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IronCutie
09-15-2004, 05:24 PM
Does anyone know the specific benefits of Blueberry Tea, and Green Tea?

JnJ23
09-15-2004, 05:30 PM
Green tea contains a number of polyphenolic compounds. The catechin epigallocatechin gallate (EGCG) is the most abundant (> 50% of total tea catechins). It is also believed to be the most pharmacologically active. The other main catechins are epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin (EGC). You can view the chemical structures in a new window.

In addition to stimulating thermogenesis, green tea has a variety of well documented health benefits. Green tea is an antioxidant that has a strong anticancer effects in skin, stomach, colon, etc. Green tea protects against free radicals and it is a logical addition to any supplement program designed to prevent heart disease. In fact, green tea has so many health benefits that this post will have to focus on its ability to stimulate thermogenesis.

Quick facts: The Dulloo et al. studies (1, 2) used an alcohol extract of green tea that is sold in capsule form under the name EXOLISE (Arkopharma Laboratories, Nice, France). This extract is standardized to 24.7% catechins (70% as EGCG), and 8.35% caffeine.
How Powerful Is Green Tea Thermogenesis?
Scientists have found that green tea stimulates thermogenesis and this effect cannot be completely attributed to its caffeine content because the thermogenic effect of green tea is greater than an equivalent amount of caffeine. An in vitro study by Dulloo et al (2) found that a catechin that is abundant in green tea, EGCG, increased the respiration rate of brown fat (stimulated thermogenesis). Dulloo et al. have also done an in vivo study (1) that involved "10 healthy men" who received (with each meal during a 24 hour test period) on three separate occasions:

Test 1: 50 mg caffeine and 90 mg EGCG (total catechins: 125 mg).

Test 2: 50 mg caffeine.

Test 3: Placebo.

There was a "5-10 day interval between successive 24-h trials for each subject." The conditions were controlled and the study was double blind. However, given the fact that obese people respond differently to sympathetic stimuli, it is unfortunate that these tests were performed on "healthy" subjects. The study accepted people described as ranging from "lean to mildly obese" (8-30% bodyfat). But the responses varied widely nonetheless: 24 hour energy expenditure increased "in 6 of the 10 subjects after treatment with the green tea extract, ranging from 266 to 836 kJ" They did not find a correlation between the magnitude of thermogenic response and the degree of fatness of the subjects. That's not too surprising given the number of subjects and the selection criteria. It's a shame that they didn't include more subjects and some fat people in these tests.

JnJ23
09-15-2004, 05:31 PM
Energy Expenditure
Diurnal and 24 hour energy expenditure was increased significantly during treatment with green tea extract. Nocturnal energy expenditure increased, but not significantly. Here's the numbers:

Diurnal: Green tea 4.5% > placebo; Green tea 3.2% > caffeine.
24 hour: Green tea 3.5 % > placebo; Green tea 2.8 % > caffeine.
Perhaps even more interesting is the fact that the green tea extract produced lower respiratory quotients (helped normalize FAT burning):

"Significant differences across treatments were found during the diurnal, nocturnal, and 24-h periods . . . The contribution of fat oxidation [fat burning] to 24-h EE [energy expenditure] during treatment with the green tea extract (41.5%) was significantly higher (p<0.001) than during placebo [31.6%] treatment" (1).

In addition, urinary nitrogen losses showed no significant differences across treatments during all three periods. Clearly, the increased energy expenditure reflects increased FAT burning. This is worth exploring in greater detail.

Written
Dec 2000
Last Update
Dec 2000
Respiratory Quotient
Now we are getting to the interesting stuff. The lower the respiratory quotient, the more fat you are burning. You will often see this referred to as substrate utilization, substrate oxidation (burning), or fuel mix. It is very encouraging that such a small dose of green tea had such an impressive effect on the RQ: The contribution of fat oxidation [fat burning] to 24-h EE [energy expenditure] during treatment with the green tea extract (41.5%) was significantly higher (p<0.001) than during placebo [31.6%] treatment" [emphasis added] (1). Outside of medical journals, fat oxidation and the respiratory quotient are usually only discussed in relation to aerobic exercise (I'm sure you have been told to do low intensity aerobics to burn more fat). However, as usual, the interesting stuff (the stuff that proves obesity is a REAL disease) is ignored.

You see, obese people tend to burn more carbohydrate (glucose) and less fat (fatty acids) than normal people. The Astrup/Toubro team of obesity researchers have studied this defect (4-NA, 5-NA). In fact, a growing number of scientists believe that this part of the thermogenic defect may be more important than energy expenditure. Why do we burn relatively less fat? This is caused be a number of genetic (22) and biochemical defects including insufficient release of noradrenaline and adrenaline. Arne Astrup et al. (5-NA, 22) have written about this genetic defect:

JnJ23
09-15-2004, 05:32 PM
Direct evidence for a genetic influence on RQ [respiratory quotient] was delivered by Deriaz et al., who studied the relationship between DNA variation at the genes coding for the Na,K-ATPase peptides, RQ, and body fat. Postabsorptive [after a meal] RQ was found to be associated with the alpha2-gene and linked with the beta-gene of the Na,K-ATPase, which suggests that these, or neighboring genes, influence RQ. Twin studies also support the heritability of RQ." [emphasis added] (5-NA).

