Green Tea News

[Guest guest]

Green Light for Green Tea

By Colette Bouchez

HealthScoutNews Reporter

 

TUESDAY, April 16 (HealthScoutNews) -- If a group of Chinese

researchers are right, green tea may offer important protection

against Parkinson's disease (news - web sites) -- a

neurodegenerative disorder that made headlines when it was diagnosed

in both actor Michael J. Fox and boxing legend Muhammad Ali.

 

The new finding, reported today at the annual meeting of the

American Academy of Neurology (news - web sites) in Denver, explains

how ingredients plentiful in green tea can help the flow of a brain

chemical that's at the heart of this devastating disease.

 

" In our study, we demonstrate the inhibitory effects of green tea

polyphenols, " on mechanisms directly involved in Parkinson's

disease, says study author Dr. Tianhong Pan, a researcher from China

who was working at Baylor College of Medicine in Houston during the

study.

 

Pan says she and her colleagues in China began the animal study -- a

joint effort between the National Cancer Institute (news - web

sites) and the Chinese government -- because of the lower rates of

Parkinson's disease among populations where green tea is heavily

consumed.

 

" The prevalence of Parkinson's disease was lowest in Asia and

Africa, where green tea is commonly consumed, so it seems that there

is some relationship between green tea consumption and the

occurrence of [this disease], " Pan says.

 

For neurologist Dr. Souhel Najjar, this is the first research to

document the mechanism by which green tea can protect the brain.

 

" That mechanism involves the transport of the brain chemical

dopamine, which plays a key role in Parkinson's disease, " says

Najjar, a Parkinson's disease specialist.

 

Proving green tea can work on that transport system could be key to

learning how to prevent the disease, Najjar says, who adds it could

also open the door to new treatment strategies.

 

Pan agrees: " The results suggest that green tea may have potential

both in the treatment and protective effects in Parkinson's

disease. "

 

The mechanism explored in this study involved the transport of

dopamine from the area of the brain where it is made to a second

area where it is utilized, movement that is critical in Parkinson's

disease.

 

" Normally, dopamine is made an area of the brain called the

substantia nigra, and it travels a pathway to a second area of the

brain known as the striatum, " Najjar says. Sometimes, however, too

much of the dopamine flows back into the substantia nigra. That

leaves the striatum with less dopamine than it needs to function

properly.

 

Because dopamine helps muscles move smoothly and efficiently, when a

deficiency occurs, symptoms of Parkinson's develop -- including

muscle rigidity and tremors.

 

In the new study, however, researchers demonstrated that compounds

known as polyphenols can block the back flow of dopamine, so the

transport continues, unhampered, from one area of the brain to the

other.

 

" By keeping the transport of dopamine from being disrupted,

polyphenols might be able to reduce the risk of Parkinson's disease,

as well as reduce the progression of the disease in those already

affected, " Najjar says.

 

Although both doctors are optimistic, no one is certain the results

will apply to humans. Pan's group tested levels of dopamine in mice,

and then treated some with polyphenols while leaving others

untreated.

 

They then injured the specific neurons or brain cells linked to

Parkinson's disease in all of the mice, and measured dopamine levels

again.

 

The result: Those mice treated with polyphenols appeared to be

protected from the assault on brain cells. Pan reports polyphenols

were able to " inhibit the uptake of dopamine… by blocking the

dopamine transporter. "

 

" In this way, green tea may serve to protect against Parkinson's,

particularly in the face of toxic elements that may be linked to

this disease, " Najjar says.

 

However, can drinking green tea help people as much as it helps

mice?

 

" Although green tea polyphenols have numerous biological effects in

vitro, and epidemiological studies have shown some health benefits

in tea consumption, what is not clear at this time is whether

pharmacologically effective doses of green tea polyphenols can be

attained in blood or tissues simply by consuming tea infusions, " Pan

says.

 

Najjar says it's possible, but based on this study " there is not

enough evidence to make any kind of recommendation. "

 

In addition to green tea, polyphenols are found in black tea,

grapes, red wine, chocolate and other plant sources.