A Steaming Cup of Medicine
You have to imagine it –a steaming, fragrant cup of green tea. The clear, pale green liquid gives off a delicious aroma somewhat like wet hay mixed with the scent of apples or pears. You lift the cup to your lips and take the first sip. The comforting liquid rolls over your tongue and eases down your throat, brightening and warming as it goes. Its slight astringency freshens your mouth, making it feel naturally clean. This warm, delightful beverage is soothing, especially if you take a moment to sit and sip it slowly. But at the same time, it’s also stimulating, giving you a much needed pick-me-up in the morning or the middle of the long afternoon. Is it any wonder that tea has been enjoyed for nearly 5,000 years – and that it’s the world’s most widely consumed beverage, next to water?
Yet green tea is a lot more than just a delicious and satisfying drink -- it also has medicinal properties that are nothing short of amazing. Way back in the year 1211 the Japanese monk Eisai wrote that "Tea is a miraculous medicine for the maintenance of health. Tea has an extraordinary power to prolong life." And today, scientific are confirming that what Eisai said may be true, finding that green tea can boost the immune system, inhibit the cancer process at virtually every stage, regulate cholesterol levels, assist in weight loss, fight free radical damage, and ward off viruses, fungi and food-borne bacteria. It also helps inhibit dental plaque formation, lower the risk of type 2 diabetes, slow cognitive decline, and may even help increase the lifespan. Virtually no other substance on earth can claim such a wide range of health benefits!
I’m Nadine Taylor, a Registered Dietitian with a great interest in the healing power of foods. I have been so impressed by the science behind green tea’s health benefits that I started collecting green tea studies and information about ten years ago and eventually wrote a book about it. My aim in this column is to bring that knowledge to you, explaining how green performs its health-promoting "miracles," telling about the fascinating history and customs of tea drinking, and revealing some interesting new tea tidbits. (Did you know that green tea extract can grow hair?) My articles and question-and-answer column will appear monthly, and I hope you’ll join me. And don’t forget to bring along a nice hot cup of green tea!
What is Green Tea, Anyway?
Green, black, oolong, herbal – what’s the difference? Well, first of all the word "tea" is correctly used only when it refers to leaves taken from the Camellia sinensis bush. And that means that herbal teas really aren’t tea – only green, black and oolong tea are the "real thing." That said, the way the Camellia sinensis leaves are processed will determine which of these three choices the end product becomes.
To make black tea, the freshly picked tea leaves must be fermented. Fermenting occurs when an enzyme in the tea leaf called polyphenol oxidase combines with oxygen, so the leaves are left in the sun to wither and dry for 18-24 hours, then broken up to encourage further fermentation.. Then firing the leaves stops the fermentation and dries them. Making oolong tea is similar, although the withering and fermenting processes are shorter, resulting in a partially-fermented leaf. But to make green tea the leaf isn’t fermented at all – in fact, just the opposite! The tea leaves are steamed almost immediately after picking in order to stop the fermentation process, after which they are rolled and dried.
The health benefits of the resulting tea will largely be determined by whether or not the tea leaf has been fermented. The fresh tea leaf contains large amounts of catechins (pronounced "CAT-i-kins"), powerful disease fighters and potent antioxidants that give green tea its health-enhancing abilities. But when exposed to air and polyphenol oxidase, the catechins change into completely different compounds called theaflavins and thearubigens. The theaflavins and thearubigens, which give black tea its distinctive taste, aroma and dark color, do have some health benefits, but not the same wide-ranging antioxidant and disease-fighting prowess seen in the catechins.
So in green tea manufacturing, it’s extremely important to rush the freshly picked leaves from the field to the manufacturing plant, being careful not to break or bruise them. There, the leaves are steamed or pan-fired immediately to inactivate the polyphenol oxidase. Afterwards, it’s safe to roll, twist, dry and package the leaves without worrying about obliterating the catechins. Yet even after the manufacturing process has been completed, green tea catechins can be destroyed if exposed to oxygen for too long. That’s why you should always keep your green tea in an air-tight container, even if it’s already in tea bag form. Remember: oxygen is the catechins’ worst enemy.
How Much Green Tea Do You Need?
