Drink Green Tea to Keep that Belly in Line

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Drink Tea to Keep that Belly in Line

In men and women, the degree of body fat, whether expressed as percent body fat or the ratio of waist circumference to hip circumference, tends to decrease as green tea intake increases.22 Green tea contributes to the maintenance of healthy body weight in several ways.

One of the least appreciated properties of green tea is its ability to limit the absorption of the fat taken in from the diet. Green tea catechins (especially EGCG) interfere with the lipase (fat-digesting) enzymes in the stomach and small intestine. The resulting incomplete digestion of fats produces some lipid droplets that are not able to enter intestinal cells and that therefore remain unabsorbed. These effects have produced significant decreases in the absorption of dietary fats by rats consuming green tea. While it is not known how effective green tea is in blocking fat absorption in humans, any interference with the normally highly efficient digestion and absorption of dietary fats could figure prominently in any effort to manage weight effectively.

In addition to decreasing the efficiency of absorption of fatty acids from the diet, green tea catechins interfere with the production of fat for storage in adipose tissue depots. Green tea leaf extract rich in EGCG, as well as purified EGCG itself, reduces the activity of fatty acid synthase, the enzyme that controls how rapidly the body produces fat for storage. This effect is consistent with a body of literature reviewed recently in the journal Molecular Nutrition and Food Research that shows how EGCG inhibits new fat formation (“lipogenesis”) and fat storage within adipocytes.23 Tea helps to absorb less fat from the diet and can directly interfere with the storage of fat in adipocytes, a dual mechanism for supporting healthy body weight.

The dominant green tea catechin, EGCG, also entices the body to shift some of its manner of producing energy from glucoseburning to fat-burning. There are two ways to accomplish this and EGCG seems to do both. First, if the amount of glucose available to tissues, especially the skeletal muscles, is reduced, then more fat must be metabolized to carbon dioxide and water in order to satisfy energy needs. During times when glucose is in short supply, the liver synthesizes glucose from a variety of precursors, including amino acids released by muscle cells. The first enzyme in this synthetic (“gluconeogenic”) pathway, phosphoenolpyruvate carboxykinase (PEPCK), is inhibited by EGCG. Blocking this enzyme reduces the rate of formation of new glucose, requiring cells to switch to burning fat for energy.

In an example of exquisite biochemical coordination, EGCG also stimulates the conversion of fatty acids to energy. In cell culture studies, EGCG has increased the rate of utilization of fatty acid breakdown products instead of glucose to produce energy. In a series of experiments, mice, often studied because the way they obtain energy is pretty much the same as the way humans do, have responded to the addition of catechin-rich green tea extract to a high-fat diet with less weight gain and less fat accumulation within their bodies than mice fed the same high-fat diet but not fed catechins, despite eating just as much. This phenomenon has been studied in depth. In a recent study dietary supplementation of exercising mice with tea catechins forced skeletal muscles to switch from using their glycogen reserves as energy sources to increasing their reliance on burning fats from adipose depots.24 This “switch” is so reproducible that the researchers can predict when it will happen. The powerful phytonutrients (catechins) in green tea and green tea extract can recruit muscles to help stored fat get used up faster!

In humans, such a shift from glucose-burning to fat-burning will be seen as an increase in heat production (or thermogenesis). In a convincing demonstration of the fat-burning, thermogenic effects of green tea catechins, 24-hour heat production was measured in healthy lean to overweight young men during days in which they remained essentially at rest and consumed identical diets, no caffeine-containing foods or beverages, and either a placebo, 150 mg of caffeine alone or 150 mg of caffeine plus 270 mg of EGCG and 105 mg of other mixed catechins.25 These investigators observed that the consumption of placebo or 150 mg of supplemental caffeine alone during a 12-hour period failed to affect the utilization of fat or glucose to supply energy. In contrast, the consumption of green tea catechins during a 12-hour period increased same-day 24-hour total energy expenditure and heat production. This increase in energy usage was caused by increased fat-burning and decreased use of glucose for fuel.

