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9 proven benefits of green tea

9 nachgewiesene Vorzüge von grünem Tee

Green tea is the healthiest drink on the planet. It is overloaded with antioxidants and nutrients that have powerful effects on our health. These include brain function, fat loss, a lower risk of numerous diseases and many more impressive benefits.

Below are 9 health benefits of green tea that are supported by scientific studies.

1. green tea contains bioactive compounds that improve health

Green tea is more than just a drink like any other. Many of the plant compounds in green tea make it a beverage that contains large amounts of important nutrients (1).

Tea is rich in polyphenols, which include effects such as anti-inflammatory, antioxidant and many other health benefits. Green tea contains about 30% polyphenols, which include large amounts of a catechin called EGCG. Catechins are natural antioxidants that help prevent cell damage and have numerous other benefits.

These substances can prevent the formation of free radicals in the body, thereby protecting cells and important molecules in the body from damage. Free radicals are also known to play a role in the ageing process and all kinds of diseases.

EGCG (epigallocatechin gallate) is one of the most powerful compounds in green tea. EGCG has been shown to alleviate various diseases and EGCG may also be the main reason why green tea has such powerful medicinal properties (2).

Green tea also contains small amounts of minerals that are important for health.

When buying green tea, make sure you choose a higher quality brand, as some of the cheaper varieties of green tea can contain excessive amounts of fluoride (3). However, even with lower quality green tea, the benefits of green tea are likely to outweigh the disadvantages.

Summary: Green tea is overloaded with polyphenol antioxidants, including the catechin ECGC. These antioxidants have numerous health benefits.

2. compounds found in green tea can improve brain function

Green tea does more than just keep you awake - it can also make you smarter. The key active ingredient is caffeine, which is known as a stimulant. Green tea does not contain as much caffeine as coffee, but enough to elicit a response without causing nervousness, restlessness or other side effects associated with too much caffeine.

In the brain, caffeine blocks a neurotransmitter called adenosine. In this way, caffeine increases the rate at which neurons fire and also increases concentrations of neurotransmitters such as dopamine and norepinephrine (4, 5).

Caffeine has been studied extensively in scientific studies and has been consistently linked to improvements in various aspects of brain function including improved mood, increased alertness, reduced reaction time and improved memory (6).

However, green tea contains more than just caffeine. It also contains 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 anxiolytic effects. It also increases dopamine levels and alpha wave activity in the brain (7, 8, 9).

Studies have shown that caffeine and L-theanine can have synergistic effects. The combination of these two compounds is particularly powerful when it comes to improving brain function (10, 11).

Because of the L-theanine it contains and the lower dose of caffeine, green tea can give you a milder and different kind of stimulating effect than coffee. Many people report more stable energy levels and higher productivity after drinking green tea compared to coffee.

Summary: Green tea contains less caffeine than coffee, but still sufficient amounts to produce an effect. It also contains the amino acid L-theanine, which can work synergistically with caffeine to improve brain function.

3. green tea increases fat burning and improves physical performance

If you look at the list of ingredients in any fat burner supplement, there's a good chance you'll find green tea on that list. This is because controlled human studies have shown that green tea increases fat burning and raises metabolic rate (12).

In a study conducted on 10 healthy men, green tea increased the subjects' energy expenditure by 4% (13). Another study showed that fat oxidation was increased by 17%, suggesting that green tea may selectively increase the burning of fat (14).

However, some studies conducted with green tea do not show an increase in metabolic rate, so it may be that these effects could be individual dependent (15).

Furthermore, caffeine alone has been shown to increase physical performance by mobilizing fatty acids from adipose tissue, resulting in an increase in the availability of fatty acids as an energy source (16, 17). Two relatively recent study reviews have shown that caffeine can increase physical performance by an average of 11 to 12% (18, 19).

Summary: Green tea has been shown to increase metabolic rate and fat burning in the short term, although not all studies agree.

4. green tea could protect your brain in old age and reduce the risk of Alzheimer's and Parkinson's disease

Green tea may not only improve brain function in the short term, but could also protect your brain as you age.

Alzheimer's is the most common neurodegenerative disease and one of the leading causes of dementia. Parkinson's is the second most common neurodegenerative disease and involves the death of dopamine-producing neurons in the brain.

Several studies have shown that the catechin compounds contained in green tea have numerous protective effects on neurons, at least in test tubes and animal models, and can potentially reduce the risk of Alzheimer's and Parkinson's (20, 21, 22).

Summary: The bioactive compounds in green tea may have various protective effects on the brain. It may reduce the risk of Alzheimer's and Parkinson's disease, which are the two most common neurodegenerative diseases.