By now you know that green tea catechins can do great things for your health. But how much green tea do you need on a daily basis to experience the health benefits? Most studies have concluded that the "magic number" lies somewhere between 300 -1,000 mg. of catechins per day, or the equivalent of 3-10 cups of green tea. This recommendation is based on the idea that the average cup of green tea contains 100 mg. of catechins per cup. However, studies have shown that some cups of green tea contain only half that amount or even less.
The variation in catechin content is probably due to the fact that green tea leaves are a crop like any other. They can be young or old, fresh or stale, from rich or poor soil. And during harvesting, processing and packaging, the tea leaves can be exposed to different conditions that either preserve or destroy their nutrients. The way you handle, brew and store your green tea at home can also make a difference in the catechin content.
· Use purified water, as the chlorine in tap water degrades the catechins and destroys the subtle flavor of green tea.
· Avoid tea kettles made of metal alloys containing iron since iron lowers the antioxidant of activity of catechins.1 Kettles made of high-grade stainless steel, nickel-plated metal alloys, copper,polypropylene plastic, lead-free porcelain or glass are best.
· Bring the water to a full boil and add to the tea immediately. Steeping tea leaves at 212° F for five minutes releases approximately 80 percent of the catechins. In contrast, the catechin release is over one-third less when tea is steeped at 176° F.2
· Don’t put the tea leaves in water and then microwave them. This will "overcook" them and destroy some of the catechins.
· Keep your tea in an airtight container in the refrigerator, even if it comes in pre-packaged bags. This will keep the tea leaves fresher and help preserve the catechins.
Although it may sound a little complicated, making a health-enhancing, delicious cup of tea is really easy. As Senno Rikyu, the Greatest of all Tea Masters, said back in the 16th century: "Tea is nothing other than this: Heat the water, prepare the tea and drink it with propriety. That is all you need to know."
Footnotes:
1 Kumamoto M, Sonda T, Nagayama K, Tabata M. Effects of pH and metal ions on antioxidative activities of catechins. Biosci Biotechnol Biochem 2001:65:126-32.
2 Khokhar S, Magnusdottir SG. Total phenol, catechin, and caffeine contents of teas commonly consumed in the United Kingdom. J Agric Food Chem 2002; 50(3):565-70.
Green Tea and the FDA: Who's Right?
In June 2005, a green tea company called Ito En Ltd. asked the FDA for permission to put a claim on their labels that said drinking 5 ounces of green tea daily might reduce the risk of cardiovascular disease (CVD). To back up their claim, they submitted 105 studies, articles and other publications. Nearly a year later the FDA said no, insisting that, “There is no credible evidence to support qualified health claims for green tea or green tea extract and a reduction of a number of risk factors associated with CVD.”
Yet over the past 25 years, countless studies showing the positive effects of green tea on several important risk factors for cardiovascular disease have been published in scientific journals. So was the FDA wrong? Or was the green tea claim untrue? The answer is a resounding “neither.” The fault lay on both sides. Here’s why:
The petitioner’s claim was irresponsible
Ito En Ltd. wanted permission to say that drinking just 5 ounces of green tea daily could reduce several risk factors for cardiovascular disease. Yet most studies have shown that green tea reduces certain CVD risk factors with a daily intake of 4-5 cups, 1,2 and improves cholesterol at about 10 daily cups.3 One-half cup daily? That's a hard case to prove.
The FDA used an antiquated definition of CVD risk factors
The case got even harder to prove when the FDA narrowed the definition of a cardiovascular disease risk factor to high total cholesterol, high LDL cholesterol or high blood pressure. That meant that all studies showing that green tea helps fight oxidized LDL, obesity, stress, low HDL, diabetes or platelet stickiness simply didn’t count.
Many studies were ignored
The only studies the FDA deemed worthy of consideration were human studies – all animal and “test tube” studies were ignored. And not all kinds of human studies were included – review studies and meta analyses were considered background information only.
The evidence was winnowed down
Because of all of these restrictions, the FDA managed to reduce the 105 submitted studies, articles and papers to a grand total of only 11! And it was on the basis of these 11 studies that the FDA concluded that there was “no credible evidence to support qualified health claims” for green tea and a reduction in CVD risk.
Was the FDA wrong?
