Analysis has identified nearly 500 compounds within tea leaves. Some of these are essential components for the human body, known as nutritional elements, such as vitamins, proteins, amino acids, lipids, carbohydrates, and mineral elements, which hold significant nutritional value. Another portion consists of compounds with healthcare and medicinal effects, referred to as components with pharmacological value, like tea polyphenols, caffeine, and lipopolysaccharides. Below is an introduction to the nutritional value of tea.
1. Drinking tea can supplement the proteins and amino acids needed by the human body.
The water-soluble protein content in tea that can be directly absorbed through drinking is about 2%, while most proteins are water-insoluble and remain in the tea residue. Tea contains a rich variety of amino acids, over 25 types, including six of the eight essential amino acids for humans: isoleucine, leucine, lysine, phenylalanine, threonine, and valine. It also contains histidine, which is necessary for infant growth and development. Although the content of these amino acids in tea is not high, they can serve as a supplement to daily dietary insufficiencies.
2. Drinking tea can supplement the mineral elements required by the human body.
Tea contains both macroelements and trace elements needed by the human body. Macroelements mainly include phosphorus, calcium, potassium, sodium, magnesium, and sulfur; trace elements mainly include iron, manganese, zinc, selenium, copper, fluorine, and iodine. For example, tea has a relatively high zinc content, especially green tea, with an average zinc content of 73 micrograms per gram, and up to 252 micrograms in some cases; the average zinc content in black tea is also 32 micrograms per gram. The average iron content in tea is 123 micrograms per gram of dry leaves; in black tea, it is 196 micrograms per gram. These elements play important roles in physiological functions. Regular tea consumption is one of the significant ways to obtain these minerals.
3. Drinking tea can supplement various vitamins needed by the human body.
Tea contains multiple vitamins, which can be categorized into water-soluble and fat-soluble vitamins based on their solubility. Water-soluble vitamins (including vitamin C and B vitamins) can be directly absorbed by the body through drinking tea. Therefore, drinking tea is an excellent way to supplement water-soluble vitamins and can help meet the body's needs for various vitamins.
Vitamin C, also known as ascorbic acid, enhances the body's resistance and immunity. Tea contains relatively high levels of vitamin C, typically ranging from 100 to 250 milligrams per 100 grams of green tea. High-grade Longjing tea can contain over 360 milligrams, surpassing the content in fruits like lemons and oranges. Due to the fermentation process during processing, the vitamin C content in black tea and oolong tea is reduced through oxidation, leaving only a few tens of milligrams per 100 grams, with black tea having the lowest content. Thus, higher grades of green tea generally offer relatively higher nutritional value. Consuming just 10 grams of high-grade green tea daily can meet the body's daily requirement for vitamin C.
Among B vitamins, vitamin B1 is also known as thiamine, B2 as riboflavin, B3 as pantothenic acid, B5 as niacin, and B11 as folic acid. The content of B vitamins in tea is as shown in Table 3.
Since fat-soluble vitamins are difficult to dissolve in water, they are not easily absorbed even when tea is brewed with boiling water. Therefore, it is now recommended to appropriately "eat tea" to compensate for this drawback, such as by incorporating ultra-fine tea powder into various foods like tea-infused tofu, noodles, pastries, candies, and ice cream. Consuming these tea-based foods allows for the intake of fat-soluble vitamins from tea, better realizing its nutritional value.
The above is an introduction to the nutritional value of tea, hoping to help everyone understand this knowledge.