View Full Version : Green tea, is it actually any good?


mistaben
07-15-04, 09:07 PM
I was wondering if people have ever noticed any positive benefits from drinking grean tea? I don't mean that you stopped drinking coffee and started drinking grean tea because all the caffeine in the coffe was messing with your meds but, as in grean tea made you start to FEEL better. Let me know your personal experiences - tony.

Ian
07-16-04, 01:32 AM
My wife loves the stuff. We had a friend working as an English teacher in Japan for a couple of years and he's recently home again to Canada. He sent a none stop barage of teas and other goodies.

The teas seem to come in a wild array of flavours and colours. The one Pierrette fell in love with nearly qualified as soup for me! It had a vague fish essence and was quite viscous. I howled with laughter when I first tasted it. It was so weird to my taste buds that I just wrote it off as funky stuff to keep away from my mouth.

Pierrette started to speak highly of the calming effect she found the tea had on her. She only noticed after she had run out of the tea she liked. Now she'll drink a variety of green teas but wow are there ever a bunch to choose from.

I've come to appreciate the character of some green tea.

I'm a darjeeling kind of guy most days. ian

That's a cupa Kenyan AA medium roast latte in my avatar though.. :rolleyes:

Wheezie
07-16-04, 10:32 AM
i haven't experienced any of the health benefits. then again, i suppose you'd have to drink it regularly to see some.

however, i *do* think it is tasty. i don't like it if it steeps longer than 2 minutes, it gets too bitter. i have to set my timer to make sure i pull the tea bag out in time -- my husband thought that was a hoot. i'm just happy to bring some merriment into his life. :rolleyes:

paulbf
07-16-04, 11:21 AM
This seems a reasonable intro/explanation of the benefits of green tea:
http://www.fmltea.com/Teainfo/tea-beginner.htm

Antioxidants and antibiotic effect is good for 'health'.

Caffiene comes out smoother than with coffee (probably why it doesn't satisfy as a substitute for me in the AM).

If too bitter, dump the water after a 1 minute rinse & steep again.

Steep for 3 minutes in the AM, 5 min in the PM to change caffiene ratio.

When we make it, we just steep for 30 seconds or so, pouring hot water over a strainer containing leaves is usually plenty. I like the toasted rice flavor which contains what looks like mini-half-popped popcorn. It has a unique nutty flavor.

t-bird
07-16-04, 01:58 PM
I think green tea is great, although I don't drink it often enough to notice any difference in myself. I try not to drink too much caffeine because of my meds.

Green tea comes from the same plant as black tea. Also Darjeeling tea (I think).

gabriela
07-16-04, 05:51 PM
i stopped drinking both green and black tea after i read in dr. amen's book "healing add" that caffeine reduces the effects of stimulants.
red tea's *great*!
:D

lilraine
08-19-04, 05:10 AM
Just to let you know if you are a green tea fan but try to avoid caffeine, it is also sold in decaf. :)

gabriela
08-19-04, 05:38 AM
The health benefits of green tea

Green tea specifically has been associated with protection against certain types of cancer<SUP>5,6</SUP> including lung<SUP>7</SUP>, stomach cancer<SUP>8-14</SUP> and its precancerous condition, gastritis<SUP>8,15</SUP>. Moreover, an observational study in Japan found that the regular consumption of green tea (more than 3 cups a day) might be protective against recurrence of breast cancer in the early stages.<SUP>16</SUP>

The possible protective mechanism of green tea is unclear, although a number of in vitro and animal studies are attempting to explain this, including a study that found that the green tea polyphenol (-) -epigallocatechin (EGC) inhibited the DNA replication in leukaemia cells, resulting in the death of these cells.<SUP>17</SUP> Other mechanisms by which green tea may be protective is discussed in more detail in the fact sheet 'Tea and Cancer.'

Further work is still required in understanding the protective antioxidant action of black and green teas. In one in vitro study, black tea was found to be more efficient than green tea as a chemopreventor against certain free radicals, oxygen and nitrogen species.<SUP>18</SUP> However, in another study both green tea and black tea were equally able to protect against Nitric Oxide toxicity.<SUP>19</SUP>

In addition to its potential anticarcinogenic and antioxidant<SUP>20</SUP> effects, other studies have shown green tea to have anti-inflammatory, antithrombotic<SUP>21</SUP>, cholesterol lowering<SUP>22-24</SUP>, antiviral and antibacterial properties<SUP>25-27</SUP>.

Although the scientific evidence demonstrating the health benefits of green tea is increasing it is not yet conclusive and provides an interesting area for future research.

