Green tea, native to China and India, has been consumed and hailed for its health benefits for centuries globally, but has only recently gained popularity in the US.
Tea is considered the most consumed beverage in the world behind water, however 78% of the tea consumed worldwide is black and only about 20% is green.
All types of tea except herbal tea are brewed from the dried leaves of the Camellia sinensis bush. The level of oxidation of the leaves determines the type of tea.
Green tea is made from un-oxidized leaves and is the least processed type of tea and therefore contains the most antioxidants and beneficial polyphenols.
Green tea was used in traditional Chinese and Indian medicine to control bleeding and heal wounds, aid digestion, improve heart and mental health and regulate body temperature. Recent studies have shown green tea can potentially have positive effects on everything from weight loss to liver disorders to type 2 diabetes.
NUTRITIONAL VALUE OF CONSUMING GREEN TEA
Unsweetened brewed green tea is a zero calorie beverage. The caffeine contained in a cup of tea can vary according to length of infusing time and the amount of tea infused.
In general, green tea contains a relatively small amount of caffeine (approximately 20-45 milligrams per 8 oz cup), compared with black tea which contains about 50 milligrams and coffee with 95 milligrams per cup.
Green tea is considered one of the world's healthiest drinks and contains the highest amount of antioxidants of any tea. The natural chemicals called polyphenols in tea are what are thought to provide its anti-inflammatory and anti-carcinogenic effects.
Epigallocatechin-3-gallate (EGCG) is the most studied and bioactive polyphenol in tea and has been shown to be the most effective at eliminating free radicals.
Green tea is approximately 20% to 45% polyphenols by weight, of which 60% to 80% are catechins such as EGCG.
POSSIBLE HEALTH BENEFITS OF GREEN TEA
1. Cancer:
In countries where green tea consumption is high cancer rates tend to be lower, but it is impossible to know for sure whether it is the green tea that prevents cancer in these specific populations or other lifestyle factors.
*One large-scale clinical study compared green tea drinkers with non-drinkers and found that those who drank the most tea were less likely to develop pancreatic cancer, particularly women, who were 50% less likely to develop the disease. The amount of tea required for cancer-preventive effects has also varied widely in studies - from 2- 10 cups per day.
Studies have also shown the positive impacts of green tea on breast, bladder, ovarian, colorectal, esophageal, lung, prostate, skin and stomach cancer.
2. Heart disease:
Green tea helps prevent heart disease and stroke by lowering the level of cholesterol. Even after the heart attack it prevents cell deaths and speeds up the recovery of heart cells.
A 2006 study published in the Journal of the American Medical Association concluded that green tea consumption is associated with reduced mortality due to all causes, including cardiovascular disease.
The study followed over 40,000 Japanese participants between the ages of 40 and 79 for 11 years, starting in 1994.
*The participants who drank at least 5 cups of green tea per day had a significantly lower risk of dying (especially from cardiovascular disease) than those who drank less than one cup of tea per day.
3. Type 2 Diabetes:
Studies concerning the relationship between green tea and diabetes have been inconsistent. Some have shown a lower risk of developing type 2 diabetes for green tea drinkers than for those who consumed no tea, while other studies have found no association between tea consumption and diabetes at all.
4.Weight loss:
Some studies have found that green tea is helpful in preventing dental cavities, stress, chronic fatigue, treating skin conditions and improving arthritis by reducing inflammation.
Green tea burns fat and boosts your metabolism rate naturally. It can help you burn up to 70 calories in just one day.
Some precautions while consuming green tea
*There are little to no known side effects or contraindications to drinking green tea for adults. Those with severe caffeine sensitivities could experience insomnia, anxiety, irritability, nausea or upset stomach.
*Those taking anticoagulant drugs such as Coumadin/warfarin should drink green tea with caution due to its vitamin K content.
*If taken with stimulant drugs, green tea could possibly increase blood pressure and heart rate.
*Green tea supplements however, contain high levels of active substances that can trigger side effects and interact with other herbs, supplements, or medications. Green tea supplements are unregulated by the FDA and may also contain other substances unsafe for health or with unproven health benefits. Always check with a physician before starting any herb or supplement regimen.
*In particular, pregnant or breastfeeding women(because of caffeine in green tea), those with heart problems or high blood pressure, kidney or liver problems, stomach ulcers, or anxiety disorders should not take green tea supplements or extracts.
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