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Posts Tagged ‘India’

Oolong Tea and Weight Loss

Posted by Susan Lutfallah on June 7, 2009

Even in traditional tea drinking countries like China and Japan, oolong tea has a well-known and lasting reputation for helping people to keep slim. Overall, oolong tea promotes weight loss through three different mechanisms, as seen below:

–         Increasing basal metabolic rate

–         Burning fat (through a process called lipolysis)

–         Blocking dietary fat absorption

Again, the Chinese have long believed that oolong tea is beneficial in reducing and maintaining weight. In fact, a 1998 Chinese study involving 102 females showed that continuous consumption of oolong tea for six weeks resulted in a reduction of body weight – of course, this study spurred further research.

Subsequently, Dr. William Rumpler, a physiologist at the US Agriculture Research Services’ Diet and Human Laboratory, investigated the ancient Chinese belief that oolong tea is effective in controlling body weight. The 2001 study measured how oolong tea influences energy expenditure (EE) and included 12 male volunteers who were given 4 separate beverage formulas over three consecutive days. The four beverage formulas were:  1) full strength oolong tea, 2) caffeinated water with caffeine equal to full strength oolong tea, 3) half strength oolong tea and 4) non caffeinated water.

After twenty-four hours, the energy expenditure (EE) of the participants was measured and resulted in:

EE levels of about 3% higher when they drank either the full strength oolong tea or the caffeinated water versus the non caffeinated water.
Participants burned an average of 67 more calories per day when drinking the full strength oolong tea.
Participants increased fat oxidation (‘lipolysis’ or fat burning) by a whopping 12% after consuming the full strength oolong tea versus the caffeinated water.
This data confirms that a component other than caffeine is responsible for promoting the preferential use of fat as an energy source.

The increase in fat oxidation in this study is amazing! Drinking oolong tea can actually tell your body to burn fat as an energy source!

Moreover, a 2003 Japanese study went one step further by comparing the benefits of oolong tea and green tea regarding weight reduction. In this well controlled study, eleven healthy young female student participants received three different beverage formulas: 1) oolong tea, 2) powdered green tea leaves and 3) water.

After all of the measurements were taken, the results determined that:

Oolong tea had higher energy expenditure (EE) levels from beginning to end and at intervals of 30, 60, 90 and 120 minutes.
EE levels peaked at 90 minutes for both oolong and green tea and remained at their respective levels until 120 minutes.
These results indicate that for up to two hours after consuming oolong tea, you will expend more energy than if you were to drink green tea or water.

Additionally, the concentrations of caffeine, catechins, and other polyphenols were measured producing these intriguing findings;

The caffeine content was much higher in the green tea versus the oolong tea.
The concentration of polymerized polyphenols was significantly higher in the oolong tea versus the green tea.

These findings show that it’s the polymerized polyphenols that link tea to burning fat, not just the caffeine – again, the concentrations of polymerized polyphenols are highest in oolong tea. Furthermore, the rest of the chemical compounds compared in the oolong and green teas were similar or equal to one another with no marked differences – this reinforces the result that the polymerized polyphenols principally contributed to the lipolytic effect of oolong tea.

Finally, oolong tea’s effect on blocking the absorption of fats and carbohydrates is thought to play a key role in its weight reducing benefits – in fact, oolong tea is a popular accompaniment for greasy food in Asia for that very same reason. Now, scientists have proven that it is an effective fat blocker. A study conducted by the University of Tokushima found that drinking oolong tea can double the amount of fat being excreted. During the study, tweleve young Japanese adults participated in the 17-day program, consisting of 10 days of washout (drinking nothing but water) and 7 days of treatment (drinking oolong tea). The scientists found that fat excretion was twice as high for those who consumed oolong tea compared to the placebo.

Overall, oolong tea promotes weight loss through increasing basal metabolic rate (energy expenditure), increasing lipolysis, and blocking the dietary absorption of fat. Just by drinking this tasty brew, you can help yourself on the way to a healthier, slimmer you!