Based on this study by Dulloo et al. (1), it looks like green tea can help correct this respiratory quotient defect. Of course, ephedrine/caffeine normalizes the release of noradrenaline and adrenaline and corrects the respiratory quotient:

"The respiratory quotient (RQ) indicate that relatively more lipid [fat] was oxidized during chronic ephedrine treatment than in the control study. This change was observed in the fasting state as well as after glucose administration. Certain effects of ephedrine seems to be appropriate to a thermogenic drug for the treatment of obesity: A single dose of ephedrine stimulates thermogenesis, an effect that is enhanced during chronic treatment; Chronic treatment elevates the metabolic rate; and the substrate utilization is changed in favor of lipid [fat] oxidation" [emphasis added] (6).

Is it not curious that doctors tell obese people to eat an abnormally small amount of fat rather than tell us to take thermogenic supplements to correct this genetic fat burning defect? I mean, imagine if your car was having engine trouble and your mechanic refused to fix it and told you to "just drive less." Of course, you would immediately realize that this was a bogus 'solution' and go to another mechanic. But what if they ALL ignored the problem and told you to change your driving habits? Eventually you would realize that you need to read some repair manuals so you can fix the car yourself, right? Fortunately, there is no FDA-type organization trying to pass laws against nonprofessional car repairs.

Obese people who do not want to be mislead by prejudice, ignorance, or political/financial agendas should keep this fuel mix defect in mind when they hear "experts" questioning the importance of thermogenesis. Typically, these "experts" will rattle off a bunch of energy expenditure numbers and tell you that thermogenesis is not very important and thermogenic supplements don't do much. If you want to have some fun, remind the "expert" that there is direct evidence for a genetic influence on respiratory quotient and one of the ways that thermogenic supplements help obese people is by normalizing their defective substrate utilization. Ask the "expert" if he is aware of the fact that a growing number of obesity scientists believe correcting this genetic fat burning defect is more important than those archaic energy expenditure numbers. After all, if you don't BURN fat, you BECOME fat.


Noradrenaline Storage & Release
In order to understand how green tea works we need to take a quick look at noradrenaline storage, release, and metabolism. Noradrenaline is synthesized in the sympathetic nerves and stored in storage vesicles. When sufficiently stimulated, the vesicles migrate to the end of the nerve and release noradrenaline into the synaptic cleft. As you probably already know, the noradrenaline binds to the adrenergic receptors and stimulates thermogenesis. Next in the chain of events is noradrenaline metabolism, which involves two uptake mechanisms.

General references for Noradrenaline Storage, Release, and Metabolism: 3-BK, 20-BK, 21-BK.

Advanced readers should check out "Principles of Neuropsychopharmacology" (3-BK) -- it's an excellent book!

JnJ23
09-15-2004, 05:33 PM
Noradrenaline Metabolism
Uptake 1: After stimulating the adrenergic receptors, 85-90% of the noradrenaline is taken back up into the sympathetic nerves (uptake 1) and stored in vesicles or metabolized by monoamine oxidase (specifically, MAO-A) in the mitochondria. The importance of uptake 1 (neuronal uptake) is reflected by the warnings against combining sympathomimetics (ephedrine, phentermine, etc.) that increase noradrenaline release with MAO inhibitors -- the risk of overstimulation would be much too high.

Uptake 2: Some of the noradrenaline diffuses away from the receptors and is transported by extra-neuronal cells (uptake 2) and metabolized by catechol-O-methyl-transferase (COMT). Green tea increases noradrenaline in the synaptic cleft and safely increases thermogenesis because of its ability to prevent COMT from metabolizing noradrenaline. This is safe because COMT plays a much smaller role in catecholamine dynamics than MAO.

COMT exists in both a soluble and a membrane-bound form. The soluble form of COMT is found in organs and it does not have as high of an affinity for catecholamines as the membrane-bound form.

Quick facts: Uptake 1 of noradrenaline is blocked by cocaine, amphetamines, and tricyclic antidepressants. Progesterone increases MAO and estrogen inhibits MAO.


* There is more information on how caffeine enhances thermogenesis in the following posts: How ECA Works has illustrations and there is referenced information in The "A" in ECA and my Thermogenic FAQ.
How Green Tea Stimulates Thermogenesis
The thermogenic effect of green tea involves two mechanisms: I.) green tea contains a catechin, EGCG, which inhibits catechol O-methyltransferase (COMT), an enzyme that degrades noradrenaline II.) the caffeine in green tea increases intracellular cAMP accumulation by inhibiting the enzyme, phosphodiesterase. See "How ECA Works" for more info on the importance of caffeine.

