Drinking tea as part of a healthy diet may lower blood pressure, cholesterol, and triglycerides. Tea's caffeine may be less harmful than caffeine in coffee.
Next to water, tea is thought to be one of the healthiest beverages on the market today. According to Dr. Joseph Mercola, a mounting body of research suggests drinking tea is linked to several health benefits, including: reduced risk of heart disease and cancer, improved insulin response and reduced blood sugar levels, reduced pain and inflammation associated with rheumatoid arthritis, reduced risk of dementia, reduced glaucoma risk, and improved digestion.
Antioxidants, Polyphenols and Flavonoids Have Protective Effects on Health
A review of studies on black tea from 1990 to 2004 published in the January 2007 American Journal of Clinical Nutrition linked polyphenols found in black tea equivalent to three cups a day to a reduced risk of heart disease. Polyphenols are naturally occurring antioxidants. Epigallocatechin-3-gallate (EGCG) is the antioxidant in tea that is responsible for most of its health benefits. Flavonoids found in green tea have been linked to reduced cancer risk; in this review the benefit of black teas was limited to a slight decrease in the incidence of colorectal cancer. Women concerned with caffeine's effects on bone loss might be glad to know studies reviewed showed a slight benefit or no effect of black tea on bone mineral density. Finally, except for those at risk for anemia, black tea was not found to be a contributor to iron deficiency. Pregnant and breastfeeding women should still avoid or limit consumption of caffeinated beverages.
Theanine in Tea May Counteract Caffeine Effects
Black tea was also found to provide normal hydration, similar to the effects of water, providing the caffeine content was less than 250 mg. Caffeine from tea contains theanine, a natural protein not found in coffee, which was found in reviewed studies to counteract some of the side effects of caffeine, such as raised blood pressure, headaches and tiredness. Reviewers suggests an upper limit of eight cups of tea per day to keep the side effects of caffeine to a safe level, however, the amount that produced benefits in the studies was three cups per day. Green or white tea might be the best option for those sensitive to or concerned about the effects of caffeine. Individual sensitivity to caffeine differs. The central nervous stimulant’s effects have been associated with insomnia, fatigue, anemia, osteoporosis, headache, and mood disorders.
Processing Defines the Choice of Teas
Unlike black tea, green tea is not fermented. White tea is even less processed, and tulsi tea, recommended by Dr. Mercola, is made from an East Indian herb that is purported to have all the benefits, but none of the caffeine, of regular tea. According to the label of Legends of China Green Tea, distributed by Uncle Lee’s Tea, the caffeine content of 8 oz of green tea is 20 to 40 mg., compared to 8 oz. of black tea containing 50 to 55 mg. and 8 oz of coffee at 100 to 120 mg.
Drinking three cups of tea per day may help protect against heart disease, diabetes and some types of cancer. As long as caffeine content is low, a review of studies indicates that tea is as hydrating as water and does not contribute to osteoporosis or iron deficiency anemia. Tea contains theanine, a protein that may counteract some common side effects of caffeine.
First published Jul 14, 2010 Mary Earhart - http://nutrition.suite101.com/article.cfm/how-tea-benefits-health
References:
Mercola.com, “Popular Brew May Lower Cholesterol”, accessed July 12, 2010
European Journal of Clinical Nutrition, Black Tea—Helpful or Harmful, A Review of the Evidence, Gardner EJ, et. al., 61(1), 2007
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