
Polyphenols and flavonoids
The ancient Chinese considered
tea medicine. Ancient Chinese proverbs describe tea ‘as a miraculous way to prolong life.’ Today science is confirming much of what Chinese folklore has known for
millennia. Studies all over the world have reported that tea, especially
green and
oolong tea, reduces the risk of cardiovascular disease, lowers bad cholesterol levels, prevents many of the cancers common in the modern era, lowers blood sugar levels, raises metabolism reducing body fat, and prevents tooth decay and bad breath.
Tea, especially
green and
oolong tea, contains large amounts of
polyphenol, a naturally occurring antioxidant compound. Antioxidants work to neutralize free radicals, which are implicated in a host of chronic illnesses, including cancer and heart disease. Studies indicate that the
polyphenol found in
green and
oolong teas have an antioxidant effect more powerful than vitamin E.
Polyphenols are also known to keep the influenza virus in check.
Tea naturally contains the minerals fluoride and manganese, as well as vitamins C, B2, D and K and a number of amino acids. Clearly, tea is one of those earthly wonders, delicious and good for one’s health.
From Web MD
Tea is a name given to a lot of brews, but purists consider only
green tea,
black tea,
white tea,
oolong tea, and
pu-erh tea the real thing. They are all derived from the Camellia
sinensis plant, a shrub native to China and India, and contain unique antioxidants called
flavonoids. The most potent of these, known as
ECGC, may help against free radicals that can contribute to cancer, heart disease, and clogged arteries. All these teas also have caffeine and
theanine, which affect the brain and seem to heighten mental alertness.
The more processed the tea leaves, usually the less
polyphenol content.
Polyphenols include
flavonoids.
Oolong and black teas are oxidized or fermented, so they have lower concentrations of
polyphenols than
green tea; but their
antioxidizing power is still high.
Here's what some studies have found about the potential health benefits of tea:
Green tea: Made with steamed tea leaves, it has a high concentration of
EGCG and has been widely studied. Green tea’s antioxidants may interfere with the growth of bladder, breast, lung, stomach, pancreatic, and
colorectal cancers; prevent clogging of the arteries, burn fat, counteract
oxidative stress on the brain, reduce risk of neurological disorders like Alzheimer’s and Parkinson’s diseases, reduce risk of stroke, and improve cholesterol levels.
Black tea: Made with fermented tea leaves,
black tea has the highest caffeine content and forms the basis for flavored teas like
chai, along with some instant teas. Studies have shown that black tea may protect lungs from damage caused by exposure to cigarette smoke. It also may reduce the risk of stroke.
White tea: Uncured and
unfermented. One study showed that
white tea has the most potent anticancer properties compared to more processed teas.
Oolong tea: In an animal study, those given antioxidants from
oolong tea were found to have lower bad cholesterol levels. One variety of
oolong,
Wuyi, is heavily marketed as a weight loss supplement, but science
hasn’t backed the claims.
Pu-erh tea: Made from fermented and aged leaves. Considered a black tea, its leaves are pressed into cakes. One animal study showed that animals given
pu-erh had less weight gain and reduced
LDL cholesterol.
Can Tea Be Bad for Your Health?
from Web MD
Most teas are benign, but the FDA has issued warnings about so-called dieter’s teas that contain senna, aloe, buckthorn, and other plant-derived laxatives.
The agency also warns consumers to be wary of herb-containing supplements that claim to kill pain and fight cancer. None of the claims is backed by science and some of the herbs have led to bowel problems, liver and kidney damage, and even death.
The FDA cautions against taking supplements that include:
Comfrey
Ephedra
Willow bark
Germander
Lobelia
Chaparral
These cautions aside, nutritionists say to drink up and enjoy the health benefits of tea.
“You want to incorporate healthy beverages in your diet on a more regular basis to benefit from these health-promoting properties," says Diane L. McKay, PhD, a Tufts University scientist who studies antioxidants. "It’s not just about the foods; it’s about what you drink, as well, that can contribute to your health."