I have already discussed the effects of caffeine in several posts, so I will focus on COMT. Interestingly, the medical literature showing that green tea inhibits COMT dates back over two decades (7-NA). By inhibiting COMT, green tea prolongs the life of noradrenaline in the synaptic cleft. (This lets noradrenaline stimulate the receptors for a longer time before it is metabolized). The in vivo (human) study by Dulloo et al. (1) found that, compared to placebo and caffeine, green tea significantly increased total 24 hour urinary noradrenaline excretion. The researchers commented on the significance of this:

"This observation is consistent with the inhibiting effect of green tea on COMT, the consequential reduction in norepinephrine [noradrenaline] degradation, and hence, the spillover of norepinephrine into circulation, thereby accounting for the higher urinary excretion of norepinephrine. Such effects, resulting in a prolonged life of norepinephrine in the sympathetic synaptic cleft, could explain the observed effects of the extract in stimulating thermogenesis and fat oxidation" (1).

Written
Dec 2000
Last Update
Dec 2000
Discussion
Although this research is exciting, the fact remains that green tea does NOT normalize the release of noradrenaline (the primary obesity-causing defect) -- it prolongs the action of whatever amount of noradrenaline that your body is able to release. For this reason, Dulloo concluded that the thermogenic effect of green tea is "likely to be highly dependent upon the release of endogenous NA [noradrenaline]." Clearly, green tea (by itself) is going to be a "your mileage may vary" situation. However, tissue studies performed by Dulloo et al. showed that green tea produced a significant synergistic effect when it was combined with ephedrine or ephedrine/caffeine (2).

Since green tea prolongs the action of noradrenaline, you would think that it would have a stimulatory effect. However, Dulloo et al. noted that green tea caused no significant differences in heart rate. The most logical explanation for this is that the stimulatory effect of increased noradrenaline action is being countered by other mechanisms. For example, green tea contains the amino acid, theanine, which has been found to lower blood pressure (. Green tea also has a vasorelaxing effect (9, 10). One recent study found that regular tea consumption had no significant effect on blood pressure (11), but it is difficult to achieve a therapeutic dose without taking concentrated supplements. Further complicating the picture, however, is the fact that they also found that green and black tea caused a short term increase in blood pressure (11).

I hope there will be further research aimed at determining the optimal dosage for the ephedrine/caffeine/green tea combination. It seems likely that the addition of green tea will make it possible to normalize sympathetic tone with a less stimulating stack. In addition, green tea (without ephedrine/caffeine) may permit people with hypertension to obtain a mild increase in fat oxidation and thermogenesis. Clearly, additional research is needed to expand our understanding of the effect of green tea on blood pressure. Hypertensives that want to take green tea should definitely work with a doctor and monitor their blood pressure.

Green tea is an extremely logical supplement for obese people. In addition to its weight loss effect, green tea protects against a number of conditions that are VERY common among the obese:

Green tea has been found to reduce the risk of having a stroke (12, 13).
Green tea has anti-cancer and anti-tumor effects (14, 15).
Green tea can improve glucose/insulin levels and your blood lipid profile (16, 17, 18-NA, 19).
However, it is difficult to obtain all of these health benefits if one does not take green tea supplements -- without supplements, you would have to drink at least ten cups of green tea every day!


Green Tea Products
Green tea has so many health benefits that it's impossible to pick a single best product. The only logical way to evaluate green tea products is to separate them according to their suitability for specific purposes such as weight loss, blood pressure reduction, etc. If you are interested in green tea for cancer prevention and health enhancement, I would shoot for at least 10 cups of tea per day. That's a lot of tea! Perhaps a combination of supplements and drinking tea is the easiest way to consume enough tea.

For the price comparison, whenever possible, I calculated the price per 100 mg of polyphenols and the price per 100 mg of EGCG. These calculations make it easy to compare products with different size capsules and extracts that are standardized to different potencies. I was surprised to find that, based on polyphenol and EGCG content, there were huge price differences between products. For example, Natrol Green Tea Extract is only 3.6 cents per 100 mg of polyphenols; Natures Way Green Tea Extract is a whopping 28.21 cents.

Green Tea For Weight Loss
Research suggests that EGCG is the most important catechin for weight loss. Although most products specify the amount of polyphenols, only a few list the EGCG content. For weight loss purposes, the most powerful Green Tea extract is the standardized Green Tea Extract by NSI -- it contains a whopping 220 mg of EGCG per capsule. The second most powerful green tea extract is the Life Extension Super Green Tea Extract, which contains 122 mg of EGCG per capsule.

Apparently, all of these green tea extracts that are standardized to extremely high levels of EGCG contain very little caffeine. This is good if you are adding green tea to win ECA stack; however, if you are interested in using one of these high EGCG green tea supplements by itself, you'll get much better results if you take some caffeine with it.

