Green Tea Keeps Your Mind Humming

Choosing Green Tea = Choosing Good Health

Green Tea Keeps Your Mind Humming
Higher consumption of green tea is
associated with lower prevalence of cognitive impairment
By Will Block

Thank God for tea! What would the
world do without tea?—how did it exist?
I am glad I was not born before tea.
— Rev. Sydney Smith (1771–1845)

ot being born before tea has been easy for almost 5000 years, because that’s about how long ago tea was discovered—or invented, depending on which story you believe. Either way, the great event occurred in China. All things considered, it really was a great event, and not just because tea became, and remains to this day, the world’s most popular beverage other than plain old water. It was also because tea became what may well be the most beneficial substance ever discovered, in terms of the ubiquity and value of its use.

As the Rev. Smith surely knew, tea has been a great civilizing influence on humankind, acting not just as a delightfully soothing and refreshing beverage, but also as a social lubricant (of the nonintoxicating variety) in many cultures throughout history. It has also long been revered for its health-giving and illness-alleviating properties. But, although Smith had studied chemistry and medicine, he surely didn’t know how marvelous a beverage tea was in terms of its medicinal value. In fact, we don’t really know, because we’re still in the process of finding out. Much has been learned in recent years about the medicinal value of tea—green tea in particular—but much is surely still unknown.

How Can We Promote Healthy Aging?

One thing we have learned recently comes from a study constituting a part of the Tsurugaya Project, a community-based “comprehensive geriatric assessment” (CGA) conducted among elderly residents of the Tsurugaya residential district in the city of Sendai in northern Japan.1 A CGA is a systematic way of measuring the physical, mental, and social functioning and well-being of elderly people; its purposes are to promote healthy aging in the population in question and to assess early signs of deterioration that might result in the need for long-term care.

In this study, the researchers evaluated 1003 residents aged 70 or older, with primary emphasis on their cognitive function, which they measured by means of a standardized test called the Mini-Mental State Examination (MMSE). The volunteers also underwent physical examinations and gave medical histories, and they filled out a comprehensive questionnaire regarding their demographic characteristics (age, sex, education), social factors (visits with friends), lifestyle habits (smoking, alcohol, exercise), and physical health. Also included were questions about diet and supplements.

Of particular interest was the frequency of their consumption of certain beverages in five categories, namely: green tea; oolong or black tea;* coffee; cola or juice (an odd pairing, frankly); and 100% fresh vegetable juice. For the purposes of this aspect of the Tsurugaya Project, the volunteers were divided into three groups according to their frequency of green tea consumption: Group 1 drank 3 or fewer cups/week; Group 2 drank 4–6 cups/week, or 1 cup/day; and Group 3 drank 2 or more cups/day.


*There are four kinds of true tea, made from leaves of the tea tree, Camellia sinensis: green, oolong, black, and white. Green tea is made from unfermented leaves, oolong tea from partially fermented leaves, and black tea from fully fermented leaves. White tea, long known in Asia but only recently introduced in the West (and quite expensive), is made partly or wholly from leaf buds that have not yet fully opened and are still covered with a fine, silvery fuzz. Like green tea, it is unfermented.


By Consuming Green Tea . . .

The researchers then analyzed the data to see whether green tea consumption was significantly correlated with the prevalence of cognitive impairment, as measured by the MMSE. It was, and the correlation was negative, i.e., the greater the green tea consumption, the lower the prevalence of cognitive impairment. This was verified after correcting for the potential confounding effects of many other variables through what is called multivariate analysis.

Group 1 (minimal green tea consumption) served as the reference group. In comparison with this group, the probability of having any substantial degree of cognitive impairment (whether mild, moderate, or severe) was 38% lower in Group 2 and 54% lower in Group 3. A similar analysis for the category oolong or black tea showed a weak and inconclusive effect, and an analysis for coffee showed no effect. (No analyses were performed for the other two categories of beverage, because too few people consumed them to provide sufficient data.)

. . . And By Adopting a Healthy Lifestyle

These results suggest that green tea inhibits cognitive impairment, but they don’t prove it. It’s possible that the results were confounded by factors that could not be measured. Perhaps, e.g., more green tea is consumed by healthy, active people just because they’re healthy and active (especially if they visit frequently with their friends, because tea drinking is a common social activity in Japan). And because they’re healthy and active, their risk for cognitive impairment is reduced to begin with.


