Tea is the second most consumed beverage in the world, just behind water. In China, it has been using for almost 3,000 years, not only for its stimulant properties, but because it helps prevent and improve many ailments.In traditional Chinese medicine, is used to relieve headaches, help eliminate toxins and to prolong youth. However, it was not until the seventeenth century, that tea was extended and became a popular drink in Europe.Despite that tea drinking has for thousands of years, scientific research documenting the potential health benefits of this ancient drink, only took place in past decades.

Of these studies have found that green tea contains high levels of substances called polyphenols, which have antioxidant properties, including anticancer and antibiotic. Green tea may also help prevent heart disease and liver
One group, growing clinical studies conducted both in humans and experimental animals suggest that regular consumption of green tea may reduce the incidence of a variety of cancers, including colon, pancreas and stomach.

Green tea may also help prevent heart disease and liver cancer. Both black tea and green tea come from the same plant.

Green tea leaves are made from steamed and then dried, while black tea is prepared, leaving the leaves wither, which then rolled, allowed to ferment and dry. But green tea is less processed than black tea contains more antioxidants and therefore is the most powerful of the two.

Botanical Survey

Tea is one of the world’s known plants, in fact, its cultivation is widespread in all tropical areas of the planet.

Description of the plant

The plant part used for therapeutic purposes are the leaves. But depending on the processing to be subjected get different forms: green tea and black tea.

The tea belongs to the family Teácea. It is a small evergreen tree that can grow to 5-10 m high in the wild, even when cultured rarely exceed 2 m in height.

His lanceloladas and sharp leaves are dark green, alternate and are arranged generally measure 5-10 cm long by 2-4 cm wide, one of the characteristics that have these sheets is that they are jagged in its 2 / 3 higher. The plant part used for therapeutic purposes are the leaves.

It has a delicate flowers, creamy white or pinkish, which emit a pleasant aroma. They are small and are arranged alone or in groups of 2 or 3 flowers. Each flower has 5 sepals and 6-9 petals oval. The fruit is a small, rounded capsule, inside which the seeds are located.

Although originating in Southeast Asia, from India and Sri Lanka to China or Japan, the tea grows extensively in the tropics and subtropics. In the vicinity of the Earth Ecuador can be found at an altitude of almost 2,000 meters.

Culture conditions and harvesting

For growth of tea is optimal, requires well-drained soil rich in organic matter and slightly acidic pH. As for temperature, ideally range between 14-27 º C (although it is evergreen, does not tolerate frost). It needs sun and plenty of water.

The root hairs are very thin, so it is very sensitive to lack of moisture that can cause the plant to dry. When in full bloom, you need a more abundant irrigation. Harvesting takes place when the plant reaches the age of 3 years.

Depending on the birthplace of tea, the climatic conditions vary and this is why there are different varieties of green tea, each with some peculiar characteristics in terms of aroma, flavor and color of the tea ready.

Harvesting takes place when the plant reaches the age of 3 years and is often repeated three times a year. Young shoots are chosen which are formed by 5-6 leaves arranged around a closed terminal bud.

Chemical study

Tea leaves contain 5-6% water and 4-7% mineral salts, especially rich in potassium and manganese. Other minority compounds also found in tea are organic acids such as malic, succinic, oxalic and galoquínico; glucidic as inositol compounds, reducing sugars, gums and pectin, and even a small percentage of lipids.

Among the active principles responsible for the therapeutic activity of green tea highlight their content in phenolic compounds (3%), which fall into three categories: flavonoids, catechins and tannins. It is important to note that the polyphenols decrease with plant age and the time of harvest, for plants of the same age, is lower in spring and peak in August-September.

Among the flavonoids, the most important are the kemferol, quercetol (quercetin) and miricetol. Catechins are most abundant in the fresh plant and green tea, black tea that, among all these, the most active are the catechol, epicatecol and their esters with gallic acid. Finally, catechists condensed tannin (8-25%). It also has a small amount of essential oil (0.007-0.014% in fresh leaves), which is higher in black tea because it is formed during the fermentation of the leaves.

Remember that green tea undergoes stabilization by steam and dried, while black tea, it undergoes fermentation and drying. This essential oil contains hexenol, and small amounts of aldehydes, and isobuteraldehido Butyraldehyde and phenolic alcohols, geraniol, linalool and citral. It is important to note that the polyphenols decrease with plant age and harvest time.

Perhaps, of all tea components, alkaloids (2-4%) are the most popular. Are derivatives of purine, more commonly known as ‘xanthan bases’, the most abundant are caffeine and theophylline.