JnJ23
09-15-2004, 05:34 PM
Mechanism found for green tea in cancer fight

In research conducted at H. Lee Moffitt Cancer Center & Research Institute in Tampa Florida, a mechanism of green tea polyphenols' ability to cause the death of cancer cells was elucidated. By testing green tea polyphenols effect on prostate cancer cell lines, varying concentrations of the polyphenols were found to diminish a protein called Bcl-XL which protects cancer cells from apoptosis, which is programmed cell death.

Green tea has been shown to prevent several types of cancer in animal models. Human populations who consume green tea have lower rates of stomach, liver, pancreatic, breast, lung, esophageal and skin cancers.

Aslamuzzaman Kazi, PhD, research fellow in the Drug Discovery Program at Moffitt Cancer Center, described the finding: "The higher the concentration, the better the response - meaning more apoptosis, or programming that tells cells to die -- apparently occurring as a result of a greater decrease in Bcl-XL, a protein that protects cancer cells from apoptosis. At all concentrations, response was apparent within three hours."

Pin Dou, PhD, associate professor of oncology, biochemistry, and molecular biology at Moffitt further explained, "Because Bcl-XL is overexpressed in many cancers, it could be a key target in all these cancers and explain why green tea polyphenols (are) able to prevent human cancers in mouse models . . . Data from our laboratory suggests that at least one enzyme may modify Bcl-XL and that it is the actual target of tea. We also want to see if that target is present in all human cancers or just some of them."


Green tea has been shown to lower "bad" LDL cholesterol and serum triglyceride levels. Further, green tea's potent antioxidant effects inhibit the oxidation of LDL cholesterol in the arteries, which plays a major contributory role in the formation of atherosclerosis. "There is considerable epidemiological evidence that tea drinking lowers the risk of heart disease" (FEBS Lett., Aug. 1998, 433(1-2):44-46).

The cholesterol-lowering (hypocholesterolemic) effects of green tea (as well as black tea) have been confirmed by both animal and human epidemiological studies. High consumption of green tea by humans, especially more than 10 cups a day, was found to be associated with higher HDLs and lower LDL and VLDL cholesterol, as well as with various biomarkers indicating better liver health. Lower levels of lipid peroxides in the liver are one well-confirmed benefit of green-tea supplementation found in study after study.

A Japanese study relates, "Green tea catechin acts to limit the excessive rise in blood cholesterol" based on a series of studies reported in 1996 (Journal Nutritional Science Vitaminol., 32:613).

Additionally, some very exciting results were found when rats were fed 2.5% green tea leaves in their diet. The experimental group showed a drop in total cholesterol, low-density cholesterol, and triglycerides. The body weight of green tea-fed rats was 10 to 18% lower than that of rats not consuming green tea. In addition, the activity of antioxidant enzymes superoxide dismutase (SOD) and catalase, and of anticarcinogenic phase-II enzyme glutathione S-transferase (GST), were significantly higher in the green tea group, as was the glutathione level in the liver. There was no liver or kidney toxicity. Thus, the study demonstrated combined cardiovascular and anticancer effects of green tea.

The relation between green tea consumption and serum lipid concentrations were examined using cross-sectional data on 1306 males in Japan. Results indicated that total cholesterol levels were found to be inversely related to the consumption of green tea. "Adjusted mean concentrations of total cholesterol were significantly lower in men drinking nine cups or more a day than in those consuming zero to two cups a day" (Prev. Med. July 1992, 21(4):526-31). No wonder the Japanese people have the longest life span. Most Japanese sip tea all day long.

Green tea also has been shown to elevate levels of HDL, the good cholesterol that helps remove atherosclerotic plaque from arterial walls. Green tea is a natural ACE inhibitor. This is an extra benefit for those with high cholesterol and blood pressure, as published studies show lowered blood pressure in animals and humans given green tea extracts. We recommend one capsule (350 mg) of green tea 95% extract daily, or drinking one to ten cups of green or black tea a day.

Also maybe help burn cals...

A study has found: "Subjects spent 24 hours in a respiratory chamber designed to measure the rate calories were burned and energy expenditure. Those receiving the green tea experienced what researchers consider a significant increase in both tests. Tea extract subjects burned 4 percent more calories, and overall energy expenditure rose 4.5 percent."

BELTSVILLE, Md., Oct 10, 2002 (United Press International via COMTEX) -- Common tea can be an effective weapon in the fight against diabetes because it boosts insulin activity in the body by more than 15-fold, scientists at the U.S. Department of Agriculture said Thursday.

Insulin problems lie at the root of the potentially fatal illness diabetes, so researchers hope tea-based treatments will help treat or prevent the disease, which affects 17 million Americans. Not only that, this insulin-boosting phenomenon may explain why tea can help fight heart disease and high blood pressure as well.

"This is just one of the many well-established benefits that tea may have," researcher Richard Anderson, a biochemist at the USDA's Beltsville Human Nutrition Research Center in Maryland, told United Press International.

Tea has a long history as a folk remedy for diabetes in China, the West Indies and central Africa. Over the past 20 years scientists also have uncovered potential benefits from tea against cancer, high blood pressure and infection.