According to their current standards, no. However, the FDA desperately needs to acknowledge such well-documented and universally accepted CVD risk factors as increased LDL oxidation, excess body weight, low HDL, diabetes and increased platelet “stickiness” – all of which are positively influenced by green tea.
It would also help if future petitioners would consider recommending up to 10 cups of green tea per day (or the equivalent in green tea extract) instead of the ridiculously small amount of 5 ounces.
And, last but notleast, we need researchers to conduct more human studies on green tea’s effects on CVD. Then maybe next time we’ll have the ammunition we need to get the FDA’s much-wanted stamp of approval.
Footnotes:
1) Kuriyama S, Shimazu T, Ohmori K, et al. Green tea consumption and mortality due to cardiovascular disease, cancer and all causes in Japan: the Ohsaki study. JAMA 2006;296(10):1255-65.
2) Sasazuki S, Kodama H, Yoshimasu K, et al. Relation between green tea consumption and the severity of coronary atherosclerosis among Japanese men and women. Ann Epidemiol 2000;10(6):401-8.
3) Tokunaga S, White IR, Frost C, et al. Green tea consumption and serum lipids and lipoproteins in a population of healthy workers in Japan. Ann of Epidemiol 2002;12(3):157-65.
The Origins of Tea
For nearly 5,000 years people have been drinking and enjoying tea. But who discovered this delicious, health-promoting beverage? Credit typically goes to the Chinese Emperor Shen-Nung, also known as the "Divine Healer." According to legend, the Emperor was boiling a pot of water when some tea leaves blew in through the window and settled into the pot. Shen-Nung drank the resulting brew and the rest was history. The first written record of tea is found in Shen-Nung’s medical book the Pen Ts’ao, written in 2737 B.C., in which he noted that this remarkable beverage "quenches thirst. It lessens the desire for sleep. It gladdens and cheers the heart."
According to a different legend, tea was discovered by Dharma, the father of Zen Buddhism. In 520 A.D., so the legend goes, Dharma made the trek from India to China, where he demonstrated the Zen art of meditating by sitting in front of a wall for nine straight years. Not surprisingly, Dharma accidentally dozed off one day and when he woke up again he was so furious with himself that he vowed never to sleep again. To make good on this promise, he proceeded to cut off his eyelids! The bloody eyelids fell to the earth where they became the seeds of a tea plant from which a beverage could be made that lessened sleepiness.
Most likely, the true discovery of tea was made by the aboriginal natives living in what we now call Southeast Asia, where tea grows wild. The first historical record of tea was written in China in 350 A.D. by Kuo P’o, who was updating a Chinese dictionary. Kuo P’o added tea to the entries, describing it as "a beverage…made from the leaves by boiling." By this time, tea was prized as a medicine that could cure digestive disorders and nervous conditions. The tea leaves were also applied externally as a paste to ease the pains of rheumatism. But tea was not yet used as an everyday beverage.
As the desire for tea began to grow, a sufficient supply could not be collected just plucking the leaves off of nearby bushes. So tea plants began to be cultivated in the hills of Szechwan in central China, with the practice spreading throughout China and Japan courtesy of Buddhist priests. By the 5th century A.D., drinking tea for pleasure had become commonplace throughout China, and farmers typically dedicated a portion of their land to tea cultivation, while peasants often grew a few bushes in their gardens for private use. Thus, tea drinking became a part of daily life, even for the common people
Is Green Tea a Brain Food?
Can green tea prevent or ease Alzheimer's disease, that devastating disease that can rob you of your ability to learn, reason, communicate, remember and carry out daily activities? Well, no one's saying that yet. But recent studies of the effects of green tea's catechins on animal brains are intriguing:
* Delayed brain aging
A study of mice genetically programmed to age rapidly found that taking in green tea catechins on a daily basis prevented oxidative damage to the DNA in their brain cells, slowed memory loss and delayed brain aging.¹
* Reversed mental deterioration
Another study of rapidly-aging mice measured the extent of their brain degeneration over time.² Mice that received green or oolong tea as their sole source of drinking fluid for 16 weeks reduced degenerative changes to their brains and actually reversed their mental deterioration. (These mice actually got smarter!)
