Tea for Children

child tea withdrawal

Me aged four with a definite look of caffeine withdrawal!!

Growing up I was sent to school every day with a 500ml flask of black tea. The tea was left in the flask so it steeped for about 4 hours before I got to it! A conservative estimate would put my caffeine intake at about 215mg. Most studies suggest that children should limit daily caffeine consumption to 2.5 mg per kg body weight. High caffeine intakes (i.e. >5 mg per kg body weight) are associated with an increased risk of anxiety and withdrawal symptoms (see photo right!). I was getting at least three times my daily allowance but it’s unclear what exactly are the cumulative affects of stimulants on a developing brain. Wikipedia reassures me that there is no evidence that coffee stunts a child’s growth but a 2010 review study by Temple was concerned about the “particular areas of the brain involved in executive function, impulsivity control, and planning”.

A UK study, compared diets for children in 1950 with those of children of roughly the same age in 1992-93. In the 1950s, 55% of four-year-olds drank tea with their meals while just 10% had soft drinks and juice. The consumption of soft drinks and fruit juices rose to 90% for soft drinks and 36% for fruit juices in 1992. During the same period the consumption of tea dropped to 30%.  Since the nineties though the situation is turning around again with a decrease in the consumption of soft drinks for children and a correlated increase in tea and coffee. Similar studies in the US are showing the same trends with coffee increasing from 10% in 2000 to 24% in 2010 while tea remains steady at ~25%.

To avoid this flip-flopping between sugar and caffeine, maybe it’s time to consider herbal teas that are naturally sweet without the added sugar and sometimes helpful for minor ailments:

Peter Rabbit

Peter Rabbit (source)

Ginger: This tastes warm and will sooth upset stomachs and help with nausea and car sickness.

Chamomile is a mild sedative that is also considered to be a colic-remedy.

When Peter Rabbit was not very well during the evening, his mother put him to bed, and made some chamomile tea “One table-spoonful to be taken at bedtime.”

Rooibos: the south African plant is renowned for its soothing and calming effects especially on allergic and colicky babies.

 

 

 

Quick disclaimer: I am not a medical herbalist. Always check with a doctor before using herbs.

Caffeinated: How Our Daily Habit Hooks, Helps and Hurts

Murray Carpenter approaches caffeine as a drug because most of us take it every day, it has predictable physiological effects and we are dependent on it. His new book Caffeinated: How Our Daily Habit Hooks, Helps and Hurts (Hudson Street Press) was launched on 13 March and sounds like it will make for a very interesting read:

  • Women on birth control metabolize caffeine twice as slowly—which means they get double the jolt from the same cup of coffee
  • Smokers metabolize it twice as fast so they needto up their intake to get the same buzz
  • Some people are genetically predisposed to metabolize caffeine slowly and they will be extremely sensitive to caffeine
  • 100 milligrams of caffeine daily is enough to get an adult dependent
  • 250ml of cola has ~24mg of caffeine but Coke used to contain ~80mg of caffeine (the same as Red Bull today)
  • Caffeine withdrawal-symptoms can include lethargy, irritability and headaches
  • Post-operative headaches are linked to caffeine withdrawal
  • Migraine, hangover and cold medicines often include caffeine and caffeine suppositories can be used medicinally
  • Extroverts get more cognitive enhancement from caffeine
  • A tablespoon of pure caffeine would kill you
Caffeinated Owls - Dave Mottram (Image Source)

Caffeinated Owls – Dave Mottram (Image Source)

 

As I previously wrote, there have been several papers written on the effect of caffeine on sleep disruption and even more papers written on the positive and negative effects of caffeine on other health issues. A major problem in this type of research is that the papers tend to use very different values for the caffeine content in beverages and foods  and most ignore the effects of other substances like theobromine, tanninic acid, caffeol etc.

For tea in particular it can be hard to pin down the precise caffeine content. Preparation plays a large role and differences in the time and temperature of steepings, the size of the tea leaf and the type of tea used will all influence the caffeine content of tea. The plant variety, soil, nutrients, picking season and the part of plant used will also play a role.

After a lot of searching, I eventually collected some reliable information on the caffeine content of tea.

[Note: moderate caffeine use is generally considered to be 200 – 300 milligrams per day]

 

Tea (~200ml after one steeping of three minutes)

Chinese white tea – 75mg

Darjeeling white – 56mg

Indian Green – 59mg

Kenyan Green – 58 mg

Chinese Oolong (Ti Kwan Yin) – 37mg

Assam (FTGFOP) – 86mg

Darjeeling Black (SFTGFOP1) – 54mg

 

For comparison here are some for coffee and other beverages:

Coffee (~200ml)

Coffee (ground roasted) – 115mg

Coffee (instant) – 80mg

Cola – 20mg

Decaffeinated coffee – 4mg

Espresso, single shot – 75mg

Espresso, double shot – 150mg

Red Bull (250ml can) – 80mg

 

Chocolate

70% Green and Black dark chocolate (30g) – 4.5mg

Green and Black milk chocolate (30g) – 2mg

White chocolate (30g) – 0mg

Yerba Mate

gourd bombilla and mateWhen my sister told me she was going to South America, I had two words for her: “yerba mate”. Not only did she bring back a big bag of yerba mate but she also brought back the gourd (vessel) and bombilla (filter tipped metal straw). Happiness :-)

