Aug 29 2013
The Truth About Green Tea
By Maryam Henein, HoneyColony Original
I associate green tea with sushi restaurants—that complimentary cup they often place before you in welcome. If you’ve never tried a cup, you may assume it tastes grassy because of its name, but a good cup of green tea has a distinct orchid-meets-chestnut flavor, which is structured and rounded and fills your mouth with a tinge of bitter, due to the presence of polyphenols (catechins) and caffeine (called theine).
“Better to be deprived of food for three days, than tea for one,” goes an ancient Chinese proverb. After water, tea is the most popular drink consumed. An annual 3 billion kilograms of tea are produced each year worldwide, according to the Tea Council of the USA.
There are hundreds of varieties of the Camellia sinensis plant, a shrub native to Asia, and the two main types hail from China and Japan. Overall Chinese varieties are less vegetal than most Japanese varieties, which may sound more inviting to new drinkers. Because of its smokiness, my personal fave is gunpowder, which is a classic from Zhejiang province, China. As the name suggests, this tea is made up of leaves hand-rolled into tiny pellets.
I am very sensitive to caffeine, so when I do indulge, green tea is the wise alternative, not only because an eight-ounce cup has about 32.5 milligrams of caffeine compared to about 100 milligrams in java, but because this tea boasts a number of positive health effects. The Chinese have known the healing power of green tea for generations. In fact, in parts of Asia it is common for people to sip three to four cups daily.
Interest in tea’s potential health benefits has grown exponentially. In just the past five years there have been more than 5,600 scientific studies.
“There is now an overwhelming body of research from around the world indicating that drinking tea can enhance human health,” said Dr. Jeffrey Blumberg, professor at the Friedman School of Nutrition Science and Policy.
Heart Healthy And Fit
Our society is notoriously harsh on the heart. The prevalence of fatty foods and high-stress lifestyles that leave little time for exercise have made heart disease a leading killer in North America.
Even the healthiest among us occasionally succumb to the stress of a hectic life or the lure of fattier or processed foods. Any little bit we can do to keep our hearts safe is welcome, and while green tea may not make us immune to the risk of a heart attack, it might makes things just a little easier for the poor, overworked heart.
“I think people should know these are important studies, that everyday foods that are an option may actually have health benefits,” said Dr. Nieca Goldberg, an American Heart Association spokesperson.
The antioxidants in green tea help keep arteries flexible and dilated, reducing the risk of the kind of clogging that leads to heart attacks. Among teas, green tea polyphenols have been extensively studied in connection to preventing cardiovascular disease.
For instance, in its June 2008 issue, the European Journal of Cardiovascular Prevention and Rehabilitation published the results of a trial led by Dr. Nikolaos Alexopoulos and colleagues at the Athens Medical School in Greece, which found that drinking green tea improved endothelial function in men and women. Dysfunction of the endothelial cells which line the circulatory system is a critical event in the development of atherosclerosis, which leads to heart attack and stroke.
And in September 2006, the Journal of the American Medical Association published a study that tracked the green tea consumption of 40,530 adults over an 11-year period. The most striking finding from this study was the reduction in cardiovascular death in those who consumed the most green tea. Women who drank five or more cups of green tea daily had a 31 percent reduced risk of dying from cardiovascular disease, whereas men who drank five or more cups had a 22 percent reduced risk of dying from cardiovascular disease.
Those same studies showed tea-drinkers also enjoyed lower blood pressure and lower levels of LDL cholesterol, or “bad” cholesterol, both of which are contributors to heart disease.
There’s also evidence that shows green tea might help with another major health crisis of the modern age: obesity. Yup, green tea can help you lost weight.
In a comprehensive review of the published data on this topic, researchers from Maastricht University in the Netherlands found that 24-hour energy expenditure and fat oxidation increased when subjects consumed green tea and caffeine.
The results of a meta-analysis suggest that the increase in caloric expenditure is equal to about 100 calories over a 24-hour period, or 0.13 calories per milligram catechins. In addition, green tea and caffeine also appear to boost fat oxidation over 24 hours by an average of 16 percent or 0.02 grams per milligram catechins. In a related review, researchers concluded that subjects consuming green tea and caffeine lost an average of 2.9 pounds within 12 weeks, while adhering to their regular diet.
This effect was less pronounced but still apparent even when the participants drank decaffeinated tea. So for those who are struggling to lose weight, it may be time to invest in a teapot.
Beverages now account for 20 percent of total calories in the typical American diet.
“As tea is calorie-free, it’s an ideal choice to help consumers meet fluid requirements without adding calories to their diet, and the modest increase in energy expenditure and fat oxidation can also add to the role of tea as part of a healthy, calorie-controlled diet that promotes weight loss or maintenance,” Maastricht Univeristy researcher Dr. Rick Hursel explains.
Potential Sips To Ward Off Cancer
Another major health concern for many people is the risk of cancer, and it looks like green tea might help that battle as well.
