Living Well: Green tea brims with benefits
Reported September 28, 2008As a naturopathic physician and faculty member at Bastyr University in Kenmore, Paul Anderson has plenty of opportunity to practice what he prescribes. In the case of drinking green tea for health protection, Anderson says he is a regular — but not daily — drinker.
“Green tea has a significant amount of antioxidants,” said Anderson the other day, taking a break from moving to a new office. “That helps with regulating cholesterol and burning fat.”
Another positive about green tea in Anderson’s view: It contains amino acid molecules called thiamine that “can be quite calming to the brain.” This relaxing effect seems to run counter to the fact that green tea’s active ingredients include caffeine. The caffeine is less than the typical cup of coffee or soda, but it is still, well, caffeine.
“The caffeine effect is immediate while thiamine needs to build up over time,” said Anderson. “Only regular green tea drinkers will get the calming effect, and the thiamine sort of balances out the caffeine.”
Research on the health benefits of green tea is burgeoning. Earlier this year, researchers at the Fred Hutchinson Cancer Research Center and the University of Washington reported that women who drank one or more cups per day of green tea reduced ovarian cancer risk by 54 percent. Even women who drank green tea occasionally enjoyed decreased risk. This protectiveness is even more significant considering the difficulty of detecting ovarian cancer until it is advanced and less treatable.
The Hutch Center scientists noted green tea has high levels of epigallocatechin-3-gallate or EGCG, a powerful antioxidant shown in lab studies to inhibit ovarian cancer growth. Additional studies connect green tea’s EGCG level and reduced risk for several other cancers, including breast cancer (in experiments on mice at the University of Mississippi) and colorectal cancer (according to a large study of Chinese women).
Anderson said some cancer patients drink green tea to help offset the intended ravages of chemotherapy and radiation, which kill some normal cells as a byproduct of destroying cancer cells.
A major Japanese study concluded that individuals who drink at least a pint of green tea per day appear to significantly decrease their risk of death from heart disease, especially from cardiac episodes earlier than life expectancy would predict. The 2006 research, published in the Journal of the American Medical Association, offered that the common green tea habit among Japanese adults might go a long way in explaining why the mortality rate from heart disease and stroke is about 30 percent lower in Japan than in the United States.
EGCG is considered a substance that protects cells from damage and premature aging, which is no doubt why it has become a favorite of beauty and cosmetics manufacturers. But there is no research to show whether topical application of green tea extracts have the same effect as consuming the tea.
Anderson said one of the first things a naturopathic physician determines about medicinal plants and herbs is whether there is a toxicity level for the substance. He said green tea presents no such dangers, especially as a brewed tea. He acknowledged that someone would have to take “extremely large” amounts of green tea extract to cause any toxic effect. He did include a few cautions: The caffeine in green tea might still adversely affect someone with uncontrolled high blood pressure, similar to coffee. And he said some people become nauseated when they drink green tea.
For his part, Anderson opts for matcha green tea, which is a fine powder made from grinding the tea leaves. The physician says he chooses it primarily for flavor and “ease of going down,” yet he also explains that a tea as powder is likely to “expose” your water to a greater amount of antioxidants (more leaves, more concentrated) than if brewed with in its loose-leaf or tea-bag versions. Plus, matcha powder is absorbed completely into the water (you can mix it cold or hot) while the loose leaves or bag will be discarded.
One study conducted by researchers at the University of Colorado at Colorado Springs isolated the EGCG counts in matcha green tea compared with brewed cups. They concluded the matcha is 137 times more potent than a China tips leaf tea — a fact, as you might imagine, not lost on purveyors of matcha.
There is an ongoing debate about whether the specific grade of matcha tea matters for optimal health benefits. Anderson said he buys his matcha at a favorite tea shop and trusts the retailer’s sources. “I’m sure the grades are better in Japan, but the quality is better in the U.S. these days,” he said.
At $15 to $20 per container, matcha might appear to be pricier than loose tea or bags. But one container might well last three months or more, making it economical as either a total replacement for coffee or becoming your pick-me-up beverage of choice in the afternoon.
No matter the type of green tea you choose, be sure not to make it with boiling-hot water. You want the tea water to reach just boiling and then sit for a moment. When possible, pour the water first, then add the tea.
“The reason is extreme heat can change the nature and healing properties of any herbs,” said Anderson. “If you add the tea second rather than pour the hot water right over it, there is less shock to the plant. You are trying for the highest amount of antioxidants and flavonoids, so don’t make the water too hot.”