... Drinking green tea will keep dementia at bay, scientists say
The Source: /http://www.theeastafrican.co.ke/hadhramaut.info - 17/01/2011
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A Ugandan born scientist’s research has led to an international breakthrough in the battle against dementia. Ugandan-born Dr Ed Okello, who came to Britain in 1983, led an international team study into the potential benefits of drinking green tea, in the belief that the brew could protect the brain against Alzheimer’s and other forms of dementia.
The drink, which originated in ancient China, may also play a vital role in guarding against cancer, the study which has received widespread international coverage, suggests.
Scientists at Newcastle University set out to discover whether the protective properties of the tea — previously shown to be present in the freshly brewed form — are still active once it has been digested
Lead researcher, Dr Okello, who is also a lecturer with Newcastle University’s School of Biology, said: “Although there is no cure for Alzheimer’s, tea could potentially be another weapon in the armoury which is used to treat this disease and slow down its development. It would be wonderful if our work could help improve the quality of life for millions of sufferers and their carers.”
Dr Okello, himself a green tea drinker, said the findings of the research suggested tea could boost the memory of everyday drinkers: “The ageing UK politician, Tony Benn, is a prime example of somebody who drinks tea and has a fantastic memory. He is said to drink 18 pints a day and has a very sharp mind for a man of his age,” he added.
Prof Clive Ballard, director of research, Alzheimer’s Society, said: “This interesting research builds on previous evidence that suggests that green tea may be beneficial due to anti-oxidant properties.”
The results of laboratory tests by the University team found that green and black tea inhibit the activity of certain enzymes in the brain which are associated with memory.
The findings may lead to the development of a new treatment for a form of dementia which affects an estimated 10 million people worldwide, Alzheimer’s disease.
At the start of their experiment, the research team investigated the properties of coffee and green and black tea in a series of scientific experiments.
Black tea – traditional English breakfast tea – is derived from the same plant as green tea, Camellia sinensis, but has a different taste and appearance because it is fermented.
They found that both green and black tea inhibited the activity of enzymes associated with the development of Alzheimer’s disease, but coffee had no significant effect.
Both teas inhibited the activity of the enzyme acetylcholinesterase (AChE), which breaks down the chemical messenger or neurotransmitter, acetylcholine. Alzheimer’s is characterised by a drop in acetylcholine.
Green tea and black tea also hinder the activity of the enzyme butyrylcholinesterase (BuChE), which has been discovered in protein deposits which are found on the brain of patients with Alzheimer’s.
Green tea went one step further in that it obstructed the activity of beta-secretase, which plays a role in the production of protein deposits in the brain which are associated with Alzheimer’s disease.
Scientists also found that it continued to have its inhibitive effect for a week, whereas black tea’s enzyme-inhibiting properties lasted for only one day.
There is no cure for Alzheimer’s but it is possible to slow the development of the disease.
Drugs currently on the market hinder the activity of AChE, and others are being developed which scientists hope will inhibit the activity of BuChE and beta-secretase.
However, many of the drugs currently available, such as donepezil, have unpleasant side effects and the medical profession is keen to find alternatives.
The Newcastle University researchers now aim to work towards the development of a medicinal tea which is specifically aimed at Alzheimer’s sufferers.
The next step is to find out exactly which components of green tea inhibit the activity of the enzymes AChE, BuChE and beta-secretase.
Digestion is a vital process which provides our bodies with the nutrients we need to survive.
But, says Dr Okello, it also means that just because the food we put into our mouths is generally accepted to contain health-boosting properties, we can’t assume these compounds will ever be absorbed by the body.
“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,” explains Dr Okello, based in the School of Agriculture, Food and Rural Development at Newcastle University and executive director of the university’s Medicinal Plant Research Group.
“In addition to this, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of the tumour cells which we were using in our experiments.”
As part of the research, the Newcastle team worked in collaboration with Dr Gordon McDougall of the Plant Products and Food Quality Group at the Scottish Crop Research Institute in Dundee, who developed technology which simulates the human digestive system.
It is this which made it possible for the team to analyse the protective properties of the products of digestion.
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