Tea and Health
Tea has been a special herbal remedy in China for 5,000 years. It started out as just one of many herbal medicines, but because of tea’s powerful restorative and preventative health benefits, not to mention its beautiful aromas and tastes, it set itself apart from the rest. China has known about the healing power of tea for millennia, Britain figured it out a few hundred years ago, and America is just waking up to this fact. In recent years, modern science has been looking more closely at tea, and the medical world is now discovering a long list of health benefits that come from drinking tea.
Even though tea is all the same plant, the natural processing techniques that are used to make white, green, oolong, black, and dark teas change the composition, and quite dramatically in some cases.
According to a study of the composition of different teas conducted by the US Department of Agriculture’s Food Composition Laboratory, “[Antioxidants] were found in all the tea infusions examined, ranging in concentration from 1-13 mg dl-1. These levels indicate that even moderate tea consumption can contribute a substantial quantity of [antioxidants] to the diet. Although some differences between the three brewed teas were evident, all were comparably good sources of these catechins.”
Green teas and white teas are heated, dehydrated, sealed, and then stored at cold temperatures to keep them fresh, and they are closest to raw tea leaves. The composition of green tea has been studied extensively and is well known to science. Its current popularity, especially in Japan, has lead to a lot of recent research on the health benefits of green tea. Being so close to raw tea leaves means green and white teas contain only the simple polyphenol antioxidants called catechins.
Black teas are fully aged, or oxidized, before they are heated and dehydrated. There are several processes by which black teas are made, and even in modern China most of these processes are well-kept local secrets. It involves twisting, rolling, breaking, pressing, and fermentation to break up the leaves’ cell structure. Because of the presence of an active oxidase within tea leaves, these processes lead to the formation more complex polyphenols called flavanoids, theaflavins, and more. The catechin quinones also react during oxidation to form hundreds of protean compounds that form the aromas of black teas. This is why black teas are so variable and why they are so popular throughout the world. This is also why it’s so important to smell your teas, as sensing the aroma is the only way to get the full essence of a fine tea. The composition of the more complex elements of black tea are not well known at this time. Research on the health benefits of Britain’s, and the world’s, most popular beverage is only just beginning.
Oolong teas lie somewhere in between green and black teas. They are partially aged (oxidized) teas, and their colors can range from green to black. Oolong teas are aged longer than green teas but less than black teas, and their composition lies somewhere in between as well.
According to University of Michigan Health, tea is one of the healthiest things you can consume, and its health benefits cover nearly the whole body. “Teas are rich in antioxidants called polyphenols which are plant chemicals that may help prevent cancer, heart disease, metabolic syndrome, hypertension, stroke, obesity, arthritis, and other diseases,” the article says.
According to the study, everyone should drink 2-4 cups per day to reap the health benefits of tea. They discovered that tea protects the body by:
Inhibiting growth of cancer cells
Reducing high blood pressure
Protecting against stroke
Improving blood flow to the heart
Reducing total and LDL (“bad”) cholesterol
Inhibiting the formation of blood clots in artery walls
Stabilizing blood sugar levels
Lowering the risk for osteoporosis
Acting as an anti-inflammatory agent
Enhancing immune function and helping fight infections
Protecting against viral infections and liver disease
Inhibiting the growth of bacteria that can cause gum disease, cavities, and bad breath
Exhibiting an antibacterial effect on harmful bacteria inside the body
Improving brain function and preventing brain cell death