The Health Benefits of Green Tea

Cat Cunningham explores how this ancient medicine-turned popular beverage might improve your health.

Photo by Nathan Dumalo

Green tea comes from the Camellia Sinensis plant and remains unprocessed, unlike black tea (one example of which being English breakfast tea) which is fermented to change the colour and flavour. As it is one of the least processed types of tea, it contains the most antioxidants and beneficial polyphenols.

The origin of green tea goes back as far as 5000 years. It is thought to have been discovered in 2737 B.C. when the Chinese Emperor Shennong drank water that had a dead tea leaf boiled in it by mistake. The Emperor found the flavour to be very refreshing and as such, a new drink was born.

To begin with, green tea was very expensive and only available to the highest tiers of Chinese society. It took until the 14th Century for tea to be enjoyed by the general public in China and the Far East, before travelling across to the West in the 19th Century. The popularity of green tea has increased in the last few decades, with many discoveries about its impressive health benefits.

A brief disclaimer: we are not medical professionals, so please consult your doctor before making any significant adjustment to your diet.

1. High in Antioxidants

Green tea is rich in catechins and epigallocatechin gallate (EGCG) - active antioxidants that are able to prevent and fight against cell damage. They form an important part of a healthy diet and are also known to protect against disease.

2. Boosts Brain Function

Green tea contains the mental stimulant, caffeine. Caffeine increases the firing of neurons and the concentration of neurotransmitters like dopamine and norepinephrine by blocking the inhibitory neurotransmitter, adenosine. It has consistently been proven that in moderation, caffeine improves various aspects of brain function such as memory, mood, vigilance and reaction time.

Green tea also contains the amino acid L-theanine which increases dopamine levels in the body, the activity of the inhibitory neurotransmitter GABA and the production of alpha waves in the brain which regulate mental alertness.

The combination of caffeine and L-theanine improves brain function and provides a more stable, productive energy than other drinks containing caffeine such as coffee. Research has also suggested that the brain’s cognitive functions could be enhanced by green tea, a discovery that could be promising in the treatment of cognitive impairments associated with neuropsychiatric disorders such as dementia.

3. Heart Benefits

A 2006 study on the benefits of green tea followed 40,000 Japanese adults between the ages of 40 and 79 for 11 years. The study concluded that green tea consumption can be associated with reduced mortality, including death from cardiovascular disease. The study found that those who drank at least 5 cups of tea a day had a lower risk of dying than those who only drank one cup.

4. Protects Against Cancer

Research has suggested that green tea has an impact on the following types of cancer: breast, bladder, lung, prostate, ovarian, bowel, throat, skin and stomach. The National Cancer Institute have claimed that the polyphenols in tea have been shown to decrease tumour growth in laboratory and animal studies. It is thought that the high levels of polyphenols can kill cancer cells and stop them from growing. It has also been observed that in countries where green tea consumption is higher, cancer rates are often lower.

However, there is no way to know for sure if this comes as a result of drinking green tea or other lifestyle factors. These findings are up for debate as other studies have not found that green tea can reduce cancer risk, and the amount of tea required for cancer-preventative effect varies in studies from 2-10 cups a day.

5. Treatment for Inflammatory Skin Diseases

In 2007, a study found that green tea could potentially be used to treat skin disorders such as dandruff and psoriasis. An animal model was studied for inflammatory skin diseases, often characterised by inflammation and overproduction of skin cells. They found there was a slower growth of skin cells, as well as the presence of a gene that regulates the cell’s life cycles, in those treated with green tea.

6. Lowers Cholesterol and Blood Pressure

The catechins in green tea can also lower cholesterol and blood pressure, helping to protect against the damage that a high-fat diet can cause.

As you can see, green tea is thought to have a range of health benefits; however, some of the evidence is inconclusive. Historically, it has been used in traditional Indian and Chinese medicine for years, which may explain the basis for some of the health claims. The information in this article has come from the expertise of different expert sources rather than the author herself, but there remain some conflicting opinions as to the extent of the various health benefits outlined.

Article on a similar topic: The Health Benefits of Turmeric

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