The knowledge about tea is vast and profound. How much do you know about these aspects of tea drinking?

1. How much tea should a healthy adult consume in a day?

The amount of tea one drinks depends on factors such as drinking habits, age, health status, living environment, and local customs. For a generally healthy adult who regularly drinks tea, consuming around 12 grams of tea per day, divided into 3-4 brews, is suitable. For those who engage in heavy physical labor, consume a lot, or work in high-temperature environments or are exposed to harmful substances, drinking around 20 grams of tea per day is also appropriate.

Those who eat a lot of greasy foods or smoke and drink heavily may consider increasing their tea consumption. Pregnant women and children, as well as those suffering from insomnia or tachycardia, should reduce their tea intake.

2. The chemical composition of tea and its Health benefits for the human body

The chemical composition of tea consists of 3.5-7.0% inorganic substances and 93-96.5% organic compounds. There are approximately 27 types of inorganic mineral elements in tea, including phosphorus, potassium, sulfur, magnesium, manganese, fluorine, aluminum, calcium, sodium, iron, copper, zinc, selenium, and others. The major organic compounds in tea include proteins, lipids, carbohydrates, amino acids, alkaloids, polyphenols, organic acids, pigments, aromatic components, vitamins, saponins, sterols, and more.

Tea contains 20-30% leaf protein, but only about 3.5% of it is soluble in tea infusion. Tea contains 1.5-4% free amino acids, with over 20 different types, most of which are essential amino acids for humans. Tea contains 25-30% carbohydrates, but only 3-4% of them are soluble in tea infusion. Tea also contains 4-5% lipids, which are also essential for the human body.

3. How many times should a cup of tea be steeped?

Different types of tea have varying levels of steepability. People often find that very delicate, high-quality teas do not hold up well to multiple steeps, losing flavor after just two infusions.

Ordinary black and green teas can typically be steeped 3-4 times. The steepability of tea is influenced by both the tenderness of the leaves and the degree to which they are processed. Finely processed teas release their flavors more quickly, while coarser, whole leaves release flavors more slowly.

In general, over 50% of the soluble components in any type of tea are released in the first Steeping. The second steeping yields about 30%, the third about 10%, and the fourth only 1-3%. From a nutritional perspective, 80% of the vitamin C and amino acids are extracted in the first steeping, and 95% are extracted by the second steeping. Other beneficial components like polyphenols and caffeine are also primarily released in the first steeping, with almost complete extraction after three steepings.

Thus, for ordinary black, green, and floral teas, three steepings are usually sufficient. Oolong teas, due to the larger quantity used per steeping, can be steeped several times. Bagged teas made from Black Tea fragments, being highly extractable, are best suited for single steeping.

4. Can leftover tea from the previous night be consumed?

There was once a belief that leftover tea from the previous night should not be consumed because it could cause cancer. The reasoning was that such tea contains secondary amines, which can transform into carcinogenic nitrosamines.

This claim lacks scientific evidence. Secondary amines are present in many foods, with particularly high concentrations found in pickled products. For example, bread typically contains 2 mg/kg of secondary amines. If bread is a staple food, one would consume 1-1.5 mg of secondary amines daily. In comparison, the amount of secondary amines ingested through tea is only 1/40th of what is consumed through bread, making it negligible.

Furthermore, secondary amines themselves are not carcinogenic; they must be combined with nitrates to form nitrosamines, which can then reach levels high enough to be carcinogenic. Drinking tea provides a rich source of tea polyphenols and vitamin C, both of which effectively inhibit the synthesis of nitrosamines in the body.

Therefore, drinking leftover tea will not cause cancer. However, from a nutritional and hygiene perspective, tea left out in the air can easily spoil and become rancid. Additionally, the longer tea sits, the more likely its beneficial components like tea polyphenols and vitamin C are to oxidize and diminish. While drinking leftover tea is not harmful, it is generally better to drink freshly brewed tea. It is advisable to avoid drinking leftover tea when possible.

5. After eating salted vegetables and preserved meat, it is beneficial to drink more tea

Salted vegetables, such as pickles and pickled vegetables, and preserved meats, such as cured meats, sausages, ham, and bacon, often contain higher levels of nitrate. When consumed alongside secondary amines, nitrates can react to form nitrosamines, a dangerous carcinogen that can cause cell mutations leading to cancer.

Catechins in tea have the ability to block the synthesis of nitrosamines. Therefore, after consuming salted vegetables and preserved meats, it is advisable to drink more high-grade Green Tea, which has a higher catechin content. This can inhibit the formation of carcinogens and enhance immune function, promoting overall health.

6. Diabetics benefit from drinking more tea

A common symptom of diabetes is high blood sugar, thirst, and fatigue. Studies have shown that drinking tea can effectively lower blood sugar levels and relieve thirst while also boosting energy.

Diabetics generally benefit from drinking green tea and can increase their tea intake, brewing several cups throughout the day to maintain a high concentration of beneficial components in the body. Drinking tea alongside pumpkin-based foods can have a synergistic effect. A month-long course of this treatment can produce good results.

7. Drinking black tea offers numerous benefits

Black tea is produced through fermentation and baking. During fermentation, the oxidation of the tea leaves turns them into red oxidized compounds, resulting in black tea. Black tea is mild in nature and has a rich flavor. It is rich in water-soluble vitamins and also contains trace amounts of potassium. When brewed, approximately 70% of the potassium becomes soluble in the tea.

Potassium helps strengthen heart circulation and reduces the loss of calcium in the body. Black tea is also rich in manganese, an essential element for bone health. Regular consumption of black tea can contribute to stronger bones.

Research indicates that black tea contains flavonoids, which act similarly to antioxidants and help prevent strokes and heart disease. A recent American study shows that individuals who drink one cup of black tea daily have a 40% lower risk of heart disease compared to those who do not drink tea.

8. Do not drink tea immediately after meals

Drinking tea immediately after eating will dilute stomach acid and interfere with digestion. The tannic acid in tea can also cause food to solidify, placing additional strain on the stomach and hindering the absorption of protein. It is best to drink tea about an hour after a meal.

9. Drinking tea can mitigate the harmful effects of smoking

For smokers who struggle to quit, drinking