"Food Safety Guide" Series | Chinese medicine says tea, are you drinking it right?

When I was a kid, I only heard of two kinds of tea: big bowl tea and Biluochun. Later, I learned about tea because I studied Chinese medicine and found that tea is also a medicine. For example, Chuanxiong tea is mixed with water. "Compendium of Materia Medica" records: "Tea tastes bitter and sweet. It enters the Shaoyin, Taiyin and Jueyin meridians of the hands and feet. It is good at clearing the heart and lungs and cleansing the stomach. Chamomile can cure headaches, and ginger water can cure stagnation. Drinking it after drinking alcohol can lead to the bladder and kidney meridians." But tea is cold after all. I have a weak spleen and stomach. I remember drinking Pu'er tea once and went to the bathroom halfway through. I rarely drank tea afterwards, but an encounter changed my view.

Not long ago, I went to Wudaoying Hutong near the Lama Temple in Beijing and came to a small shop. The owner of the shop is my good friend and invited me to drink Biluochun. This is a green tea. It was time for dinner. How could I dare to drink green tea on an empty stomach? So I politely declined. But my friend said, try it, it is guaranteed not cold. She said that this tea comes from an 80-year-old tea tree, picked from the mountain of Dongting Lake, the mountain faces the sun. This is the first batch of Mingqian tea picked from this tree. It has been manually picked and withered, and it is not the same as other green teas. I couldn't resist the persuasion, so I sat down and tasted this Biluochun. After a few cups, I was surprised to find that my stomach and intestines felt slightly warm and comfortable, and there was no sign of diarrhea at all. I burped a few times, feeling quite comfortable, and even felt full. I drank until 8 o'clock in the evening before leaving. I drank tea on an empty stomach without any discomfort, and I felt a slight sense of fullness and hunger. The warm tea entered my stomach and I sweated slightly, feeling very comfortable. Later, a friend gave me some Biluochun. I went back to drink it and the feeling was the same every time. It seemed to be no coincidence.

This chance encounter changed my view of tea, especially green tea. It also reminded me of an elder who once said that his father was over 90 years old and had been drinking tea all his life. He lived a long and healthy life, and so did the elder. I initially thought it was due to my physical condition, but now it seems that this is not entirely true. Recently, I have been thinking carefully and suddenly realized something.

Although tea is cool in nature, its coldness or warmth depends on two factors. One is the growing environment, whether it is a cold and damp place or a warm and sunny place. Just like grapes grown in the north and grapes grown in Xinjiang are different, there is a Chinese herb called Achyranthes bidentata in Chinese medicine. Sichuan Achyranthes bidentata in Sichuan invigorates blood circulation, while Henan Achyranthes bidentata in Henan nourishes the liver and kidneys. Another example is ginseng. Ginseng grown in the northeast is warm in nature, while American ginseng is cool in nature. This is because of different origins. Different origins are essentially different growing environments, including temperature, sunshine, soil, and planting methods.

The second is the processing method, which may be more important. Most teas have to go through the process of withering, and one of the steps in withering is to roast it with fire. Chinese medicine believes that the properties of Chinese and raw herbs processed by fire are often different. For example, raw licorice is cold and cool and clears away heat and detoxifies, while roasted licorice strengthens the spleen and replenishes qi; raw rehmannia is cool and cools blood and activates blood circulation, while cooked rehmannia is slightly warm and replenishes the kidneys. Generally speaking, most medicinal materials processed by fire will have some warmth, which of course depends on the specific method of fire processing, and even firewood and ovens are not exactly the same.

There are many processes in tea processing, most of which involve fire processing, such as baking or steaming. This tea processing technology determines the temperature of the tea. I used to think that fermented teas such as black tea and dark tea were not cold because I did not understand the fermentation process of tea. Tea fermentation is mostly done by spreading the tea leaves flat at room temperature of about 25 degrees Celsius to ferment, so it is different from fire processing. So in summary, the temperature of tea depends on the environment and the process.

It seems that people with cold constitutions are not unable to drink green tea, but some fermented teas, such as Pu'er tea, may not be suitable. Therefore, if you find the tea that suits you and understand the principle of "too much is as bad as too little", you will find the way to maintain your health.

(The author is the chief physician of the Department of Cardiology at Xiyuan Hospital, China Academy of Chinese Medical Sciences)