The bulk of tea’s immunity-boosting and overall health benefits are tied to a group of antioxidants known as polyphenols. “A significant amount of epidemiological data has shown that a diet rich in polyphenols is protective against chronic health conditions such as cardiovascular disease and type 2 diabetes,” says Megan Meyer, PhD, the Durham, North Carolina–based senior director of science communications for the International Food Information Council. Her past research examined the effects of nutritional antioxidants on the immune system’s response to influenza.
Herbal teas may also support your immune system’s health. “Most herbal teas are known to have health-supporting qualities,” Lee says.
More Research on Tea and Immune System Health Is Needed
While the research on tea and immune system health sounds promising, the studies thus far either haven’t used humans or the population sizes involved were relatively small. Many studies also use tea in capsule or tablet forms, both of which usually pack a far greater dose of plant compounds than you’d find in a tea bag. Given these limitations, it’s tough to know whether a cup of tea will benefit a typical person’s immune system health. More large studies of humans using brewed tea are needed.
That said, health experts generally agree that brewed tea without a sweetener is a healthy beverage choice. “I personally believe that teas are a great way to add functional foods and herbs to your diet on a daily basis,” Lee says. So drink up! And if immune system health is your top concern, you might want to start with this list of the five top teas for a healthy immune system, in order of strongest evidence to weakest.