Green tea is a beverage made from the plant Camellia sinensis that
has excellent health-promoting properties. It is traditionally consumed in
Asiatic countries such as China and Japan, and its use has become popular in
the West in the last decades. The Japanese book called Kitcha-Yojoki,
written by a Zen priest in 1211, describes a number of medical effects of its
prolonged intake. Another book titled Yojokun, published in
the Tokugawa period (17th-19th century), recommends long-term drinking of green
tea for a lean body. Today, it is well known that epigallocatechin gallate
(EGCG) is the major compound present in green tea which is responsible for its
amazing health benefits.
Some of the scientifically proven effects of EGCG are:
- Cancer prevention, anti-cancer
and anti-metastatic activities
- Liver protection
- Enhances insulin activity and
sensitivity - excellent for diabetes!
- Reduction of body fat
- Prevention of cardiovascular
disease
- Cholesterol lowering effects
- Neuroprotective
- Antibacterial and antiviral
activities
 |
| The different catechins present in green tea |
EGCG belongs to a family of molecules called catechins that are found in
many plants. The catechins epicatechin, epigallocatechin and epicatechin
gallate are also present in green tea and they all collaborate for the
therapeutic activities. This is called synergistic effect and it is perhaps the
most important reason for consuming green tea or green tea extract instead of a
purified form of EGCG. The king cannot work by himself; he needs his page-boys!
In addition, the king molecules of different foods work together to promote
health.
EGCG, normal and cancer cells
EGCG plays a very interesting role in aiding cells to stay healthy. Normal
cells have an impressive molecular system that controls their growth and
division. They reproduce only when and where needed, sticking together to form
tissues encapsulated in membranes. Also, they become mature cells and as their
cycle is over their program sends specific death signals to themselves. More
interestingly, healthy cells have the ability to repair their DNA which could
be damaged for a variety of reasons. On the contrary when such molecular system
fails, cells grow and reproduce uncontrollably, forming a tumor. They separate
from their normal tissue and invade other places - a process called metastasis
- spreading their malignancy throughout the body. Moreover, cancer cells are
not able to repair themselves, so they accumulate a tremendous number of
mutations including resistance to drugs.
Several cells and animal experiments have shown that EGCG can positively
modulate normal and cancer cell functions. It is able to prevent cells from
escaping their original tissue, which is an anti-metastasic activity. It also
stops cell growth and triggers tumor cell death by inhibiting and activating
specific proteins involved in both processes. Furthermore, green tea components
are able to mitigate cellular damage arising due to oxidative stress. Although
most of the effects of EGCG have been shown in cells and animal studies,
clinical trials are further needed to verify its efficacy in human beings.
Epidemiological studies are another source of valuable data and they have
shown the protective effects of green tea against cancer in
specific populations that consume green tea for a prolonged
time. Therefore green tea has a great potential for preventing and
fighting cancer. We should seriously start drinking green tea now! Three
or four cups of green tea a day can help us keep healthy.
More blog posts will be dedicated to explain the benefits of green tea for
cancer and other diseases. Please look at the following sources for a deeper
scientific explanation of the different pharmaceutical effects of green tea:
1. Sozuki Y, Miyoshi N, Isemura M. Health-promoting effects of
green tea. The Proceedings of the Japan Academy, Series B. 88 (2012).
2. Butt MS, Sultan MT. Green tea: nature's defense against
malignancies. Critical Reviews in Food Science and Nutrition. 2009 May;49(5):463-73.
No comments:
Post a Comment