Introduction and description
Tea is a drink, and can be made with numerous plants, but in this section I will concentrate on the drink made from Camellia sinensis. According to Wikipedia, this form of tea “ prepared by pouring hot or boiling water over the cured leaves of the tea plant, is, after water, the most widely consumed beverage in the world."
And unfermented teas have extensive healing properties.
They are said to "help reduce the risk of cardiovascular disease and some forms of cancer, promote oral health, reduce blood pressure, help with weight control, improve antibacterial and antivirasic activity, provide protection from solar ultraviolet light, increase bone mineral density, and have anti-fibrotic properties, and neuroprotective power"! So a lot of claims. But as you will be able to see from the papers from PubMed, a few of these claims are starting to be verified by research. But there are also a lot of claims that are being disproved.
One claim that has been disproved is that it helps you lose weight “Green tea preparations appear to induce a small, statistically non-significant weight loss in overweight or obese adults. Because the amount of weight loss is small, it is not likely to be clinically important. Green tea had no significant effect on the maintenance of weight loss”. [PMID: 23235664]
Furthermore tea is not a relaxant, it is a stimulant. Tea contains theophylline and caffeine, both stimulants, so tea is obviously not a relaxant. The caffeine and theophylline actually cause the blood pressure to rise after consumption, thus negating another claim
"Contrary to our initial hypothesis, tea ingestion caused larger acute increases in blood pressure than caffeine alone. However, any acute effects of tea on blood pressure did not translate into significant alterations in ambulatory blood pressure during regular tea consumption". PMID: 10404946
This said, tea was in use in China as a medicinal drink long before it arrived in the west. Anecdotally one legend says that tea was discovered by Shen-Nung in 2337BC, a Taoist herbalist. It was used in Cha'an rituals as it helped keep them awake during meditation.
"Tea contains L-theanine, an amino acid whose consumption is strongly associated with a calm but alert and focused, relatively productive (alpha wave-dominant), mental state in humans. This mental state is also common to meditative practice."
It became known in the west through the Portugeuse, but as its popularity increased in Europe and America, the British imported the tea plant into India in order to counter the monopoly the Chinese enjoyed.
Teas are classified according to whether they are unfermented or fermented. White tea, green tea and yellow tea are unfermented, whereas black tea is fermented. Oolong tea is half way between – semifermented.
When teas are unfermented, a process such as hot air drying, hot sun drying or steaming is used to stop the ongoing enzymatic degradation in the leaf that takes place once the leaf is picked. A fermented tea on the other hand has been allowed to dry slowly perhaps on racks, and deliberately allowed to degrade before the process is halted again usually using heat, which deactivates the enzymes causing the degradation. The oxidation process changes the chemical constituents of the resulting tea. Unfermented teas have not been oxidised [and as a consequence often have anti-oxidant properties], whereas black teas have been oxidised [and as a consequence have different, often preservative, properties often achieved via tannin]. The leaves turn progressively darker as their chlorophyll breaks down and tannins are released. There are six main types of tea:
- White tea – is expensive, delicate and delicious. It has no hint of tannin and is a very pale colour when infused. Boiling water must not be used, it must be just warm, the leaves can be reused a number of times. It is grown and harvested primarily in China, mostly in the Fujian province and Ningbo, Zhejiang province .The buds and new leaves of the plant are used and it is an unfermented tea. The name "white tea" derives from the colour of the tea itself which is actually a silver to white colour.
- Yellow tea – is also expensive and is an unfermented tea. The leaves are processed in a similar manner to green tea, but the damp tea leaves are allowed to sit and yellow. The tea generally has a very yellow-green appearance and a smell different from both white tea and green tea.
- Green tea – is less expensive than white or yellow tea, but more expensive than black tea. Green tea properly processed also has no hint of tannin or bitterness, but it has a little more astringency than white or yellow tea. It is, as the name suggests green in appearance and the tea itself is also a greenish colour when made. Green tea is delicious with herbs such as mint or sage, lemon balm or basil for example, although it is often served with lemon and on its own. Sun drying and heating may be used to process the tea, and it is classified as unfermented. When the processing is correct, the maximum amount of polyphenols and antioxidants are retained.