* Improved memory-related learning
Long term administration of green tea catechins to young rats lowered levels of damaging free radicals in a part of the brain that's vital to memory processing.³ The catechin-consuming rats also experienced improved memory-related learning ability, compared to those that didn't receive the catechins.
* Less buildup of plaque
Finally, mice specially bred to develop Alzheimer's disease developed up to 54% less beta-amyloid buildup in their brains when they were given daily injections of the green tea catechin EGCg.4 Beta-amyloid plaques are believed to be a major cause of the brain cell death and dissue loss seen in Alzheimer's disease.
Of course, the big question still looms: Does green tea have the same effects in humans as it does in mice and rats? While few human studies of green tea's effects on brain function exist, one published in 2006 in the American Journal of Clinical Nutrition offers hope.5 Researchers gathered information from 1,003 Japanese men and women age 70+, measured their cognitive function, and tallied the frequency of their green tea consumption. After analyzing the data, the researchers concluded that, A higher consumption of green tea is associated with a lower prevalence of cognitive impairmenmt in humans." In other words, the more green tea they drank the less likely they were to have problems related to thinking and memory.
Footnotes:
1) Unno K, Takabayashi F, Yoshida H, et al. Daily consumption of green tea catechin delays memory regression in aged mice. Biogerontology 2007;8(2):89-95. 2) Chan YC, Hosoda K, Tsai CJ, Yamamoto S, et al. Favorable effects of tea on reducing the cognitive deficits and brain morphological changes in senescence-accelerated mice. Journal of Nutritional Science and Vitaminology (Tokyo) 2006;52(4):266-73.
3) Haque AM, Hashimoto M, Katakura M, et al. Long-term administration of green tea catechins improves spatial cognition learning ability in rats. Journal of Nutrition 2006;136(4):1043-47.
4) Rezai-Zadeh K, Shytle D, Sun N, et al. Green tea epigallocatechin-3-gallate (EGCG) modulates amyloid precursor protein cleavage and reduces cerebral amyloidosis in Alzheimer transgenic mice. Journal of Neuroscience 2005;25(38):8807-14.
5) Kuriyama S, Hozawa A, Ohmori K, et al. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 1. American Journal of Clinical Nutrition 2006:83(2):355-61.
Green Tea & Chronic Fatigue
Chronic fatigue syndrome (CFS) is a disease that can make you so tired and depressed that you may not be able to get through your normal daily tasks. This constant feeling of exhaustion is long-term (lasting more than 6 months), and any physical or mental activity intensifies the fatigue. Unfortunately, getting lots of rest probably won't improve the symptoms.
Although the cause of CFS is unclear, some studies have shown that it could be partially due to oxidative stress (the excess production of free radicals in the body). Since green tea has powerful free radical-quenching abilities, a team of researchers in India decided to find out whether the tea might also have anti-CFS effects.
In order to do this, they induced fatigue in mice specially bred to develop CFS by forcing them to swim in a water filled glass cylinder for 6 minutes a day for 7 straight days.¹ As expected, the mice developed signs of oxidative stress: their lipid peroxidation levels went up, while their levels of glutathione (the body's most powerful antioxidant) went down.
As the days went by, the mice also began to take on an "immobile posture" earlier and earlier in each swimming session. When mice are forced to swim in a container and can't escape, they quickly adopt a sort of "frozen" posture, moving only as much as they must to keep their heads above water. This immobile posture is believed to be a sign of despair or depression - an indication that the animals have given up hope of escaping.
So what happened when the mice were given green tea extract or green tea catechins? Compared to the mice in the control group, their lipid peroxidation levels were lower, their glutathione levels were restopred, and their increased immobility time was reversed. In other words, green tea protected the mice against oxidative stress and depression/despair, both of which are linked to CFS. The researchers concluded that green tea extract and catechins "could be used as potential agents in the management of CFS..."
Footnote:
¹Singal A, Kaur S, Tirkey N, et al. Green tea extract and catechin ameliorate chronic fatigue-induced oxidative stress in mice. J Med Food 2005;8(10):47-52.
Bottled or Brewed
Have you ever wondered if bottled green tea has the same health benefits as freshly brewed green tea? Well, sorry to break the news to all of you bottled tea drinkers, but in most cases the answer appears to be no.
