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Tea and Health

Tea and Health


There are two really good reasons for drinking tea: remarkable health benefits, and a wonderful variety of tastes. People have enjoyed tea for over five thousand years. There must be something to it so let’s take a closer look at the types of tea, the scientific research, why drinking tea in winter is especially important, and how much should you drink.


True tea is a beverage brewed only from the leaves of the camellia sinensis plant, an evergreen shrub native to Asia. Herbal “teas” that come from other plants are properly called tisanes. Camellia leaves are harvested and processed in different ways to give us four types of tea: white, green, oolong, and black.


White teas are fairly rare. New tea leaves are plucked from the plant and allowed to wither and dry in the shade. They produce a pale infusion the color of straw with a delicate taste.


Green teas are from leaves that are dried in the shade until limp then heated until fully dry to prevent their natural oils from interacting with air. The heat can come from the sun, a warm air source, or "pan fried" in a wok. This is the most common beverage in Japan. Most of the research into the health benefits of tea has been focused on greens.


Oolong teas are "semi-oxidized". Leaves are plucked and immediately placed in direct sunlight. They are then lightly bruised through shaking in a bamboo basket in order to release some of the natural oils. At a certain point, judged by the tea master, the natural oxidation process is halted by quickly heating the leaves until they are dried. Oolongs are very popular in China along with green teas.


Black teas are also withered and bruised allowing the oils to interact with air. This turns the leaves copper to red in color. Then they are quickly “fired” at very hot temperatures to stop the oxidation process and fully dry the leaf. This last step of "firing" turns the leaf black. When steeped about 5 minutes the leaves only slightly expand in volume. Black teas are popular in Europe.

 

WHAT SCIENCE SAYS
Age-old wisdom about tea is now being taken seriously by mainstream researchers. Funding for studies has come from groups such as the National Cancer Institute and the National Institute of Health. Tufts University, the University of Arizona, the Sloan-Kettering Cancer Center, Columbia University, Case Western Reserve University, the University of Kansas, Indiana University School of Medicine, Rutgers University, the USDA, and others are now studying tea and health.


A group of scientists from around the world met at the US Department of Agriculture in Washington, DC for a Symposium on Tea and Human Health in September 1998. The event was co-sponsored by The American Cancer Society, the Nutrition Committee of the American Heart Association, the American Health Foundation, and others. This conference marked a milestone in the medical and science communities’ recognition of the health benefits of tea.


Dozens of new studies reaffirmed earlier work done in Europe and Asia concluding that three or more 6 oz. cups of tea a day help fend off cancer, reduce heart disease, fight the negative effects of aging, and promote elimination of dietary fats, among other health benefits.


Whether you drink tea because you like it or for health – or both, you might be interested in some of the current research findings and trends:


Polyphenols – Experts believe that the health benefits of tea come mainly from polyphenols, natural compounds found in all four tea types at various levels. Many of the polyphenols are antioxidants which have antiviral, antibacterial, and anticancer properties. The most potent are catechins and flavonoids. According to the USDA, the antioxidant activity of green tea is more potent than that found in 22 fruits and vegetables including orange juice, carrots, and broccoli.


Cancer – Some antioxidants - like the catechins - will counter the damage from "free radicals" and make DNA more resistant to mutation. This prevents some cancers from forming and inhibits the growth of some tumors already in existence. Green tea shows special promise against cancers of the skin, lymph, mouth, stomach, esophagus, liver, bladder, colon, prostate, and lung.


Heart Disease and Stroke – Studies show that tea can lower fatty deposits in artery walls, decrease blood levels of cholesterol and triglycerides, lower blood pressure, and reduce the clotting tendency of blood.


Immune Booster – Tea has been shown to enhance and increase the number of immune system components including "B" cells, "T" cells, and "killer" cells.


Digestion – Tea is thought to encourage the growth of beneficial bacteria in the digestive tract, stimulate digestive juices, break down dietary fats, and help control levels of glucose in the blood stream.


The bottom line is that tea has wonderful health enhancing effects for your body and mind.

 

HOW TO MAKE TEA


White teas are very delicate and should be brewed only a minute or two in water that is hot but not boiling, about 170-175 Fahrenheit degrees.


Green teas taste fresh and grassy and must be brewed in 175-180 F water for only 1 – 3 minutes in order to achieve the best flavor. Of all tea types, the greens have the highest catechin content. This polyphenol compound is largely responsible for the health benefits but it is also bitter in taste. If brewed too hot or too long the taste becomes more bitter.


Oolong teas should be steeped for 4-6 minutes in water just off the boil, 180-190 F. The leaves will unfurl until three or four times the dried volume. Always brew oolong tea in a pot so there is room for expansion. Don’t use tea bags. Oolongs have a wide range of tastes and colors and are midway between greens and blacks in the degree of their healthy components.


Black teas are steeped about 5-6 minutes in very hot water, 208-212 F. They have a robust and lingering flavor. Black tea is very helpful for overall digestion and metabolism of dietary fats. It is the tea of choice for those wanting a coffee substitute.


