Green tea is derived from the plant called Camellia sinensis, which originated in China. But after awhile, this became associated with other cultures in Asia and been widely used in the West as well. Green tea is used both as a medicine and beverage in most countries in Asia including Vietnam, China, Japan Korea, and Thailand. It has been used as a common raw material in different health foods, beverages, cosmetic items, and dietary supplements that are available in the market.
Over the years, green tea has undergone several clinical and medical studies to conclude the long-term health benefits it can provide to any person. According to some evidences, drinking green tea regularly may help a person lower his or her risk in developing heart diseases. Aside from that, caffeine and polyphenol (green tea extract contents) can help boost the metabolism and help in the weight loss process. Green tea also contains high amount of flavonoids, a group of phytochemicals that provides antioxidative and anticarcinogenic effect. However, it was reported that the amount of flavonoids varies depending upon the tea products itself.
What is Green tea used for?
During ancient times, green tea had been used to control bleeding, regulate body temperature, help in wound healing, promote digestion, and maintain normal blood sugar levels.
After several years of intensive research and experimentation, green tea have been proven to provide several health benefits particularly on heart diseases and cancer.
There are many researches that are done to show the positive effect of green tea in the heart. In Japan, an experiment is done involving 500 participants. Researchers eventually concluded that drinking a minimum of four cups of green tea each day may help decreased the severity of coronary heart diseases particularly on male participants. Also, in a Dutch study, it shows that if more green tea is being consumed, there is less severity of clogging in the blood vessels of the heart. A researcher also stated that the powerful anti-oxidant property of green tea helps a lot in improving the overall condition of the heart.
According to a study, green tea’s epigallocatechin-3-gallate (EGCG) can help in regulating and inhibiting the growth of cancer cells. The consumption of green tea before and after surgery (for patients with Stage I and II breast cancer) can help lower the chances of cancer recurrence. Several studies indicate that drinking green tea can lessen the risk of developing lung cancer, esophageal cancer, stomach cancer, prostate cancer, colorectal cancer,and pancreatic cancer.
Aside from these two important health benefits of green tea, there are also other various positive health effects it can provide including;
- Powerful anti-oxidant
- Orthostatic hypotension
- Helps in weight loss
Research shows that green tea can help lower the bad cholesterol and fight against obesity. This will also eventually result to lowered blood pressure.
Common green tea side effects
For most adults, green tea is likely safe especially to those who use it short-term. However in some people, this can lead to constipation and stomach upset.
If a person exceeds to five cups a day, this can possibly lead to some unwanted side effects because too much caffeine is in the body. The side effects can be mild to severe, and this includes the following;
- Sleep problems
- Irregular heartbeat
- Tinnitus (ringing of the ear)
- Iron deficiency anemia (due to decreased iron absorption)
- Liver disorders
- Kidney problems
- Allergic reaction (identified through signs and symptoms like difficulty breathing, rashes, pruritus, and swelling of the mouth and throat)
Green tea side effects on children
The amount of caffeine that is usually found on many foods is possibly safe for children. However, green tea may contain 40 mg of caffeine per cup, and this is somewhat a high amount. If it is taken on a large quantity, the caffeine can stimulate the child, leading to hyperactivity.
It is recommended that children should not to take green tea because it also contains high amount of tannin acids. Tannin acids may interfere in nutrient absorption such as in fats and protein. Also, green tea can cause weakening of the bones and dental problems.
Green tea side effects on men
According to a study, drinking more green tea can help men in lowering their risk of acquiring prostate cancer. However, more research is needed to support this claim since another research shows that higher consumption of green tea does not affect the Prostate-Specific Antigen (PSA) levels.
The risk for lung cancer (another disorder that is common in men) can be reduced through drinking green tea more regularly.
If green tea is not taken properly, men can experience the side effects that are listed above.
Green tea side effects on women
For women, green tea can help reduce their risk of having breast cancer. According to studies, polyphenols (green tea content) inhibit the growth of cancer cells. Women who drank more green tea have lesser spread of cancer cells. Also, they found out that those women who drank at least five cups of green tea every day before they were diagnosed with breast cancer have lesser chances of having recurrence. Green tea is also said to be beneficial for women with ovarian cancer.
Women who are taking oral contraceptive pills should take precaution because green tea can interact with this medication. Contraceptive pills can prolong the stay of caffeine in the body. In effect, it may increase the stimulating effects of green tea.
Green tea side effects on pregnant women
Drinking green tea in small amounts is likely safe for pregnant women. Consuming more than 200 mg of caffeine (or approximately more than 2 cups of green tea a day) can be dangerous to the unborn child. This can lead to miscarriages and neural tube defects.
Caffeine from green tea can also pass into the breast milk and this can affect the infant. In order to be safe, avoid drinking too much green tea during breastfeeding.
Green tea side effects on elderly
For elderly clients who are diagnosed with glaucoma, green tea should be avoided since it can further increase the pressure in the eyes.
Also, elders with osteoporosis should be cautious when taking green tea. Remember that caffeine should only be consumed for 300 mg or below per day (approximately 2-3 cups) since it can flush out calcium out of the body. Once there is inadequate calcium in the body, the bones might be weakened. However, you can supply the calcium that was lost in the body by taking calcium supplements.