Green tea and skin protection

A number of animal studies have shown that topical treatment or oral consumption of green tea polyphenols, inhibit chemical carcinogen or ultraviolet radiation-induced skin tumours in different animal models<SUP>28-30</SUP>. Treatment of green tea polyphenols to skin has been shown to have a beneficial effect on the biochemical pathways involved in skin inflammation, cell proliferation and chemical tumour promoters. These results have been confirmed in a human model, where topical application of green tea polyphenols protected against UV light induced DNA damage<SUP>31</SUP>. Based on results mainly from animal studies, many companies are now supplementing their skin care products with green tea extracts. However, the effects on human skin are still not well understood and further research in this field is required.

Green tea extract and weight loss

Preliminary research published in the American Journal of Clinical Nutrition suggests that an extract from green tea may help with weight loss by speeding up fat oxidation.<SUP>32</SUP> In this study, researchers conducted a 6 week study of 10 healthy men in their 20's and found that those men who were given a green tea extract used more calories in a day than those who did not. Further research is required before any firm conclusions about green tea and weight loss can be drawn.

Caffeine Content of Green Tea and Black Tea

Black and Green teas are produced from the same plant Camellia sinensis so both green and black tea naturally contain caffeine. Further information about caffeine and tea can be found in the Fact Sheet, 'Caffeine: The Facts'.

Which to drink?

The health benefits gained from drinking black and green tea are comparable, both helping towards promoting health and well-being. The decision about which to drink is simply a matter of taste.

(article "stolen" from www.teahealth.co.uk (http://www.teahealth.co.uk))

gabriela
08-19-04, 05:40 AM
Tea and Caffeine

(http://www.teahealth.co.uk/th/facts/pdf/Caffeine%20fact%20sheet%20.pdf)



<TABLE cellSpacing=0 cellPadding=0 width=460 align=center border=0><TBODY><TR><TD colSpan=3>What is caffeine?

People have enjoyed caffeinated beverages for many years Caffeine is a naturally occurring substance found in the leaves, seeds or fruits of at least 100 different species worldwide and is part of a group of compounds known as methylxanthines. The most commonly known sources of caffeine are coffee, cocoa beans, cola nuts and tea leaves. Caffeine is also added to specifically formulated 'energy drinks' and pharmaceutical products such as cold and flu remedies.

Coffee and tea also contain other dimethylxanthines; theophylline which has similar properties to caffeine and theobromine whose pharmacological actions is far less potent than caffeine and theophylline.

The amount of caffeine present in products depends on the type of the product, the serving size and the preparation method. For example a 190ml cup of tea contains 50mg of caffeine, one third less than the same amount of an instant cup of coffee (75mg). Table 1 gives an indication of the amount of caffeine found in other drinks compared to tea:

Table 1

<TABLE borderColor=#000000 cellSpacing=0 cellPadding=0 width=460 align=center bgColor=#ffffff border=1><TBODY><TR><TD class=head2 height=17>Type of Product</TD><TD height=17> </TD><TD class=head2 height=17>Caffeine (mg/ serving)</TD></TR><TR><TD>Tea</TD><TD>All types </TD><TD>50mg/ 190ml serving<SUP>1</SUP></TD></TR><TR><TD>Coffee</TD><TD>Brewed (filter or percolated)</TD><TD>100-115mg/ 190ml serving<SUP>1</SUP></TD></TR><TR><TD> </TD><TD>Instant</TD><TD>75mg/ 190ml serving<SUP>1</SUP></TD></TR><TR><TD>Cola drinks</TD><TD>Standard and Sugar Free </TD><TD>11-70mg/ 330 ml can<SUP>2</SUP></TD></TR><TR><TD>'Energy' drinks</TD><TD>All types</TD><TD>28-87mg/ 250ml serving<SUP>2</SUP></TD></TR><TR><TD>Chocolate </TD><TD>Bar</TD><TD>5.5-35.5mg/ 50g bar<SUP>2</SUP></TD></TR></TBODY></TABLE>On average we consume 3.98mg of caffeine /kg body weight per day ie 239mg/ day for a 60kg person<SUP>3</SUP>.

What is a safe intake of caffeine?

Up to 300mg/day (6 cups of tea) is considered moderate, with no evidence of harmful effects in the vast majority of the adult population. Some individuals are sensitive to caffeine and will feel effects at smaller doses than other individuals who are less sensitive. For this reason, these individuals may need to limit their caffeine intake.

