September 2, 2013 | by Kris Gunnars | 47,712 views | 42 Comments
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).
Bottom Line: Green tea has been shown to boost the metabolic rate and increase fat burning in the short term, although not all studies agree.
4. Antioxidants in Green Tea May Lower Your Risk of Various Types of Cancer
Cancer is caused by uncontrolled growth of cells. It is one of the world’s leading causes of death.
It is well known that oxidative damage contributes to the development of cancer and that antioxidants can have a protective effect (21).
Green tea is an excellent source of powerful antioxidants, so it makes perfect sense that it could reduce your risk of cancer, which it appears to do:
- Breast cancer: A meta-analysis of observational studies found that whomen who drank the most green tea had a 22% 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: A study of 69,710 Chinese women found that green tea drinkers had a 57% lower risk of colorectal cancer (24).
Multiple other observational studies show that green tea drinkers are significantly less likely to get various types of cancer (25, 26, 27).
It is important to keep in mind that it may be a bad idea to put milk in your tea, because it can reduce the antioxidant value (28).
Bottom Line: Green tea has powerful antioxidants that may protect against cancer. Multiple studies show that green tea drinkers have a lower risk of various types of cancer.
5. 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, potentally lowering the risk of Alzheimer’s and Parkinson’s (29, 30, 31).
Bottom Line: The bioactive compounds in green tea can have various protective effects on neurons and may reduce the risk of both Alzheimer’s and Parkinson’s, the two most common neurodegenerative disorders.
6. Green Tea Can Kill Bacteria, Which Improves Dental Health and Lowers Your Risk of Infection
Some studies show that they can kill bacteria and inhibit viruses like the influenza virus, potentially lowering your risk of infections (32, 33, 34, 35).
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 (36, 37, 38, 39, 40, 41).
Bottom Line: The catechins in green tea may inhibit the growth of bacteria and some viruses. This can lower the risk of infections and lead to improvements in dental health, a lower risk of caries and reduced bad breath.
7. Green Tea May Lower Your Risk of Type II Diabetes
Type II diabetes is a disease that has reached epidemic proportions in the past few decades and now afflicts about 300 million people worldwide.
This disease involves having elevated blood sugar levels in the context of insulin resistance or an inability to produce insulin.
One study in Japanese individuals found that those who drank the most green tea had a 42% lower risk of developing type II diabetes (46).
According to a review of 7 studies with a total of 286,701 individuals, green tea drinkers had an 18% lower risk of becoming diabetic (47).
Bottom Line: Some controlled trials show that green tea can cause mild reductions in blood sugar levels. It may also lower the risk of developing type II diabetes in the long term.
8. Green Tea May Reduce Your Risk of Cardiovascular Disease
Cardiovascular diseases, including heart disease and stroke, are the biggest causes of death in the world (48).
Studies show that green tea can improve some of the main risk factors for these diseases.
Green tea also dramatically increases the antioxidant capability of the blood, which protects the LDL cholesterol particles from oxidation, which is one part of the pathway towards heart disease (50, 51, 52).
Given the beneficial effects on risk factors, it is not surprising to see that green tea drinkers have up to a 31% lower risk of cardiovascular disease (53, 54, 55).
Bottom Line: Green tea has been shown to lower total and LDL cholesterol, as well as protect the LDL particles from oxidation. Observational studies show that green tea drinkers have a lower risk of cardiovascular disease.
9. Green Tea Can Help You Lose Weight and Lower Your Risk of Becoming Obese
Given that green tea can boost the metabolic rate in the short term, it makes sense that it could help you lose weight.
Several studies show that green tea leads to decreases in body fat, especially in the abdominal area (56, 57, 58).
One of these studies was a randomized controlled trial in 240 men and women that went on for 12 weeks. In this study, the green tea group had significant decreases in body fat percentage, body weight, waist circumference and abdominal fat (59).
However, some studies don’t show a statistically significant increases in weight loss with green tea, so this needs to be taken with a grain of salt (60).
Bottom Line: Some studies show that green tea leads to increased weight loss. It is particularly effective at reducing the dangerous abdominal fat.
10. Green Tea May Decrease Your Risk of Dying and Help You Live Longer
Of course, we all have to die eventually. That is inevitable.
However, given that green tea drinkers are at a lower risk of cardiovascular disease and cancer, it makes sense that it could help you live longer.
In a study of 40,530 Japanese adults, those who drank the most green tea (5 or more cups per day) were significantly less likely to die during an 11 year period (61):
- Death of 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 in 14,001 elderly Japanese individuals aged 65-84 years found that those who drank the most green tea were 76% less likely to die during the 6 year study period (62).
