example:

Bud	4.70 %
First leaf	4.20 %
Second Leaf	3.50 %
Third Leaf	2.90 %
Upper stem	2.50 %
Lower stem	1.40 %

Both tea and coffee contain the methylated xanthines, caffeine, theophylline and theobromine. Brewed coffee is said to have the highest caffeine content among those dietary items containing caffeine- approx. 100 mg per cup. A 300-ml bottle of cola has 30- 60-mg caffeine and approx. 37-mg caffeine is there in 56g dark chocolate bar. There are a wide variety of drug products that contain caffeine- typically 200 mg per tablet or capsule (pharmacologically active dose of caffeine). A cup of tea has approx. 28 -44 mg caffeine- (FDA 1980).

The quantity of caffeine in tea, on dry solids basis, is more than the quantity of caffeine in an equal weight of dried coffee beans. However, as a result of getting more cups of tea from a unit quantity of black tea than from an equal quantity of ground coffee beans, the quantity of caffeine per cup of tea is less than the caffeine in an equal cup of coffee.

Excessive caffeine is said to have adverse effects on the human system and brewed tea has only half the caffeine levels in brewed coffee. However, it is important to note that research proves that the presence of caffeine in tea does not produce unhealthy results due to its combination with tea polyphenols.

How much caffeine is considered safe?

The Food Guide to healthy eating recommends caffeine consumption in moderation. According to the current findings for most people an intake of caffeine up to 400-450 mg per day does not increase the risk of heart disease, hypertension or have an adverse effect on pregnancy or the foetus. This level of caffeine is equivalent to approximately 10 to 12 cups (170 ml) of tea per day.

As explained by Prof. T. W. Wickremanayake (Ph D Glasgow, Visiting Research Fellow Glasgow, Wisconsin and California) the pharmacologically active dose of caffeine is 200 mg and the acute fatal dose is about 10,000 mg. Those who drink more than 5 cups of coffee or 9 cups of tea are regularly consuming 5% of the fatal dose. The T 1/2 of caffeine is about 3 hr. It is excreted quickly in urine as 1-methyl uric acid.

Prof. Wickramanayake also states the following. "There is a positive association between Myocardial infarction and heavy coffee consumption, whereas the correlation between infarction and heavy tea drinking is negative. In rats and rabbits maintained on atherogenic diets, caffeine increases serum lipid concentrations and therefore the incidence of atherosclerosis. Coffee has the same action but not decaffeinated coffee. Tea has the opposite effect to caffeine alone or caffeine in coffee. Similar results have been reported in a study of human subjects with and without heart ailments. Russian scientists have demonstrated that a course of tea consumption improved the condition of atherosclerotic patients. The alleged adverse effects of caffeine are apparently eliminated in tea either by a modification of its activity by other constituents, or by the opposing action of some anti-atherosclerotic constituent."

Does green tea have the same Caffeine level as black tea?

Green tea, as well as Oolong tea & Black tea, are produced from the herb Camellia Sinensis. They all contain the same amount of caffeine. Caffeine content in a cup of tea is 2.5% to 4%, which is about a third of that in coffee. It is claimed that 80% of the caffeine in tea remains unabsorbed by the human body.

From the above you would realise that Green tea, Oolong tea & Black tea may taste different but the caffeine content is the same.

Why should one never reboil water when brewing tea?

Taste, colour and mouth feel depend on the interaction between the two main components of tea, polyphenols and caffeine. Each component is astringent on its own, but as a complex the astringent character is reduced.

Water is known to contain dissolved gases absorbed from the air. Carbon dioxide (CO2) gas that is present in water affects the acidity. Acidity of water plays a critical roll in the ionization of tea polyphenols and it contributes to the stability of the above complex.

CO2 in water is gradually released during the boiling process. Re-boiling will in fact further reduce CO2 levels, resulting in a decrease in the acidity. As mentioned above this will affect the caffeine and polyphenol complexion, and bring about changes in the colour as well as the character of the brew.

Twice boiled water will therefore affect the taste of a good tea and hence our request that only freshly boiled water is used for brewing tea.

Questions surrounding caffeine intake and risk of miscarriage and health of the foetus continue to be raised by pregnant women.

