Since some of the bioactive compounds in green tea are anti-viral and anti-bacterial, in much the same way as green tea can kill bacteria in your mouth, it can also inhibit bacteria and viruses in your bloodstream and throughout the rest of your body. Similarly, green tea may inhibit viral and bacterial infection via your nasal passages. All this means that green tea may help prevent colds and the flu, and furthermore seems to be able to alleviate the symptoms of colds and the flu once you are sick.
Still, there have been some interesting findings. A 2014 study looked at 25 randomized controlled trials on the link between tea and blood pressure and reported that when people drank tea—especially green tea—for 12 weeks, their blood pressure dropped significantly. A 2011 study reported that drinking green tea appeared to be linked with lower levels of bad LDL cholesterol, but more research is needed. Because matcha is a type of green tea, they may share similar benefits, but there’s not enough research to make that claim.
Steeping, or brewing, is the process of making tea from leaves and hot water, generally using 2 grams (0.071 oz) of tea per 100 millilitres (3.5 imp fl oz; 3.4 US fl oz) of water (H2O) or about 1 teaspoon of green tea per 150 ml cup. Steeping temperatures range from 61 °C (142 °F) to 87 °C (189 °F) and steeping times from 30 seconds to three minutes.
can increase energy and mental focus. Green tea contains a small amount of caffeine, which a 2008 study in Nutrition Bulletin found can improve mood, cognitive function and physical performance. Green tea contains less caffeine than does coffee, and provides L-theanine, an amino acid shown to promote a state of calm awareness. Result: green tea provides the benefits of alertness associated with caffeine without the “jittery” feeling often experienced as a side effect of coffee.
Like black and green tea, rooibos is rich in polyphenols, such as rutin and quercetin. Cell and animal studies, mostly from South Africa, have shown that rooibos extracts have antioxidant, immune-stimulating, and anti-cancer properties. But studies of rooibos tea in people are limited. There’s little or no evidence to back claims that it relieves constipation, headaches, eczema, asthma, insomnia, high blood pressure, mild depression, ulcers, diabetes, and so on.
The polyphenols in green tea, especially EGCG, have been shown to have a particularly powerful effect in supporting skin cells and cellular DNA in the presence of UV radiation from sunlight. May different clinical studies have shown EGCG to help skin defend against UVA and UVB rays. And because these polyphenols can accumulate in the skin, regularly drinking green tea or taking a green tea supplement with EGCG can act as all-day supplemental protection.
On this episode of Consumed, host and Eater Drinks editor Kat Odell looks into the matcha production process — how it differs from that of more traditional steeped green tea, and how two of New York's noted matcha purveyors (Ippodo Tea Company and Matchabar) are working with the product today. Watch the video above for a lesson in powdered green tea; if your interest is piqued, check this map for the best places to drink matcha across the country, and these recipes for making iced matcha drinks at home, perfect for the summer.