Though there are several types of tea known as black tea, green tea, oolong tea and so on, are all obtained from the same plant, but different processing conditions. About ¾ of the total is the tea, although, at present, the green tea is considered most beneficial properties on the body. The first is preferred by most western countries, the other - from the Far East countries. The chemical composition of tea differs from the climate zone to another, depending on the age and type of leaves, the method of processing. Pharmacological and physiological effects differ between varieties of tea. Global popularity enjoyed this drink is one of the reasons why, at present, there are numerous studies on the beneficial effects and negative, of tea. The first is due mainly antioxidant substances, the latter being caused by the accumulation of minerals such as Al, F, the leaves of the plant.

1.
The benefits and risks of Tea
With a history of over 5,000 years, tea is the most consumed beverage in the world after water. It
is prepared by infusing dried leaves of Camellia sinensis (Theaceae Fam.) ­ a perennial plant
originating in China. Upon reaching adulthood (a process that takes 7 years), this culture as
shrubs can bear fruit up to 100 years.
Though there are several types of tea known as black tea, green tea, oolong tea and so on, are
all obtained from the same plant, but different processing conditions. About ¾ of the total is the
tea, although, at present, the green tea is considered most beneficial properties on the body.
The first is preferred by most western countries, the other ­ from the Far East countries. The
chemical composition of tea differs from the climate zone to another, depending on the age and
type of leaves, the method of processing. Pharmacological and physiological effects differ
between varieties of tea.
Global popularity enjoyed this drink is one of the reasons why, at present, there are numerous
studies on the beneficial effects and negative, of tea. The first is due mainly antioxidant
substances, the latter being caused by the accumulation of minerals such as Al, F, the leaves of
the plant.
Types of tea

2. 1. White tea
is obtained by collecting the buds and young leaves early, which then is heated and allowed to
dry. In this way, the processing is minimal, and the final product will taste and aromatic qualities
superior.
2. Green tea
leaves wither, and then treated with steam or dry in special pans to avoid oxidation. It runs in
various forms or shapes (spiral, granules) and dried. Contains the largest amount of oxidants of
all kinds of tea
3. Black tea
leaves are left to wither (naturally or artificially), then running and obey the complete process of
fermentation. After about two weeks to dry. The method of processing gives the black leaf and
has the advantage of better preserve the taste and flavor.
4. Pu­erh tea
is processed like black tea, but can be used for preparing many varieties of leaves (including
their maturity criterion). Another difference is in the stage of aging (may take a few years to a
century), which improves the taste and aroma characteristics of these varieties.
5. Oolong
tea is a variant of intermediate characteristics of green and black. This feature results from the
semifermentaţie to which it is subjected. Rich in antixidanţi (polyphenols).
6. Yellow Tea
Green tea is obtained similarly, but takes longer wilting.
Chemical content of leaves of tea
polyphenols (catechins and flavonoids) are substances that detemine the most beneficial
effects on health.
● Flavonoids have antioxidant, antimicrobial, anti­allergic, anti­inflammatory and constitute
up to 30% by weight of dry tea.
● catechins are abundant in black tea and antioxidant.
● Teaflavinele are derivatives of catechins undergo oxidation (contained in black tea and
oolong). Injections influences the taste and flavor and also antioxidant properties.
Alkaloids (caffeine, theobromine, theophylline)