A study published in the journal of American Medical Association found no evidence that moderate caffeine use increases the risk of spontaneous abortions, growth retention or account for other factors. Another seven-year epidemiological study on 1,500 women examined the effect of caffeine, during pregnancy as well as on subsequent child development.

Caffeine consumption equivalent to approximately 3 to 5 cups of tea per day had no effect on birth weight, birth length and head circumference of the baby. A follow-up examinations at age's eight months, four and seven years also revealed no effect of caffeine consumption on the child's motor development or intelligence.

A number of factors influence the metabolism of caffeine and the individual's response to caffeine indigestion. These include pregnancy, age, sex, body weight, diet, exercise, and stress smoking and alcohol consumption.

Pregnancy hampers caffeine metabolism. For example, in non pregnant women the break-down of half of the caffeine takes an average of 2.5 - 4.5 hours, 7 hours during mid-pregnancy and 10.5 during the last few weeks of pregnancy. As caffeine retention is longer during pregnancy, women sensitive to caffeine may be affected. As a result a moderate consumption of approximately 3-4 cups a day, is recommended for women during pregnancy.

What is decaffeinated tea ?

For teas to be labelled decaffeinated, the caffeine content should not exceed 0.4% by dry weight, which is equivalent to approximately 4 mg of caffeine per 170 ml serving.

The process of decaffeination extracts the caffeine in tea. The current commercially available methods for decaffeinating black tea are solvent based extraction using ethyl acetate or methylene chloride, and extraction using supercritical (solid) carbon dioxide. All three methods extract caffeine with minimum effect to the quality of tea.

Tannic acid - what is it and is it present in tea?

Tannins or tannic acid are not present in tea. Tea polyphenols were formerly referred to as tannins or tannic acids due to the similarities in the chemical structure. This has left many misguided notions about the effect of tea upon the human digestive system. Chemists generally group compounds into 'families' on account of common features in the synthesis of the molecules. For example both strychnine and morphine are alkaloids and have common structural features but the action on the human body is different. Strychnine is a powerful stimulant and morphine a powerful hypnotic.

Vegetable tannins are a large chemical family and some of them are loosely called tannic acids. These compounds possess the property of hardening animal tissues and turning hide into leather. Tea polyphenols on the other hand are called catechins, theaflavins and thearubigens, and are responsible for many of the health benefits associated with tea. Such as anti-hypercholestemic action, anti-hyperglycemic action, fat reduction action, anti-hypertensive action, anti- cancer action and many other health promoting effects. Current scientific literature points to the fact that tea polyphenols are biochemically very different to tannins.

Nutrients in tea what is in your cup of tea, and how it can affect your body

What are the nutritional benefits of tea?

Tea composition varies with climate, season, horticultural practices and variety. Polyphenols are the most important component in tea, as they constitute approximately 36 percent of the dry weight of tea. Other components of fresh green leaf include caffeine, protein and amino acids, carbohydrates, lipids, vitamins and minerals.

Green and black tea have similar chemical make-up. The primary difference between the two types lies in the chemical changes that take place during their production. In black tea the plant Polyphenols are oxidized and this is prevented in the manufacture of green tea.

One of the most important groups of Polyphenols in tea is the catechins in green tea, theaflavins and thearubigens in black tea. A variety of physiological effects have been attributed to tea catechins which are currently best known for their antioxidant activities.

Black tea is all-natural (non flavoured) and contains no additives. It is virtually calorie-free (1 calorie per 100 ml) and sodium free and is therefore a suitable beverage for individuals on calorie-reduced or low sodium diet. Tea includes fluoride, traces of vitamins A, K, C, B carotene and B vitamins.

Average daily consumption of tea in the United Kingdom, 3.43 cups (650 ml), provides very few calories and only a small amount of fat, whilst contributing valuable minerals and vitamins to the diet. It provides:

. Over half of the total intake of dietary flavonoids.
. Nearly 16% of the daily requirement of calcium
. Almost 10% of the daily requirement of zinc
. Over 10% of the folic acid need
. Around 9%, 25% and 6% of vitamins B1, B2 and B6 respectively.

Does tea affect the absorption of Iron?

Although concerns have been expressed about consumption of iron, existing research and dietary knowledge indicate that tea is not likely to cause health risk, in individuals consuming a typically Western diet.