Drinking tea is most rewarding when a heaping teaspoon of loose tea is brewed in a clay teapot for the appropriate time. Then, with deliberate attention, the tea is poured into a cup that is reserved for only tea. The ritual enriches the experience. However if you’re on the go, brewing white, green and black tea in bags is acceptable. But not for oolongs – they must be allowed to expand and a teabag prevents this from happening.


True tea has caffeine which accounts for some of its appeal. Coffee and tea are tied for second as the most frequently consumed drinks in the world. Caffeine has good and bad effects mostly determined by the amount imbibed. The following chart shows the range of caffeine in tea and coffee.


Beverage        Caffeine Per 8 oz Serving
White Tea       30-55 mg
Green Tea      35-70 mg
Oolong Tea    50-75 mg
Black Tea       60-90 mg
Coffee            100 mg

 

WHY TEA IS ESPECIALLY GOOD IN WINTER


Tea will warm you up. In fact, I personally find that drinking tea makes me feel warmer than drinking coffee. Over the years of enjoying both tea and coffee I have come to the conclusion that tea is more of a “head trip” while coffee tends to affect my body. Tea gives me a pleasant sense of mildly increased alertness and warm composure. Coffee, in excess, makes me feel jittery and oddly acidic.


My series of classes, Qigong Through The Seasons, presents a complete plan for staying healthy throughout the year. The program is tailored to those specific health needs that change with the seasons. The Five Phase paradigm of Chinese medicine tells us that winter is the time to focus on the bones, teeth and other aspects of the Kidney Network. Tea has very beneficial effects on bones and teeth. Below are some of the details from research.


Evidence That Green Tea May Help Improve Bone Health
Journal reference: Ko et al. "Effects of Tea Catechins, Epigallocatechin, Gallocatechin, and Gallocatechin Gallate, on Bone Metabolism". Journal of Agricultural and Food Chemistry, 2009; 57 (16): 7293 DOI: 10.1021/jf901545u

Researchers in Hong Kong are reporting evidence that green tea may help improve bone health. They found that the tea contains a group of chemicals that can stimulate bone formation and help slow its breakdown. The beverage has the potential to help in the prevention and treatment of osteoporosis and other bone diseases that affect millions worldwide.

The scientists exposed a group of cultured bone-forming cells (osteoblasts) to three major green tea components — epigallocatechin (EGC), gallocatechin (GC), and gallocatechin gallate (GCG) — for several days. EGC in particular, boosted the activity of a key enzyme that promotes bone growth by up to 79 percent. EGC also significantly boosted levels of bone mineralization in the cells, which strengthens bones. The scientists also showed that high concentrations of EGC blocked the activity of a type of cell (osteoclast) that breaks down or weakens bones.

 

Green tea may help promote healthy teeth and gums
Science Daily (Mar. 13, 2009)

A study recently published in the Journal of Periodontology, uncovered yet another benefit of green tea consumption. Researchers found that routine intake of green tea may also help promote healthy teeth and gums. The study analyzed the periodontal health of 940 men, and found that those who regularly drank green tea had superior periodontal health than subjects that consumed less green tea.

"It has been long speculated that green tea possesses a host of health benefits," said study author Dr. Yoshihiro Shimazaki of Kyushu University in Fukuoka, Japan. "And since many of us enjoy green tea on a regular basis, my colleagues and I were eager to investigate the impact of green tea consumption on periodontal health, especially considering the escalating emphasis on the connection between periodontal health and overall health."

Male participants aged 49 through 59 were examined on three indicators of periodontal disease: periodontal pocket depth (PD), clinical attachment loss (CAL) of gum tissue, and bleeding on probing (BOP) of the gum tissue. Researchers observed that for every one cup of green tea consumed per day, there was a decrease in all three indicators, therefore signifying a lower instance of periodontal disease in those subjects who regularly drank green tea.

"Periodontists believe that maintaining healthy gums is absolutely critical to maintaining a healthy body," says Dr. David Cochran, DDS, PhD, President of the AAP and Chair of the Department of Periodontics at the University of Texas Health Science Center at San Antonio. "That is why it is so important to find simple ways to boost periodontal health, such as regularly drinking green tea – something already known to possess certain health-related benefits."

 

SO, HOW MUCH TEA SHOULD YOU DRINK?


Most things that are good for you can be bad if consumed in excess. This applies to caffeinated beverages. I find that two cups of tea a day is just right for me. It helps me be alert but relaxed, and I feel fully united in body and mind. Although I’ll drink green and black tea, my all time favorite is oolong, actually a certain variety called Tung Ting from China.


The active agents in tea – the catechins and flavonoids – are incredibly helpful in limited doses. But like all good things, if overly ingested they may have detrimental effects on body tissues or physiology. The amount of tea shown to be helpful in many research studies ranges from two to six cups a day.


Buy good tea for goodness sake. Bulk teas stored in gallon jugs exposed to light have lost a lot of their flavor and potency. The best teas come in loose leaf form from reputable suppliers like Strand Tea in Oregon. You can get relatively high quality green and black teas in bags if they are well-sealed in foil, paper or plastic.


If you are already a tea drinker you may want to expand your experience by trying different varieties. If you haven’t yet tasted tea the coming cold weather may be just the right time to try this highly acclaimed and delicious drink.


Let’s raise a cup to our health!