Due to the variety of minerals, vitamins and other elements contained in tea, this drink improves health, relieves fatigue, strengthens the immune system and has an overall tonic effect on the body.
Mineral substances contain in green tea leaf and in finished products, it constitutes about 5-6% of dry matter. Among them are the following: potassium, phosphorus, calcium, magnesium, sulfur, iron, manganese, fluoride and others. With the aging of the plant total number of minerals increases, while the most valuable part of the soluble reduces. Only the components of relatively small molecular weights which are infused with hot water give a specific accent to the tea infusion. Between the quality of tea and the content therein of soluble mineral substances there is a direct link.
The potassium content in the tea leaf is 50-60% of all mineral substances and depends on the mineral nutrition of plants. This compound plays a very important role in the livelihood of tea tree; it is given a great importance in the synthesis of carbohydrates and proteins, and in the general metabolism. Potassium is very important to the human body; it prevents muscle cramps and regulates fluid and electrolyte balance.
Another important mineral is located in the tea - phosphorus. Its content ranges from 15-20% of weight of all mineral substances in tea. The properties of the finished product depend on its quantity. The two top leaves and a bud have higher content of phosphorus compare to the lower coarse tea leaves and stems. It is known fact that phosphorus is needed for the human body for normal functioning, as part of the nervous, brain tissue and bones.
Despite the slight content, copper and iron play an important role in plant’s life. They are part of some physiologically important organic compounds, such as enzymes. Another, small in content, but necessary for redox processes, is manganese. Its share is approximately 1-4%. Due to the iron content, tea has a beneficial effect on the human blood, as well as a good means for the prevention of various vascular diseases. In addition, the body needs iron to transport oxygen.
The complex experiments revealed effects of the duration of brewing tea and the quantity of the tea leaves on the degree of content in the drinks of various trace elements. Adding citric acid increased the yield of all elements, except copper. In the end, it was found that a tea drink satisfies the daily requirement of zinc, copper and manganese at 1, 2 and 50% respectively.
Now let us turn to vitamins contained in tea. This is mainly vitamins B complex and C. The tea shoot has the following B complex vitamins: B1 (thiamin), B2 (riboflavin), B3, and B5 (PP), B6, B12 and P. Since these compounds are very stable, in the processing they are almost completely transformed into finished products. Content of vitamin B1 is small - an average of 0.3 - 10 mg per 1 kg of dry tea leaves. In the body this vitamin (B1) regulates metabolism of carbohydrates, amino acids, fatty acids, has versatile affect on the function of the cardiovascular, endocrine and central nervous system. Vitamin B2 has positive effect on the skin and mucous membranes, the health of the liver. The most important is the presence in tea of vitamin P. One of its most important properties is the strengthening of the capillaries of the plant. During the technological processing of raw material quality and quantity of the vitamin are undergoing significant changes. Its content is reduced from 20-25% in green tea to 8-15% in the final. Along with others, the tea contains vitamin PP that is important for normalizing the higher nervous activity, the functions of the digestive system. It also affects the cardiovascular system, in particular, expanding the small vessels.
Tea leaves are rich in Vitamin C. Gentle leaves contain approximately 2-3 times more of this vitamin than the coarse. In the process of refining its amount is sharply reduced, especially during the fermentation and drying. This vitamin is essential for strengthening the immunity of a person, it reduces the risk of infections, but also useful for the prevention of osteoporosis and periodontitis (inflammation of the periodontal tissue, i.e. tissue surrounding the tooth root). Tea fluoride also provides the beneficial effect on teeth. This element exists in tea leaf as anion. Fluoride anion produces various fluoride compounds and covers the surface of teeth to prevent bacterial attack. Just wanted to point out that tea is very useful for vision, because it contained β-carotene and other elements, strengthens blood vessels.