Metabolism and Clearance

Caffeine does not accumulate in the body over a course of time and is normally excreted within several hours of consumption. The rate of caffeine elimination varies between individuals and this maybe as a result of genetic factors affecting the enzymes involved in the metabolism, or due to certain lifestyle factors eg smoking. Children also metabolise caffeine at a quicker rate. Generally caffeine absorption is complete within about one hour after ingestion and the plasma concentration peaks after about 60-90 minutes. The half-life of caffeine in the plasma is about 2.5 - 4.5 hours in healthy adults.<SUP>4</SUP>

Caffeine Tolerance

A number of different factors affect individual tolerance to caffeine, including the amount ingested, the frequency of caffeine consumption and individual metabolism. It is widely recognised that gradual tolerance develops with prolonged caffeine use.

top (http://www.teahealth.co.uk/th/facts/7.htm#top)

Physiological Effects

Caffeine is a pharmacologically active substance, and depending on the dose, has a number of actions:-


Central Nervous System Stimulant. A moderate caffeine intake can cause mild stimulation that maybe beneficial in terms of increased alertness, concentration, improved performance and decreased fatigue.<SUP>5-10</SUP> However, higher intakes may affect sleep, cause nervousness and an irregular heartbeat.
Weak Bronchodilator. As a result, interest has been shown in its potential role as an asthma treatment. A number of studies have explored the effects of caffeine in asthma and the conclusions from a Cochrane Review suggest that caffeine appears to improve airways function modestly in people with asthma for up to four hours after consumption.<SUP>11</SUP>
Diuretic. The diuretic action of caffeine may be due to an increase in renal blood flow, leading to an increased glomerular filtration rate (GFR), or due to a decreased reabsorption of sodium in the renal tubules. The diuretic effect of caffeine is dependent on the amount consumed and duration of intake eg the caffeine in tea does not have a diuretic effect unless the amount of tea consumed at one sitting contains more than 250-300mg of caffeine, equivalent to between 5 and 6 cups of tea.<SUP>12-17</SUP>
In fact, due to the volume of fluid that is drunk whilst enjoying a cup of tea, the British Dietetic Association advises that tea can contribute towards the daily-recommended fluid intake of 1.5 to 2 litres.


Cardiac Muscle Stimulant. Moderate caffeine consumption does not increase cardiac arrhythmias.<SUP>18</SUP>
If regular caffeine consumption is stopped abruptly, symptoms such as headaches, irritability and fatigue may occur. These effects are usually temporary, disappearing after a day or so and can be avoided if caffeine cessation is gradual.

Caffeine and Health

The role of caffeine in the development of certain diseases and conditions has been the subject of extensive research in recent years.


Cancer
A number of studies investigating the impact of caffeine in the development of cancer have failed to establish a relationship.<SUP>19-22</SUP> In fact, tea is one of the richest sources of flavonoids, a powerful group of antioxidants. The role of antioxidants in the prevention of free radical damage has led to suggestions that tea maybe anti-carcinogenic.<SUP>23</SUP> Despite interesting preliminary research, further work is required to prove its beneficial effect in this area.
Heart Disease
A number of studies have investigated the relationship between caffeine and heart disease and results from these and epidemiological studies have led to the conclusion that the ingestion of moderate amounts of caffeine is not associated with any increased risk of heart disease.<SUP>24-28</SUP> The Committee on Medical Aspects of Food Policy concluded that 'there is little evidence that caffeine itself has any relation with CHD risk' in the 1994 Nutritional Aspects of Cardiovascular Disease report.<SUP>29</SUP>
Parkinson's Disease
Observational studies have suggested that caffeine may play a role in protecting against Parkinson's disease,<SUP>30-31</SUP> although further research is required to determine the exact mechanism.
Relief of headaches
In a study of 301 regular headache sufferers, researchers found that a combination of ibuprofen and caffeine was better than either drug alone in relieving pain.<SUP>32</SUP> Although a caffeine 'pill' was used in this trial, the researchers believed that caffeinated beverages would work just as well. However, they did warn that chronic headache sufferers should avoid caffeine because it might exacerbate symptoms. More work is required in this field before firm conclusions about caffeine and pain relief can be drawn.
Pregnancy
Caffeine crosses the placenta and achieves blood and tissue concentrations in the foetus that are similar to maternal concentrations. For this reason recent advice published by the Food Standards Agency<SUP>33</SUP> recommends that pregnant women should limit their intake of caffeine consumption to less than 300mg/ day (equivalent to 6 cups of tea/ day). At this level there is little evidence to suggest that the health of the unborn child or mother is affected.
top (http://www.teahealth.co.uk/th/facts/7.htm#top)

In Summary…

Despite recent publicity about caffeine, the fact remains that the consumption of caffeine at intakes of 300mg/ day has no adverse effects in the vast majority of the adult population. For this reason an average intake of three to four cups of tea<SUP>s34</SUP> a day is well within the level considered safe.

("stolen" off www.teahealth.co.uk (http://www.teahealth.co.uk))
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