Green tea is made from the leaves of an evergreen tree related to the Magnolia family with the botanical name of Camellia sinensis. Green tea leaves are typically less processed then other types of tea leaves, and the tea also provides the most antioxidant polyphenols. One type of antioxidant polyphenol found in green tea is a catechin called epigallocatechin-3-gallate, or EGCG. Many of the health benefits of green tea are linked to EGCG.
Nutritional Profile of Green Tea
One bag of green tea contains 0 calories, approximately 0.06 mg of caffeine, and 80 to 100 mg of polyphenols, 25 to 30 mg of which are EGCGs. Green tea is not a source of protein, carbohydrates, fiber, sugar, saturated fats, mono fats, poly fats, vitamins, minerals, amino acids, taurine, alcohol, citric or other acids.
Health Benefits
Green tea is rich in flavonoids, including catechins. The most abundant catechin in green tea is EGCG, which, according to MayoClinic.com, may play a role in the anticancer and antioxidant effects of green tea. However, most of the research about the health benefits of green tea shows the overall benefits depend on the amount of tea consumed. Typically, in Asian countries people consume on average 3 cups per day equaling 240 to 320 mg of polyphenols. According to a study conducted by researchers from the University of Kansas, EGCG is more powerful then resveratrol, the polyphenol found in wine. This may explain the low incidence of heart disease among Japanese men.
Metabolism and Green Tea
A study conducted by the University of Geneva that subjects who drank green-tea extract showed an increase in their 24-hour energy expenditure. This increase differed significantly from the increase effect of caffeine alone. According to the Memorial Sloan-Kettering Cancer Center, green tea elevates body temperature and promotes fat oxidation. This is not only explained by its caffeine content, but also by the effects of green tea's ECGC. Additionally, green tea may help to reduce body fat, an effect related to catechins. Green tea also helps to prevent acute increases on blood-insulin, which can promote fat-burning. The ECGC in green teas can also stimulate the production of noradrenaline, which helps to fuel your body's metabolism.
Interesting Facts
In traditional Chinese medicine, doctors recommend green tea for headaches, poor digestion, general toxicity, and immune system disfunction. Additionally, green tea has theanine which according to the Encyclopedia of Herbal Medicne can promote a feeling of well-being and aid in concentration. The polyphenols in green tea also have cancer-preventive properties.
References
- Encyclopedia of Herbal Medicine; Andrew Chevallier; 2000
- Memorial Sloan-Kettering Cancer Center; Green Tea; November 2010
- Mayo Clinic; Green Tea Extract Shows Promise in Leukemia Trials; May 2009
- The American Journal of Clinical Nutrition; Efficacy of a Green Tea Extract Rich in Catechin Polyphenols and Caffeine in Increasing 24-h Energy Expenditure and Fat Oxidation in Humans; Abdul Dulloo; December 1999
- Dare To Lose: 4 Simple Steps to a Better Body; Shari Lieberman; 2002
Member Comments