Tea is an ancient beverage dating back more than 5,000 years. It is used medicinally, ceremonially and socially in various cultures and countries. Second only to water, tea is the most commonly consumed beverage worldwide. The three main types of tea – green, black and red (oolong) – all are made from leaves of the Camellia sinensis plant.
Green tea is the least processed type of tea with its leaves undergoing only quick steaming or heating before packaging. In addition to heating, black tea leaves are partially dried, crushed and exposed to light, which causes a natural biochemical process to occur that turns the leaves a deep brown color and intensifies the flavor. Red tea is considered the in-between tea because it is also exposed to heat, light and crushing, but for a lesser amount of time than black tea.
Tea’s potential health benefits: Whether green, black or red, all teas contain polyphenols. Polyphenols are phytonutrients that appear to work as antioxidants by protecting the body’s cells from free-radical damage. Cell damage caused by free radicals has been shown to cause a slow chain reaction that ultimately may lead to cancer and/or heart disease.
Over the past several years, studies have linked tea drinking to lower risk for cancer and heart disease. A number of research studies have demonstrated that, in addition to reducing cellular damage caused by free radicals, the polyphenols found in tea may inhibit tumor growth and deactivate cancer promoters. With regard to heart disease, animal studies have generally indicated that polyphenols prevent the oxidation of LDL ("bad") cholesterol, reduce blood lipids, exhibit anti-inflammatory actions and improve blood vessel function. Results from human studies, however, have not been as clear, although a recent Dutch study reported in the American Journal of Clinical Nutrition found that tea drinkers had a substantially lower risk of heart attacks than nondrinkers. Further, several epidemiological studies have linked tea consumption to protection from both heart disease and stroke.
For now, the general consensus is that, while there is still much to be learned about tea’s potential health benefits, it’s reasonable to drink tea as part of the six to eight cups of fluid recommended daily.
A few tea-time tips:
– Teas with the highest antioxidant properties are brewed from loose leaves or tea bags of black, green or red tea. To release the maximum amount of antioxidants, allow tea to steep for three to five minutes.
– Iced teas made from loose leaves or tea bags can provide as much antioxidant power as hot teas but are best kept covered in the refrigerator and stored only a day or two.
– For an added boost of calcium, try milk tea made by adding milk to hot or iced tea.
– Try drinking tea without added sugar or honey. Instead, add a slice of lemon, fresh ginger or fresh mint leaves.
– Check the label on bottled teas for added sugars. Bottled teas often have as much added sugars as soda. Bottled teas also may have a lower level of antioxidants because they contain mostly water and sugar.
– Herbal teas are generally made from a variety of different plants and may include parts other than leaves, including roots and flowers. Because most herbal teas do not contain leaves from the Camellia sinensis plant, they may not contain the same health-promoting polyphenols as green, black and red teas.
by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension
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