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Oolong Tea: Origin of the Name and History

Posted by Susan Lutfallah on June 7, 2009

Oolong Tea is a traditional Chinese tea that’s also known as ‘Wulong’ Tea. The name Oolong (or Wulong) means black dragon in Chinese, where Wu means black, and Long means dragon. Oolong tea is also known as Qing Cha, is a semi fermented tea, and it is named after the person who discovered this tea.  The Chinese province most noted for its oolong tea production is Fujian.

According to Fujian tea folklore, Oolong tea was discovered by a tea farmer who lived in Fujian Province during the Qing Dynasty – his name was “Su Long”. However, because he had a dark complexion, the local farmers all called him “Wu Long” – of course, this is how the name ‘Wulong’ Tea was derived.

All tea comes from the plant Camellia Sinensis – actually, if it doesn’t come from that plant it is not considered proper ‘tea’. Over time, Camellia Sinensis has protected itself from photosynthetic stressors by forming chemical compounds known as polyphenols. Polyphenols, which include flavonoids, have the same beneficial class of compounds – known as antioxidants – that make fruits and vegetables good for you.

Green Tea is treated or boiled following picking to prevent the leaves from oxidizing and retaining their natural colour. Black Tea is left to oxidize following picking, that’s how it gets their distinctive colour. For Oolong Tea, the raw leaves are sun-wilted and then bruised, which exposes their juices to the air, so the leaves oxidise and start to turn brown like a cut fruit. They are allowed to oxidise only partially, giving them a rich, floral flavour. The tea is then dried fully – this locks in the rich flavours that oolong tea is known to offer.

Unbeknownst to many, oolong tea can range from bright green and slightly fermented to dark-leafed and hearty – a rule of thumb is that the greener varieties are less fermented. Oolong tea therefore comes in a wide range of tastes and aromas – these include teas very close in taste to green tea to those very close to black tea.

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Black Tea vs. Green Tea

Posted by Susan Lutfallah on June 6, 2009

Antioxidant Showdown

Until recently, medicinal research regarding tea has focused on green tea – actually, this is understandable, given that green tea is loaded with the compound epigallocatechin gallate (EGCg), a powerful and easily detected anti-oxidant.

Generally speaking, since the fermentation process used to make black tea converts EGCg into other compounds, researchers in the past assumed black tea had less health benefits than green tea.

However, recent studies indicate the compounds contained in black tea – theaflavins and thearubigens – do more than contribute to its dark color and rich flavour – that is, theaflavins and thearubigens also provide health benefits which were originally attributed solely to green tea!

A recent article by Dr. Leung at the Chinese University of Hong Kong reported that drinking black tea has benefits equal to those of drinking green tea in terms of their antioxidant capacities – briefly, this is because theaflavins present in black tea possess at least the same antioxidant potency as catechins present in green tea.

As reported in related studies, it is clear that a group of theaflavins (TF) in black tea, specifically theaflavin-3,3′-digallate (TF3), has strong antioxidant activity similar to (-)-epigallocatechin gallate (EGCG), which is a major antioxidant in green tea.

However, the concentration of diverse antioxidants in the different teas should be first considered before drawing any conclusions about overall health benefits of teas.

In several studies, the total concentration of antioxidants in green tea and black tea were tested – for example, in a study from Cornell University, black and green teas contained total phenols equal to 124 and 165 mg gallic acid (an antioxidant measurement standard), respectively. Moreover, those same researchers found that the antioxidant capacity per serving of green tea (436 mg vitamin C equivalents) was much higher than that of black tea (239 mg).

Therefore, we must conclude that green tea has more health benefits than an equal volume of black tea in terms of antioxidant capacity.

Ok ok, but what about the TASTE?!

Let’s be honest – the recent surge of health food products may help lengthen our lifespan, but they don’t do much in terms of stimulating our taste buds. Put plainly, the taste of green tea for some folks is a major turn off – on the other hand, some don’t mind the taste of green tea initially, but then find the ‘grassy’ aftertaste to be unpleasant.

