Digestion strengthens green tea benefits

While the digestive process enables us to absorb and benefit from the nutrients contained in food, it can have varying effects on therapeutic plant compounds that have been shown to have specific benefits in vitro. However, research described in the journal Phytomedicine reveals that the neuroprotective properties of green tea are actually improved by digestion, meaning that its benefits could be greater than anticipated.

Research has demonstrated that polyphenols in green and black tea help protect brain cells by binding with hydrogen peroxide and amyloid beta, which are toxic compounds that are increased in the brains of Alzheimer's disease patients.These tea phytochemicals are broken down to produce a number of compounds during digestion. "It's one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements," explained lead researcher Dr Ed Okello of England's Newcastle University. "There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good."

Dr Okello's team collaborated with Dr Gordon McDougall of the Scottish Crop Research Institute in Dundee who developed technology that simulates human digestion. "What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer's development than the undigested form of the tea," Dr Okello remarked. "In addition to this, we also found the digested compounds had anticancer properties, significantly slowing down the growth of the tumor cells which we were using in our experiments."

In the experiments with cultured tumor cells, varying concentrations of the digested green tea compounds were administered and the effects were noted. "The digested chemicals protected the cells, preventing the toxins from destroying the cells," Dr Okello revealed. "We also saw them affecting the cancer cells, significantly slowing down their growth.

"Green tea has been used in Traditional Chinese medicine for centuries and what we have here provides the scientific evidence why it may be effective against some of the key diseases we face today," he stated. "There are obviously many factors which together have an influence on diseases such as cancer and dementia - a good diet, plenty of exercise and a healthy lifestyle are all important."

Green tea polyphenols protect and benefit skin

A report published online on April 27, 2011 in the Journal of Nutrition describes protective benefits for green tea polyphenols against ultraviolet light-induced skin damage, as well as an ability to improve elasticity, density and other skin properties.

Researchers at the University of Witten-Herdecke and Heinrich Heine University in Germany assigned 60 women with light to normal ultraviolet sensitivity to receive a green tea beverage containing 1,402 milligrams per liter total catechins or a control beverage daily for twelve weeks. Before the treatment period and at six and twelve weeks, participants received a dose of irradiation to the skin from a solar simulator. Reddening, elasticity, roughness, scaling, density and water homeostasis were evaluated at these time points and blood samples were analyzed for flavonoids and other variables.

Ultraviolet-induced reddening of the skin was reduced by 16 percent after six weeks and 25 percent at 12 weeks compared to pretreatment responses among those who received green tea, indicating increased photoprotection. Skin elasticity, density, hydration, blood flow and oxygen saturation increased in those who received green tea, while roughness, volume and scaling declined. A decrease in scaling and volume and an increase in hydration were also observed in the control group; however, the degree of improvement was significantly less than that experienced by women who received green tea.

"Our green tea catechin beverage data are in accordance with the literature reporting protective effects of various polyphenols against UV-induced photo oxidation, induction of inflammation, oxidative stress, and DNA damage from different stress sources in cell cultures and animals," the authors write. "The mechanisms underlying photoprotective effects of flavonoids in humans have not been elucidated; however, they are efficient antioxidants contributing to photoprotection in plants."

"We demonstrated that ingestion of green tea catechins improved skin hydration, transepidermal water loss, density, and elasticity," they observe. "These observed skin changes were probably an outcome associated with long-term consumption of green tea polyphenols and not likely a transitory response."

http://www.lef.org/newsletter/2011/0510_Green-Tea-Polyphenols-Protect-and-Benefit-Skin.htm?source=eNewsLetter2011Wk19-1&key=Article&l=0#article