what is in green tea?

What is in green tea?

Green tea, like black tea,  is made from the Camellia sinensis shrub. The major difference between the two types comes in the processing method. For green tea, the leaves are picked and sent straight off to be steamed or dried to prevent fermentation. Black tea leaves are left to ferment after picking.

How is it made?

Green tea is grown and processed in a number of different ways. Harvesting usually takes place three times a year. After the leaves are harvested, it is important to prevent any oxidization from taking place. Oxidization is the process that occurs when enzymes in the leaves react with oxygen in the air and the leaves turn brown. By gently heating the leaves, this chemical reaction is stopped and the leaves remain green.  Leaves are heated using both traditional and modern methods. In China, green teas are often pan-fired in large woks where the leaves are stirred constantly for even drying. They are also sun dried or oven dried. In Japan the leaves are steamed – they may be steamed in a bamboo tray over water or processed by mechanical means.

What does it taste like?

When green tea is brewed it is a light greenish, yellow color. What it tastes like depends on many factors. There are different types of green tea grown and produced all over the world today and the environment in which they are grown affects their final flavor. Tea grown in a hot, tropical environment tastes different to one grown in a cool, mountainous climate.

Other factors that can affect the final product are cultivation practices, parts of the plant used, time of year when tea is plucked, whether the plants are treated with chemicals and how the leaves are shaped, rolled and dried. The taste of green tea is commonly described as earthy, nutty, toasty, seaweed-like, lush and grassy. If brewed correctly, its taste is mildly astringent.

What is in it?

The main green tea nutrients are polyphenols (catechins), caffeine, tannin (flavonols), theophylline, theobromine, fat, wax, saponins, essential oils, carotene, vitamin C, vitamins A, B1, B12, K and P, fluoride, iron, magnesium, calcium, strontium, copper, nickel, zinc, and other trace of elements.


The catechins are the component that makes the tea astringent. Green tea is rich in catechin polyphenols. The fact that green tea is made from unfermented leaves, means it contains a higher concentration of powerful antioxidants or catechin polyphenols.  A catechin called apigallocatechin gallate (known as EGCG) is  the most active of these compounds.

Researchers think the reason green tea is good for your health is mostly due to the powerful antioxidant potential of the catechins. In fact, the antioxidant effects seem even greater than vitamin C.  Antioxidants fight free radicals in the body that damage the DNA and even cause cell death. Free radicals are believed to accelerate aging and can cause many health problems.


Green tea contains about 30 to 50 milligrams of caffeine per cup, but the percentage is influenced by various factors such as the growth stage of the leaf.  The effects of caffeine on the body have been studied extensively. It stimulates the nervous system, heart and muscles by increasing the release of certain chemicals in the brain. It is well known to improve various aspects of brain function, including thinking and alertness.

Green tea also contains L-theanine, an amino acid that has been studied for the calming effect it has on the nervous system. It promotes the formation of the neurotransmitter, dopamin, and changes serotonin levels in the brain.  Studies of L-theanine and caffeine in combination have showed how they act together to improve brain performance. This is a way of getting the benefit of caffeine and yet feeling calm at the same time.

Vitamins and Minerals

Green tea is a rich source of a variety of vitamins and minerals. It contains a number of the B vitamins as well as vitamin C and K.  The carotine it contains is a precursor to vitamin A.  Folic acid, manganese, potassium and fluoride are all minerals that contribute towards its beneficial effect.

Health benefits

The health benefits of drinking green tea have been widely discussed. The most significant benefits are covered briefly below.

Cardiovascular diseases, including strokes and heart attacks are a major cause of death. Studies show that green tea improves some main risk factors for such diseases. One study proved that the antioxidants in green tea can help to significantly reduce LDL cholesterol as well as protect the LDL particles from oxidation. The results of various studies have lead researchers to conclude that consumption of green tea can reduce the risk of cardiovascular disease.

Multiple studies have showed that green tea drinkers have a lower risk of various types of cancer. The University of Maryland Medical Center cites several of these studies. Researchers believe that polyphenols help kill cancerous cells and stop them from growing. Some of the studies have showed reduced risk for several types of cancers, including skin, breast, and bladder.

Data from several studies show that green tea polyphenols may possibly protect against neurodegenerative diseases. They have some protective effect on neurons.

When combined with the natural caffeine content of green tea, EGCG seems to stimulate the central nervous system and transform fat into fuel (thermogenesis). One study, a randomized controlled trial in 240 men and women that went on for 12 weeks showed significant decreases in body weight, body fat percentage, abdominal fat and waist circumference. Various other studies have been done that don’t show significant weight loss and inconclusive results mean more research is needed in this area.

Some controlled trials have showed a mild reduction in blood sugar levels from green tea. This could possibly lower the risk of developing type II diabetes with long term consumption.

Not all green teas are created equal

An analysis of the purity and strength of 30 green tea products by ConsumerLab.com offered some interesting results. They found greatly varying EGCG levels in the various brands, including bottled and brewable green tea. Brands also varied considerably in the amount of caffeine they contained. While some contained virtually none, others contained a similar amount to what is found in a regular cup of coffee. Their tests of brewable teas even revealed lead contamination in the tea leaves of some of the products.  None of the products exceeded the USDA lead limit when brewed but high amounts of lead remained in the tea leaves.

What to look for in a green tea

It is critical to choose and use green tea wisely.

  • Green tea brewed from loose tea leaves appears to offer the most potent source of antioxidants like EGCG. Drinking some bottled green teas is just as good as drinking flavored water!
  • You have probably heard of Matcha which is a fine powder made from green tea leaves. When you drink this tea, you are consuming the leaves so you get the fully potency of the antioxidants. However,  some of these powders contain additives and sweeteners. Another concern is the possibility of contaminated leaves being used to make the powder.
  • When selecting tea of any kind, it should preferably be organic (no pesticides!)
  • Even when you buy organic tea, you need to check where it is grown. Heavy metals and other toxins from soil and water subjected to pollution can penetrate into the tea leaves. The purest, high quality tea will come from a pristine growing environment.
  • Remember that caffeine content can vary widely.


It is important to drink green tea in moderate amounts. Drinking excessive amounts  is not advised as this can cause some serious side effects.  Pregnant and breastfeeding women should avoid green tea. To be safe, it’s always best to check with a health care provider before drinking green tea, especially if you also take other medications.


Drinking green tea every day has the potential to benefit your health in many ways. It can even prolong your life by lowering your risk of chronic diseases such as heart disease and cancer. It may help you to lose weight and feel better too.  However, you need to make sure the brand you are drinking is of good quality and be wise about the amount you drink.

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