In December 2006, the U.S. Department of Agriculture made public its database of the flavonoid content of foods.¹ (Flavonoids, a type of polyphenol, are a group of compounds found primarily in fruits and vegetables which act as powerful antioxidants. Green tea’s catechins are a sub-group of the flavonoids.) The USDA list, which includes the levels of catechins found in green tea prepared in different ways, is a real eye-opener for those who drink bottled tea for health reasons!
For example, the level of EGCg (green tea’s most potent catechin) in brewed loose-leaf tea was 78 mg per 100 grams of infusion. But ready-to-drink green tea (the kind that comes in a can or a bottle) contained a minuscule 4 mg of EGCg, 95 percent less than that found in freshly brewed green tea. And instant green tea was even worse, with a practically nonexistent .5mg EGCg!
Similar studies measuring the health-promoting compounds in green tea were done in 2005 by researchers at Oregon State University.² They found that the polyphenol content and antioxidant activity in some bottled tea products were 10 to 100 times lower than those found in brewed tea!
Why does bottled (or canned) green tea have such low levels of catechins? A major reason is that the catechins are sensitive to heat and oxygen, making them easy to destroy during the processing, transporting and storing of bottled tea. Also, many bottled tea products are made from tea extracts, which have far fewer antioxidants to begin with than brewed tea. To make matters worse, bottled tea products are often loaded with sugar or high fructose corn syrup which, besides being unhealthy and unnecessary, can contribute to catechin breakdown.
If you still want to drink bottled green tea, be sure to look for a high quality product made from brewed tea that contains no added sweeteners and has the polyphenol or catechin content listed on the label. Your best bet is a product that contains at least 75 mg polyphenols or 50 mg EGCg per cup. If you can’t find one, how about just settling for a nice cup of hot green tea?
Footnotes:
¹ http://www.nal.usda.gov/fnic/foodcomp/Data/Flav/Flav02-1.pdf(Scroll to database pages 87-88)
² http://oregonstate.edu/dept/ncs/newsarch/2005/Oct05/teaprotection.htm
The Eyes Have It
The biggest natural threats to your eyesight are diseases that cause the degeneration of the retina, such as age-related macular degeneration and glaucoma. An important cause of retinal degeneration is oxidative stress (free radical damage). The good news is that recent studies have found that green tea, a potent antioxidant, may give the retina some much-needed protection.
Age-related macular degeneration, the leading cause of blindness in people over the age of 55, affects the part of your eye that allows you to see fine detail. It blurs the sharp, central vision you need for "straight-ahead" activities like reading, writing and driving. Glaucoma, the second leading cause of blindness, is actually a group of diseases that cause damage to the optic nerve.
Oxidative stress plays a part in both of these diseases. The retinal neurons, which send messages to the photoreceptor cells (rods and cones), become damaged by free radical generators like UV light and smoking. The free radicals attack the structure of your eye, wearing down its natural defense systems and leading to the death of cells in the retina. As a result, vision fades, sometimes to the point of being completely lost.
For a 2006 study published in Brain Research¹, researchers wanted to find out if green tea’s EGCg might be able to lessen oxidative stress to the retina and protect it from damage. They gave two groups of laboratory rats intraocular (within the eyeball) injections of sodium nitroprusside (SNP), a substance known to cause free radical damage to retinal tissue, impair the function of the rods and cones, and increase cell death. One group of rats also received injections of EGCg.
At the study’s end, the researchers discovered that the rats that received the EGCg had developed significantly fewer signs of retinal damage. Subsequent studies using other forms of oxidative stress and giving the rats green tea extract via their drinking water² or abdominal injections³ showed similar results.
Although we’re certainly not suggesting that you start injecting green tea into your eyeballs(!), we do think these are interesting pieces of evidence that demonstrate green tea’s formidable free radical-quenching abilities and potential for warding off disease.
Footnote:
¹Zhang B, Osborne NN. Oxidative-induced retinal degeneration is attenuated by epigallocatechin gallate. Brain Res 2006;1124(1):176-87. ²Zhang B, Rusciano D, Osborne NN. Orally administered epigallocatechin gallate attenuates retinal neuronal death in vivo and light-induced apoptosis in vitro. Brain Res 2008;1198:141-52.