The evidence for a myriad of
health benefits of green tea is so
voluminous that it would be almost
crazy not to consume it.


It thus appears that, to cover our bases, we have two reasonable options: (1) consume green tea so as to be healthier, or (2) try to be the kind of healthy, active people who consume green tea so that we’ll be healthier even if we don’t consume green tea. Here’s a hint: bet on #1. The evidence (mostly from laboratory and animal experiments) for a myriad of health benefits of green tea is so voluminous that it would be almost crazy not to bet on #1, even though #2 obviously has much to recommend it (so take both options).

The Secret Is in the Catechins

Green tea’s remarkable medicinal value comes primarily from a class of polyphenolic compounds called catechins (CAT·eh·kins), of which the most potent—and, as good luck would have it, also the most prevalent—is epigallocatechin gallate, or EGCG.* In the oxidative fermentation process that transforms green tea into oolong tea or black tea, the catechins are mostly lost—transformed into other compounds called theaflavins and thearubigins. Although those compounds have health benefits of their own, they’re not as potent as the catechins. That’s why green tea is best in terms of health benefits, but oolong and black teas are also good. All teas, of course, have one sterling virtue on top of everything else: no calories.


*For more on this subject, see “Green Tea May Help Control Blood Sugar” (February 2003), “Green Tea May Help Keep Your Ticker Ticking” (March 2003), “Lose Weight with 5-HTP and EGCG” (April 2003), “Theanine May Help You Fight Off Disease” (July 2003), “Tea Extract Helps Reduce Cholesterol Levels” (December 2003), “Green Tea May Help Prevent Alzheimer’s” (January 2005), and “EGCG Can Help You Lose Weight” (December 2005).


More on Galantamine’s Benefit in Schizophrenia

Chemical manipulation of the human brain can have unexpected and disastrous consequences, as many a drug addict has found out—as well as many psychiatrists when they sought to treat mental disorders such as schizophrenia. A common approach in that disease is to use drugs that reduce dopamine levels in the brain. Although this can reduce or even eliminate many of the symptoms of schizophrenia, such as hallucinations and delusions, it can also produce some of the symptoms of Parkinson’s disease, such as tremors and impaired motor function.

Worse yet, it can cause tardive dyskinesia, a spectrum of bizarre, involuntary movements of the facial muscles (e.g., twitching, grimacing, lip-smacking, and tongue protrusion) and of the limbs. These disturbing actions are the result of the drugs’ chemical alteration of the brain’s dopamine receptors, and they are sometimes irreversible—a classic case of the best intentions gone horribly wrong.

Naturally, scientists keep searching for new antischizophrenic agents that are both effective and safe. One such agent is galantamine, a plant alkaloid known primarily for its efficacy—and safety—in treating mild cognitive impairment and Alzheimer’s disease. According to several recent reports, galantamine has shown remarkable ability to help some patients in whom other drugs had failed, when it was added to their existing drug regimens.*


*We reported on a few such cases in the galantamine articles in the September 2002 issue and in "Galantamine Rescues Damaged Brain Cells" in the March 2003 issue; see also “Galantamine May Help in Schizophrenia” in the October 2004 issue.


Galantamine is not only an acetylcholinesterase inhibitor, like most other anti-Alzheimer’s agents, but it is also (unlike those agents) a modulator of the brain’s nicotinic acetylcholine receptors, which play a crucial role in the transmission of neural signals involved in memory and learning, among other things. And unlike the antischizophrenic drugs that damage dopamine receptors, galantamine is known to preserve and protect the function of the nicotinic acetylcholine receptors—an extremely important aspect of its function.

Two new case histories of galantamine’s success in treating schizophrenics have been reported by psychiatrists in California.1 One case involved a 54-year-old white man (a heavy smoker) who exhibited disorganized behavior and thinking and who spoke very little. He had been noncompliant with his medication regime (olanzapine) for 4 months. His doctor restarted the olanzapine, then added galantamine (8 mg/day) 2 days later. Within 20 days, the patient’s behavior and outlook had improved markedly: his thoughts were more organized, and he could maintain a coherent conversation.