Because under the conditions of this experiment all energy expenditure was essentially “resting” energy expenditure, the catechin-induced increase in resting energy expenditure reflects enhanced thermogenesis. That is, more heat production as a “byproduct” of energy production. Since increased heat production to satisfy the same energy demand means that the efficiency of energy production decreased, more stored energy needed to be “burned” – accelerating the rate at which energy stored in fat depots would become depleted. Of course, as stored fat becomes depleted, both body weight and fat depot size decrease.

The increase in fat utilization in this experiment, which was minimized by keeping the subjects in a “resting” state, could result in the loss of one pound of excess body weight in 1 to 2 months and a loss of 6 to 12 pounds in a year. Consistent with this rough prediction, overweight adults consuming 270 mg of EGCG daily for 3 months experienced an average loss of 4.6% of total body weight, with an average decrease in waist circumference of 4.5%.26 This thermogenic effect of green tea catechins, when combined with a healthy diet and exercise, could be extremely beneficial for those looking to support weight management efforts.

Beneficial results also were obtained in a “gold standard,” randomized placebo-controlled clinical trial, published recently in the American Journal of Clinical Nutrition.27 In this study healthy men supplemented their diets with either 22 mg or 690 mg of total catechins daily for 12 weeks. At the end of the experiment, the men who were consuming 690 mg of total catechins daily had lost more weight, more inches off their waist, more total body fat and more abdominal fat.

What about Stress and Abdominal Fat?

A growing body of evidence indicates that in both men and women, stress and mood issues are associated with increased abdominal fat storage and a larger waistline. How is stress and belly fat connected?

Stress can increase the secretion of a hormone called cortisol. This hormone increases the rate of fat accumulation by abdominal fat cells. Even among healthy individuals, repeated episodes of stress-related cortisol secretion is implicated in increased abdominal fat.28

What Can Green Tea Do About It?

Green tea contains an unusual amino acid – L-theanine. This amino acid comprises up to 2.5% of the total dry weight of unfermented green tea leaves, is absorbed efficiently and can enter the brain from the blood. Within the brain, L-theanine exerts relaxing physiologic effects. In so doing, L-theanine may act to reduce perceptions of stress with possible beneficial effects on abdominal fat formation. For example, mice fed L-theanine have gained less weight and accumulated less abdominal fat.29,30 By supporting the body’s stress response, green tea and green tea extracts containing L-theanine can make important contributions to healthy weight maintenance.

Next Best Kept Secrets to Healthy Aging topic:
Tea Helps Keep Healthy Kidneys Healthy

References:
22. Wu CH, Lu FH, Chang CS, Chang TC, Wang RH, Chang CJ. Relationship among habitual tea consumption, percent body fat, and body fat distribution. Obes Res 2003;11:1088-1095.
23. Wolfram S, Wang Y, Thielecke F. Anti-obesity effects of green tea: From bedside to bench. Mol Nutr Food Res 2006;50:176-187.
24. Murase T, Haramizu S, Shimotoyodome A, Tokimitsu I, Hase T. Green tea extract improves running endurance in mice by stimulating lipid utilization during exercise. Am J Physiol Regul Integr Comp Physiol 2006;290:R1550-R1556.
25. Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P, Vandermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999;70:1040-1045.
26. Chantre P, Lairon D. Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity. Phytomedicine 2002;9:3-8.
27. Nagao T, Komine Y, Soga S, Meguro S, Hase T, Tanaka Y, Tokimitsu I. Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men. Am J Clin Nutr 2005;81:122-129.
28. Rosmond R, Dallman MF, Bjorntorp P. Stress-related cortisol secretion in men: Relationships with abdominal obesity and endocrine, metabolic and hemodynamic abnormalities. J Clin Endocrinol Metab 1998;83:1853-1859.
29. Juneja LR, Chu D-C, Okubo T, Nagato Y, Yokogoshi H. L-theanine, a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Technol 1999;10:199-204.
30. Zheng G, Sayama K, Okubo T, Juneja LR, Oguni I. Anti-obesity effects of three major components of green tea, catechins, caffeine and theanine, in mice. In Vivo 2004;18:55-62.