Dietary iron exists in two forms, heme iron (derived from animal) and non-heme iron (found in plants). The body better absorbs heme iron than non-heme iron. Between 15-35 % of heme iron is absorbed, while 2-20% is absorbed of non-heme iron. Non-heme iron is generally modified by other dietary components.

Certain components in grain, fruit and vegetables as well as polyphenols in tea reduce the availability of iron to the body. However, studies have shown that tea only decreases iron absorption when it is consumed simultaneously with food containing non-heme iron. Tea drinking between meals has no effect on iron absorption.

Moreover the ability of tea polyphenols to decrease iron absorption is reduced by the presence of other dietary constituents particular ascorbic acid (known to increase absorption of non-heme iron) and milk.

What are antioxidants?

Antioxidants are components which help to protect cells from harmful "free radicals", known as oxidants. Free radicals occur naturally in the body as a by-product of the respiration process and can bring about cell damage. Antioxidants help to prevent this cell damage, which can contribute to ageing and a number of chronic diseases, including cancer and heart disease and strokes.

Are the antioxidants in green and black tea the same?

It was thought until comparatively recently that green tea was the most effective antioxidant-containing tea and that green-tea catechins (the unoxidized polyphenols present in tea leaf) alone were the antioxidants giving tea its health-giving attributes. It is now well known that the theaflavins and thearubugins produced by the condensation of oxidized catechins, during the fermentation stage of black tea manufacture, are equally effective antioxidants (Leung et al 2001).
The catechins present in tea flush and as such in green tea are:

Expressed as a % of dry weight

Epicatechin 1 - 3%
Epicatechin gallate 3 - 6%
Epigallocatechin 3 - 6%
Epigallocatechin gallate 9 -13%
Catechin 1 - 2%
Gallocatechin 3 - 4%

During manufacture of Black Tea these catechins get oxidized & polymerized (condensed), for example :

Epicatechin + Epigallocatechin gallate + Oxygen ---> Theaflavin

The paired catechins as they appear in Black Tea are now known to be equally effective antioxidants. The body produces free radicals (FRs) under certain conditions. Carcinogens and radiation from the environment facilitates the formation of FRs. These FRs within the body cause oxidative changes to DNA (the genetic material present in all cells). Changes to DNA carry the risk of cancers. The FRs are inhibited and destroyed by the antioxidants in tea, both green and black tea.

Green and black tea comes from Camellia Sinensis. Green tea is unfermented, steamed immediately after plucking, and retains a lighter colour and flavour. Black tea is allowed to ferment and is then dried, resulting in a darker leaf colour and a more flavour and aroma.

Can the consumption of tea be good for my memory as I grow older?

Research conducted at the University of Newcastle shows that drinking tea could help improve memory and also slow the development of Alzheimer's disease.

The functioning of the brain cholinergic system, which is involved in attention and memory declines during normal aging and is further affected in Alzheimer's disease. Current drugs for the symptomatic treatment of dementia are aimed at enhancing the associated cholinergic deficit by inhibiting acetylcholinesterase, an enzyme that cleaves the neurotransmitter acetylcholine. Butyrylcholinesterase increases in the brains of people with Alzheimer's disease and may play a role in the progression of the disease by its ability inter alia to hydrolyse the neurotransmitter Acetylcholine. Inhibition of both these enzymes is one of the objectives in treating cognitive dysfunction associated with diseases such as Alzheimer's disease.

During the study it was found both green and black tea inhibited the activity of the enzyme acetylcholinesterase, and also hinder the activity of the enzyme butyrylcholinesterase. It was further observed that Green tea obstructed the activity of beta-secretase, which plays a role in production of protein deposits in the brain that are associated with Alzheimer's disease. So this study reports that tea infusions in vitro have dual anti-cholinesterase and anti--secretase activities relevant to the treatment of dementia.

