Tea is the second most consumed beverage after water. But unlike water tea is rich in antioxidant compounds called flavonoids which is said to constitute 35% of the weight of tea (Health news line from Tea Counsil of CANADA). Research has confirmed that flavonoids are potential antioxidants that have biological activities and may be responsible for many of the health benefits of tea. Tea contains no addictives. It has been chosen as a drink which is most calming and refreshing according to healthy drink survey conducted in Britain and sponsored by the UK Tea Council.
Antioxidants are nutrients found naturally in the body as well as in plants such as fruits & vegetables. Tea contains high quantities of antioxidants, however the better quality the tea and the fresher the leaves the higher concentrations will be.
This is why it is important to drink a good, fresh, whole leaf tea as opposed to the dust in tea bags. It would be wrong to say that ‘tea-bag-tea’ did not contain any goodness, however because of the number of processes it has been through and the fact that it has been ground up, many of the molecules the antioxidants are based on will have been destroyed.
Common antioxidants found in tea include compounds called polyphenols. Included within the broad antioxidant polyphenol class are flavonoids and catechins. The most important dietary sources for flavonoids are fruits, tea and soyabean.
Flavonoids are a class of water-soluble plant pigments and it is the catechin called Epigallocatechin-3-gallate (EGCG) in Green Tea that is particularly beneficial. EGCG contains 3 phenol rings and therefore has very strong antioxidant properties.
EGCG is the main active component in Green Tea leaves. Black Tea leaves also contain EGCG but in much lower quantities. Studies have shown that Green Tea has 5 times the EGCG content of regular tea. This is because Black Tea leaves are fermented, during which many of the catechins are oxidized to darker coloured molecules (theaflavin and thearubigen).
EGCG possess the most potent antioxidant activity of the catechins. ECGC may provide health effects by protecting our cells from oxidative damage from free radicals. A number of chronic diseases have been associated with free radical damage, including cancer, arteriosclerosis, heart diseases and accelerated aging. ECGC interferes with many enzyme systems: it inhibits fast-binding and reversible fatty acid synthesis, increases tyrosine phosphorylation of the insulin receptor, activation of ornithine decarboxylase. ECGC can protect the DNA in the human cells from ultraviolet and visible radiation-induced damage. ECGC may be effective in promoting fat oxidation and lowering body weight.
As cells function normally in the body, they produce damaged molecules — called free radicals. These free radicals are highly unstable and steal components from other cellular molecules, such as fat, protein, or DNA, thereby spreading the damage.
This damage continues in a chain reaction, and entire cells soon become damaged and die. This process is called peroxidation. Peroxidation is useful because it helps the body destroy cells that have outlived their usefulness and kills germs and parasites. However, peroxidation, when left unchecked, also destroys or damages healthy cells.
Antioxidants help prevent widespread cellular destruction by willingly donating components to stabilize free radicals. More importantly, antioxidants return to the surface of the cell to stabilize rather than damage other cellular components.
When there are not enough antioxidants to hold peroxidation in check, free radicals begin damaging healthy cells which, can lead to problems.
In addition to valuable antioxidant properties and contributing to our daily fluid intake target of 2.5 litres, tea contains many vitamins, minerals and amino acids that includes
Can green tea prevent cancer?
The majority of current research is focussed around cancer as it is thought that the antioxidant components of tea, and in particular Green Tea, can help to prevent cancer by combating the dangerous free radicals and inhibiting uncontrolled cell growth, due to it’s high Antioxidant levels.
Scientific findings suggest that Green Tea may prevent the following types of cancer in humans; Skin, Lung, Stomach, Colon, Pancreas, Bladder, Prostate, Oral and Oesophageal.
Tea has been shown to inhibit tumorigenesis at the initiation, promotion and progression stages of cancer (Middleton E, et al (1994), Dreosti IE, et al (1997), Katiyar SK, et al (1996))
Researchers at the University of Murcia in Spain and the John Innes Center in Norwich, England, report that EGCG (epigallocatechin-3-gallate) prevents cancer cells from growing by binding to a specific enzyme.