On the contrary, black tea tasting ‘sweeter’ and it being more pleasantly smelling is commonly accepted, at least in Western culture – conversely, in China and many Eastern countries, the taste of green tea is preferred to black tea. However, black tea is the most consumed type of tea world-wide – therefore, if it is a consumption numbers match-up, black tea wins it.

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Black Tea and Cancer Prevention

Posted by Susan Lutfallah on June 6, 2009

The U.S. Department of Agriculture recently conducted a study which adds to the growing body of evidence that compounds found in both green and black tea have strong anticancer properties on tumours. In fact, the results, which are published in the Journal of the Agricultural and Food Chemistry, suggest that consumers may benefit more by drinking both green and black tea together!

During the study, nine green tea catechins, three black tea theaflavins, and theanine – extracted using either water or a water/ethanol mix – were used on human cancer cells and normal cells.

The majority of the compounds, and all general tea extracts, reduced human breast, colon, liver and prostate cancer cells.

The water/ethanol extracts were found to contain higher levels of flavonoids and kill more cancer cells – because all of the compounds were most effective when used together (a phenomenon known as ‘synergism’), the researchers recommended that consumers drink both green and black teas mixed together!

Moreover, studies done at Rutgers University reveal that black tea may help prevent stomach, prostate, and breast cancer – again, the scientists confirmed that it is the compounds known as thearubigins and theaflavins which may slow down cancer growth. Dr. Kuang Yu Chen and his team at Rutgers argued that some of the cancer cells were undergoing programmed cell death (apoptosis), which seemed to be induced by the thearubigins and theaflavins found in black tea.

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Black Tea and Tooth Decay

Posted by Susan Lutfallah on June 6, 2009

Drinking black tea may prevent tooth decay – several studies have indicated that the polyphenols found in the refreshing brew can impede or completely suppress tooth decay!

Scientists at the University of Illinois found that the bacteria present in dental plaque simply stopped growing when people rinsed their mouths with black tea!

Briefly, the research found that the polyphenol components of black tea fight dental plaque, a complex material composed of 300 different species of acid-secreting bacteria. Unfortunately, these bacterial plaques can stick to teeth, and can eat away at the protective enamel.

Similarly, a separate study by Swedish scientists also found that people who rinsed their mouths with black tea accumulated significantly less bacterial plaque than a comparable group who rinsed their mouths with only water.

So, if you’re an avid black tea drinker, you can rest easy knowing that your healthy habit is fighting the plaque causing bacteria that can ruin your teeth!

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Black Tea, Chronic Stress, and Heart Health

Posted by Susan Lutfallah on June 6, 2009

Drinking black tea has been linked with reduced risk of heart disease in several studies – in fact, a number of these studies suggest that this benefit may be due to lowering of blood levels of low density lipoprotein (LDL) cholesterol (bad cholesterol). Unfortunately, elevated levels of LDL cholesterol are linked with heart disease.

However, the mechanism behind the beneficial effect of black tea in lowering LDL cholesterol levels was unclear – only recently have studies began to demonstrate that it is theaflavins, one of the complex flavonoids in black tea, which is responsible for this LDL-reducing effect.

Recently, researchers at the University College London and Unilever Research Colworth conducted the first randomized clinical trial on the effects of black tea on stress – overall, their results found that drinking black tea may reduce stress hormone levels (cortisol) and ease the burden of heart disease.

During the study, the researchers recruited 75 healthy young males and put them through a four-week “washout” period during which they were not allowed to consume tea, coffee, caffeinated beverages, dietary supplements, and many other substances. Subsequently, 37 of the men were given four cups of black tea per day for six weeks while the 38 members of the placebo group were given an identical-tasting caffeinated drink, with no active tea ingredients, for the same time period.

Afterwards, both groups were asked to perform stressful tasks – these included verbally responding to threats of unemployment and accusations of shoplifting while sitting in front of a camera. During the procedure, the researchers measured the cortisol, blood pressure and blood platelet levels of the subject, and also asked them to self-rate their stress levels.

