Tea is a hot infusion of Camellia Sinensis (tea plant) leaves. It is one of the most consumed beverages for its beneficial effects on human health.
Phytonutrients in tea leaves attributed to smooth functioning of body metabolism and thereby overall general wellness and health. Research evidence suggests that tea drinking confers protective health effects on the neuromuscular, cardiac, digestive, and skeletal systems in the body.
Green tea. |
Camellia sinensis
is a small to medium-sized evergreen tree originally from Sub-Himalayan parts of India, and South-Western China.In the tea gardens, the tea plant is trained and pruned into manageable-sized bushes in order to gather fresh leaves. It grows best in the mountain slopes supplemented by humid, tropical semitropical highlands and plenty of rainfall.
Tea leaves vary in appearance and taste depending on their age and maturity. The older, dark green leaves are larger, elongated, and smooth, while the younger, light-green, tender tips and leaves are plucked for tea-making. These fresh, succulent parts are harvested from mature plants throughout the growing season. They are processed to create tea beverages or for commercial distribution. Notably, the older leaves produce teas with less vibrant flavors compared to their younger counterparts.
Tea leaves contain no fats and negligible amounts of calories. A cup of unsweetened tea serving carries just 2 calories and zero cholesterol.
Tea leaves are composed of plant-derived nutrients such as poly-phenolic antioxidants, pigment antioxidants, caffeine, theanine, saponins, and minerals.
Catechins constitute the main portion of phenolic antioxidants. Some important catechins include epicatechin, epigallocatechin, epigallocatechin gallate (EGCG), and epicatechin gallate.
Catechins, especially EGCG, play an important role in the fight against cancers. Tea leaf saponins include barringtogenol-C, and camelliagenin-A.
Apart from this, tea leaves compose some important minerals like fluorine which help in bone and dental health.
Tea leaves also carry very small but important minerals such as phosphorus, selenium, magnesium, copper, iron, and fluorine.
In traditional Chinese medicine, tea is viewed as both yin (green tea) and yang (black tea) effects. The yin effect makes the body cool, and yang warmth.
According to TCM understanding, tea has both sweet and bitter flavors and possesses cooling properties.
In the TCM (traditional Chinese medicine), tea consumption is attributed to a cooling effect on the body and a refreshing effect on the mind. It enhances alertness and boosts concentration.
It can also promote vitality, clear phlegm from the chest, and improve breathing capacity.
Traditionally, it is served to relieve headache, giddiness, stress-induced body pain, and to overcome sleepiness.
Together with ginger and other herbs, tea leaves infusion helps to relieve indigestion and promote smooth bowel movements.
Tea is also believed to boost immunity and fight against cancer-causing oxygen-species free radicals.
Principle | Nutrient Value | Percent of RDA |
---|---|---|
Energy | 1 Kcal | 0% |
Carbohydrates | 0.20 g | <1% |
Protein | 0 g | 0% |
Total Fat | 0 g | 0% |
Cholesterol | 0 mg | 0% |
Dietary Fiber | 0 g | 0% |
Vitamins | ||
Folates | 0 µg | 0% |
Niacin | 0.030 mg | <1% |
Pyridoxine | 0.005 mg | <1% |
Riboflavin | 0.058 mg | <1% |
Thiamin | 0.007 mg | <1% |
Vitamin-A | 0 IU | 0% |
Vitamin-C | 0 mg | 0% |
Electrolytes | ||
Sodium | 1 mg | <1% |
Potassium | 8 mg | <1% |
Minerals | ||
Calcium | 0 mg | 0% |
Iron | 0.02 mg | <1% |
Magnesium | 1 mg | <1% |
Zinc | 0.01 mg | 1<1% | Phyto-nutrients |
Caffiene | 12 mg | -- |
Soon after the harvest, tea leaves undergo various stages of treatments before being sold in the markets. Depending on the techniques employed while harvesting, picking, and processing, four classes of tea were obtained: white, green, oolong, and black.
White tea consists of leaf buds and terminal one or two leaves of the harvest. It is the least processed and the most superior of all teas, wherein the leaves are subjected to minimal oxidation. Here, tea buds are generally air-dried or steamed.
On the other hand, the tea leaves undergo rigorous treatment to obtain black tea. The treatment process for green and oolong is somewhat in between the methods employed for obtaining white and black teas.
There are other types of teas too. Perfumed tea is made from tea leaves flavored with spices, fruit peels, or flowers (Jasmine, cinnamon, mint etc).
Earl grey tea is perfumed with bergamot essence.
Decaffeinated tea is a drink from which some of the tea caffeine is removed.
While buying, decide beforehand the type and quantity of tea enough for a short period of time; you can finish in a span of one month. Do not buy large stocks as the leaves lose flavor over a period. Buy tea from an authentic place that has a quick turnover of stock.
Check for the tea type, grade, and place of origin. In the case of packed tea products, read carefully for their date of processing and packaging, description of leaves inside, the authenticity of the company, etc. You can have a firsthand look at the quality of leaves, flavor, and color if you buy loose tea. Also, buy loose tea, which is more economical than buying tea bags.
Keep tea packs, bags, and boxes in cool places away from heat, humid, and moist environments. If buying loose tea, keep it in a metallic container away from heat and light. Use freshly bought tea and do not store it for more than 3-4 months. Some black teas may keep for up to 18 months, but it is not good to keep tea for more than 6 months.
In many Chinese and Japanese households, tea is still prepared in a ceremonial way with the utmost respect in front of the visiting guests. Teas are mostly drunk hot, but some prefer it cold. Traditionally, teas are enjoyed without any additions in China.
Over the years, its acceptance as a branded beverage with other herbs and spices popularized in many parts of the Western world, including the USA and Europe. In the UK, it is appreciated slightly sweetened with sugar and tamed with milk.
Some prefer it with honey and ginger and a squeeze of lemon to mask bitter tannins. Decaffeinated tea is also available for those who dislike caffeine drinks. Tea is also fortified with vitamin C to further boost its health-benefiting properties.
To make an infusion, boil fresh mineral water to just simmer. The ideal temperature of the water should be around 85 degrees C. Add 1 teaspoon (15 ml) of dried tea leaves to make 2 cups (300-350 ml). Infuse for about 3-5 minutes. Cover the teapot during infusion to preserve its active principles. A small amount of honey or stevia may be added to improve acceptance.
Tea leaves carry significant levels of caffeine and theanine compounds. Persons on beta-receptor stimulant medications like theophylline should therefore limit tea consumption. Tea can be safely enjoyed during pregnancy in moderate servings.
Persons suffering from stomach ulcers and GERD (esophageal reflux disease) should consult a physician as it may aggravate these conditions. (Medical disclaimer).
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Further Resources:
UNCTAD INFOCOMM (pdf-opens in new window).
USDA National Nutrient Database. (opens in new window).
Stanford School of Medicine Cancer information Page-Nutrition to Reduce Cancer Risk (Link opens in new window).
National Cancer Institute-Tea and cancer prevention.