Is tea good for you? A simple question about an ancient elixir. Let's take a look at some of the science supporting the health benefits of green tea, black tea, and others.
Camellia sinensis. Carl Linnaeus, that master catagorizer of life on earth, named it after a missionary in the 18th century. Though, the Chinese had been drinking tea for thousands of years by then. Camellia sinensis is the source of black, white, green, matcha and oolong teas. This plant is definitely one of the Wise Ape tribes best friends. We appreciate it’s flavor and dig it’s brain boosting effects. But could this impressive plant also save the lives of dedicated tea drinkers?
Numerous studies claim a decreased risk of death for tea drinkers while others show mixed results. As you can imagine any study that tries to simplify the complexity of human existence down to just two variables, tea and death, has it’s work cut out for it. Often these studies survey participants on their green and black tea consumption. One such study was a large Japanese study of 40,530 people that found the risk of death for both all cause mortality (all causes of death lumped together) and death from cardiovascular disease (CVD) dropped with higher levels of green tea consumption. For CVD the effect was stronger in women, so strong that ladies who kicked back 5+ cups of green tea per day had their risk of death from CVD slashed by 31%. If that sounds like a lot of tea, don’t worry; benefits were seen for men and women after 1 cup per day. In another study, a meta analysis, which is a study of other studies, 18 separate studies of green and black tea were compiled. Studies like this are often done when health research is inconsistent and it’s hard to tell what exactly is going on. The meta analysis found decreased risk of CVD and death from all causes as tea consumption went up. This was seen with both green and black tea. In fact, when it comes to dosage each cup per day of green tea reduced the risk of death from CVD by 5% and each cup of black tea per day dropped it by 8%. There was also a decreased risk of death from cancer for tea drinkers but only when smoking was removed.
These tea related benefits are likely coming from a family of polyphenols called catechins, chief among them is the mouthful of a molecule: epigallocatechin-3-gallate (or EGCG). Catechins are antioxidants and in cultures they inhibit DNA damage. Green tea has higher concentrations of catechins than black tea. Black tea has another class of polyphenols called theaflavins with similar antioxidant effects. There also may be an estrogen mimicking effect from plant phyto-estrogens which may explain why the Japanese study found female tea lovers had a greater drop in CVD mortality.
The Wise Ape tribe knows there’s a lot to love about camellia sinensis, and studies like these, imperfect as they are, offer another exciting reason. So reach for your tea knowing it might just be a lifesaver.
Kuriyama S, Shimazu T, Ohmori K, Kikuchi N, Nakaya N, Nishino Y, Tsubono Y, Tsuji I. Green Tea Consumption and Mortality Due to Cardiovascular Disease, Cancer, and All Causes in Japan The Ohsaki Study. JAMA. 2006;296(10):1255-1265. doi:10.1001/jama.296.10.1255
Tang, J., Zheng, J., Fang, L., Jin, Y., Cai, W., & Li, D. (2015). Tea consumption and mortality of all cancers, CVD and all causes: A meta-analysis of eighteen prospective cohort studies. British Journal of Nutrition, 114(5), 673-683. doi:10.1017/S0007114515002329