3. ● caffeine (up to 5% by dry weight of tea). Concentration varies greatly during processing
because it has the property to bind with other substances to form new compounds.
● Theobromine and theophylline (0.6­0.8%)
Volatile oils determines the taste and aroma of the tea, have the effect of stimulating secretion
stomach, improve digestion.
carbohydrates (glucose, fructose, sucrose, starch, cellulose, etc.).
amino acids (glutamic acid, aspartic acid) have an important role in ensuring the gustatory and
aromatic teas.
Theanine has a neuroprotective effect, improves cognitive abilities. It is found in greater quantity
in green tea (2­3 times more than black).
Vitamins (thiamine,riboflavin, PP, vitamin C, A, K, E, etc.)
minerals (K, Ca, F, Al , magnesium), the amount of which increased with the aging of the
leaves.
Benefits of tea and effects on the health
antioxidant effect is due to polyphenol content that have the ability to reduce free radical activity
and increased activity of enzymes involved in detoxification. Thus, drinking tea prevents
atherosclerosis (coronary artery disease) 1, anticancer effect, liver protector, cardioprotective.
Improving respiratory dysfunction is favored theophylline ­ a material effect on airway dilator
and respiratory relief. It is effective asthma, pulmonaryemphysema,chronic bronchitis.
treatment of skin disorders may be performed using preparations of tea (external) due to their
anti­inflammatory, antimicrobial, anti pruritic. It is a good healing, regenerates the skin, helps to
stop bleeding and the effect of sunscreen.
digestive disease Phenomena gastrointestinalimproves its effect antimicrobial and detoxifier.
effect Antiviral of poliomyelitis virus has the herpes, influenza and rotavirus.
Prevents and relieves osteoarthritis and rheumatoid arts through anti­inflammatory and
inhibitory molecules in autoimmune disease.
prevents diabetes. Although the mechanism of action is not fully understood, it is assumed that
tea has the following effects:
● reduce the absorption of carbohydrates in the body
● hypoglycemic effect by decreasing insulin resistance
improves the immunesystem.
Hypocolesterolemiantby activating the metabolism, is effective in the treatment of obesity.
Prevents neurodegenerative diseases (Alzheimer's Parkinson)due to the action ofantioxidants.
Negative effects of tea consumption

4. high aluminum content is given by the absorption of this mineral in the growth of the plant
Camelliasinensis.Maximum recommended daily dose for adults is 5 mg (with a limit of 0.2 ppm
in drinking water). Aluminum accumulation in the nerve tissues, including the brain is correlated
with the occurrence of Alzheimer's disease. Large amounts of mineral were detected:
● teas grown on soils with acidic pH (below 5.5)
● old tea leaves (about 10 times more than in the young)
● cultivars with small leaves (large leaves Assam tea containing less aluminum),
● Pu erh tea (compared with other types)
● ceaiul­cărămidă/puer­shu, (to form the leaf tea)
content of fluorine arising from capturing thein the mineral accumulation in the soil and in the
leaves of tea. The maximum dose recommended by the World Health Organization is 2 mg / day
for children and 4 mg / day for adults (between 0.5­1.5 ppm in drinking water). A constant intake
of fluoride can cause increased fluorosis­ a destructive disease of bones and teeth. However,
the optimal amount of fluoride protects teeth from decay and bones from osteoporosis.
Concentration of fluoride is higher:
● leaves (98% of total F of the bush), especially in the old (the opposite is roots and plant
branches, containing trace amounts of mineral),
● small leafy varieties and soil acidic pH, as in the case of aluminum,
● black tea, brick
in order to reduce the concentration of such mineral tea, have been proposed as measures
alkalization tea plantation soils by treatment with calcium salts and imposing selection criteria
leaves.
Hepatotoxicity has been observed in some cases, people who administered nutritional
supplements based on green tea.
Implications of tea consumption in the sphere of
oro­dental
Recently intensified research on fluoride concentration of tea because of the massive use of
these liquids on an international scale. Some researchers consider it a real public health
problem, because in many countries the use of tea grew, especially after numerous studies
have demonstrated the beneficial properties of the plant Camelliasinensis.
Drinking water is considered to be the main source of insurance body fluoride. Toothpastes
phenomenon of industrial pollution, drugs and some cosmetics can complement this
contribution difficult to control.

5. Proprietatea Tea has to mineral soilaccumulate in the growth process. Studies have shown
that the variability in the amount of fluoride contained in the final infusion prepared by the
consumer depends on: the
● acidity of the soil in which the plant grew (give a pH of 5 to 5.6, lower values ​​are
correlated with higher absorption of minerals ground),
● the time of collection of the leaves (as these are older, the higher the amount of
accumulated fluoro)
● processing method that is the subject material (it is considered that black tea contains
more than the other types fluoro) ,
● presentation and packaging method (leaves, sachets, granules, filling),
● the time of infusion, and its repetition,
● the hardness of the water injection is prepared (the amount of fluorine increases when
using soft water),
● the fluorine concentration of the water to tea, etc..
Supplementing general intake of fluoride, tea becomes a food able to trigger, along with other
sources, chronic intoxication called fluorosis.This disease is manifested by impaired
mineralization process destructive to enamel and bones.
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