Wu-long tea (also known as "Oolong tea", "Wulong tea", and "Wu long tea") has
been receiving increasing attention lately. Many reports and articles
touting the benefits of wulong tea have been brought to light, and it
has been talked about on the Oprah Winfrey Show and widely across the
Internet.
Does wulong tea really work for weight loss?
The
Chinese have traditionally believed wulong tea to be effective in
controlling and maintaining a healthy body weight. Recent scientific
studies have been conducted to determine if wulong is in fact a slimming
tea. In one recent study, 102 Chinese women who drank four cups of wulong tea per day lost over a kilogram of body weight over a 6 week period.
But what is wu-long tea? How is it different from green tea or black tea?
There
are herbal and nonherbal teas and the Camellia sinensis plant is the
source of all nonherbal teas. Leaves from the plant are processed three
different ways to produce the three major classes of tea, known as
black, green, and wu-long. About 75 percent of the tea produced
worldwide is black; about 23 percent is green; and about 2 percent is
wu-long.
Wu-long tea differs from other teas in the degree to
which it is allowed to ferment after the tea leaf has been picked. The
fermentation process is what gives tea its color. Green teas are made
from leaves that have been prevented from fermenting through an intial
boilng process, while at the other end of the spectrum black teas are
made from leaves that have been permitted to fully ferment. Wu-long teas
are in between green teas and black teas in that the leaves have been
allowed to partially, but not completely, ferment.
Is it true that wu-long (oolong) tea burns fat?
In
one study conducted by researchers from the Suntory Research Center,
University of Tokushima, and the U.S. Department of Agriculture (USDA),
drinking wu-long tea was shown to increase the rate of fat oxidation.
This is probably why it is gaining a reputation as a fat burning food.
In
the study 12 men consumed each of four treatments: plain water,
full-strength tea, half-strength tea, and water containing 270 mg
caffeine (the same amount of caffeine contained in the full-strength
tea).
Each man received each treatment for 3 days. At the end of
each three day period their metabolic rates were indirectly measured by
observing their energy expenditure in a closed setting.
It was
shown that the metabolic rate of the men who had consumed the
full-strength tea and the caffeineated water had increased by 2.9% and
3.4% respectively (relative to the plain water treatment), indicating
what was already known; that caffeine is effective in increasing
metabolic rate.
The more interesting finding however was that the
men who had consumed the full-strength tea had experienced a 12.9%
increase in fat oxidation (fat burning); an increase that was not shown
for the caffeinated water alone.
"Our data suggested that a component of tea other than caffeine might have promoted preferential use of fat as an energy source,"
said Beverly Clevidence, a study coauthor and head of the Diet and
Human Performance Laboratory at the USDA''s Agricultural Research
Service. "But the information is tentative, and we need more studies to
confirm it," she adds.
Can wu-long tea help regulate blood sugars?
In yet another study reported in "Diabetes Care" involving subjects with type 2 diabetes, drinking wu-long tea was shown to have a glycemic affect, significantly reducing blood glucose levels.
Researchers
from the Suntory Research Center, Providence University, Chorng Kuang
Hospital, University of Tokushima, and the U.S. Department of
Agriculture (USDA) tested a total of 20 subjects who had type 2 diabetes
and took hyperglycemic drugs as prescribed. In the study the subjects
each consumed either wu-long tea or water for a 30 day period, after
which they were monitored for blood plasma glucose and fructosamine
concentrations.
It was found that relative to the control group who only drank water, wu-long tea significantly lowered concentrations of plasma glucose and fructosamine.They concluded that wu-long tea may be an effective adjunct to oral hypoglycemic medications in the treatment of type 2 diabetes.
Is it fair then to call wu long a slimming tea?
There
still remains much work and research to universally and scientifically
validate the nutritional and medical claims of drinking wu-long teas,
but the research to date certainly paints the many benefits of wu-long
tea in a positive light.
Aside from all the health and weight loss claims, its important not to forget that drinking a nice cup of gourmet tea is a reward in and of itself.
So if you''re already a coffee or tea drinker, why not give wu-long tea
a try the next time you''re looking for a nice warm beverage to sit
down and relax with?