In the fresh plant, caffeine is combined with organic acids to form a compound known as ‘tanins’. This is the reason that black tea has a more stimulating to the nervous system, green tea, because during the fermentation process breaks this tanins freeing caffeine. Finally, we can not forget to mention the presence of vitamins and enzymes.

Pharmacological Action

With its varied chemical composition, tea has interesting therapeutic effects.

* The green tea polyphenols are potent antioxidants. Some studies have shown that most common polyphenols of green tea (catechins) are more potent to suppress free radicals than vitamins C or E.

* In addition several studies have found that green tea is anti-carcinogenic, being able to counteract the occurrence and development of different cancers. And it helps slow the progression of aging and degenerative diseases.

* Xanthan bases, especially caffeine, are acting nervous system stimulant and bulbar (stimulates the respiratory and vasomotor centers which are at the bulb).

* Green tea also has diuretic, bronchodilator, and astringent (anti-diarrheal).

* You lipid lowering, ie able to reduce levels of LDL-cholesterol and plasma triglycerides while increasing HDL-cholesterol, good cholesterol. And thanks to its antioxidant properties, prevents oxidation of cholesterol and has anti-atherosclerotic effect.

* The formation of blood clots (thrombosis) is the leading cause of heart attack and angina, and green tea has been shown to reduce the abnormal formation of blood clots with an efficacy similar to aspirin, with its vitamin activity P.

* Green tea lowers blood sugar levels, ie is hypoglycemic and has slight antibiotic effects against certain bacteria such as staphylococci and some viruses.

Therapeutic applications

Laboratory studies show that green tea extract protects against many common degenerative diseases.

* The ability of green tea to prevent cancer is so established, that current studies are testing green tea as a possible potential therapy against cancer. Experimental studies carried out suggest that components of green tea may help prevent skin cancer when applied directly to the skin. Tea polyphenols may also help the skin tan and protect against the damage caused by the sun.

* The powerful antioxidant effects of green tea inhibit the oxidation of LDL cholesterol in the arteries. The oxidation of LDL plays an important role to counteract the formation of atherosclerosis, and thanks to its antithrombotic effects, can be effective in preventing heart diseases.

* For his actions nervous system stimulants, can be used to alleviate fatigue both physical and mental fatigue. You can also reverse the symptoms of an asthma attack, for its bronchodilator activity.

* In case of diarrhea, the tea can stop it because its tannins give it astringent activity, but we must be cautious because in some cases may cause some gastrointestinal discomfort.

Precautions

Since green tea is widely consumed beverage, is generally considered safe. However, it should be noted that contains caffeine, although at a lower level than black tea or coffee.

Side Effects

For its caffeine content, green tea can cause insomnia, nervousness and other similar symptoms. Moreover, since xanthan bases have a diuretic action, one can observe an increase in the urine. As for its tannin content, whether concentrated or infusions are taken on an empty stomach may cause nausea and vomiting, although this effect is more pronounced in tea nergro.

Contraindications

Because everything discussed above, green tea should not be given to children.

Drug Interactions

If you take MAOIs like drugs (inhibitors of mono-amino-oxidase), we must bear in mind that the caffeine in green tea can cause problems.

Preparations of interest

Different studies carried out suggest that drinking 3 cups of green tea, help protect against cancer. But since many people dont like the tea, pharmaceutical capsules made with green tea extract liquid or presentations.

In these cases, follow the signs given by the manufacturer, especially when the extract is not standardized, because the concentration of active ingredients can vary from one brand to another.

Green tea is slightly aromatic, bitter taste and the green tea is obtained, unlike the black tea is more aromatic, astringent flavor and is reddish infusion. The tea extract is used to flavor drinks, ice cream and other dairy desserts. Also used as a source of food colors (black, green, orange, yellow, etc.)..

Iced tea with mint

Taste the pleasure of an iced tea is easy, simply make a tea with a teaspoon of green tea per cup of boiling water allowed to stand for 10 minutes, holding his cup to avoid loss of volatile active ingredients.

Elapsed time sneaks and just before taking it adds a bit of crushed ice and a sprig of mint or mint. If desired, can be sweetened with cane sugar or honey to taste. Green tea is slightly aromatic, bitter taste and the green tea is obtained.

Green tea compress for tired eyes

Tea bags, once used, can be used as poultices on tired eyes and reduce bags that form around them.

Similarly, one can prepare an infusion and apply it as compress on the forehead to relieve headaches.

As you can see the health benefits of green tea are endless. You can learn more about their qualifications in the green tea note: preparation and properties. Moreover, the latest daily report on new studies, as he has discovered that citrus are enhancers of green tea antioxidants.