"Tea wasn't the only factor we looked at, but it was the best," Anderson said.

Anderson and his colleague Marilyn Polansky analyzed a host of herbs, spices and plants for any beneficial effect involving insulin, the hormone the body needs to convert sugar into energy. They took fat cells from rats and grew them in test tubes because fat cells are highly sensitive to insulin, Anderson explained. Then, they gave the cells mildly radioactive sugar, insulin, and various tea extracts. The radioactive sugar is easy to track and the more the extracts aided insulin activity, the more sugar the cells would convert.

The scientists found black, green and oolong teas boosted insulin activity the most. This insulin-augmenting effect was seen with both caffeinated and non-caffeinated teas, but not with herbal teas, which do not use leaves from tea bushes.

They also identified tea's most insulin-enhancing chemical, called epigallocatechin gallate. Adding whole or skim milk, nondairy creamers or soy milk appears to soak up tea's insulin-augmenting compounds and inhibit the insulin boost, although these milky sponges may release the tea extracts in the stomach, Anderson said. No absorption problem was seen with lemon juice.

"Hopefully people can get better simply by drinking tea," Anderson said. "These compounds clear from the body quite quickly, some in less than six hours, some less than four. The effects are not going to be that large, so you're going to need to continue drinking tea."

Anderson said his team also found cinnamon showed similar insulin-enhancing power. He suggests tea and cinnamon affects the cell proteins insulin binds to.

Diabetes is a disease where the body either does not make insulin or does not properly use it when it does produce it. The scientists think tea increases the body's sensitivity to insulin by setting off a chain reaction. As a result, the body attaches chemicals to insulin-binding proteins that enhance their activity.

Tea's insulin-boosting activity also might explain why tea seems to help prevent heart disease and high blood pressure, Anderson said. Medical investigators think high blood sugar damages blood vessels, and increasing insulin activity lowers blood sugar levels.

"This work seems to be truly new and extremely exciting," biochemist Anne-Marie Roussel at the Universite Joseph Fourier in Grenoble, France, told UPI. "This work is well done, and the data is promising not only to treat diabetes but perhaps also in preventing it." Roussel and Anderson added more tea studies need to be conducted with patients, not in lab models.

JnJ23
09-15-2004, 05:36 PM
Green tea benefits digestive tract

Tea catechins undergo various metabolic changes after they are taken orally, though a large percentage is excreted intact with the feces. Epidemiological studies suggest a protective effect of tea against various human cancers, including colon and rectum. The bactericidal property of tea catechins plays several roles in the digestive tract. In the small intestine, catechins inhibit alpha-amylase activity, and a certain amount is absorbed into the portal vein. Although catechins are bactericidal, they do not affect lactic acid bacteria. Including tea catechins in the diet for several weeks decreases putrefactive products and increases organic acids by lowering pH. These changes were achieved with 100 mg of tea catechins (equivalent to two to five cups of green tea) three times daily with meals for three weeks. When catechin administration ceased, the effects reversed after one week. Catechins should be considered further in colon carcinogenesis studies.

JOURNAL OF CELLULAR BIOCHEMISTRY, 1997, Suppl. 27, pp 52-58


The inhibitory action of tea polyphenols towards the development and growth of bacterial spores was examined. The heat resistance of B stearothermophilus spores (a thermophilic spore-forming bacterium) was reduced by the addition of tea polyphenols. Clostridium thermoaceticum, an anaerobic spore-forming bacterium, also exhibited reduced heat resistance of its spores in the presence of tea polyphenols. Epigallocatechin gallate, the main component of tea polyphenols, showed strong activity against both B stearothermophilus and C thermoaceticum. The heat resistance of these bacterial spores was more rapidly decreased by the addition of tea polyphenols at high temperatures.

JOURNAL OF BIOSCIENCE AND BIOENGINEERING, 2000, Vol 90, Iss 1, pp 81-85

Green tea protects against alcohol-induced liver injury

A study examined the antioxidant polyphenolic extract of green tea against early alcohol-induced liver injury. Rats were fed high-fat liquid diets with or without alcohol and green tea (300 mg kg/day) continuously for four weeks. After four weeks, the blood ALT (sign of liver damage) levels were increased significantly from 35 to 114 (four-fold over placebo group values). However, the inclusion of green tea extract in the diet significantly blunted the increase to 65. The alcohol also caused severe fatty accumulation, mild inflammation and tissue death in the liver. However, with green tea extract, the increase in tissue death caused by alcohol were significantly reduced, while not affecting fat accumulation or inflammation. Alcohol also significantly increased the accumulation of protein adducts (products of lipid peroxidation and an indication of oxidative stress). However, green tea extract blocked this effect almost completely. Green tea extract also blunted the increase of TNFalpha (causes inflammation) protein levels in the liver by alcohol. The results indicate that dietary antioxidants, such as those found in green tea, prevent early alcohol-induced liver injury, most likely by preventing free radical stress.