³Peng PH, Ko ML, Chen CF. Epigallocatechin-3-gallate reduces retinal ischemia/reperfusion injury by attenuating neuronal nitric oxide synthase expression and activity. Exp Eye Res 2008;86(4):637-46.
Don't Fear the Reaper
Well, we’ve said it before and we’ll say it again: Drinking green tea is one of the best things you can do for your health! A study involving more than 40,000 people, published in the Journal of the American Medical Association, proves that point. It showed that green tea is linked to reduced mortality rates – in certain cases by as much as 62%!
In 1994, researchers for The Ohsaki National Health Insurance Cohort Study began following 40,530 Japanese adults age 40 to 79 for up to 11 years. They tracked the participants’ rate of mortality, cause of death and the amount of green tea they drank. The participants had no history of stroke, coronary heart disease or cancer at the beginning of the study, and lived in an area in northeastern Japan where 80% of the population drinks green tea.
At the study’s end, the researchers found sharp reductions in the risk of mortality in those who drank at least 5 daily cups of green tea, compared to those who drank less than one cup. Specifically, in men, the heavy green tea drinkers decreased their risk of death from stroke by 42 percent, from cardiovascular disease by 22 percent, and from all causes by 12 percent. But in women the results were even more impressive: Those drinking 5 or more cups of green tea per day decreased their risk of death from stroke by a whopping 62 percent, from cardiovascular disease by 31 percent, and from all causes by 23 percent.
So have another cup of green tea and increase your chances of living a long and healthy life!
Kuriyama S, Shimazu T, Ohmori K, et al. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. JAMA 2006,296(10):1255-65.
Brewing the Perfect Cup of Tea
Back in Article 2 we discussed ways of brewing green tea to get the maximum amount of catechins. But how about maximizing the delicious taste of green tea? Although brewing techniques that maximize the catechin content differ slightly from those that maximize taste, you can easily find a middle ground. Try following these simple rules to ensure that your green tea is both healthful and delicious every time.
1) Choose the proper water. The wrong kind of water can ruin a cup of tea, and transform the catechins into compounds typically found in black tea. (That's the reason green tea sometimes takes on a brownish color.) Try using soft water that contains few minerals or water filtered by reverse osmosis. Avoid water that is hard, distilled, flouridated or chlorinated.
2) Boil the water. Bring the water to a full boil, but not for more than a few seconds, as the water's flavor-releasing oxygen can escape and you can end up with a flat-tasting cup of tea. For the best tea flavor, let the water cool for a minute (to about 180-190° F), then pour it over the tea leaves. This guards against the "stewing" of the leaves. If you're looking for maximum catechin release, however, pour the boiling water over the leaves.
3) Warm the teapot - Before brewing the tea, swish a little bit of hot water around inside the tea receptacle, whether it's a teapot or a cup, to help your tea stay warm for a longer period of time.
4) Measure the tea - Figure one tea bag or 2-3 g. of loose tea per 8 oz. cup of water. Loose tea leaves can go directly into the cup or pot, but must be strained later. Tea bags are easier and less messy.
5) Steep the tea - For best taste, steep your green tea for just 2-3 minutes. But for the highest catechin content, steep it a minimum of 3 minutes - the longer the better. Be aware, however, that the longer you steep the tea, the more astringent the resulting brew.
6) Pour the tea - Remove the tea bags or strain the tea as soon as it has finished steeping. Otherwise it will continue to brew and may become too bitter. Then pour it (if you're using a pot) or simply raise the cup to your lips.
Now sit back, sip slowly and enjoy!
Tissue Preservation Without Freezing
We’ve all heard about cryopreservation – preserving living tissue by freezing it and storing it at super low temperatures. It works by stopping all biological activity, including the biochemical reactions that would normally lead to cell death. But the process is far from perfect. Cell injury or death can and does occur, especially during the initial freezing and warming stages. But now, thanks to green tea, there may be a much gentler approach.
A researcher at Kyoto University in Japan has demonstrated that several kinds of tissues can actually be preserved at room temperature when immersed in a solution containing green tea polyphenols.¹ He found that tissues such as blood vessels, cartilage, islet cells (the cells responsible for making insulin), and corneas can be preserved for several months at room temperature as long as they are immersed in this green tea solution.