"We have shown for the first time that EGCG, which is present in Green Tea at relatively high concentrations, inhibits the enzyme dihydrofolate reductase (DHFR), which is a recognized, established target for anti-cancer drugs. This is the first time, to our knowledge, a known target for an anti-cancer drug has been identified as being inhibited by EGCG and EGCG is probably just one of a number of anti-cancer mechanisms in Green Tea " Professor Roger Thorneley, of JIC stated.
We are only beginning to discover the benefits of regularly taking tea, and research will continue to discover new and exciting benefits to the wonderful leaf. Needless to say by regularly drinking Green Tea we are doing wonders for our bodies whilst relaxing the mind.
It is believed that free radicals are the cause of heart disease, some kinds of cancer and increase the risk of strokes. We all take in fats and occasionally treat ourselves with the odd high cholesterol treat, they are a part of life. In order to remain healthy we must manage our levels. Green Tea acts to reduce cholesterol levels and regular consumption is therefore recommended.
Recent research has shown the following:
In 2004 a report by Sano J, Inami S, Seimiya K, Ohba T, Sakai S, Takano T, Mizuno K. concluded that Green Tea consumption was associated with a lower incidence of CAD in the present study population in Japan. Therefore, the more Green Tea patients consume, the less likely they are to have Coronary Artery Disease.
A long term study in Japan found, tea drinkers consuming more than 230gms of tea per day had significantly less risk of dying from heart disease and a lower rate of first heart attacks than those who drank less tea. Men in the study whose antioxidant intake was greatest had one-third the risk of death from coronary heart disease than those who consumed minimal levels.
One study in Japan found an average decrease of eight total cholesterol levels for men with the highest daily intake of Green Tea, compared to ones with the lowest.
In 2004 a study in China (Yang YC, Lu FH, Wu JS, Wu CH, Chang CJ.) showed habitual moderate strength Green or Oolong Tea consumption for 1 year, significantly reduces the risk of developing High Blood Pressure (hypertension) in the Chinese population.
Drinking tea regularly has been shown to improve the immune system. The Polyphenols in tea have been shown to help increase the white blood cell count, which is responsible for fighting infection. The high vitamin C content found primarily in Green Tea also helps to strengthen the immune system.
Increase your metabolism
Did you know that drinking tea can help you lose weight and when taken without milk contains no calories?
Many of the modern diet supplements now contain Green Tea Extract, the reason is that it makes the body burn fat quicker.
The leaves of tea plant are thermogenic, which means that Green Tea raises the metabolism without increasing the heart rate, meaning you burn more calories.
Much has been written lately about Pu Erh tea and it’s ability to assist in weight management. This type of tea is widely drunk in China with meals to aid digestion. It’s ability to increase digestion of fatty foods with incredible efficiency is why it is recommended that this tea is drunk with meals. It is also proven to reduce cholesterol levels when drunk regularly, again with meals.
Tea, Caffeine and your body
Caffeine acts as a stimulant to the nervous system, and its mild action may help to prevent a feeling of fatigue. However, it is also a weak diuretic, which stimulates the production of urine by depressing secretion of anti-diuretic hormone. The suggested maximum daily intake is 300mg.
Tea does contain caffeine, however significantly less than coffee. A typical cup of Black Tea contains around 50mg per 190ml cup compared to up to 150mg in a coffee. Green Tea contains even less caffeine, typically around 25mg per cup, with White Tea containing even less at an average of 20mg.
Over the past decade or so we have become far too used to popping into Starbucks for a Skinny Latte or a Double Espresso on a regular basis without thought for the amount of caffeine we are consuming. This puts undue stress on the body and the mind and we are slowly beginning to move towards a more health conscious society in which Tea will play an important role once again.
Recently a panel of experts, which included internationally renowned nutritionists and biochemists, identified tea drinking as being hydrating rather than dehydrating and something that, due to its relatively low caffeine content, was mood enhancing yet had no negative effect on sleep quality or duration.
Up to 70% of our body is water and it is therefore important to replace fluids that are lost through day-to-day activities. The suggested daily intake of water is 2.5 litres.
Due to the low caffeine levels found in Green Tea and White Tea, they would not be classed as being diuretic and can be drunk throughout the day all of which will count toward your daily intake of fluids.