The mainland is a big country that drinks tea, and the research on tea has been mainly focused on green tea. However, recent research suggests that regular consumption of black tea may also bring a range of benefits.
A study conducted by the National Institutes of Health analyzed data from about 500,000 subjects aged 40~69 years in the UK Biodatabase. The researchers conducted a questionnaire survey during 2006~2010 and followed the subjects for an average of 11.2 years.
The study found that subjects who drank ≥ 2 cups of tea per day were moderately associated with a reduced risk of all-cause mortality, and people who drank 2~3 cups of tea per day had a lower risk of death than those who drank ≤ 1 cup of tea per day. Especially in the group that mainly drank black tea, those who drank ≥ 2 cups of tea per day had the lowest risk of death, and were also associated with a reduced risk of cardiovascular disease, ischaemic heart disease, and stroke mortality.
Researchers believe that this is related to the rich tea polyphenols, flavonoids and other substances, which help reduce oxidative stress and inflammatory response.
First, the black tea, green tea, and black tea at home have been left for a few years, can they still be drunk?
There is a rumor that "the older the tea, the more fragrant it is", is this true?
In fact, tea also has a shelf life. Unlike what many people think, tea is actually very easy to spoil.
First of all, tea leaves are very hygroscopic, if not properly sealed, it is easy to get moisture, and at the same time absorb peculiar smells in the air. Secondly, tea polyphenols, theanine and other components in tea are not very stable and will change over time, affecting the flavor and quality of tea.
Of course, not all tea leaves are suitable for long periods of time. For example, white tea, black tea and Pu'er raw tea, if properly preserved, will indeed become older and more fragrant. However, this requires the right preservation conditions as well as the right time conditions.
Specifically, the shelf life of green tea at room temperature is generally about one year, which is not suitable for long-term storage.
After opening, oolong tea is refrigerated and has a shelf life of about 8 months.
The shelf life of black tea is generally three years.
The shelf life of Pu'er raw tea is about 5 years, and the shelf life of cooked tea is more than 15 years.
The longer white tea and black tea are left out, the better the taste and quality.
If the tea leaves have gone bad, never drink it. To identify whether the tea leaves have deteriorated, you can use the method of smelling, seeing and brewing three times. First, smell the tea leaves, whether there is a stale or musty smell. Secondly, observe the color of the tea leaves, if the color becomes dark, it will break with a pinch, and it is likely to have deteriorated. Finally, brew tea to observe the color of the tea, if the tea is cloudy, it means that the tea leaves may have deteriorated. After tea deteriorates, harmful substances may be produced, which is harmful to health.
Second, people with different physiques are suitable for drinking different teas
Do you know? Different teas have different production processes, suitable for people with different physiques. Therefore, if you want to drink tea to be beneficial to the body, you also need to consider your personal constitution and choose the right tea.
Black tea belongs to fermented tea, sweet and warm, with the effect of warming the stomach and warming the spleen and stomach. Although after fermentation, tea polyphenols, caffeine and other substances in black tea are reduced, it is more suitable for people who are caffeine intolerant to drink black tea.
Green tea is an unfermented tea, which is slightly cold and helps to reduce the fire, suitable for people with internal heat and stomach heat. However, people with cold body, stomach ulcers, and easy insomnia are not suitable for drinking green tea.
Green tea, that is, oolong tea, is cold and hot in nature, spicy and sweet, can clear heat and moisturize the lungs, suitable for most people to drink.
Black tea belongs to post-fermented tea, which has the effects of warming the spleen and warming the stomach, quenching thirst, eliminating food and phlegm, etc., especially suitable for people with cold physique, and the elderly are also suitable for drinking.
Therefore, understanding our physique and choosing the right tea leaves can allow us to better enjoy the benefits of tea.
Third, the precautions for drinking tea
Although drinking tea is beneficial, the following four points need to be paid attention to to ensure the healthy effects of tea.
First, avoid overly hot tea. Our esophageal mucosa has limited tolerance to heat, and high-temperature tea can cause damage to the esophageal mucosa, and long-term damage and repair process can easily lead to esophageal cancer.
Secondly, it is not advisable to drink tea on an empty stomach. Drinking tea on an empty stomach may cause the active substances in tea to bind to gastric proteins, produce adverse stimulation to the stomach, and may cause dizziness, palpitation and other uncomfortable symptoms.
Third, reduce or avoid strong tea. Strong tea contains a lot of caffeine, excessive drinking will increase the burden on the heart, cause dizziness, headache and other discomfort, and may also stimulate the stomach, which is not good for health.
Finally, do not drink tea immediately after a meal. The tannic acid in tea inhibits the secretion of gastric acid and intestinal fluid, which can easily lead to indigestion, and at the same time binds to proteins to form tannic acid proteins with astringent effects, which may lead to dry stools.
Paying attention to these aspects can ensure that we enjoy the pleasure of drinking tea without negative health effects.
Source: Family Doctor