Previous studies have shown that both green tea and black tea possess pharmacologically protective, properties such as antioxidative, anticarcinogenic, neuroprotective and hyppocholesterolaemic effects. This study indicates that Tea, Camellia sinensis has the potential to enhance cholinergic function and therefore may have a role in ameliorating and cholinergic deficit in Alzheimer's disease and other age related memory impairments. The effects of tea infusions on the cerebral cholinergic system and -secretase in vivo will depend on the levels of the enzymes in the brain, the type and chemistry of the tea, infusion concentration (strength), dose (number of cups per day) and duration of consumption. It is also possible that regular consumption of tea by patients with dementia prescribed cholinesterase inhibitors may alter the effects of such drugs. Clinical and scientific investigation of the chemistry and activities of cholinomimetic and anti- -secretase compounds in C. sinensis, and cognitive effects of tea consumption is warranted in order to establish the relevance of these novel findings to the maintenance of cognitive function in old age and in diseases such as Alzheimer's Disease.

Is regular tea consumption good for my immune system?

A Harvard Medical School study discovered that regular consumption of tea could boost the body's defenses against infection. A component in tea was found in laboratory experiments to prime the immune system to attack invading bacteria, viruses and fungi, according to a study in the Proceedings of the National Academy of Sciences.

A second experiment, using human volunteers, showed that immune system blood cells from tea drinkers responded five times faster to germs than did the blood cells of coffee drinkers. Researchers claim that the results give clear proof that five cups of tea a day sharpen the body's disease defenses.

In the study a substance called L-theanine was isolated from ordinary black tea. L-theanine is broken down in the liver to ethylamine, a molecule that primes the response of an immune system element called the gamma-delta T cell, considered the first line of defence against bacteria, viral, fungal and parasitic infections.

The T cells prompt the secretion of interferon, a key part of the body's chemical defense against infection. To further test the finding, the researchers had 11 volunteers drink five cups a day of tea, and 10 others drink coffee. Before the test began, they drew blood samples from all 21 test subjects.

After four weeks, they took more blood from the tea drinkers and then exposed that blood to the bacteria called E-coli. The immune cells in the specimens secreted five times more interferon than did blood cells from the same subjects before the weeks of tea drinking researchers claimed. Blood tests and bacteria challenges showed there was no change in the interferon levels of the coffee drinkers.

Can tea be part of a healthy adult's daily fluid intake?

As brewed tea contains almost 98% water it makes a healthy contribution to the delay fluid balance. Tea contains no additives or artificial colours. Research indicates possible antioxidant benefits so drinking tea can be a calorie-free way to increase intake dietary antioxidants.

Does tea reduces the diuretic effect in comparison to coffee?

The diuretic can be attributed to the caffeine present in tea and coffee. Caffeine increases diuretic action on the kidneys, increasing urinary volume and sodium extraction as a result of a decrease in the tubular re-absorption of sodium and water. Coffee contains a higher content of caffeine compared to tea. Research has shown that a 170ml (6-oz) serving of tea contains, on average 34mg of caffeine in comparison to 99 mg of caffeine in 170 ml serving of brewed coffee.
As a result the diuretic effect of coffee is greater compared to tea.

Why does tea cloud when it is cooled?

Clouding in tea is a result of the colloidal precipitate that is formed. This is called 'tea cream'. Tea creaming takes place when black tea is cooled below 400 C. A weak complexion is formed between caffeine and polyphenols (theaflavins and thearubigins). The tendency to cream down varies from tea to tea. In black tea without milk complexation and subsequent precipitation that occurs is negligible due to just 4% of caffeine.

In tea with milk a similar association takes place between the milk protein casein and various polyphenols. Due to the availability of casein in milk tea the complexion is greater resulting in larger precipitation.

Does the water affect the tea brew?

The water used to brew the tea significantly affects the colour and the taste of a cup of tea. Tea brewed in soft water or permanently hard water (which contains CaSO4) appears brighter than if it is brewed in temporary hard water (that contains Calcium bicarbonate CaCO3).

High pH water that contains bicarbonate makes the infusion look darker brown due to the greater ionisation of the tea polyphenols. While lower pH as in lemon tea the infusion turns yellow. As for taste some teas are more suited to softer water such as the orthodox manufactured Assam leaf, while high grown Ceylon and CTC manufactured teas are better with temporary hard water.

What is tea scum or the dark skin on top of the brewed tea?

It is the result of the high molecular weight components which are formed due to the influence of calcium and bicarbonate ions at the liquid water interface. The scum can be removed in two ways

1) by filtering the calcium ions,
2) by adding acids to covert bicarbonate ions to CO2.