The other case involved a 47-year-old black man (a light smoker) with behavioral disturbances and prominent alogia (an inability to speak due to mental deficiency or an episode of dementia). He had been symptomatically stable on his drug regimen (olanzapine and divalproex) but was briefly hospitalized for uncontrollable behavior. The doctor added galantamine (10 mg/day) to his medications. In 12 days, this patient too showed marked improvement in his behavior, verbalizing his feelings and doing better on a test of mental function.

Two years later, this same patient was re-examined. He had dropped the galantamine but had remained on the other drugs, and his condition had become substantially worse. The doctor reintroduced galantamine (8 mg/day), and in 34 days the patient showed remarkable improvement in memory and delayed recall; unfortunately, however, his impairments in learning ability and speech fluency did not improve.

The reason why it’s important for a doctor to know the patient’s smoking status in mental disease is that nicotine is a potent stimulator of the nicotinic acetylcholine receptors (hence their name). In tiny amounts, this deadly poison (one drop can kill you) acts as a cognitive enhancer and can thus improve mental function. For that reason, most schizophrenics are heavy smokers. Galantamine accomplishes this too, but without the huge health liabilities associated with smoking.

Reference

  1. Ochoa ELM, Clark E. Galantamine may improve attention and speech in schizophrenia. Hum Psychopharmacol Clin Exp 2006;21:127-8.

What Do You Know?

Be glad you were not born before tea—because your birthday cake would have about 5000 candles on it, and even the fire department would have trouble putting them out. No one can guarantee that you’ll live for 5000 years if you start consuming green tea now, but your odds of living healthier, and perhaps a little longer, will probably improve if you do.

Drinking green tea is delightful, of course—billions of people throughout history can’t have been wrong about that—but there’s an easier way to get the optimal amounts of green tea catechins every day, and that’s through supplementation. The Rev. Smith might have mocked this idea, but what did he know?

Reference

  1. Kuriyama S, Hozawa A, Ohmori K, Shimazu T, Matsui T, Ebihara S, Awata S, Nagatomi R, Arai H, Tsuji I. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project. Am J Clin Nutr 2006;83:355-61.

The Wit of a Clergyman

Sydney Smith was a brilliant English clergyman, writer, and literary editor who drew standing-room-only crowds for his entertaining sermons and his lectures on moral philosophy at the Royal Institution. Despite his great erudition—or perhaps because of it—he shunned ivory tower idealism in favor of a strong and practical worldview, and his fearlessly outspoken manner (including a loathing of taxes) appealed greatly to the public.

In addition to his many scholarly activities, he served for some years both as magistrate and doctor in a town in Yorkshire. For a man of such great talent, he never rose high in the church hierarchy, because he discomfited too many of his superiors with his caustic wit—a trait for which he has been compared with Swift and Voltaire. His bishop probably didn’t appreciate remarks such as, “What bishops like best in their clergy is a dropping-down-deadness of manner.” Here’s a further small sample of his wit and wisdom:

  • Macaulay has occasional flashes of silence that make his conversation perfectly delightful.
  • What you don’t know would make a great book.
  • What would you attempt to do if you knew you would not fail?
  • Daniel Webster struck me much like a steam-engine in trousers.
  • I look upon Switzerland as an inferior sort of Scotland.
  • I never read a book before reviewing it; it prejudices a man so.
  • He not only overflowed with learning, but stood in the slop.
  • Obstacles are those frightful things you see when you take your eyes off your goals.
  • I am going to pray for you at St. Paul’s, but with no very lively hope of success.

The Rev. Smith is also credited, by the way, with having hatched a concept we’re all too familiar with: trying to fit a square peg in a round hole. For a clergyman, he was certainly no square.

And what does all this have to do with green tea? Nothing—just thought you’d enjoy it.


Will Block is the publisher and editorial director of Life Enhancement magazine.

FREE Subscription

  • You're just getting started! We have published thousands of scientific health articles. Stay updated and maintain your health.

    It's free to your e-mail inbox and you can unsubscribe at any time.
    Loading Indicator