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Tea is the most popular beverage in the world, outstripping coffee, juice, and soda. There is no real difference between loose leaf tea and tea in bags, except that loose leaf tea should cost a bit less. All teas should be made with boiling water, and allowed to steep for three to ten minutes, depending on the tea (follow manufacturer's instructions on the package.)

There are big differences among green, black, and herbal teas many varieties of which can be found in the Tea Shop at MotherNature.com.

Green, Black and Oolong Tea
Green and black teas are made from the dried green leaves of Camellia sinensis, a family of white-flowering evergreen bushes native to Asia. There are two basic varieties; dark green, small-leafed China tea (C. sinensis) and light green, large-leafed Assam tea (C. assamica). Tea is processed in different ways to make the three major varieties of commercial leaf tea.

Green Tea leaves are roasted or steamed to destroy the fermentation enzymes that would eventually turn them reddish-black. Green tea is uniquely rich in potently cancer-preventive, antioxidant polyphenols called catechins — of EGCg (epigallocatechin gallate) may be the most important.

Black tea is made by allowing fresh green tea leaves to oxidize from the natural action of enzymes in the leaf—changes that include shifts to a red-brown or black color and smoky flavor. Unfortunately, the fermentation process oxidizes beneficial gallocatechins, reducing the plant's cancer-preventive properties to a substantial extent. Black tea also comes with added flavors (e.g., Earl Grey, flavored with bergamot essence), and in decaffeinated form.

Oolong tea undergoes less fermentation than black tea, and therefore has a catechin content about halfway between green tea and black tea.

Health Benefits of Green Tea

Tea versus Cancer
Based on test tube and animal experiments, tea polyphenols (catechins) and related compounds appear to help prevent cancer in several ways:

1. Increase antioxidant and phase II enzyme activities in several organs, including the liver. More carcinogens are effectively neutralized by the body's enzyme-mediated detoxification system.
2. Inhibit conversion of testosterone to 5-alpha-dihydrotestosterone a process associated with prostate enlargement, prostate cancer, and male pattern baldness.
3. Enhance gap junctional communication between immune cells.
4. Inhibit tumor-promoter binding to cell receptors.
5. Bind to and neutralize certain carcinogens.
6. Stimulate production of immune system B-cells.
7. EGCg inhibits a cancer growth-stimulating enzyme called tNOX, but not the normal NOX enzyme that healthy cells express in response to release of growth hormone.
8. Up-regulate apoptosis in pre-neoplastic/neoplastic cells.

Human population studies have produced conflicting evidence on the question of green teas anti-cancer powers. Evidence from well-controled animal studies suggests that these inconsistencies may be attributable to the confounding factors that can plague epidemiological research.

Heart-Healthful Properties of Tea
Epidemiological studies indicated that tea consumption reduces the risk of cardiovascular disease. But research indicates that it does not work like other phenolic antioxidants (vitamin E, etc.). A recent study concluded that daily consumption of 6 cups of green or black tea per day for 4 weeks had no effect on serum lipid concentrations or resistance of LDL cholesterol to oxidation in the human body both being major risk factors for cardiovascular disease. It appears that other mechanisms are responsible for tea's apparent ability to reduce the risk of cardiovascular disease.

Tea in Dental Health
Several studies indicate that green tea has a powerful inhibiting effect on development of dental caries (cavities). It seems to work by inhibiting growth of cavity-causing bacteria, reducing their ability to adhere to tooth enamel, and reducing acid damage to enamel.

Herbal Teas
The drinking of herb teas such as chamomile and mint was widespread in Europe long before the arrival of black tea. Herbal teas are made from the leaves, flowers, roots, bark and seeds of many plants, and offer a kaleidoscope of myriad flavors, colors and aromas.

Most herb teas contain no caffeine at all, which accounts for their soothing reputation, and their growing popularity in today's hectic, high-pressure world. The only exceptions are teas made with naturally caffeine-containing herbs like guarana, yerba mate, or kola nut.

While some herbs are cultivated on large farms, most of are still small operations. And many herbs simply grow wild in fields and forests. Because of their delicate and specialized nature, a few herbs can be harvested just as their flowers begin to bud, when the plant's natural juices are at their best and most concentrated. The parts of the plant that are picked depend on the type of plant and the usage intended - leaves, flowers, roots, bark and seed are all potential herb tea ingredients.

After harvest, the herbs are dried by spreading them on large screens or by tying them in bundles and hanging them upside down. Oven drying is less effective, in terms of preserving natural oils and flavor. After drying, the herbs are shipped to the tea maker, who cleans, mills, sifts, and blends the herbs.

Health Benefits of Herbal Tea
Naturally, the health benefits of herbal teas vary. Some herbs are used primarily as sources of flavor, but most possess some medicinal or health-protective powers. In fact, immersion of herbs in boiling water helps make many of their active medicinal constituents more available to the body. (Alcohol extracts of herbs usually contain a wider range of beneficial constituents than herb teas or water decoctions.)

Examples of common herb teas with definite effects include chamomile (calming, sleep-inducing), peppermint (soothes stomach), ginger (antiinflammatory, anti-nausea) and bearberry (diuretic). Almost any medicinal herb you can think of ginseng, echinacea, black cohosh, ginkgo, milk thistle, or St. John's wort is available as a tea. Often, pungent-tasting medicinal herbs are blended with better-tasting herbs such as raspberry, lemon, orange or cinnamon

References

• Imai K, et al. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ. 1995 Mar 18;310(6981):693-6.
• Kinjo Y, et al. Mortality risks of oesophageal cancer associated with hot tea, alcohol, tobacco and diet in Japan. J Epidemiol. 1998 Oct;8(4):235-43.
• Kuroda Y, et al. Antimutagenic and anticarcinogenic activity of tea polyphenols. Mutat Res. 1999 Jan 8;436(1):69-97.
• McCarty MF. Selenium, calcium channel blockers, and cancer risk's the Yin and Yang of apoptosis? Med Hypotheses. 1998 May;50(5):423-33. Review.
• Otake S, et al. Anticaries effects of polyphenolic compounds from Japanese green tea. Caries Res. 1991;25(6):438-43.
• van het Hof KH, et al. Consumption of green or black tea does not increase resistance of low-density lipoprotein to oxidation in humans. Am J Clin Nutr. 1997 Nov;66(5):1125-32.
• Yu H, et al. Anticariogenic effects of green tea. Fukuoka Igaku Zasshi. 1992 Apr;83(4):174-80.

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