BIOLOGICAL CHEMISTRY 2002;383(3-4):663-70

Green tea, grape juice, and colon cancer
Full source: BIOLOGICAL & PHARMACEUTICAL BULLETIN, 2000, Vol 23, Iss 6, pp 695-699

A study reported the effects of tea and juice on the activity of the intestines. Green tea strongly inhibited the E. coli-expressed mouse intestinal phenol sulfotransferases (P-STs) activity in vitro. The active component of green tea, (-)-Epigallocatechin gallate (EGCG), was found to be the most potent inhibitor among the catechins tested. (-)EGCG also inhibited the P-ST activity of the human colon cancer cells. Among fruit juices examined (apple, grape, grapefruit and orange), grape juice exhibited the most potent inhibitory action on the P-ST activity of mouse intestines and human colon cancer cells. The inhibitory activity of grape juice was located mainly in the skin and seeds. Flavonols, such as quercetin and kaempferol, inhibited the P-ST activity at low concentrations. The results suggest the possible inhibition of P-ST activity in human intestines by green tea or grape juice.

Curr Med Chem Anti-Canc Agents 2002 Jul;2(4):441-63 Related Articles, Links


Green tea catechins as novel antitumor and antiangiogenic compounds.

Demeule M, Michaud-Levesque J, Annabi B, Gingras D, Boivin D, Jodoin J, Lamy S, Bertrand Y, Beliveau R.

Laboratoire de Medecine Moleculaire, UQAM-Hocric;pital Sainte-Justine, Montreal, Canada. oncomol@nobel.si.uqam.ca

The concept of cancer prevention by use of naturally occuring substances that could be included in the diet is under investigation as a practical approach towards reducing cancer incidence, and therefore the mortality and morbidity associated with this disease. Tea, which is the most popularly consumed beverage aside from water, has been particularly associated with decreased risk of various proliferative diseases such as cancer and atherosclerosis in humans. Various studies have provided evidence that polyphenols are the strongest biologically active agents in green tea. Green tea polyphenols (GTPs) mainly consist of catechins (3-flavanols), of which (-)-epigallocatechin gallate is the most abundant and the most extensively studied. Recent observations have raised the possibility that green tea catechins, in addition to their antioxidative properties, also affect the molecular mechanisms involved in angiogenesis, extracellular matrix degradation, regulation of cell death and multidrug resistance. This article will review the effects and the biological activities of green tea catechins in relation to these mechanisms, each of which plays a crucial role in the development of cancer in humans. The extraction of polyphenols from green tea, as well as their bioavailability, are also discussed since these two important parameters affect blood and tissue levels of the GTPs and consequently their biological activities. In addition, general perspectives on the application of dietary GTPs as novel antiangiogenic and antitumor compounds are also presented.

JnJ23
09-15-2004, 05:38 PM
Green Tea Linked to Skin Cell Rejuvenation

Christine Hurley Deriso

Research into the health-promoting properties of green tea is yielding
information that may lead to new treatments for skin diseases and
wounds.

Dr. Stephen Hsu, a cell biologist in the Medical College of Georgia
Department of Oral Biology, has uncovered a wealth of information
about green tea in the last few years. Most importantly, he helped
determine that compounds in green tea called polyphenols help
eliminate free radicals, which can cause cancer by altering DNA. He
also found that polyphenols safeguard healthy cells while ushering
cancer cells to their death.

He recently began studying the most abundant green tea polyphenol,
EGCG. Using pooled human keratinocytes (skin cells), he and his
colleagues studied the normal growth of the skin cells and compared it
to the growth of the cells when exposed to EGCG.

To their astonishment, they found that EGCG reactivated dying skin
cells. "Cells that migrate toward the surface of the skin normally
live about 28 days, and by day 20, they basically sit on the upper
layer of the skin getting ready to die," Dr. Hsu said. "But EGCG
reactivates them. I was so surprised."

The skin consists of three layers: the epidermis (outer layer), dermis
(mid-layer) and hypodermis (inner layer). Dr. Hsu learned that green
tea polyphenols arenít absorbed beyond the epidermis, so any benefits
are limited to that outer layer of skin. But the benefits, he
stressed, seem significant.

Cells in the epidermis, or keratinocytes, are in a constant state of
renewal. The newly formed cells, stem cells, are undifferentiated but
rapidly dividing. As they push through the epidermis, they begin
differentiating. During this migration and differentiation process,
the cells are very active, expending and consuming vast amounts of
energy.

Once they reach the surface of the skin, their metabolic activity
slows dramatically and they prepare to die, while forming a
water-proof, sheet-like structure. As they die off about a month into
their life cycle, they are replaced by another wave of migrating cells
supplied by stem cells, starting the process all over again.

But EGCG seems to be a fountain of youth for skin cells. "When exposed
to EGCG, the old cells found in the upper layers of the epidermis
appear to start dividing again," Dr. Hsu said. "They make DNA and
produce more energy. They are reactivated. There are lots of
unknowns--this is the first step into the door--but if we can energize
dying skin cells, we can probably improve the skin condition."