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A Healthy Skeleton Benefits from Green Tea

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
A Healthy Skeleton Benefits from Tea

Several decades ago, several scary articles received a great deal of publicity.16,17 These articles attempted to show that drinking beverages containing caffeine somehow could weaken a woman’s bones. — Wrong! — The real story: three more recent studies proved that the earlier articles had shown that women who drank even large amounts of beverages containing caffeine experienced reductions in bone density only if they also were deficient in calcium or vitamin D!18-20 In fact, research shows that caffeine intake has no effect on bones in anyone at any age.19,20

Drinking at least 2 cups of phytonutrient-packed black or green tea every day enhances bone health and strength. This was shown most powerfully in the 91,465 postmenopausal women who participated in the U.S. government’s Women’s Health Initiative study.21 The results of this study, published in the American Journal of Epidemiology make it quite clear that instead of avoiding tea, women who drink at least 2 cups of tea every day can enjoy optimized bone mass throughout their bodies, and especially in parts of the vertebral spine.

Next Best Kept Secrets to Healthy Aging topic:
Drink Tea to Keep that Belly in Line

References:
16. Ilich JZ, Brownbill RA, Tamborini L, Crncevic-Orlic Z. To drink or not to drink: How are alcohol, caffeine and past smoking related to bone mineral density in elderly women? J Am Coll Nutr 2002;21:536-544.
17. Kiel DP, Felson DT, Hannan MT, Anderson JJ, Wilson PW. Caffeine and the risk of hip fracture: The Framingham Study. Am J Epidemiol 1990;132:675-684.
18. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700.
19. Lloyd T, Rollings NJ, Kieselhorst K, Eggli DF, Mauger E. Dietary caffeine intake is not correlated with adolescent bone gain. J Am Coll Nutr 1998;17:454-457.
20. Lloyd T, Johnson-Rollings N, Eggli DF, Kieselhorst K, Mauger EA, Cusatis DC. Bone status among postmenopausal women with different habitual caffeine intakes: A longitudinal investigation. J Am Coll Nutr 2000;19:256-261.
21. Chen Z, Pettinger MB, Ritenbaugh C, LaCroix AZ, Robbins J, Caan BJ, Barad DH, Hakim IA. Habitual tea consumption and risk of osteoporosis: A prospective study in the Women’s Health Initiative Observational Cohort. Am J Epidemiol 2003;158:772-781.

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Green Tea Helps Keep Your Blood Flowing

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Tea Helps Keep Your Blood Flowing

There is some scientific evidence that drinking tea helps to maintain healthy blood vessel function and the delivery of oxygenated blood to the heart to keep tissues healthy. Regular tea consumption also has been reported to help blood vessels respond properly to vasodilating stimuli – in other words, the vessels expand to allow more blood to pass when more oxygenated blood is needed, especially to the heart muscle. Tea maintains circulatory function through the heart and to the peripheral tissues and organs.

The catechins in green tea not only help blood vessels respond properly to stimuli, they also help protect the interior lining of blood vessels from invasion by over-stimulated smooth muscle cells (blood vessels that can expand and contract are surrounded by smooth muscle cells that control the vessels’ diameter). Catechins can thus support the pliability of vessel tissue, keeping vessels healthy and keeping them functioning as they are intended. The results of a study published recently in Cardiovascular Research have shown that the catechins in green tea extract prevent the secretion of enzymes by over-stimulated vascular smooth muscle cells, supporting the integrity of the lining of blood vessels and ensuring they remain healthy and undamaged, maintaining their normal structure and function. This modulatory effect of green tea catechins on blood vessel health leads to their ability to healthfully support cardiovascular function.15

Next Best Kept Secrets to Healthy Aging topic:
A Healthy Skeleton Benefits from Tea

References:
15. El Bedoui J, Oak MH, Anglard P, Schini-Kerth VB. Catechins prevent vascular smooth muscle cell invasion by inhibiting MT1-MMP activity and MMP-2 expression. Cardiovasc Res 2005;67:317-325.

