Green tea anti-oxidant (EGCG) fights Alzheimer's

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A new study shows EGCG in green tea significantly reduced Alzheimer's

disease in mice.

Link and full text:

http://my.webmd.com/content/article/112/110306

Antioxidant in Green Tea May Fight Alzheimer's

Ingredient May Prevent Buildup of Plaque in Brain Linked to

Alzheimer's Disease

By Warner

WebMD Medical News Reviewed By Brunilda Nazario, MD

on Tuesday, September 20, 2005

Sept. 20, 2005 -- An antioxidant found in green tea may protect the

brain and fight the memory-robbing effects seen with plaque deposits

in Alzheimer's disease.

A new study shows high doses of the green tea ingredient -- known as

epigallocatechin-3-gallate (EGCG) -- significantly reduced the

formation of beta-amyloid proteins in the brains of mice that were

altered to develop Alzheimer's disease. An abnormal buildup of

beta-amyloid plaque in the brain is implicated in the nerve damage and

memory loss seen in Alzheimer's disease.

EGCG is one of a group of antioxidants called flavonoids found in

plants. They have been linked to a variety of health benefits seen in

diets rich in fruits and vegetables, such as protecting against cancer

or reducing the risk of heart disease.

Antioxidant May Protect Brain

In the study, published in the Journal of Neuroscience, researchers

studied the effects of treating mice genetically altered to develop

Alzheimer's disease with high doses of the green tea antioxidant.

After several months of daily injections of EGCG, the results showed

that the nerve cells of treated mice generated as much as 54% fewer

beta-amyloid protein than nontreated mice nerve cells.

" The findings suggest that a concentrated component of green tea can

decrease brain beta-amyloid plaque formation, " says researcher Jun

Tan, PhD, MD, director of the Neuroimmunology Laboratory at the

University of South Florida, in a news release. " If beta-amyloid

pathology in this Alzheimer's mouse model is representative of

Alzheimer's disease pathology in humans, EGCG dietary supplementation

may be effective in preventing and treating the disease. "

Drinking Green Tea Not Enough

Green tea contains many different antioxidants. The researchers found

other green tea antioxidants actually decreased EGCG's ability to

reduce beta-amyloid protein production. Therefore, drinking green tea

alone may not be enough to fight Alzheimer's disease.

" This finding suggests that green tea extract selectively

concentrating EGCG would be needed to override the counteractive

effect of other flavonoids found in green tea, " says researcher Doug

Shytle, PhD, of the University of South Florida, in the release.

Researchers say the dose of the green tea antioxidant humans would

need to replicate the dose given the mice would be about 1,500 to

1,600 milligrams daily. That dose has already been studied in humans

and found to be safe.

If further studies show treatment with EGCG can reduce memory loss in

mice with Alzheimer's disease as well as reduce plaque formation,

researchers say the next step would be clinical trials of the green

tea antioxidant in humans to prevent and treat Alzheimer's disease.

SOURCES: Rezai-Zadeh, K. Journal of Neuroscience, Sept. 21, 2005; vol

25. News release, University of South Florida Health.