- Oolong (or wulong) – Oolong means Black dragon, thus this is known in China as black dragon tea. It is produced through a unique process that includes withering under the strong sun and oxidation. The leaves are then either rolled into long curly leaves, or 'wrap-curled' into small beads, each with a tail. The degree of oxidation can range from 8 to 85%, depending on the plant cultivar and production style. Thus this is a semi-fermented tea. It is usually made from unique tea plant cultivars that are exclusively used for particular varieties and these teas are regarded and appreciated in much the same way that we might regard wines in the west. The taste can be 'sweet and fruity with honey aromas', or 'woody and thick with roasted aromas', or 'green and fresh with bouquet aromas'.
- Black tea (called red tea in China) – this is the tea most drunk in the west. Go to a supermarket and buy tea or tea bags and this is what you are getting. It is a fermented tea. The leaves are indeed almost black in colour, but the tea itself has a reddish tinge which is why the Chinese call it red tea. Black tea has a high tannin content and a slight bitterness. It is far more oxidised than any of the other teas and has a much deeper colour when made and stronger flavour than the other teas. Whereas only the tips of the tea plant might be use for white tea, for example, the entire plant can be used for black teas. Furthermore both the small-leaved Chinese plant Camellia sinensis subsp. Sinensis and the larger leaved Assamese plant Camellia sinensis subsp. Assamica are used. As you can see black tea is a more commercially oriented product capable of being produced in much larger quantities. Whilst green tea usually loses its flavor within a year, for example, black tea retains its flavour for several years. It accounts for over ninety percent of all tea sold in the West.
- Post-fermented tea (or black tea for the Chinese) – is used medicinally in China as well as being used as a beverage. The process for producing it is a Chinese speciality and produces tea known as Hei Cha, commonly translated as dark, or black tea. This type of tea is completely different from what in West is known as "black tea". The most famous variety of this category of tea is Pu-erh from Yunnan Province. Pu'er traditionally begins as a raw product known as "rough" Mao Cha which then undergoes a process of gradual fermentation and maturation with time. All types of pu-erh can be stored to mature before consumption, which is why it is commonly labelled with year and region of production.
Tea may contain a small amount of caffeine, polyphenols, protein, fibre, beta carotene, vitamins - B, C and D [C is not found in black tea], tannins, catechins[found only in the unfermented teas], and theophylline [which acts in this context as a mild diuretic].
"Tea is contraindicated for the insomniac and the manic" [Dale Pendell - Pharmakodynamis]
Note that the phrase "herbal tea" is usually used to refer to infusions of fruit or herbs made without the tea plant, such as rosehip tea, chamomile tea, or rooibos tea. Thus these teas are different and will have their own properties. Alternative phrases for these are tisanes or herbal infusions. Clearly each plant will have its own effects both in terms of taste and healing.
Use hot but not boiling water for unfermented teas and drink alone or with herbs, lemon or if you like milk. The leaves may be reused a second time, occasionally a third time, as long as you have not left them soaking in the water, but have drained them.
How it works
See the observations. Drunk as tea, the effects are universally those of healing.
It is, however, worth adding this little extra tidbit of information.
For reasons I am unable to get my head round, the Americans have developed a Green tea dietary supplement – a pill. It is according to one PubMed paper “the fourth most commonly used dietary supplement in the US” You do not get health benefits by overdosing on a concentrated extract. In fact any concentrated dose will eventually act like a poison
“A total of 216 case reports on green tea products were analysed, including 34 reports concerning liver damage. Twenty-seven reports pertaining to liver damage were categorized as possible causality and seven as probable causality. Clinical pharmacokinetic and animal toxicological information indicated that consumption of green tea concentrated extracts on an empty stomach is more likely to lead to adverse effects than consumption in the fed state”, [PMID: 18484782]
Health regulation agencies in France and Spain have suspended market authorization of a product containing green tea extract because of hepatotoxicity concerns.
So if you get hallucinations it is because you have overdosed on an extract.
Calming but not soporific
The best teas are not cheap, but then quality never is.
References and further reading
There is quite a good description of tea and its history in Dale Pendell's PhamarkoDynamis.
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