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Green Tea Helps Keep Your Heart Healthy

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Tea Helps Keep Your Heart Healthy

Tea, especially green tea, is great for the heart. It helps keep arteries healthy, the heart pumping strong and protects cholesterol and lipids from free radical damage.

Scientists have found that tea is heart protective and the incidence of heart-related events is inversely proportional to the consumption of green tea.11 In other words, the more green tea (or green tea catechins) you consume, the better your chances of staying heart-healthy longer.

More evidence of green tea’s heart prowess comes from additional research. In one 25-year long study of the same group of elderly men in Europe, the habitual daily consumption of at least 86 mg of total catechins (equivalent to one-half cup of green tea) was found to double the chances of having optimal cardiac function with age.12 Investigators who pooled the results of previous studies worldwide calculated that every cup of black or green tea consumed on a regular daily basis reduced the risk of heart-related events by about 4%.13 They explained that they found a weaker effect in the overall results because in the U.S. few men drink tea. Nonetheless, these reports are consistent in concluding that healthy hearts are more common among tea drinkers.

Due to the antioxidant benefits among tea drinkers, cardiac protection is increased. The catechins in green tea may directly contribute to healthy heart function by scavenging various free radical species that could be detrimental to heart tissue. Studies show again and again that those individuals consuming tea are more likely to have stronger hearts than those who consume less or none at all. For example, a study performed through Harvard University examining about 1900 men and illustrates this point well.14 Among these men and women, those who drank one or two cups on a routine daily basis lived on average 28% longer and those who drank an average of more than two cups daily lived about 44% longer.

While it is not clear exactly what attribute of tea improved the survival and longevity of these study subjects, and a number of theories have been suggested, including the benefits of an increased antioxidant status among tea drinkers, it is clear that the benefits to the heart of tea and catechin consumption cannot be denied.

Next Best Kept Secrets to Healthy Aging topic:
Tea Helps Keep Your Blood Flowing

References:
11. Sano J, Inami S, Seimiya K, Ohba T, Sakai S, Takano T, Mizuno K. Effects of green tea intake on the development of coronary artery disease. Circ J 2004;68:665-670.
12. Arts IC, Hollman PC, Feskens EJ, Bueno de Mesquita HB, Kromhout D. Catechin intake might explain the inverse relation between tea consumption and ischemic heart disease: The Zutphen Elderly Study. Am J Clin Nutr 2001;74:227-232.
13. Peters U, Poole C, Arab L. Does tea affect cardiovascular disease? A meta-analysis. Am J Epidemiol 2001;154:495-503.
14. Mukamal KJ, Maclure M, Muller JE, Sherwood JB, Mittleman MA. Tea consumption and mortality after acute myocardial infarction. Circulation 2002;105:2476-2481.

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Healthy Blood Pressure with Green Tea

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Healthy Blood Pressure with Tea!

Some people and many uninformed physicians still wrongly think that caffeine intake somehow increases blood pressure. Even the U.S. Food and Drug Administration has ruled that habitual consumption of caffeine-containing foods and beverages is unrelated to blood pressure.7 The final word should have been had by the scientists who reported recently in the Journal of the American Medical Association that when they studied 155,594 adult women in the United States, there was no connection between caffeine consumption and blood pressure.8 There is no reason to fear that tea will affect this parameter of health.

Quite to the contrary – as demonstrated by a study from China.9 Scientists found that the regular daily consumption of even only one cup of tea enhanced the ability to maintain blood pressure levels that are normal by 80%. The results of another study support this rather astonishing finding.10 Tea consumption benefits the arteries and contributes to healthy blood pressure maintenance.

Next Best Kept Secrets to Healthy Aging topic:

Tea Helps Keep Your Heart Healthy

References:
7. Food and Drug Administration. Department of Health and Human Services. Final Rule Declaring Dietary Supplements Containing Ephedrine Alkaloids Adulterated Because They Present an Unreasonable Risk; Final Rule. Fed Reg 2004;69:6787-6854.
8. Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA 2005;294:2330-2335.
9. Yang YC, Lu FH, Wu JS, Wu CH, Chang CJ. The protective effect of habitual tea consumption on hypertension. Arch Intern Med 2004;164:1534-1540.
10. Hodgson JM, Devine A, Puddey IB, Chan SY, Beilin LJ, Prince RL. Tea intake is inversely related to blood pressure in older women. J Nutr 2003;133:2883-2886.

