Low Caffeine

Green tea contains about 30mg of caffeine per 8oz. (240ml) cup. Compare this to a cup of regular brewed coffee, which contains around 100mg. In a report published by the John Hopkins University of Medicine, it was revealed that of the 80-90% of the North American population that consumes caffeine, on average 280mg is consumed per day. This caffeine comes from consuming coffee, tea, soft drinks and chocolate products. The university also reported that an over-consumption of caffeine (over 200mg), could result in nervousness, anxiety and an upset stomach. If we follow the recommendations to consume up to and not over 200mg of caffeine, that equates to 2 cups of coffee, or about 1 cup of coffee and a couple of cans of soft drink. With this guide in mind, we can safely consume 5-6 cups of green tea a day.

The report also suggests that despite the low caffeine content in green tea, people with anxiety disorders, insomnia and pregnant women should reduce their intake or stop consuming green tea altogether.

Green Tea for Health

These days you can often find decaffeinated green tea in your supermarket or specialty stores. Unfortunately during the process of removing the caffeine from green tea, the flavour is also altered. This is why in Japan, where so many people drink green tea, that decaffeinated green tea is almost impossible to find in any supermarkets or stores.

It is also thought that by removing the caffeine content in green tea, much of the health benefits are also lost from the polyphenolic content.

There are some simple ways to reduce the caffeine content in green tea. The first way would be by brewing the leaves or tea bag for just 1 minute (compared with the normal 2 minutes). The other way would be to just discard the first cup of brewed tea, and drink the second and third brewing only.

Moderation is the key to consuming anything in life, and the same can be said for green tea. The great thing with green tea is it contains so many healthful properties and still contains the right balance of caffeine, so we can refresh and energize without experiencing the irritability and anxiety which can often happen with coffee.

Red wine and Australian fruit tea Strawberry

We do not know whether decaf teas have the same polyphenols, and thus the same health benefits. It is not yet known if removing caffeine also removes polyphenols in the decaffeinating process.

The Bottom Line

Tea is a healthy beverage containing many health benefits (if you skip the cream and sugar). Brew your tea for at least 3 minutes to bring out the beneficial polyphenols. Enjoy the aroma of tea.

Black, green, white, and oolong teas derive their leaves from a warm-weather evergreen tree known as Camellia sinensis. The leaves from this tree contain polyphenols. The more processing tea leaves undergo, the darker they will turn. Green tea and white tea are the least processed tea. They are simply steamed quickly. White tea is derived from the young new leaves from the Camellia plant in early spring. These young leaves contain no chlorophyll, so they are silvery white. Black and oolong teas are partially dried, crushed and fermented. As we have mentioned before, regardless of the processing method, black, green, white and oolong teas all contain polyphenols. In fact, tea ranks as high as or higher than many fruits and vegetables in the ORAC score, a score that measures antioxidant potential of plant-based foods.

Researcher Professor Colin Binns, of the School of Public Health at Curtin University in Western Australia, says their research shows people who drink at least one cup of green tea a day reduce their risk of ischemic stroke.

For those who drink more than two cups daily the risk is cut by as much as 60%.

“We can say if you are going to drink a beverage, then tea is the healthier option,” says Binns.

If green tea does not take your fancy, black teas also reduce risk, albeit not as much.

“We believe other kinds of tea are half as effective as green tea in reducing risk,” says Binns.

The findings, published this week in the journal Stroke, follow on from earlier research by the same group that found green tea also cuts ovarian and prostate cancer risk.

Binns says the results could help reduce the incidence of strokes, which account for more than five million deaths worldwide each year.

China study
The study tracked green tea consumption among ischemic stroke patients in the southern Chinese province of Guangdong.

Ischemic strokes, which are those caused by a clot that cuts off blood to the brain, account for about 70% of all strokes that occur.

The research, which included academics from the Curtin Health Innovation Research Institute and three Chinese hospitals, was conducted between 2007 and 2008.

The study interviewed 400 patients diagnosed as having had a stroke and 400 healthy people.

Binns says the choice of basing the research in southern China was important because the diet in that area has been relatively unchanged for the past 10-20 years, the population is homogenous and tea drinking is a traditional practice.

He says because people’s tastes in Australia are constantly changing, it would be hard to replicate the study here.

However, the researchers believe green tea would have the same benefits within a western diet.

Laboratory tests found that regular cups of green and black tea inhibit the activity of certain brain enzymes that bring on Alzheimer’s, a form of generative dementia that affects an estimated 10 million people worldwide.

But the researchers are not sure if tea’s active ingredients would work in the body, particularly if they would reach the brain.

The research by the medicinal plant research centre at University of Newcastle upon Tyne, northeast England, is published in the journal Phytotherapy Research.

Scientists tested coffee as well as green and black tea. Coffee had no significant effect on the activity of enzymes associated with developing Alzheimer’s. But both green and black tea inhibited the enzymes.

According to the journal, tea inhibited the activity of the enzyme acetylcholinesterase, which breaks down the chemical messenger, or neurotransmitter acetylcholine.

Alzheimer’s is characterised by a drop in acetylcholine.

Green tea and black tea also hindered the activity of the enzyme butyrylcholinesterase, seen in protein deposits found on the brains of patients with Alzheimer’s.

But green tea alone had a further effect, obstructing the activity of beta-secretase, which has a role in the production of protein deposits in the brain associated with Alzheimer’s.

The effects of green tea also last a week, scientists found, as against only a day for black tea.

“Although there is no cure for Alzheimer’s, tea could potentially be another weapon in the armory which is used to treat this disease and slow down its development,” said head researcher Dr Ed Okello.

“It would be wonderful if our work could help improve the quality of life for millions of sufferers and their carers.

“Our findings are particularly exciting as tea is already a very popular drink, it is inexpensive, and there do not seem to be any adverse side effects when it is consumed.

“Still, we expect it will be several years until we are able to produce anything marketable.”