Green tea is the healthiest beverage on the planet.
It is loaded with antioxidants and nutrients that have powerful effects on the body.
These include improved brain function, fat loss, a lower risk of cancer and many other impressive benefits.
- Green Tea Contains Bioactive Compounds That Improve Health
Green tea is more than just liquid.
Many of the plant compounds in the tea leaves do make it into the final drink, which contains large amounts of important nutrients (1).
Tea is rich in polyphenols that have effects like reducing inflammation and helping to fight cancer.
Green tea is about 30 percent polyphenols by weight, including large amounts of a catechin called EGCG. Catechins are natural antioxidants that help prevent cell damage and provide other benefits.
These substances can reduce the formation of free radicals in the body, protecting cells and molecules from damage. These free radicals are known to play a role in aging and all sorts of diseases.
EGCG (Epigallocatechin Gallate) is one of the most powerful compounds in green tea. It has been studied to treat various diseases and may be one of the main reasons green tea has such powerful medicinal properties (2).
Green tea also has small amounts of minerals that are important for health.
Try to choose a higher quality brand of green tea, because some of the lower quality brands can contain excessive amounts of fluoride (3).
That being said, even if you choose a lower quality brand, the benefits still far outweigh any risk.
- Compounds in Green Tea Can Improve Brain Function and Make You Smarter
Green tea does more than just keep you awake, it can also make you smarter.
The key active ingredient is caffeine, which is a known stimulant.
It doesn't contain as much as coffee, but enough to produce a response without causing the "jittery" effects associated with too much caffeine.
What caffeine does in the brain is to block an inhibitory neurotransmitter called Adenosine. This way, it actually increases the firing of neurons and the concentration of neurotransmitters like dopamine and norepinephrine (4, 5).
Caffeine has been intensively studied before and consistently leads to improvements in various aspects of brain function, including improved mood, vigilance, reaction time and memory (6).
However, green tea contains more than just caffeine. It also has the amino acid L-theanine, which is able to cross the blood-brain barrier (7).
L-theanine increases the activity of the inhibitory neurotransmitter GABA, which has anti-anxiety effects. It also increases dopamine and the production of alpha waves in the brain (7, 8, 9).
Studies show that caffeine and L-theanine can have synergistic effects. The combination of the two is particularly potent at improving brain function (10, 11).
Because of the L-theanine and the smaller dose of caffeine, green tea can give you a much milder and different kind of "buzz" than coffee.
Many people report having more stable energy and being much more productive when they drink green tea, compared to coffee.
- Green Tea Increases Fat Burning and Improves Physical Performance
If you look at the ingredients list for any fat burning supplement, chances are that green tea will be on there.
This is because green tea has been shown to increase fat burning and boost the metabolic rate, in human controlled trials (12, 13).
In one study in 10 healthy men, green tea increased energy expenditure by 4% (14).
Another study showed that fat oxidation was increased by 17%, indicating that green tea may selectively increase the burning of fat (15).
However, some studies on green tea don't show any increase in metabolism, so the effects may depend on the individual (16).
Caffeine itself has also been shown to improve physical performance by mobilizing fatty acids from the fat tissues and making them available for use as energy (17, 18).
In two separate review studies, caffeine has been shown to increase physical performance by 11-12%, on average (19, 20).
- Antioxidants in Green Tea May Lower Your Risk of Some Types of Cancer
Cancer is caused by uncontrolled growth of cells. It is one of the world's leading causes of death.
It is known that oxidative damage contributes to the development of cancer and that antioxidants may have a protective effect (21).
Green tea is an excellent source of powerful antioxidants, so it makes sense that it could reduce your risk of cancer, which it appears to do:
Breast cancer: A meta-analysis of observational studies found that women who drank the most green tea had a 20-30% lower risk of developing breast cancer, the most common cancer in women (22).
Prostate cancer: One study found that men drinking green tea had a 48% lower risk of developing prostate cancer, which is the most common cancer in men (23).
Colorectal cancer: An analysis of 29 studies showed that those drinking green tea were up to 42% less likely to develop colorectal cancer (24).
Many observational studies have shown that green tea drinkers are less likely to develop several types of cancer. However, more high-quality research is needed to confirm these effects (25, 26).
It is important to keep in mind that it may be a bad idea to put milk in your tea, because some studies suggest it reduces the antioxidant value (27).
- Green Tea May Protect Your Brain in Old Age, Lowering Your Risk of Alzheimer's and Parkinson's
Not only can green tea improve brain function in the short term, it may also protect your brain in old age.
Alzheimer's disease is the most common neurodegenerative disease in humans and a leading cause of dementia.
Parkinson's disease is the second most common neurodegenerative disease and involves the death of dopamine producing neurons in the brain.
Multiple studies show that the catechin compounds in green tea can have various protective effects on neurons in test tubes and animal models, potentially lowering the risk of Alzheimer's and Parkinson's
- Green Tea Can Kill Bacteria, Which Improves Dental Health and Lowers Your Risk of Infection
The catechins in green tea also have other biological effects.
Some studies show that they can kill bacteria and inhibit viruses like the influenza virus, potentially lowering your risk of infections (31, 32, 33, 34).
Streptococcus mutans is the primary harmful bacteria in the mouth. It causes plaque formation and is a leading contributor to cavities and tooth decay.
Studies show that the catechins in green tea can inhibit the growth of Streptococcus mutans. Green tea consumption is associated with improved dental health and a lower risk of caries (35, 36, 37, 38).
Multiple studies also show that green tea can reduce bad breath (39, 40).