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How Do the Phytonutrients in Green Tea Benefit Health?

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
How Do the Phytonutrients in Tea Benefit Health?

In general, the catechins act throughout the body as very efficient antioxidants. The ability of these beneficial phytonutrients to detoxify free radicals and other harmful chemicals has been demonstrated beyond any doubt. In fact, the results of a study published recently in the Journal of Agricultural and Food Chemistry proved that the greater the catechin content of a dietary supplement, the greater its antioxidant capacity (measured in units of its “oxygen radical absorbance capacity” or “ORAC value”, which is a standard measure of in vitro antioxidant capacity).2

Other research has shown that the catechins and the theaflavins all possess about the same capacity to act as antioxidants.3 However, the total catechin content of green tea is about 2 to 3 times the total catechin plus theaflavin content of black tea (because some of the catechins are destroyed during the fermentation process). Therefore, when consumed in equal amounts, green tea should be 2 to 3 times more effective than black tea as an antioxidant (though black tea has unique benefits all its own). This has been confirmed in experiments on hamsters that were fed diets containing very high levels of cholesterol – adding green tea to the diet of these hamsters was about twice as effective in preventing the oxidation of the cholesterol in their blood as was adding black tea.4 Furthermore, men and women who smoke cigarettes typically exhibit a vastly accelerated rate of oxidative damage to the DNA in their bodies; when they drink 4 cups of green tea daily, they experience a large decrease in DNA free radical damage.5,6

Next Best Kept Secrets to Healthy Aging topic:
Healthy Blood Pressure with Tea

References:
2. Seeram NP, Henning SM, Niu Y, Lee R, Scheuller HS, Heber D. Catechin and caffeine content of green tea dietary supplements and correlation with antioxidant capacity. J Agric Food Chem 2006;54:1599-1603.
3. Leung LK, Su Y, Chen R, Zhang Z, Huang Y, Chen ZY. Theaflavins in black tea and catechins in green tea are equally effective antioxidants. J Nutr 2001;131:2248-2251.
4. Vinson JA, Dabbagh YA. Effect of green and black tea supplementation on lipids, lipid oxidation and fibrinogen in the hamster: Mechanisms for the epidemiological benefits of tea drinking. FEBS Lett 1998;433:44-46.
5. Hakim IA, Harris RB, Brown S, Chow HH, Wiseman S, Agarwal S, Talbot W. Effect of increased tea consumption on oxidative DNA damage among smokers: A randomized controlled study. J Nutr 2003;133:3303S-3309S.
6. Hakim IA, Harris RB, Chow HH, Dean M, Brown S, Ali IU. Effect of a 4-month tea intervention on oxidative DNA damage among heavy smokers: Role of glutathione S-transferase genotypes. Cancer Epidemiol Biomarkers Prev 2004;13:242-249.

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Does the Source of Green Tea Matter?

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Does the Source of the Tea Matter?

The exact amounts of the catechins and theaflavins that are present in any sample of tea, (green, black or oolong) depends on where the leaves are grown and just how the leaves are processed prior to drying. Of course, factors such as the soil the tea is grown in can influence the content of polyphenols. In addition, whether the tea is decaffeinated, blended or freeze-dried (“instant”) and the specifics of its preparation (how much tea is used per cup or glass, how long the tea is left to steep, brew or dissolve, and at what temperature) all affect the resulting beverage’s phytonutrient content. The process of decaffeination removes some of the phytonutrients along with the caffeine (an unavoidable consequence of the chemistry of decaffeination).

Brewed hot tea contains the largest amount of phytonutrients, “instant” teas have lost about 80% of their phytonutrients and “iced” and other ready-to-drink tea products contain even less. Diluting tea with milk, water or ice obviously reduces the amount of phytonutrients contained in each cup or glass. Interestingly, recent studies have found that taking tea with milk may reduce its ability to enhance blood circulation and hinder some of its antioxidant benefits. It’s also important to realize that so-called “herbal teas” really are not “teas” but are boiled decoctions of the herbs used to make them – and they contain none of the beneficial tea catechins or theaflavins, although they certainly do contain beneficial compounds present in the particular herbs.

