|Health benefits of drinking tea
by Dr. D. P. Atukorale
Tea is one of the healthiest beverages today. As part of the dietary intake tea has been gaining popularity as a health beverage due to its high content of antioxidants. Antioxidants in tea are called flavonoids. Both black and green tea are very rich sources of antioxidants.
Antioxidants and free radicals
Antioxidants are substances found in food and drinks which can protect us from harmful effects of free radicals. Well known examples of antioxidants are vitamin A, C, E and betacarotene.
Free radical is an unstable substance which can disrupt and damage molecules in the body. Although the oxygen we breath is vital to life it is also incorporated in very reactive substances called free radicals which are harmful to our bodies.
Free radicals have been implicated in the slow chain reaction of damage leading to heart disease, cancer and aging process. Antioxidants in our diet help to prevent and repair the damage caused by free radical attack. Best known antioxidants are Vitamin C, E and and betacarotene found in fruits, vegetables, cereals and vegetable oils.
Antioxidant capacity of tea
Doctors Prior and Cao of Tufts University have analysed the antioxidant capacity of various types of tea and have found that black tea had more antioxidant capacity than green tea. Green tea has more antioxidant called EGCG compared to black tea. Antioxidant capacity of tea depends on how long you brew tea. Within five minutes of brewing, 85% of antioxidant potential of tea was released and other 15% released after another 5 minutes.
Tea versus wine
Dr. Andrew Waterhouse of University of California at Davis found that tea supplied as many antioxidants known as catechins as red wine. He found that a glass of red wine has 300 milligrams of catechins. A cup of green tea has 375 milligrams of catechins. So drinking tea provides as much antioxidant protection as red wine.
Tea is superior to coffee
The New York Academy of Medicine held a symposium on Pharmacological and Physiological effects of tea in 1955 and had found that tea, unlike coffee does not cause nervousness, insomnia, fatigue or stomach irritation when drunk in quantity. They found that tea is a good agent in releaving fatigue and aids clearness of thought and digestion.
Consume tea in moderation
One should not drink gallons of tea. Remember nutritions cardinal rule "Everything in Moderation." One should not drink more than 10 cups of tea per day. In addition to drinking tea eat a well balanced diet, including a variety of whole grains, fruits and vegetables and take regular exercises. Like most foods when consumed in excess tea produces undesirable effects as those susceptible to kidney stones may consume much of the oxalate when they drink excessive amounts of tea. Tea contains two compounds caffeine and theophylline that have diuretic effect. So drink tea in moderation and dont consume more than 10 cups of tea per day.
Healthy heart with your cup of tea
Various research studies conducted on tea gives us an insight into benefits of tea to keep heart diseases at bay.
According to Rotterdam study published in a recent edition of Archives of Internal Medicine, women in Netherlands who drank 1 to 2 cups of tea reduced risk of severe atherosclerosis, key factor contributing to coronary heart disease. The women who drank more than 5 cups of tea per day had the lowest risk of atherosclerosis.
The research of the Rotterdam study concluded that the "data provide evidence for protective effect of tea drinking against severe atherosclerosis, especially in women". The study also showed a similar trend in men. 3454 men and women aged 55 years and over who were free of cardiovascular diseases were used for the study.
Saudi women study
At the Epidemiological Congress 2001, a joint meeting of Canadian and American Scientific Societies, a new research paper on health benefits of drinking black tea was presented. 1764 women in Saudi Arabia had been studied and this showed that tea drinkers are 19% less likely to suffer from cardiovascular disease. The Saudi women who consumed black tea had total cholesterol, triglycerides and LDL cholesterol (bad cholesterol) which were significantly lower than non- tea drinkers. Most marked reduction in blood lipid levels were observed in women who consumed 6 or more cups of black tea per day. Dr. Iman Hakim M.D., PhD. the lead researcher demonstrated an inverse relationship between tea drinking and blood lipid levels.
In a study conducted by Joseph A. Vita of Boston University School of Medicine, it was found that drinking up to 4 cups of tea per day improved endothelial function of blood vessels. This study demonstrated that drinking tea reverses an underlying abnormality of blood vessel function related to heart disease and stroke.
