Green tea, a beverage with a rich historical background, has been found to offer numerous health benefits. Studies have shown that regular consumption of green tea can help prevent cognitive decline in older individuals and reduce stress and depression.
Because some people find green tea bitter and experience gastrointestinal discomfort after drinking it, Dr. Jonathan Liu, a professor at Georgian College in Canada, shares tips on maximizing the health benefits while drinking green tea through proper selection and methods of brewing in the “Health 1+1” program produced by The Epoch Times.
Liu explains that green tea is rich in tea polyphenols, which are powerful antioxidants. Free radicals are produced during the body’s metabolic processes, and these highly reactive molecules can damage cells and tissues. Tea polyphenols help eliminate free radicals, inhibit cellular mutations, and enhance the body’s immune system, thus providing anti-cancer and anti-aging effects. Green tea also contains many vitamins, amino acids, and trace elements.
Green tea, known for its non-fermented nature, contains a high catechin concentration. A review published in CNS Neuroscience and Therapeutics in 2008 highlighted the neuroprotective effects of epigallocatechin gallate (EGCG), a catechin found in green tea, which can reduce the risk of diseases such as Alzheimer’s and Parkinson’s.
A study conducted at Kanazawa University in Japan found that among 490 cognitively normal elderly individuals aged 60 and above, those who frequently consumed green tea had a significantly lower rate of cognitive decline during subsequent years of follow-up compared to those who regularly consumed black tea or coffee.
However, the researchers also noted that in Japan, people who frequently consume black tea or coffee are less likely to drink green tea, so it cannot be concluded that black tea or coffee has no effect in preventing cognitive decline.
Animal experiments have also demonstrated that green tea has antidepressant effects, helping to prevent premature aging caused by excessive stress.
A study conducted at Shizuoka University in Japan, published in Nutrients in 2022, revealed that mice with depression exhibited improvements in adrenal enlargement and brain inflammation after consuming green tea extract. Furthermore, abnormal behaviors associated with depression were reduced. The study also identified that the greatest improvement in depression occurred when the combined ratio of caffeine to EGCG was approximately 4 to 5, about the combined ratio of theanine to alanine. Among Japanese teas, sencha demonstrated better antidepressant effects than matcha or hojicha.
Another study at Shizuoka University found that male mice living together in a cage experienced higher stress levels, resulting in shorter lifespans. However, when these stressed mice consumed water containing green tea extract’s theanine, their lifespans were comparable to normal mice’s.
Additionally, when normal mice ingested theanine from green tea extract, their lifespans did not increase. Researchers believe that theanine extends the lifespan of mice by relieving stress.
Some individuals may find the taste of green tea bitter and need to become more accustomed to it. Variations in flavor may be due to improper tea selection or brewing methods. Liu advises paying attention to the following three points when brewing tea:
Choose fresh green tea with a vibrant green color and a noticeable aroma. Avoid tea with a smoky, burnt, or moldy smell.
The ideal water temperature for brewing green tea is around 185°F (85°C). The steeping time should not be too long, typically around two to three minutes, with some adjustments based on the specific type of green tea. The recommended tea-to-water ratio is 1:50, using 3 grams of tea leaves for 150–200 milliliters of water, resulting in a balanced and moderate strength of green tea.
Using porcelain or transparent glass cups for drinking green tea is recommended. Metal cups are not suitable as they can react with the tea.
In addition, green tea can also be used as a seasoning ingredient, such as in tea eggs or tea-infused chicken. Matcha powder can be used in baking to make treats like Longjing tea cookies or matcha cakes.
According to traditional Chinese medicine, foods have varying properties of cold, hot, warm, or cool, and green tea falls into the cold category, which can have a cooling effect on the body. People with a constitution leaning towards coldness may experience discomfort if they consume excessive amounts of green tea, especially those prone to diarrhea after drinking cold beverages.
Liu advises that if someone feels uncomfortable after drinking green tea, they can try lightly fermented white or yellow tea, which has similar benefits but milder properties.
The temperature of the tea should not exceed 140°F (60°C) and is ideally between 25– 77-122°F (50°C). Drinking excessively hot tea can damage the esophageal mucosa and increase the risk of esophageal cancer.
As green tea’s properties are cold, consuming tea below 50°F (10°C) can harm digestion, leading to bloating and stomach pain.
Strongly brewed tea contains a high concentration of tea polyphenols, which can cause headaches, nausea, insomnia, restlessness, and other adverse reactions.
Drinking tea on an empty stomach can dilute gastric juices and reduce digestive function.
While drinking tea after a meal can aid digestion and alleviate greasiness, waiting at least half an hour after the meal is recommended. Drinking strong tea immediately after a meal may affect the absorption of nutrients such as iron and proteins.
Tea leaves can lose most nutritional value after being steeped three to four times.
Tea polyphenols, vitamins, proteins, and other substances in tea can undergo oxidation while promoting microbial growth, leading to potential health issues.
Tea may interact with the components of certain medications.
Individuals with neurasthenia or insomnia should avoid drinking tea before sleep.