Benefits of Green Tea

Since 500 years ago, humans have enjoyed steeping tea leaves in boiling water. Tea (Camellia Sinnensis) is the most widely consumed beverage in the world after water.

Modern medical research shows many benefits of green tea for health. Most of the benefits related to polyphenols, a powerful antioxidant phytochemical that gives a bitter taste of green tea. There are four primary polyphenols found in the tea leaves,i.e. Epigallocathecin Gallate (EGCG), Epigallocatechin (EGC), Epicatechin Gallate (ECG), and Epicatechin (EC). Recently, researchers have focused amino acid of tea called theanine. Theanine (also called L-Theanine) is a primary amino acid in green tea leaves which gives a distinctive flavor tea.

Here are the benefits of green tea

1. Reducing the risk of heart disease and colorectal cancer. People who regularly drink green tea can significantly reduce the risk of death from heart disease or colorectal cancer. According to a Japanese study, consuming 7 cups of green tea per day is necessary to achieve long-term profitability. the study evaluated 12,251 Japanese adults aged 65-84 years old. The researchers found that people who drank at least 7 cups per day lowered the risk of death from heart disease by 75% compared to people who drank less than a cup per day. The researchers also found that the risk of colorectal cancer is 31% lower for people who drank 7 cups a day than people who drank less than 3 cups of green tea a day. Benefits of green tea on cardiovascular disease and colorectal cancer is caused by the green tea polyphenol level are high (30%-40%) than black tea that only 3%-10%.
2. Helping to against esophageal and bladder cancer. A 1994 study published in the official journal of the U.S. National Cancer Institute have shown that drinking green tea reduced the risk of esophageal cancer by 60%. An August 2009 study concluded that green tea may be useful against bladder cancer.
3. Reducing cholesterol and blood pressure. A Japanese study also reported that theanine of green tea reduces hypertension, but had no effect on normal blood pressure. The Japanese researchers found that theanine lowers cholesterol, increases good cholesterol and prevent it become bad cholesterol due to the oxidation.
4. Reducing depression and stress. Green tea contains a small amount of stimulated natural caffeine. Theanine balances the stimulatory effects of caffeine on the nervous system. Theanine creates a sense of relaxation within 30-40 minutes after ingestion in two ways. First, it stimulates the brain's electrical activity to produce alpha waves in the brain. It implies creating relaxation and mental alertness similar to achievement through meditation. Then, theanine effects brain chemistry to enhance neurotransmitters, dopamine, and serotonin. The important chemical components of the brain produces a feeling of well-being and relaxation.
5. Increasing the concentration of learning. Theanine contained in green tea increases the ability to learn, remember, and concentrate. That's why historically the monks and scholars drank tea to aid the meditation and study. A 2007 study found that green tea work synergistically with caffeine to stimulate cell activity in the brain. The researchers found that 100 milligrams of theanine (from 4 cups of tea) is enough to make more focused on complex tasks.
6. Improving the quality of life of cancer patients. A Japanese study published in 2002 found that theanine from green tea can help improving the quality of life of cancer patients by optimizing the effectiveness of anti-cancer drugs and relaxing. The study found that theanine increases the concentration of anti-cancer drugs in tumors while reducing the level of these drugs in normal tissues. The beneficial effects theanine increases the effectiveness of treatment and reduces the side effects. Theanine also inhibits the growth of cancerous tumors. The survey conducted in Japan, where green tea is very popular, it has been found that drinking green tea reduced the incidence of liver cancer, pancreatic, breast, prostate, lung, throat, and stomatch.
7. Strengthening the immune system. A study conducted by Harvard Medical Schools showed that theanine in green tea enhance immunity to colds and flu and a strong immune response.
8. Losing weight. According to a Japanese study in 2004, theanine can help losing weight. In studies conducted in animals, giving theanine increases the metabolism and lose weight, body fat, and triglyceride.
9. Strengthening bones. Hongkong researchers have found that green tea may be beneficial to bone. Their laboratory experiments found that one of the main components of green tea (Epigallocatechin, EGC) stimulates the enzymes which encourage bone growth. Epigallocatechin also improves bone mineralization in the cells which strengthens bones and reduces the activity of osteoclasts that weaken bones.
10. Reducing the risk of colon cancer for women. A study by Japan's National Cancer Center found that women who drank at least five cups of green tea a day have 20% lower risk of developing colon cancer. The researchers said that a component of green tea fight against the bacteria associated with colon cancer. Instead, men apparently did not get the benefits of anti-colon cancer of green tea.

Besides, other studies have shown that green tea useful for diabetes, stress, cavities, arthritis, protection of UV radiations, and viral infections.

After knowing the many health benefits of green tea, you may want to immediately prove it. 

But, How Many Cups a Day Should You Drink?

Most studies have found that the health benefits of green tea experienced by people who drink 3 to 10 cups a day. Green tea give a few side effects even consumed in large quantities. Staining of teeth is probably the most common problem. Using a toothpaste containing bicarbonate and hydrogen peroxide can prevent it.

Most side effects of green tea related to caffeine. Caffeine in green tea can cause problems such as increased heart rate or insomnia for some people. Caffeine can cross the placenta and are found in the breast milk, which means the pregnant and lactating mothers may need to avoid green tea. Caffeine can also interact with some medicines. Green tea should not be mixed with adenosine, aspirin, benzodiazepines, beta-blockers, blood thinners, chemotherapy, clozapine, ephedrine, lithium, monoamine, oxidase inhibitors, oral contraceptives, and phenylpropanolamine. For interaction with other medications, discuss with your doctor :)

Green tea also contains tannins, which may restrict the absorption of iron from fruits or vegetables. Brewed tea with lemon (which is rich in vitamin C) to overcome it.

How to Serve Green Tea?

You will get the most benefits of green tea by brewing into hot water and let it for 3-5 minutes to pull out its catechins. Green tea which is made from older leaves tend to have more catechins. Green-teabags have more fewer catechins than brewed tea, while green tea on extra capsules give a similar amount of catechins of brewed tea. Typically, you need at least 250-400 mg of green tea polyphenols a day or three cups.

Sources: majalahkesehatan

Picture taken from slimming-greentea.blogspot