Green Tea: The Power of EGCG (epigallocatechin-3-gallate)

The consumption of tea, particularly green tea, has been touted for centuries as being beneficial for health. When discussing teas one needs to be aware that there are three main varieties: green, black, and oolong. Each of these three teas are prepared from the leaves of Camellia sinensis. Why are there three different teas from the same species of plant? This relates to the process by which the tea leaves are prepared. Green tea is made from unfermented leaves that are not subjected to any oxidation. Black tea is made from leaves that undergo a four step process of withering, rolling, oxidizing and drying. The rolled leaves are spread out in cool and humid rooms and exposed to oxygen for several hours, which causes chemical changes in the leaves and turns them from green to coppery red. Finally, the completely oxidized leaves are fired to stop oxidation. Oolong tea represents a partially oxidized tea leaf designed to generate a full-bodied tea. The oxidation period for oolong teas is less than that for black teas and depends on the type of oolong. After the desired oxidation level is reached, the leaves are fired to prevent further oxidation. Because of the different mechanisms used in the preparation of the various types of teas, green tea is believed to contain the highest levels of bioactive phytochemicals, specifically the potent anti-oxidant flavonoid polyphenols.

The primary flavonoids in green tea are catechin, gallogatechin, epigallocatechin-3-gallate (EGCG), epicatechin, epicatechin-3-gallate, and epigallocatechin. EGCG is the most abundant polyphenolic constituent of green tea representing 50%-80% of the total polyphenolic content. EGCG has been extensively studied in the clinical setting and results of these studies have associated the compound with numerous health benefits in humans. These benefits include anti-aging, anti-inflammatory, anti-cancer, anti-diabetic, anti-bacterial, and blood cholesterol lowering activity.

Obesity, particularly in the industrialized world, is reaching epidemic proportions. Overweight and obese individuals are at the highest risk for serious and potentially lethal diseases including the metabolic syndrome, type 2 diabetes, and a range of cardiovascular disorders. Methods for the prevention of obesity have become a major focus of health professionals and pharmaceutical companies in developed countries. With the aim to discover functional nutraceuticals to help in preventing obesity recent evidence suggests that EGCG, such as that in green tea, may exert a distinctive thermogenic effect through the promotion of fatty acid oxidation. In addition to promoting fatty acid oxidation EGCG may be a viable weight loss supplement through mechanisms that include the suppression and/or inhibition of fat absorption and enhancement of energy consumption. EGCG has been shown to improve energy metabolism and metabolic capacity both at rest and during exercise in studies that were carried out in patients with multiple sclerosis. EGCG administration in these patients showed improvement in muscle metabolism during exercise. EGCG has also been shown to influence energy metabolism during athletic performance in normal healthy individuals. Having the capacity to exert changes in energy balance by contributing to greater rates of fatty acid oxidation suggest that EGCG is indeed a viable weight loss inducing supplement.

So, in addition to many benefits attributable to the anti-oxidant properties of plant-derived polyphenolic compounds such as the flavonoid EGCG, the consumption of green tea is likely to play an important role in ones overall efforts to attain and maintain a healthy weight and log life!!!


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