In addition, the researchers found that EGCG accelerates the
differentiation process among new cells.

Combining these effects of EGCG on skin cells in different layers of
the epidermis, Dr. Hsu noted potential benefits for skin conditions as
diverse as aphthous ulcers, psoriasis, rosascea, wrinkles and wounds.
"If skin cells surrounding wounds or infections donít heal in time,
fibroblasts in the connective tissue may rush in to fill the void and
cause scar tissue formation," he said. "If we can spur the skin cells
to differentiate and proliferate, we can potentially accelerate the
wound-healing process and prevent scarring."

This potential benefit is particularly exciting for conditions such as
diabetes, which stubbornly inhibits the wound-healing process, Dr. Hsu
said.

He and his colleagues hope to identify dermatologists interested in
collaborating on clinical studies of EGCG and other polyphenols on
patients.

Dr. Hsuís research, which is excerpted on the online version of the
Journal of Pharmacology and Experimental Therapeutics, is funded by
the Dental Research Foundation, the MCG School of Dentistry and MCG
Research Institute.

JnJ23
09-15-2004, 05:39 PM
Some other tea's benefits:

Persimmon Tea:
The leaves when dried and crushed make a fine strong tea. Can be used all year round.
Rich in vitamin C. Used as a healthful tonic.


~~~~~~~~~~~~~~~~


Sassafras Tea:
Boil fresh roots after washing, until water turns reddish brown. Can be sliced and dried for later use.
Claimed by some to be a blood thinner, a blood purifier, to help bronchitis, a stimulating spring tonic. Mostly it is used for pure enjoyment.


~~~~~~~~~~~~~~~~


Birch Tea (Wintergreen):
Black, yellow and white birch. Dried leaves can be used year round.
A large handful of fresh leaves steeped in hot water was drunk 1 to 2 cups a day for rheumatism and headaches. Said to reduce pain of passing kidney stones, and a fever reducer. Cold it was used as a mouthwash.


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Blackberry/Raspberry Tea:
The dried mature leaves of these brambles make a good tea.
Used to help control diarrhea, as a blood purifier and tonic. Use all year round.


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Blueberry Tea:
The dried mature leaves are steeped until cool and drunk.
1 to 2 cups per day as a blood purifier and tonic. Also used to help inflamed kidneys and increase the flow of urine. Somewhat bitter. Use all year round.


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Alfalfa Tea:
The dried and powdered leaves and flower heads make a very nutritious tea, but it is somewhat bland.
We suggest mixing them with normal teas to stretch them and add nutrition. Its vitamin content was the reason it was used. Used all year round.


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Wild Strawberry Tea:
Use dried leaves normally. Pour several cups boiling water over a handful of fresh leaves in the evening. Cover and let steep overnight. Strain water and reheat in the morning.
Believed to help with a multitude of things, from stomach troubles, eczema, diarrhea, etc. According to experts, it is much more healthful than purchased coffee or teas. Use all year round.


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Wild Rose-Hip Tea:
A handful of these steeped for 10 minutes, then strained, make a healthful tea. Can be used dried or fresh in season. Instead of boiling, place a handful in cool water overnight, then stain and reheat in the morning. Use all year round.
Strong Vitamin C content. Helps with Colds and the flu. Also for sore throat.


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Sweet Goldenrod Tea (Anise):
Can use dried or fresh leaves or flowers. Makes a very flavorful tea.
Pure enjoyment only!! Used all year round.


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Soldier's Herb Tea:
This common yard weed with green leaves and two seedie spikes was used by the colonials and Indians alike.
One teaspoon of seeds per cup of boiling water steeped for 1/2 hour was used for dropsy and jaundice. A tea from fresh leaves (chopped fine), one heaping teaspoon per cup of boiling water steeped for 1/2 hour. For dried powdered leaves, use one level teaspoon and reduce time to 15 minutes. Drunk 4 to 5 times a day until relief was obtained. Used for gout, to help clean out nasal passages and to slow menstruation. Also used to expel worms. A tea cooled made from rainwater was used as an eyewash.

JnJ23
09-15-2004, 05:41 PM
http://www.enjoyingtea.com/greentea.html

TEA IS HEALTHY! SO DRINK UP

shazz
09-16-2004, 05:25 AM
Two sides to every story I guess, don't jump on either bandwagon of its super great or horribly bad, just drink in moderation:

Tea
TEA originated in China several thousand years ago. There are two basic kinds of tea -- black and green -- containing more than 300 known compounds. The difference between the black and green tea is generated during the manufacturing process. Oolong tea is semi-fermented but is closer to black tea than green.

Black tea undergoes a fermentation step whereby enzymes, present in the tea flush, convert certain components present (for example, proteins, amino acids, fatty acids, and polyphenols) into compounds that are responsible for the characteristic aroma and flavor of black tea. India and Sri Lanka are the major producers of black tea.

