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green tea and health

There seems to be an ever growing weight of scientific evidence out there, to support the claim that "tea is the planets healthiest beverage”. Let’s couple this scientific evidence, with over four thousand years of history, supporting the legendary health benefits of tea. Chinese books from ancient times write of teas ability to quench thirst, aid in digestion, ward off sleepiness, check phlegm and stimulate renal activity. Tea was also said to dispel boredom, dissolve greasy food, as well as improve eye sight and mental prowess. Overall, it has been maintained throughout the ages, that when made a regular part of one’s diet, tea helps us attain positive health and assures a full and quality life span. It was largely due to green tea's ability to bring calm and focus, with an elevated level of awareness during meditation, that led to its distribution, first in Japan, and then throughout the world, through the channels of Buddhist monks. But, for now, let us turn back to what science is telling us.

A scientific analysis of green tea shows that it is packed full of nutritional value. It contains vitamins A, B, B5, C, D, E, H and K. It is a rich source of manganese and contains beneficial minerals such as Chromium, Zinc and Selenium. Fresh green tea is also stacked with polyphenolic antioxidants like flavonoids and catechins, the most active, powerful and researched of which is Epigallocatechin-3-Gallate or EGGC. Studies into EGCG thus far have had promising results for health issues such as Alzheimer’s, brain function, weight loss and maintenance, type 2 diabetes, cholesterol, cardiovascular health, as well as prevention and treatment of various forms of cancer. Further studies have also found fresh, young, leaf green tea has 8 to 10 times the antioxidant levels found in fruit and vegetables and has shown to be 6 times more active than in black tea.(1) Not bad so far, hey? But wait there's more! Green tea also contains an amino acid unique to tea called L-Theanine, which has the very rare ability to pass through the brain-blood barrier. L-Theanine has been involved in studies to examine its use as a relaxing agent, for improving one’s ability to learn, as well as memory retention and for the prevention and treatment of cancer. There is also research into L-Theanine's ability to prevent vascular and blood vessel diseases.

The active compounds within green tea are extremely complex, with as many as 200 bioactive compounds. Being plant material, these compounds are not only complex, but they vary greatly in level, dependant on the area and harvesting season (Terroir) from which they came, as well as the tea making process.

At this point, I would like to expand upon this information with answers to the five most routinely asked questions I receive when out and about at events.


Can green tea help reduce cholesterol and benefit heart health?

Evidence says yes. Study results show that the antioxidant EGCG extract from green tea, lowers LDL (bad) cholesterol and triglycerides, which are linked with diabetes and heart disease. Green tea has also been shown to work as effectively as aspirin in inhibiting the formation of abnormal blood clots, or thrombosis, (the leading causes of heart attack and stroke). Several studies have concluded that pronounced cardiovascular (heart and blood vessels) and metabolic health benefits can be obtained by the inclusion of 5 or more cups of fresh, seasonal green tea to the diet each day.

 

 

Can green tea help me lose weight?

Evidence says yes. Numerous studies show that the combination of EGCG and Caffeine (not to mention the hundreds of other components in green tea) do have a significant effect on energy expenditure and fat oxidation within the human body. The thermogenic properties of green tea increase the body's metabolic rate. A study using men shows the possibility of an additional burn of between 60 and 200 calories over a 24hr period. This can be attributed to just a few cups of quality green tea per day, over and above the calories one would burn had they not ingested green tea. In addition, green tea has also proven to enable fat oxidation. One study showed an increase in fat oxidation of 17%, leading researchers to conclude green tea may selectively increase the burning of fat. All very exciting stuff, but I must point out that whilst the vast majority of studies were considered conclusive, some studies showed no metabolic increase for some individuals. They also determined that not all teas are equal in their antioxidant/ nutrient content. Unfortunately not all details of each study, such as the type of tea used, are always published, so it is difficult to know the exact reasons for these results. That said, the inclusion of green tea to one’s diet can obviously help a majority of folk maintain and even lose weight when coupled with a healthy eating plan and physical activity suited to their body type. Other related studies have found 6-8 cups of green tea per day can have an anti-obesity effect as well as reducing the risk of type 2 diabetes by up to 33%.