According to the results, both groups showed significant increases in blood pressure, heart rate and subjective stress levels during the tasks.

However, 50 minutes after the tasks were complete, cortisol levels in the tea-drinking group had dropped by 47 percent compared to only 27 percent in the placebo group!

Additionally, the black tea drinkers showed lower blood platelet activation — which has been linked to blood clotting and subsequent heart attack risk — and a greater degree of relaxation after the tasks.

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General Health Benefits of Black Tea: Thearubigins and Theaflavins

Posted by Susan Lutfallah on June 6, 2009

Polyphenols are components of the tea plant and the primary source of the health benefits in tea (e.g. antioxidant properties). Polyphenols undergo changes during the processing of the leaves. These changes result in the difference between black and green teas polyphenols and subsequent benefits.

Researchers have determined that the beneficial properties in green teas, primarily EGCG polyphenols, are easier to identify than the flavonoid polyphenols in black teas, which are known as thearubigins and theaflavins.

–          Black teas contain more complex flavonoids then green teas; specifically thearubigins and theaflavins.

–          Thearubigins and theaflavins are powerful antioxidants.

–          Flavonoids, because of their complexity, do not absorb as quickly in the body and initially can be harder to identify (this is why most studies focused on green tea and EGCG polyphenols instead!)

Briefly, scientific reviewers took an in-depth look at epidemiological and clinical studies relevant to tea from 1990 – 2004. Overall, the review’s objective was to determine if consuming black tea has a positive or negative impact on health.

The review concluded;

–          Drinking three cups of black tea per day for two weeks increased the concentration of flavonoids in the blood by about 25%.

–          The consumption of flavonoids can lower the risk of coronary heart disease through a number of mechanisms.

–          Tea flavonoids have also been shown to reduce low-density lipoprotein (LDL) cholesterol by 11.1%.

–          Animal studies and in-vitro (e.g. test-tube experiments) studies both reveal positive effects of flavonoids which go beyond antioxidant capacity – that is, they induce an anti-inflammatory response.

This review of scientific research makes it clear that black tea is good for your health in general, and that black teas complex flavonoid polyohenols specifically can play an important role in daily antioxidant consumption and disease prevention. All-in-all, while green teas continue to steal the health-craze limelight, black tea belong center stage right alongside them!

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Black Tea Introduction/History

Posted by Susan Lutfallah on May 6, 2009

Black tea is a variety of tea that is more oxidized than the oolong, green, and white varieties – however, all four varieties are made from leaves of Camellia sinensis. Generally speaking, black tea is stronger in flavour and contains more caffeine than the less oxidized teas. Two principal varieties of the species are used: the small-leaved Chinese variety plant (C. sinensis sinensis), also used for green and white teas, and the large-leaved Assamese plant (C. sinensis assamica), which was traditionally only used for black tea.

In Chinese and Chinese influenced languages, black tea is known as “crimson tea”, which is perhaps a more accurate description of the colour of the liquid. In Chinese, “black tea” is a commonly used classification for post-fermented teas, such as Pu-erh tea. In the West, the expression “black tea” is also used to describe any cup of tea without milk (“served black”), similar to coffee served without milk or cream.

While green tea usually loses its flavour within a year, black tea retains its flavour for several years. For this reason, it has long been an article of trade, and compressed bricks of black tea even served as a form of de facto currency in Mongolia, Tibet, and Siberia into the 19th century.

The tea originally imported to Europe was either green or semi-oxidized. Only in the 19th century did black tea surpass green in popularity.  Although green tea has recently seen a revival due to its purported health benefits, black tea still accounts for over ninety percent of all tea sold in the West.

Assam Black Tea

Assam is a black tea named after the region of its production; that is, Assam, India. Assam tea is manufactured specifically from the plant Camellia sinensis var. assamica (Masters) – in fact, this tea is known for its body, briskness, malty flavour, and strong, bright color.

Assam teas, or blends containing Assam, are often sold as “breakfast” teas – for example, English Breakfast tea, Irish Breakfast tea, and Scottish Breakfast Tea are common generic names.

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