According to ancient Chinese medicine, green tea has been consumed for 4,000 years for its beneficial health qualities. Enjoyed for its taste, it has been primarily lauded for its potential medicinal benefits including reducing the risk of cancer, strokes, improving brain function, and so much more.
Although hundreds of studies have been done, none have been entirely conclusive. Many studies point to a positive link between consuming green tea and potential health benefits, but the hard evidence is not all there. Regardless, it is generally believed that green tea may be among one of the healthiest things you can drink.
Green tea may improve your brain function, make you smarter, and think quicker. Green tea contains the amino acid L-theanine, which in conjunction with the caffeine contained in green tea, may reduce anxiety.
Green tea contains less caffeine than coffee but has enough to keep you awake and improve brain function. Although, some people with a sensitivity to caffeine might want to stay away.
Green tea may protect your aging brain, too, by reducing your risk of getting Alzheimer’s and Parkinson’s disease. A 2010 laboratory study found green tea can protect against the nerve cell death associated with dementia and Alzheimer’s disease. Meanwhile, more research demonstrated a link between the polyphenols contained in green tea to be a brain protector that assists with nerve regeneration.
Some studies have shown that green tea may help your body to burn fat and boost your metabolic rate. One study involving 10 men found that drinking green tea regularly increased energy expenditure by 4 percent. Another study showed fat oxidation increased by 17 percent.
There have been hundreds of studies reviewing the effect of green tea on cancer mainly as a preventive agent, however, it may potentially be used as a medicine to treat it as well. Many studies support the belief that the catechins (or flavonoids) found in tea may prevent tumor formation. There have been specific studies conducted, too:
- Stomach and breast cancer: Green tea might be part of a cure for stomach and breast cancer. A 2015 study found a compound from green tea when combined with a drug called trastuzumab (Herceptin) may be used in the treatment of stomach and breast cancer. Additionally, a meta-analysis of studies found women who drank a lot of green tea had a 22 percent lower risk of developing breast cancer, the most common cancer in women.
- Prostate cancer: One study found that men who drank a lot of green tea had a 48 percent lower chance of developing the most common type of cancer in men—prostate cancer.
- Colorectal cancer: A study of over 69,000 women in China found that regular green tea drinkers had a 57 percent lower risk of colorectal cancer. Colorectal cancer is cancer that can form in the colon, rectum, or bowel.
Cholesterol, Diabetes, and Blood Pressure
It is believed that drinking green tea may help to lower cholesterol. A review from 2013 that involved 821 people found that if you drink green tea or black tea on a daily basis it may help cut down your cholesterol and lower your blood pressure due to the catechins in the tea.
A study in Japan found that those who drank a lot of green tea had a 42 percent lower risk of developing Type 2 diabetes. Diabetes, which affects approximately 300 million people, involves having elevated levels of blood sugar and a reduced ability to produce natural insulin. Green tea may improve insulin sensitivity and reduce blood sugar levels.
Teeth, Skin, and Immunity
Green tea is potentially good for your teeth. The catechins in green tea can kill bacteria and can reduce the chance of catching the influenza virus.
Green tea may have skin benefits, too. The antioxidant and anti-inflammatory properties within green tea can help with wrinkles and the signs of aging. Both human and animal studies have shown green tea applied topically can reduce sun damage.
Drinking more green tea may even prolong your life. In a Japanese study, 40,530 adults who drank five or more cups of green tea a day were significantly less likely to die over an 11-year period—women more than men—woman were 23 percent less likely, meanwhile, men were 12 percent less likely.
How Much Should You Drink?
There are mixed opinions about how much green tea you should consume daily. The reality is one cup of green tea is probably not enough to affect your health. Some believe two cups of green tea will show benefits while others say five. Some people say up to 10 cups is ideal, but if you are concerned about making many trips to the bathroom, instead, you can add a green tea capsule-like supplement to your diet.
Green Tea Side Effects
Generally speaking, the benefits of green tea seem to outweigh the risks. However, green tea may not be for everyone, it can have a few side effects. Green tea contains tannins which can decrease the absorption of iron and folic acid. So, if you are pregnant or trying to conceive, green tea may be less than ideal.
Other potential risks may include a higher risk of osteoporosis since the tea tends to flush calcium from the system when consumed in higher amounts. Other side effects include jitteriness from the caffeine, and maybe an upset stomach if you are sensitive to caffeinated drinks.