I think we should also take into account the many other positive health effects attributed to tea, not only within our digestive system, but right down to the level of cell health. It is well known by most that tea is antibacterial and targets bad bacteria, but recognition should also be given to the fact that tea protects good bacteria in the gut. Good gut flora enables us to better process our food efficiently and attain maximum nutritional value, which in turn pushes along the metabolism. From a holistic perspective, the synergy of tea components not only work on improving our physical body, but perhaps more importantly, reaffirm calm of mind, which can be achieved through mindful preparation of tea.

 

 

Can green tea help fight cancer?

Evidence says yes. It is well documented that antioxidants are a powerful protective agent which assist in keeping our cells and molecules safe from the destructive effects of free radicals. These free radicals are known to play a major role in physiological ageing and are the foundation of all manner of disease, one of which is cancer. Literally thousands of studies have been conducted, (half of which have been during the past few years) into the active components of green tea and their preventative and curative effects on many forms of cancer. The continuance of this research speaks volumes in itself. Published papers routinely state that, among other things, ECGC is a promising cancer treatment, both alone and with other therapies. It is also stated that "green tea and its components effectively mitigate cellular damage, arising from oxidative stress". For those interested in delving deeper into this subject I do suggest following a few of my research links. From there you can find yourself lost for days, even months as I have. I shall definitely look to write a more detailed article on this subject in the future.

 

 

Does adding milk and sugar to tea affect its health benefits?

Evidence says yes and no. An in vivo study (human) found conclusive evidence that the addition of milk to your cuppa, blocked absorption of bioactive components within tea, namely antioxidants. This is thought to be due to the complexation of tea polyphenols by milk proteins. Sugar however, has not shown to negate the positive effects of tea. That said, I will state that sugar (in the highly processed form commonly used) does pose its own oxidative risks. These risks are numerous enough to support their own article at another point. Always keep in mind there are natural herbal sweeteners available which have nutritional and health value, very few calories and great taste in their own right, such as stevia and licorice root. Local honey is also a great sweetening option that has amazing benefits of its own to share. It does however, contain a few calories, so keep this in mind if you are trying to lower your intake.

Can green tea improve brain function and my memory?

Evidence says yes. Studies show there are three key active components in green tea which have a positive effect on spatial memory and cognitive function as a whole. In short, green tea can stop memory degradation and help you become more ‘switched on’. Caffeine blocks an inhibitory neurotransmitter in the brain called Adenosine, which results in an increased firing of neurons and an increased level of neurotransmitters like dopamine and norepinephrine. As a result, improvements in mood, vigilance, reaction time and memory have been consistently recorded during studies. Next we have L-Theanine, an amino acid unique to tea. L-Theanine has the ability to cross the blood-brain barrier and increases activity of the inhibitory neurotransmitter GABA, which has anti-anxiety effects. It also increases dopamine and the production of alpha waves in the brain. So what does this mean? L-Theanine brings calm and focus to our thought patterns whilst opening blood vessels around the brain to improve cerebral circulation. This increases oxygen to the brain and enhances brain function. Studies show that Caffeine and L-Theanine work together synergistically to form a potent brain function tonic by providing an elevated level of awareness and brain function as well as enhancing memory retention, while maintaining a calm and focused state. While there is nowhere near the level of research into the effects of other components in green tea on the brain, there are some that I think rate a mention here. I have come across a study which states in conclusion; there is evidence that long term EGCG consumption may alleviate Alzheimer’s disease related cognitive deficit, meaning, it can have a preventative effect against the disease. Another study concludes the consumption of a green tea extract, rich in catechins, other than EGCG also gives protection from age related memory decline. As all tea types are rich in catechins, there is the potential benefit for brain health from all types of tea. Considering years of positive research results pertaining to the subjects enhanced focus levels and productive output, I am quite amazed that drivers at corporate level have not grabbed this information and run with it.

 

 

Considerations.