Another study found that rat aortas preserved for a month in a solution containing green tea polyphenols kept their mechanical strength and were not rejected when transplanted.² A third study found that nerve segments stored in a polyphenol solution reduced transplant rejections in rats.³
Considering green tea’s potent antioxidant, anti-inflammatory and antibacterial properties, these results may not be too surprising. Today, green tea extract is widely used as a preservative in foods and cosmetics, is ten times more effective than vitamin E, and is 2.5 times more potent than vitamin C at preventing the spoilage of fats and oils.
Although scientists still aren’t sure exactly how green tea polyphenols preserve living tissue, the fact that it can do so without apparent side effects heralds an exciting new discovery in the field of tissue transplantation.
¹Hyon SH. A non-frozen living tissue bank for allotransplantation using green tea polyphenols. Yonsei Med J 2004;45(6):1025-34.)
²Hyon SH, Kim DH, Cui W, et al. Preservation of rat aortic tissue transplant with green tea polyphenols. Cell Transplant 2006;15(10):881-883.
³Ikeguchi R, Kakinoki R, Okamoto T, et al. Successful storage of peripheral nerve before transplantation using green tea polyphenol: an experimental study in rats. Exp Neurol 2003;184(2):688-96.
History of Tea: The Clipper Ships
Up until the early 1800’s, tea was imported from China and brought back to Europe and the United States on slow-moving frigates that took forever to make the trip (thus the expression “a slow boat to China”). But in 1841, a U.S. invention called the clipper ship radically changed the business of tea importation.
Clipper ships had a narrow, knife-like form and a concave bow that sliced through the water, cutting in half the time it took to make the trip. The ships quickly caught on in America and Europe, and soon even faster versions were created that could hold more than a million pounds of tea. Although sailing to and from China had once taken an entire year, on the clipper ship it took just four months! This was especially important in the spring. The first batch of tea grown in spring (called the spring flush) made the most delicious tea and brought the most money. But it had to be delivered before it lost its taste, so a swift sea voyage was a number one priority.
To provide an incentive to speed up the trip, the tea companies gave a handsome reward to the captain of the ship that arrived first with the new tea. The spring flush was plucked in April, processed and packed into the ships by the end of May, and then the race was on! The mighty clipper ship that arrived first was not only well-rewarded, but received a hero’s welcome from cheering throngs plus plenty of newspaper coverage when it sailed into the harbor.
The glorious era of the clipper ships ended abruptly with the opening of the Suez Canal in 1869. Suddenly, a steamer could make the trip to and from China in just 44 days, which meant even the fastest clipper ships were now completely obsolete. But the clipper ships, with their billowing sails and elegant form, remain a fascinating and glamorous part of the history of both sailing ships and tea.
Afternoon Tea
Legend has it that the creator of afternoon tea was one of Queen Victoria's ladies-in-waiting, Anna Maria Stanhope (1783-1857), also known as the Duchess of Bedford. In those days, the aristocracy was accustomed to eating a large breakfast, a very light lunch and a late supper. But the Duchess got hungry around four o’clock every afternoon and began to suffer from "a sinking feeling." To make herself feel better, she started snacking on sandwiches and a pot of tea in the latter part of the afternoon. Soon the Duchess began inviting friends to join her in the afternoon for tea, small cakes, bread and butter sandwiches and assorted sweets. This practice proved so popular that other social hostesses picked up on it and started inviting friends over to “take tea” with them in the afternoon. Thus a pleasant and diverting custom was born – one that is still very much alive and well in Britain.
Tea cuisine soon grew to include tiny, wafer-thin sandwiches, fish or liver patés, toast with jam, and scones (Scottish) or crumpets (English). Some people referred to afternoon tea as “low tea,” as it was served in the “low” (latter) part of the afternoon on low tables in the parlor. Low tea featured gourmet tidbits rather than solid meals.
“High tea,” on the other hand, which was also referred to as “meat tea,” was the main or high meal of the day and included dinner-like items such as roast beef, mashed potatoes, peas and – naturally – tea.
But no matter which kind of tea was taken – high or low - it quickly became and remains a beloved and much-anticipated part of the day in Britain and many of its former colonies.