A symptom of coronary heart disease is that artery walls are not able to expand as well as accommodate blood flow. The endothelium or the inner layer of cells lining every blood vessel releases signals that control blood flow in the body by contracting and expanding the vessel wall, formation of blood clots and abnormal thickening of vessel wall which predispose to atheroma and its complications such as heart attacks and strokes.
The above studies confirm the critical role of antioxidant found abundantly in tea to prevent heart disease.
Drinking tea can cut risk of strokes
Drinking tea can soak your brain in antioxidant thus slowing down brain decline. There is evidence that tea can cut the risk of strokes. A study of 5000 Japanese women found that those who drank at least 5 cups of green tea everyday had half as many strokes as women who drank less. Tea helped to keep blood vessels especially the micro-vessels which fed the brain as well as the heart, healthy.
Other research workers have found that tea can thwart dreaded lipid peroxidation, the first step in brain cell destruction.
Long term consumption of black tea was associated with a much lower risk of stroke in a study of 552 Dutch men. Flavonoids in tea make blood "cells" called platelets less prone to clotting and act as antioxidant countering artery damaging potential of highly reactive free radicals. In the above study men with high flavonoids intake had a 73% low risk of stroke during a 15 years of follow-up compared with men with a lower intake of flavonoids. Men in the study got above 70% of their flavonoids from drinking black tea.
According to research at National Institute of Public Health and Environmental Protection in Bilthoven Netherlands, men who drank more than 4-7 cups of tea a day had 69% reduced risk of stroke compared to men who drank less than 2.6 cups a day.
Green tea and breast cancer
Japanese researchers at Saitoma Cancer Centre Research Institute have found that in heavy consumers of green tea, cancer spread to lymph nodes was less frequent. Women with less aggressive breast cancer who drank more than 5 cups of green tea a day were 50% less likely to have a recurrence than women drinking less than 4 cups daily. Green tea appears to improve prognosis and survival by suppressing spread and growth of breast cancer.
A little milk with tea actually boosts the protection against breast cancer, but, too much of milkabolishes teas anti-cancer effects according to Dr. John Weisburger PhD of the American Health Foundation. So take a couple of tea spoons of milk in an 8 ounce cup of tea.
Tea prevents tooth decay
Tea helps to prevent tooth decay in several ways. It contains solid dose of fluoride. According to research at Tokyo Dental College, it fights the kind of bacteria in the mouth that causes gum disease and eventually loss of teeth. It also kills the greatest cavity causing bacteria in the mouth, streplococus mutans. Black tea helps to keep the plaques from forming on your teeth.
Tea helps to prevent chronic gastritis
Tea drinkers suffer from chronic gastritis half as non drinkers, according to researchers at the UCLA School of Public Health and Jansson Cancer Center at UCLA.
According to a recent edition of International Journal of Cancer, green tea drinkers have low risk of stomach cancer, 48% less than non-drinkers.
Chronic gastritis is a common inflammatory condition that causes pre-cancerous lesions of stomach and progression from chronic gastritis to cancer is slow. Green tea contains antioxidant that researchers believe may inhibit the development of chronic gastritis and halt the progression of stomach cancer. According to Dr. Zuo-Feng Zhang, a Professor of Epidemiology at UCLA School of Public Health green tea should be used to treat chronic gastritis and as apreventive therapy in high risk people to reduce incidence of stomach cancer.
Most of the research in the world has been done with green tea. Both green and black tea come from the same plant, but after picking tea leaves are treated differently.
Green tea is picked, steamed and dried before packing. Black tea is picked, fermented and dried before packing. Herbal teas dont come from tea plant and do not have some antioxidant benefits as black or green tea or oolang tea (Oolang is an in between tea).
Other health benefits of drinking tea
Green and black tea may prevent sun induced skin cancer.
British researchers have found that female tea drinkers have stronger bones than non-tea drinkers.
Tea boosts your metabolism and helps you to burn more calories. Tea may stave off signs of aging.