Very little scum is formed on a cup of very strong tea. As the acidic tea polyphenols themselves partly neutralise the bicarbonate ions. It also should be noted that less than one mg of scum is formed in a cup of tea and it is not known to be harmful to human health.

Can overcooked water affect the quality of tea?

Boiling water for too long does dramatically affect the quality of tea. The desirable brisk taste of tea is created by the interaction of two of its main components, caffeine and polyphenols. Each component is harsh on its own but as a complex the compounds moderate each other. Acid levels of water affect the behaviour of these components.

Water contains minerals and gases absorbed from the earth bed and air. Carbon dioxide absorbed by air makes the water slightly acidic that influence the colour and taste. High temperature changes the acidity of water and the acidity is reduced by gradually driving out carbon-dioxide. Therefore re-boiled water might well brew tea of a different colour and strength and is unsuitable to brew a good cup of tea.

What is Real Tea?

Tea in its true sense is defined by the International Standards Organisation (ISO) as, 'tea derived solely and exclusively, and produced by acceptable processes, notably withering, leaf maceration, aeration and drying, from the tender shoots of varieties of the species Camellia Sinensis, known to be suitable for making tea for consumption as a beverage.

Real Tea is tea produced in the traditional, orthodox manner from the tender shoots of Camellia Sinensis. The process of manufacture, perfected over centuries is the most widespread in Sri Lanka with its drying, rolling, fermentation and baking into the form most people are familiar with - black tea, green tea, white tea. Orthodox Tea is distinct from the more recent process - CTC (or Cut, Twist and Curl) which was developed by companies seeking to offer quick colour in a teabag. CTC teas rob tea of its soul, losing the subtlety of flavour, aroma, variety and character that Orthodox Teas are prized for. CTC consists of just 3 grades or forms, whilst Orthodox Tea produces almost infinite variety of leaf size, colour, subtlety of character and body.

What are Herbal Infusions?

Herbal Infusions, fruit based tisanes and floral infusions are not tea. There are only three types of tea, black tea, green tea and Oolong tea. In many countries, notably the USA, these infusions are usurping the health and other benefits of tea falsely. We give below a brief introduction to the most popular herbal infusions.

CHAMOMILE (Chamomillae romanae)

Chamomile herbal infusions are derived from the plant Chamomillae romanae. It is a one-year plant, which reaches a height of approx. 55.cm. Chamomile contains 0.6% - 2.4% essential oils such as angeloyl, methacryl and flavenoids as the main constituents. The white flower heads are mechanically harvested and dried in chambers to manufacture the commercial product.

Chamomile was known for its health benefits for centuries and the ancient Egyptians dedicated it to their sun god, and used Chamomile in their aromatherapy. This legacy of Chamomile lives on. Studies have that it is beneficial for complaints such as indigestion, nervousness, depression and headaches.

In testing its Chamomile based product Kamillosan, the Chemiewerke Hamburg Pharmacy of West Germany found that it reduces gastric acid and helps prevent ulcers. It also promoted tissue regeneration after patients had operations on their intestinal tract and urinary system. Chamomile decreases histamine, implicated in ulcers and the skin swelling, puffy eyes and headaches brought about on by allergies. It is given to children for digestive and hyperactive problems.

The Greeks named Chamomiles "kamai melon" (ground apple) inspired by its distinct apple like fragrance and the Spanish called it Manzanilla or "little apple".

PEPPERMINT (Mentha piperita L.)

Peppermint originated from the Mediterranean but is now cultivated globally in the Balkans, Northern Europe and the USA. It is characterized by its strong aroma. It is a perennial herb with a flat root system. It reaches normally a height of approx. 2-ft and is harvested shortly before blooming. Peppermint contains 0.5 - 4 % essential oil that includes Menthol and menthol esters.

Written evidence of old Egypt indicates that Mentha plants were cultivated and exploited for medical use 1,000 years before Christian era. It also shows that Mint plants have represented a valuable object of trade, and was even accepted as tithes to pay taxes due.