Green tea (or any tea for that matter) is a valuable addition to our diet. We must be aware that green tea is not a substitute for a healthy, nutritional diet and life style, but more an addition to it. Green tea assists us in maintaining optimum health for our life span. It is also noteworthy that whilst many of these studies are carried out with "extracts" of certain super active compounds within green tea, namely EGCG, Caffeine and L-Theanine, the benefits of green tea taken as nature intended, in its whole form, far outweigh those attained by isolated extracts alone. This is due to 'all' components working in 'synergy' with each other.

It is also good to remember that the green tea with the highest levels of these heavily studied components, come from fresh and vibrant, young spring leaves. It is my view that green tea should have the date of harvest printed on the pack as it has a nutritional life span. Green tea is seasonal; just as we do not go out and intentionally purchase last season’s fruit and veg, we as consumers, need to be asking "Is your green tea fresh and from this season?" Seek out a reputable supplier of quality tea should you wish to gain maximum levels of active nutritional benefit. Ask questions. If you are purchasing online, scan through the site and look for signs that they are reputable tea professionals. Most of all, take time to be present. Be mindful as you prepare your favourite brew, and enjoy whatever amazing tea, or tisane you choose for your cup.



 

Links to research papers

http://www.ncbi.nlm.nih.gov/pubmed/8617188

http://www.ncbi.nlm.nih.gov/pubmed/?term=12121824

http://www.ncbi.nlm.nih.gov/pubmed/?term=10918460

Antioxidant effect ot green and black tea

http://www.ncbi.nlm.nih.gov/pubmed/16463383

Lung cancer

http://www.ncbi.nlm.nih.gov/pubmed/21827739

mechanisms, perspectives and clinical applications.

http://www.ncbi.nlm.nih.gov/pubmed/19399671

defense against malignancies.

http://www.ncbi.nlm.nih.gov/pubmed/16519995 

general anti tumor properties

egcg cancer research

http://www.ncbi.nlm.nih.gov/pubmed/20628004

prostate cancer

 

 

http://www.tandfonline.com/doi/abs/10.1080/07315724.2007.10719626#preview

heart health, cardiovascular

http://www.ncbi.nlm.nih.gov/pubmed/18356827

heart health, waist circumference, dietbeties

http://www.ncbi.nlm.nih.gov/pubmed/10584049

metabolic increase plus fat oxidisation for men

http://www.ncbi.nlm.nih.gov/pubmed/18326618

Fat oxidation of 17%

http://www.ncbi.nlm.nih.gov/pubmed/21366839

meta study on metabolic and fat oxidation increase

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3689013/

Diabeties

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3689013/

Diabeties

http://www.ncbi.nlm.nih.gov/pubmed/19008868

Diabeties Type 2

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3689013/#B7

http://www.ncbi.nlm.nih.gov/pubmed/16618952

Japenese cohort study into the risk of Diabetes in green tea drinkers

http://www.ncbi.nlm.nih.gov/pubmed/24473227

Green tea is affective in controlling cholesterolemia.

http://www.ncbi.nlm.nih.gov/pubmed/22771784

Cholesterol study on rats.

 

 

http://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier

Blood brain barrier

http://en.wikipedia.org/wiki/L-Theanine

L-Theanine

http://www.webmd.com/food-recipes/features/antioxidants-in-green-and-black-tea

http://umm.edu/health/medical/altmed/herb/green-tea

all things green tea

http://www.ncbi.nlm.nih.gov/pubmed/23993501

study shows Mao feng to be Hepatoprotective (prevents damage to the liver)

 

http://www.ncbi.nlm.nih.gov/pubmed/1356551

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0773.1995.tb00111.x/abstract

Caffeine and the brain

http://www.ncbi.nlm.nih.gov/pubmed/23660953

egcg alleviates spatial learning impairment

http://www.ncbi.nlm.nih.gov/pubmed/23473881

Catechins in green tea other than EGCG also assist preventing spatial learning impairment

http://www.eurekalert.org/pub_releases/2013-02/uol-gta020413.php

Alzhiemers

 

 


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