Yerba mate or maté comes from a species of holly called lIex paraguariensis and so it’s a herbal infusion rather than tea. The plant is native to the subtropical regions of Brazil, Paraguay and Argentina and is sometimes called “Jesuits’ tea” or “Paraguay tea”. Harvesting of cultivated plants starts at about 5 years and takes place after winter every 2-4 years. Harvesting looks a lot like tree-pruning but only the smaller branches and leaves are kept. After harvesting, the leaves and small stems are heated, dehydrated, cut, sifted and finally packaged.

brewed mate in gourdYerba mate is unusual in that it is a herbal drink but it has the same stimulating effect as tea and coffee due to the presence of mateine (i.e. caffeine). Historically in Europe it was considered a poor substitute for other caffeinated luxury goods such as tea, coffee and chocolate. It is only since the twentieth century that it has been recognised as a unique beverage and marketed as having “the strength of coffee, the health benefits of tea, and the euphoria of chocolate”. For more historical and cultural information, see this paper: “Stimulating Consumption: Yerba Mate Myths, Markets, and Meanings from Conquest to Present“.

As with tea, the flavour of yerba mate is influenced by the soil in which the plant grows but in general, it is light in colour and the taste is a distinctive combination of tree-bark and tobacco. Mate has a high tannin content but it has a lasting flavour that is very pleasant.

To prepare, the gourd is filled with yerba mate until it is three quarters full. After shaking (to ensure the smaller pieces are at the top), the gourd is tilted to one side and the bombilla placed inside. A small amount of warm water is added that is just enough to wet the leaves. The gourd is then filled with hot, not boiling water. The leaves are re-soaked several times by refilling the gourd with water.

Caffeine

I was reading an old article from Bord Bia that said that tea consumption was on the rise at night-time. The reason given was that “people are at home more often and tea is a comforting affordable reliable beverage”.

There have been several papers written on the effect of caffeine on sleep disruption and even more papers written on effect of caffeine on other health issues (good and bad). A major problem in this type of research is that all the papers tend to use very different values for the caffeine content in beverages and foods.

There are plenty of reasons for the variations. Preparation plays a large role and differences in the time and temperature of steeping, the size of the tea leaf and the type of tea used will all influence the caffeine content of tea. The variety of plant, care of the plants, soil nutrients, picking season and the part of plant used will also play a role.

Caffeine Crystals under the microscope

Caffeine Crystals under the microscope (Source)

Caffeine is a white, odourless crystal that occurs naturally in coffee, tea and chocolate and is added to colas and energy drinks. After a lot of reading, here is a summary of caffeine content in tea from sources that seems reliable:

Tea (~200ml after one steeping of three minutes)

Chinese white tea – 75mg

Darjeeling white – 56mg

Indian Green – 59mg

Kenyan Green – 58 mg

Chinese Oolong (Ti Kwan Yin) – 37mg

Assam (FTGFOP) – 86mg

Darjeeling Black (SFTGFOP1) – 54mg

 

For comparison here are some for coffee and other beverages:

Coffee (~200ml)

Coffee (ground roasted) – 115mg

Coffee (instant) – 80mg

Cola – 20mg

Decaffeinated coffee – 4mg

Espresso, single shot – 75mg

Espresso, double shot – 150mg

Red Bull (250ml can) – 80mg

 

Chocolate

It seems to be generally accepted that there are 6mg of caffeine per 30g serving. But it seems to vary a lot:

70% Green and Black dark Chocolate (30g) – 4.5mg

Green and Black milk chocolate (30g) – 2mg

White chocolate (30g) – 0mg

Cadbury dairy milk (28g) – 15mg

Herbal tea

Herbal tea – 0mg

(Note: other substances like theobromine, tanninic acid, caffeol also play a role)

 

I found it surprising how high the caffeine content of green tea is. Many claim that green and white tea have less caffeine than oolong or black tea because of the minimal oxidation. It seems to be well-proven now that this is not the case. White tea in particular uses the bud of the plant which has been shown to have a higher caffeine content that the leaf. I guess most people wouldn’t have a can of coke before bed but I wonder if they know that a Chinese white tea has three times as much caffeine?

With a few exceptions, herbal tea or tisanes have no caffeine at all. That includes Rooibos so there is a huge selection of tea alternatives for night-time. I’ve been going through a rough time with sleep lately so now I only drink tea up to about 3pm and right before bed I drink hops tea. It seems to really help. And no, by hops tea I don’t mean beer though sometimes that helps too :-).

 

Main Sources:

Barone JJ, Roberts, H.R. (1996), Caffeine consumption, Food and Chemical Toxicology, Volume 34, Issue 1, January 1996, Pages 119–129.

Richardson, B. (2009), De-bunking the At-Home Decaffeination Myth Story, Fresh Cup January 2009

Chin JM, Merves ML, Goldberger BA, Sampson-Cone A, Cone EJ. (2008), Caffeine content of brewed teas. J Anal Toxicol. 2008 Oct;32(8):702-4.