Studies have shown that peppermint tea brings about considerable increase in the production of bile due to the presence of flavonoids. Peppermint leaf or extracts prepared from it are included in many (ca. 50) prepared cholagogues and bile-duct remedies, e.g. Cholagogum Nattermann (capsules, drops), etc. gastrointestinal Remedies (ca 50), e.g. Gastricholan Iberogast Ventrodigest, etc.), liver remedies (more than 10), hypnotics/sedatives (more than 10), e.g. Nerventee Stada, Esberi-Nervin drops, etc., and laxatives.

ROSEHIP & HIBISICUS

Usually consists of 70% Hibiscus and 30 % Rosehip. Hibiscus (Hibisci flos) originated in Angola but is now cultivated throughout the tropics. It is an annual herbaceous plant with lobed leaves that grows to a height of 5 m. Flowers with a 5-lobed calyx and divided epicalyx. Hibiscus for infusions is manufactured form the dried calyxes harvested from the fruit of the species.

It is principally taken as a caffeine-free refreshing drink taken in large amounts because of the plant acids. The plant acids which are difficult to absorb act as a mild laxative.
Hibiscus has been extensively used in the African Folk medicine. The drug is ascribed, among other things, spasmolytic, antibacterial, cholagogic, diuretic and anthelmintic properties. Studies have shown aqueous extracts of hibiscus flowers relaxes the muscles of the uterus and to lower the blood pressure.

Rosehip is derived from the plant Rosae pseudofructus. It is a shrub that grows up to a height of 5 m with thorn branches with flowers close to 5 cm in diameter with five petals. The drug consists of the dried hypanthia from various species of the genus Rosa with the fruit enclosed in them. Rosehip is native to Europe, Western and Central Asia, and North Africa but now it is cultivated in Chile, Bulgaria, Romania, China and Hungary. It was used in folk medicine as a result of its diuretic and laxative action due to the pectin and the plant acid content. Due to its high content of vitamin C Rosehip are used as breakfast teas.

When Tea is not TEA

Green Tea, Oolong tea, Black tea, Decaffeinated Black & Green Tea, the Green tea component in Jasmine Green tea, and Organic tea are derived from the tea plant, Camellia Sinensis. Many brands use the word 'tea' loosely since 'tea' refers only to the dried leaves of the plant Camellia Sinensis, and does not include infusions like Rooibos, Mate, Fruit and other herbal infusions. The term Red Tea, recently associated with Rooibos, for example refers to the herb from the South Africa shrub Rooibos (meaning Red Bush).

The traditional forms of tea are White Tea (see below for details), Green Tea (unfermented), Oolong Tea (partially fermented) and Black Tea (fully fermented). These offers the health benefits associated with tea whilst others such as Rooibos, Mate, fruit and other infusions usually do not, although they may have their own specific benefits.

Organic tea

The manufacture of organic tea is carried-out without the addition of Chemical fertiliser, Pesticides and Insecticides as a result the product doesn't contain chemical residues which can bring about health effects.

What is White Tea ?

Sri Lanka traditionally produces one of the world's finest white teas in the form of Silver Tips and Golden Tips, entirely handmade from a special variant of the Camellia Sinensis plant, untouched by machines and prized for their rarity and subtle character. The Chinese also have a tradition of producing fine White Teas.

In the production of white tea the 'bud' is selectively plucked and sun dried. Since the Bud remains undamaged the Catechins or the un-oxidised Polyphenols present remain intact. What we refer to as Flavonoids in tea, or the antioxidants in tea, include the un-oxidised Polyphenols or Catechins as in Green Tea and White Tea, as well as the Theaflavins and low molecular Thearubigins in conventional Black Tea. The Catechins (Flavonoids) content in the tea becomes progressively less as we go down from the Bud to the mature leaves in a tea shoot. The bud has the highest catechin content, next the first leaf, followed by the second leaf and so on.
Hence the sun dried buds or White Tea will have a higher Flavonoid or Antioxidant property.

Further, since the bud is sun dried (not subjected to high temperature in a
drier) even the vitamin content in the White Tea will remain high and potent. So will be the Caffeine content. It has been already shown that the bad effects of caffeine is nullified in Tea by the presence of the Polyphenols in the tea (unlike in coffee and the colas). Hence the White Tea will have greater nutritive and therapeutic value than the conventional black tea.