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October 30, 2004 Newcastle upon Tyne -- Green tea, long lauded as favored substitute for coffee among the health conscience especially for its anti-oxidant capabilities, has risen a couple of notches in promoting better mental health as well. Coffee is believed to elevate cortisol to unhealthy levels which causes premature aging. The latest study out of England's University of Newcastle herald the merits of green tea in delaying the onset of Alzheimer's disease. The study has found that both green and black teas may inhibit certain brain enzymes linked to Alzheimer's disease. Black and green tea hail from the same plant. The difference between the two teas is that green tea is not fermented thus keeping its natural green color. Black tea, on the other hand, has been fermented, resulting in a change in taste and a dark appearance. Coffee, by contrast, did not show any significant effects upon Alzheimer's. The researchers discovered that both green and black tea inhibited the activity of the enzyme acetylcholinesterase (AChE), which breaks down the neurotransmitter, acetylcholine. Alzheimer's disease is characterized by a drop in acetylcholine. The teas also stopped the activity of other chemicals known to be key in making plaques and tangles in the brains of Alzheimer's patients. The second chemical is called butyrylcholinesterase (BuChE).
Green Tea Best
The study found that only green tea also obstructed the activity of beta-secretase, which plays a role in the production of protein deposits in the brain that are associated with Alzheimer's disease. The positive effects of green tea lasted for an entire week, while the enzyme-inhibiting properties of black tea only lasted for one day.
As Professor Clive Ballard, of Newcastle General Hospital and director of research at the Alzheimer’s Society, stated: "This interesting research builds on previous evidence that suggests that green tea may be beneficial due to anti-oxidant properties."
Source: Phytotherapy Research.
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