" Green tea 'cuts Alzheimer's risk'", BBC News, September 20, 2005,
Link: http://news.bbc.co.uk/1/hi/health/4261558.stm

An ingredient of green tea may help to protect the brain against the
ravages of Alzheimer's disease, research in the US suggests.

University of South Florida scientists found the component prevented
Alzheimer's-like damage in the brains of mice bred to develop symptoms.

The component - EGCG - is already strongly suspected of offering
protection against certain cancers.

The study is published in the Journal of Neuroscience.

It provides evidence that EGCG decreases production of the beta-amyloid
protein thought to play a key role in the development of Alzheimer's
symptoms.

It is this protein that forms the characteristic plaques found in the
brain of Alzheimer's patients which are thought to lead to nerve damage
and memory loss.

After treating Alzheimer's mice for several months with daily
injections of pure EGCG, the researchers observed a dramatic decrease -
as much as 54% - of brain-clogging Alzheimer's plaques.

Lead researcher Dr Jun Tan said: "The findings suggest that a
concentrated component of green tea can decrease brain beta-amyloid
plaque formation.

"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."

Green tea contains many antioxidants, including those known as
flavonoids, that can protect against damage to the brain caused by
charged particles called free radicals.

However, the Florida team showed that other flavonoids in green tea
actually block EGCG's ability to prevent the harmful build up of
beta-amyloid.

Thus drinking green tea alone would not likely have a beneficial
effect.

Supplements

Dr Doug Shytle, who also worked on the study, said: "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."

"A new generation of dietary supplements containing pure EGCG may lead
to the greatest benefit for treating Alzheimer's disease."

Humans would need a daily dose of 1,500 to 1,600 mg of EGCG to
approximate the level that had a positive impact on mice.

That dosage has already been studied in healthy human volunteers and
was found to be safe and well tolerated.

The Florida team now plans to study whether multiple oral doses of EGCG
can improve memory loss in Alzheimer's mice as well as reduce plaque
formation.

Harriet Millward, of the Alzheimer's Research Trust, told the BBC News
website: "This is quite encouraging progress, building on previous
evidence that antioxidants in green tea might be beneficial to
Alzheimer's patients either as treatment or prevention."

However, Dr Millward said the role of beta-amyloid in the brain was not
well understood, and reducing levels too far might cause damage.

It was also not clear whether the formation of plaques was a cause of
Alzheimer's, or just an effect of it.