral mechanism of EGCG was found to render the virus inactive, without inducing anti-virus effects in the cells it treated.

Notably, previous research has also uncovered other antiviral properties of tea polyphenols, including their ability to inhibit coronavirus replication and enhance the body’s immune response.

While the study offers exciting insights into the potential of teas in combatting COVID-19, it’s essential to recognize that findings from in vitro experiments involving tea leaves may not precisely replicate the effects of drinking tea. Nevertheless, tea leaves are known to be rich in nutrients, supporting overall health and immune function.

These findings underscore the importance of a balanced diet that includes immune-boosting nutrients like those found in tea leaves. Vitamins A, C, D, and E, as well as iron and zinc, play critical roles in bolstering the immune response.

When deciding between black tea and green tea, it’s worth considering their respective properties. Green tea, which has not undergone oxidation, tends to have cooling properties, making it suitable for individuals with a “heaty” constitution. Conversely, black tea, having undergone oxidation, exhibits warmer properties, making it a better choice for those with a cooler constitution. It’s essential to tailor tea consumption to one’s individual needs and sensitivities, while also being mindful of potential contraindications, such as excessive green tea consumption during menstruation for women.