Mythbusting: Green tea and the effect of caffeine

Tea has a stimulating effect often attributed to the caffeine it contains, but there is a lot of misinformation about how much caffeine is in tea.

There’s an old legend that makes an early link between tea and wakefulness. It features a Buddhist follower who accidentally falls asleep during meditation. In order to stay awake, he cuts off his eyelids and throws them on the ground where they became tea bushes.

Waking up to a cup of green tea in the morning is not nearly as brutal, but you can expect a stimulating effect from the caffeine tea contains. However, there are a number of things to consider before you refuse that cup before bedtime.

How much caffeine is in tea?
The caffeine in tea depends a lot on growing conditions, production and steeping. Even though all tea is from the same plant, Camellia sinensis, a green tea grown in Australia like Two Rivers will have a different caffeine profile to one grown in Japan or China, simply because of the elevation, soil and climate.

Time of harvest and production methods, such as whether the tea producer steams or pan-fries the leaves, plus withering time will also have an effect. Lastly, the quality and temperature of water in which you steep your tea, and the brewing time, will also make a difference on the amount of caffeine in the tea liquor.

This mean you’ll get wildly different caffeine measurements from study to study depending on the tea the scientists use and how they brew it. According to the Australian Beverage Council [link:], a cup (250ml) of green tea contains anywhere from 30 to 50mg of caffeine, while a latte or cappuccino has anywhere from 113-282mg for the same volume.

But just measuring the caffeine in green tea is not enough. How it is absorbed will give you an idea of how you can use it for stimulation—or relaxation.

Tea versus coffee
Milligram for milligram, the caffeine in tea is different from the caffeine in coffee. Coffee gives you a jolt. Within 20 minutes, the caffeine will begin to remove some of the ‘traffic lights’ in your system, making you more alert. The downside is that once you reach peak stimulation, it drops off pretty quickly, so you crash.

Green tea, however,

has a much gentler ascent due the antioxidants in tea, which slows the absorption of caffeine. You may not reach peak alertness as quickly as you do with coffee but tea will keep you on a plateau of stimulation for longer.

Another thing to note is the way caffeine works with L-theanine, an amino acid in tea, which reduces stress. That’s right, you get the alertness from the caffeine while remaining relaxed. This means no caffeine crash.

Green tea before bedtime
Will green tea keep you awake all night if you have a cuppa before bedtime? Everyone processes caffeine differently so if you’re sensitive to caffeine, a cup before hitting the pillow is probably not a recipe for a good night’s sleep.

But if you know where green tea takes you stimulation-wise—with the L-theanine strong enough to help you de-stress but the caffeine mild enough to allow you to sleep—then a cuppa before bedtime might be a good way to relax.

3 ways tea can boost hydration

Does tea make you thirsty? Or is it a good way to stay hydrated? Two Rivers finds out the truth.

It wasn’t so long ago that any article about hydration would recommend you cut down on tea and coffee. The accepted wisdom was that the caffeine in these beverages had a diuretic effect (cause you to urinate more) and were therefore dehydrating.

Not only is that not true for most tea drinkers, the issue of hydration is quite a complex one that relies heavily on the individual, including your body shape as well as the health of your renal system.

The initial study that linked caffeine to the diuretic effect was conducted under a couple of conditions that you wouldn’t consider normal consumption. Firstly, the scientists gave the test subjects a beverage of water and pure caffeine instead of tea or coffee like you or I would drink, which means the other nutrients in tea that would offset any effect were not present.

Secondly, the test subjects abstained from tea and coffee for several days prior to the test. Subsequent tests on regular tea drinkers show caffeine has a diminished effect when the drinker has built a tolerance. Regularly drinking tea makes you less susceptible to the diuretic effect, if it ever did affect you that way.

It turns out caffeine is a mild diuretic in some people—but it’s coffee that’s the culprit. For regular tea drinkers, tea has a hydrating effect equivalent to water according to a study that compared people who drank nothing but tea for the 12-hour trial with those who drank an equivalent amount of boiled water. There was no difference in hydration levels between them.


Tea’s advantage over water
Tea does have a few advantages over water as a source of hydration, however.

1. It tastes good
If it tastes good, we drink it. Some people don’t like water because of the taste; tea can help make water palatable. If people find tea easier to drink than water, they will drink more of it and stay hydrated.

2. It has additional nutrients
In addition to providing you with water for hydration, tea has a whole lot of other nutrients such as antioxidants and polyphenols that boost immunity and help you maintain physical and mental health.

3. It increases your intake of warm water
We don’t often drink warm water, but we will often drink hot tea. Warm water has a stimulating effect on your body, reducing congestion and aiding digestion, but many people find it hard to drink water at a higher temperature—but what about hot tea?

When it’s cold, such as in the early morning, at night and during the cooler months, we don’t get thirsty as often as when it’s hot, so the triggers for rehydrating aren’t as frequent. Because it’s easy to drink tea even when you’re not thirsty, for warmth and time out, this can help you stay hydrated.

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