Green tea manufacturing eliminates the fermentation process, but still inactivates the enzymes present. The initial step is subjecting the flush to either the Japanese process of steaming, or the Chinese process of dry heating. Both countries are the world's major producers of green tea.

Green tea has, for some inexplicable reason, attained "health food" status, even though it has some decidedly "unhealthy" properties. Green tea contains triterpene saponins, which have the ability to dissolve erythrocytes (a red blood cell), even when highly diluted. Green tea also has a high fluroide content (130-160mg/kg), as well as potassium and aluminum ions. Both black and green teas contain caffeine (see separately). Iced tea can contain as much as 70 mg. of caffeine per cup, and even decaffeinated is not totally free of caffeine. Caffeine was first discovered in tea in 1827 and named theine. Later, when it proved to be chemically identical to caffeine, the name was dropped, leaving caffeine as the name of similar compounds.

Both types of tea contain large amounts of catechin tannins (10-25%), with those in green tea being higher than in black. Fermentation (black) partially changes catechins into oligomeric quinones with tannin characteristics. Tannins are known to decrease the digestibility of proteins. A cup of tea contains lesser amounts of caffeine than coffee, but the tannin content is much higher. Although tannins have both anticancer and carcinogenic properties, what activates one over the other is thought to lie within an individual's own chemistry makeup.

Both also contain xanthine alkaloids (theobromine, theophylline, dimethylxanthine, xanthine, and adenine). Xanthine is a precursor to uric acid -- also found in many organ meats -- which causes kidney stones and gout. Closely related to caffeine, theobromine has diuretic properties, is an arterial dilator, and is a central nervous system stimulant. It is widely consumed, not only in tea, but in coffee, cola, and chocolate. It is also highly toxic to dogs. The USDA recently added values from research conducted by the Agricultural Research Service (1994-96 and 1998) indicating levels of caffeine and theobromine consumed by children through nine years of age. The average intake was 13.9 mg., with most being consumed in carbonated drinks and tea, with chocolate running a close second. The giving of green tea to infants and children is popular with mothers anxious to see that their children attain higher standards of health. The average intake of theobromine levels in these same children were reported to be 42.5 mg. or 23.8 mg./1000kcal. Theophylline targets the heart, bronchia, and kidneys, and is the most common medication used for asthma and COPD patients.

Precautions for green tea users are noted in the Herbal PDR. Those who have a weakened cardiovascular system, renal diseases, thyroid hyperfunction, elevated susceptibility to spasms or certain psychic disorders (for example, panic or anxiety), or who are pregnant or nursing should avoid its use. Long term usage produces the same symptoms as other caffeinated drinks do: restlessness, irritability, sleeplessness, heart palpitations, vertigo, vomiting, diarrhea, loss of appetite, and headaches. The resorption of alkaline medications can be delayed because of chemical bonding with the tannins. An overdose is considered to be greater than 300 mg. caffeine or five cups of tea, which can lead to symptoms such as restlessness, tremors, and an elevated reflex excitability. The first signs of poisoning are vomiting and abdominal spasms.

Green tea may also interfere with the absorption of atropine, if taken orally. Large quantities may also increase the activity of Warfarin (Coumadin), which is a blood thinner. In addition, tannin-containing foods have been known to affect the absorption of Codeine and Cardec medications.

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Basic message, don't go overboard, but it won't hurt you for the most part.
This article is in reference to all types of people not just those with weakend kindeys or cardiovascular risk.
(I highlighted theobromine especially because it is known to be very addictive hence people who give up caffeine still need decafe coffee as decafe contains 2/3 addictive substances theobromine being one of them. Same with chocolate.)
However that doesn't mean we avoid coffee either.

Kruger
09-16-2004, 06:51 AM
i got really tired of green teas taste so i started adding splenda (some1 suggested this before) and now im back to 20 billion cups a day =)

rick martel
09-16-2004, 09:36 AM
damn, allota info on tea ....good thing to research with free time.

saw14
09-16-2004, 11:09 AM
i got really tired of green teas taste so i started adding splenda (some1 suggested this before) and now im back to 20 billion cups a day =)

another good mixture is a little crystal lite with your green tea.

saw14
09-16-2004, 04:30 PM
does green tea have more benefits when hot or cold? or does it really matter?

DaIceman
10-05-2004, 09:46 AM
Awesome thread, just what I was looking for. But one quick question, what is the comparison of benefits between a high quality leaf green tea as compared to a pill?

johnnyironboard
10-05-2004, 10:16 AM
I drink green tea and take the caps. I have found the fat loss aspect to be very over rated.

soccer26
04-07-2006, 02:06 PM
would you recommend the higher power caps or NOW?

johnnyironboard
04-07-2006, 03:24 PM
would you recommend the higher power caps or NOW?
I take NOW- today and a year a half ago and the fat loss aspect is still over rated.

soccer26
04-07-2006, 06:29 PM
any other opinions?

soccer26
04-10-2006, 12:34 PM
bump