Green Tea: New Benefits

Two new studies suggest that more health benefits may be associated with the popular Chinese beverage, green tea.

Green tea is made from the dried leaves of Camellia sinensis, a perennial evergreen shrub. Green tea, black tea and oolong tea are all derived from the same plant. Green tea is produced by lightly steaming the freshly cut leaf, thus not allowing oxidation of the enzymes within the leaf to take place. Green tea is produced and consumed primarily in China, Japan and countries in northern Africa and the Middle East. Green tea is used as an antioxidant and has been studied for weight loss and chronic disease prevention.

Researchers have discovered new evidence suggesting that green tea may reduce the risk of oral cancer as well as help treat inflammatory skin diseases.

In the first study, researchers from Japan examined the relation of green tea consumption with oral carcinogenesis (cancer) by prospectively analyzing data from a nationwide large-scale cohort study in Japan.

A total of 20,550 men and 29,671 women aged 40-79 years, without any history of oral and pharyngeal cancer at baseline survey, were included in the study. During a mean follow-up period of 10.3 years, 37 oral cancer cases were identified.

The study found that women who drank five or more cups of green tea a day may have a reduced risk of mouth cancer. In men, no such trends were observed.

The study authors concluded that there was not enough evidence to suggest that green tea consumption is correlated with oral cancer; however, there was a tendency for a reduced risk in women.

In a related study, researchers suggested that green tea may help treat skin disorders such as psoriasis and dandruff.

Scientists form the Medical College of Georgia studied the effects of green tea on inflammatory skin diseases in an animal model.

Inflammatory skin diseases are characterized by patches of dry, red and flaky skin caused by the inflammation and overproduction of skin cells. Researchers suggested that green tea treatment may slow the growth of skin cells. They explained that green tea suppresses inflammation and regulates the expression of caspase-14, a protein in genes that regulates the life cycle of a skin cell.

Researchers suggested that traditional inflammatory skin disease treatments result in harmful side effects. For example, ultraviolet light and medication, while they may control lesions and be used long term, they may also cause squamous cell carcinoma, the second most common form of skin cancer.

Additionally, some of the most effective anti-dandruff shampoos also have carcinogens in them with unknown long-term effects.

Researchers noted that one of the problems with using green tea as an alternative treatment is that the chemicals in green tea are so active that they are oxidized too quickly when mixed with other ingredients. They also dissolve in water, which cannot penetrate the skin's barrier.

Researchers are looking for a balanced formula that can dissolve in fats and permeate the skin.

The study authors concluded that while there are no cures for inflammatory skin diseases, it is possible that green tea may be a non-toxic way to regulate them. Further study in humans is needed to determine the full effects.

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References:

1) Ide R, Fujino Y, Hoshiyama Y, et al. A Prospective Study of Green Tea Consumption and Oral Cancer Incidence in Japan. Ann Epidemiol. 2007 Jun 30. View Abstract.

2) Hsu S, Dickinson D, Borke J, et al. Green tea polyphenol induces caspase 14 in epidermal keratinocytes via MAPK pathways and reduces psoriasiform lesions in the flaky skin mouse model. Exp Dermatol. 2007 Aug;16(8):678-84. View Abstract.

3) Natural Standard Research Collaboration: The Authority on Integrative Medicine. www.naturalstandard.com. Copyright © 2007.