Tea as a Dietary Supplement

Why is all this important to you? It is important for you to remember that even though drinking tea is an extremely healthy practice, hot or cold teas prepared from either loose dried leaves, powdered leaves or “bags” are less reliable sources of tea phytonutrients than are the standardized powders used in the highest-quality dietary supplements. Standardized extracts control for the level of collective and individual tea polyphenols, and research shows that in order to receive optimal benefits from tea intake, an optimal amount of polyphenols needs to be consumed on a daily basis. This could mean drinking cups and cups of tea per day. In addition, the catechins in high-quality standardized powders are absorbed about twice as readily as they are from teas.1

Of course, when it comes to drinking tea, sometimes enough can be enough! And some days you’d just rather drink something else. Not to worry – combining tea (or even replacing tea as a beverage) with a top-of-the-line dietary supplement high in catechin content is the perfect answer. Make sure to look for products that contain the multiple polyphenols present in tea as each polyphenol has unique benefits and together they create synergistic effects.

Next Best Kept Secrets to Healthy Aging topic:
How Do the Phytonutrients in Tea Benefit Health?

References:
1. Henning SM, Niu Y, Lee NH, Thames GD, Minutti RR, Wang H, Go VL, Heber D. Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement. Am J Clin Nutr 2004;80:1558-1564.

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Green Tea: Drinking Your Way to Health and Longevity

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Green Tea – Drinking Your Way to Health and Longevity

Tea made from the leaves of the Camellia sinensis plant has been consumed for over 5000 years. After water, tea is the most popularly consumed beverage worldwide. Europeans, North Americans and North Africans drink mainly black tea, Asians seem to prefer green tea, and oolong tea is popular in China and Taiwan.

Tea is tasty, soothing and either warming or cooling (depending on whether you drink it hot or cold). But tea is so much more than that – it is a well-recognized enhancer of the health and performance of your heart, your cardiovascular system, your muscles, your teeth and your bones – just to name a few reasons why this natural food is so beneficial.

What Difference Does the Color of Tea Make?
Whatever its color or name, all true “teas” are produced from the leaves of the tropical evergreen plant, Camellia sinensis. When tea leaves are converted into black tea, the harvested leaves are allowed to ferment before and while drying – an oxidation process that changes both the color of the leaves and the nature of their phytochemical contents. In contrast, the leaves for green tea are steamed to prevent oxidation and phytonutrient change during drying. Oolong tea is produced by allowing a partial oxidation of the leaves, making oolong tea equivalent to “half-green and halfblack” tea. About 20% of the tea produced worldwide is green tea. Essentially, then, with changes in the phytonutrient profiles, drinkers of the different types of tea can experience differing beneficial effects. Each phytochemical has unique healthful properties and, as antioxidants, has affinities for different types of free radicals.

What Does Green Tea have that is missing from Other Beverages?
Tea is a rich source of “polyphenolic phytonutrients.” While this class of phytonutrients is huge, with over 4000 known members, tea leaves become heavily loaded with one particular class of phytonutrient during their growth. In unoxidized, unfermented green tea leaves, this class, the catechins, includes epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG). During the oxidation process of converting green tea to black tea, the catechins also are oxidized, changing into a class called the theaflavins: EC becomes theaflavin, ECG becomes theaflavin-3- gallate, EGC becomes theaflavin-3í-gallate and EGCG becomes theaflavin-3,3í-digallate.

It has been estimated that one cup of brewed green tea contains between 100 and 150 mg of catechins, of which about half is EGCG and a little less than half is EGC. The other catechins are present but in much smaller amounts. Hot water extraction (brewing) maintains these relative proportions; EGCG comprises about half of the dissolved solids in brewed green tea.

Next Best Kept Secrets to Healthy Aging topic:
Green Tea – Does the Source of the Tea Matter?

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