5. green tea can kill bacteria, which can improve dental health and reduce the risk of infections

The catechins contained in green tea may have other biological effects. Some studies show that they can kill bacteria and inhibit viruses such as influenza viruses, potentially reducing the risk of infection (23, 24, 25, 26)

Streptococcus mutans is the primary harmful bacterium in the mouth. It causes the formation of plaque and contributes to the formation of caries and tooth decay. Studies have shown that the catechins contained in green tea can inhibit the growth of Streptococcus mutans. The consumption of green tea is associated with improved dental health and a lower risk of tooth decay (27, 28, 29, 30).

Multiple studies have also shown that green tea can reduce bad breath (31). Summary: The catechins contained in green tea can inhibit the growth of bacteria and some viruses. This may reduce the risk of infection and contribute to improvements in dental health, a lower risk of tooth decay and a reduction in bad breath.

6. green tea could reduce the risk of type 2 diabetes

Type 2 diabetes is a disease that has reached epidemic proportions in recent decades and now affects around 400 million people worldwide. This disease involves elevated blood sugar levels in the context of insulin resistance, or an inability of the body to produce insulin.

Studies have shown that green tea can improve insulin sensitivity and lower blood sugar levels (32). A study conducted in Japan found that those who drank the largest amounts of green tea had a 42% lower risk of developing type 2 diabetes (33).

According to a study review that looked at 7 studies with a total of 286,701 individuals, people who drank green tea had an 18% lower risk of developing diabetes (34).

Summary: Some controlled studies show that green tea can cause a mild reduction in blood glucose levels. It may also reduce the risk of developing type 2 diabetes.

7 Green tea may reduce the risk of cardiovascular disease

Cardiovascular disease, including heart attacks and strokes, is the leading cause of death worldwide (35). Studies have shown that green tea can reduce some of the risk factors for the diseases. This includes a reduction in total cholesterol levels, LDL cholesterol levels and triglyceride levels (36).

Green tea also increases the antioxidant capacity of the blood, which protects LDL particles from oxidation, which is part of the pathway towards heart disease (37, 38).

Considering these positive effects on risk factors, it is not surprising that people who regularly drink green tea have up to a 31% lower risk of cardiovascular disease (40, 41, 42).

Summary: Green tea has been shown to lower total cholesterol levels and LDL cholesterol levels, as well as protect LDL cholesterol particles from oxidation. Observational studies have also shown that people who regularly drink green tea have a lower risk of cardiovascular disease.

8. green tea can help you lose weight and reduce your risk of obesity

Considering that green tea can increase metabolic rate in the short term, it makes sense that it could also help with weight loss. In fact, several studies have shown that green tea can lead to a reduction in body fat - particularly in the abdominal area (42, 43).

One of these studies was a 12-week randomized controlled trial involving 240 men and women. In this study, a significant reduction in body fat percentage, body weight, abdominal circumference and abdominal fat was observed in the group that drank green tea (44).

However, some studies do not show a statistically significant increase in weight loss with green tea, which means that these results should be taken with a grain of salt (45).

Summary: Some studies show that green tea leads to increased weight loss. It may be particularly effective in reducing dangerous belly fat.

9. green tea could help you live longer

Of course, we're all going to die at some point - it's inevitable. However, when you consider that people who drink green tea regularly have a lower risk of cardiovascular disease and other illnesses, it makes sense that green tea could help you live longer.

In a study of 40,530 Japanese adults (46), the risk of death over an 11-year period was lowest among those who drank the greatest amount of green tea (5 cups or more per day):

  • Death from all causes: 23% lower in women, 12% lower in men.
  • Death from heart disease: 31% lower in women, 22% lower in men.
  • Death from stroke: 42% lower in women, 35% lower in men.

Another study of 14001 elderly people in Japan found that those who drank the greatest amount of green tea had a 76% lower risk of dying during the 6-year study period (47).

Summary: Studies show that people who drink green tea are more likely to live longer than people who do not drink green tea.

Anything else?

If you want to feel better, lose weight and reduce your risk of chronic disease, you may want to consider making green tea a regular part of your life.

References:

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855614
  2. https://www.ncbi.nlm.nih.gov/pubmed/28864169
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  35. https://www.who.int/en/news-room/fact-sheets/detail/the-top-10-causes-of-death
  36. https://www.ncbi.nlm.nih.gov/pubmed/23780706
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Source: https://www.healthline.com/nutrition/top-10-evidence-based-health-benefits-of-green-tea#section10

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