According to the American Institute for Cancer Research, some lab studies show green tea slows and can also inhibit the growth of cancer cells in colon, liver, breast, and prostate cells. Other studies involving green tea have shown similar protective effects in tissues of the lung, skin, and digestive tract.
There are also studies looking at green tea extracts such as epigallocatechin gallate (EGCG). One such early study was done at Mayo Clinic to find safe dosing. They gave the extract in pill form to people with early-stage chronic lymphocytic leukemia (CLL). These people had no symptoms and would not usually be treated. Some of the people who got EGCG seemed to have fewer cancer cells after taking EGCG. Eventually the researchers hope to learn if the extract can help people with early stage CLL. Further clinical trials are needed to find out if the EGCG actually changes the course and outcome of their leukemia.
An Italian study published in 2006 looked at men with prostate intraepithelial neoplasi, which sometimes progresses to prostate cancer. The researchers gave half the men green tea extract and the other half sham pills. Over the next year, the men given green tea extract had fewer cases of prostate cancer than the men who got placebos. Other studies looked to see if green tea could help men who already had prostate cancer, but it didn’t seem to reduce the risk of prostate cancer continuing to grow and spread.
The American Cancer Society, however, states that studies that indicate green tea may help prevent some cancers in humans are mixed.
“Most human studies have been epidemiologic studies in East Asia, in which researchers compared tea drinkers with non-tea drinkers while trying to account for other lifestyle differences,” according to their website. “It is hard to draw firm conclusions from them unless there are multiple studies in which other factors are ruled out.”
Meanwhile, the FDA, which has reviewed several published studies, concluded in early 2011 that it is very unlikely that green tea prevents any type of cancer in humans.
Green tea boosts the number of “regulatory T cells” in the body, which are important for the immune system, according to research from the Linus Pauling Institute at Oregon State University.
“When fully understood, this could provide an easy and safe way to help control autoimmune problems and address various diseases,” researcher Emily Ho said.
Autoimmune diseases occur as the result of an imbalance in the immune system that results in the body mounting an attack against itself. Immune T cells are critical in providing a defensive shield that can protect against cancer proliferation and a host of diseases where the body recognizes healthy cells and organs as foreign. T cells also help to control systemic inflammation and can dampen the inappropriate response to normal cells seen in autoimmune conditions.
A study conducted at Indiana University’s Department of Molecular and Cellular Biochemistry revealed that epigallocatechin gallate (in green tea) reduces risk of autoimmune diseases by inhibiting a key component of the immune system that, when unregulated, can make you susceptible to developing an autoimmune condition. In the test tube study, EGCG was found to be a potent inhibitor of the receptors that initiate the immune response.
The green tea derivative also had an immune-calming effect by inhibiting pro-inflammatory molecules in this study. The researchers concluded that the results of this preliminary study indicate potential for the use of green tea as a therapeutic, as well as preventive, treatment for autoimmune conditions.
Antioxidants And Catechins
The nutritional value of green tea is very high—the most vital of all ingredients is the antioxidant known as catechin polyphenols. These antioxidants help clean up what are known as “free radicals” in your body. Free radicals are a nasty type of molecule that like to travel around your body, stealing electrons from your cells. The damage caused has been shown to bring about premature aging and increase your risk of cancer, among other things.
Antioxidants are found in many foods and drinks, including red wine, dark chocolate, and other varieties of tea, but green tea is one of the best sources around. One of the reasons is because green tea doesn’t go through a lot of processing compared to other types of tea. Black tea, for instance, is fermented for an extended period of time, and this causes it to lose some of its beneficial antioxidants. Green tea is only withered and steamed before being packaged, so most of its catechins are preserved.
Here’s To Your Health
Many supplement companies now offer extracts of green tea to aid in good health—either on their own or as part of a synergistic formula—but while these may still help, experts say the best way to reap the benefits of green tea is simply the old-fashioned way: by drinking it. This is because no one is exactly sure what precise components of green tea are providing the benefits, or if they need to be taken in combination to be fully effective.
Green tea isn’t a miracle cure, but it can help make your life just a little bit healthier, and that’s another reason to take comfort in a hot cup of tea on a cold day.
Tips For Tea
Water: I personally don’t drink tap water. Who knows what impurities lurk such as medications, chlorine, and a soup of chemicals. Best to use spring water, so as not to poison yourself or alter the taste.
Water Temperature: Green tea taste can be altered just by pouring boiling water directly over the leaves. Allow the water to cool down for at least 30 seconds before infusing.
Steeping: Don’t steep too long if you don’t want one bitter-tasting cup of tea. Look at the directions. A good rule of thumb is no longer than three minutes.
Photo by vordichtung/Flickr.
Rae0587 - 150 BeeBucks
Who doesn't want to look and feel healthy while sipping on something tasty? It's just that easy!
Murlin54 - 560 BeeBucks
I am brewing organic decaf green tea right now, infused with fresh mint. I wish the weight loss effect didn't require the caffeine. I am very sensitive to it so I try to avoid it. Since I can't go without dark chocolate, that is the only source of caffeine I can afford without ending up wide awake all night. Gotta go get my tea bags out of the pot! Good article!