It
is a usual weekday on campus: you just had a two hour lecture in the Gross Chem building and now finding yourself standing
inside the Great Hall, wondering what to get for a drink. You look at the soda
section first and say to yourself, “Nah, not healthy enough.” You
turn to the coffee: “Nope, don’t want to be staying up all night with all that caffeine.” You want to get an ice cream, but pause when you think of all the sugars in that scoop. So, you find yourself facing “the ultimate dilemma” on Duke Campus: what should I drink? Well, how about a cup of green tea? You’d
be surprised to learn that tea is one of the most commonly consumed beverages in the world, ranking only after water. But, why green tea? Recent studies done
at the National Cancer Institute shows that green tea can aid digestion, reduce blood pressure, lower cholesterols, diminish
the clotting of blood vessels that can lead to heart attacks, and even prevent cancer.
The Science Behind Green Tea and Cancer
Green
tea is a healthy alternative because it contains beneficial antioxidants. These
antioxidants are compounds that fight cancer, which is the uncontrolled cell division in the body. At the cellular level, the antioxidants block the division of cancer cell, consequently leading to a decrease
in tumor growth. What makes the antioxidants in green tea special is that they
inhibit only the abnormal growth of cancer cells, without any harmful effect on healthy cells.
How antioxidants kill cancer cells is also very ingenious: instead of attacking the harmful cells directly, they subtly
aid the cancer cells in killing themselves. In the presence of these antioxidants,
cancer cells fail to increase in size or to develop after they divide. They do
not die right away, but their inability to reach a certain size causes them to undergo cell suicide. It seems that somehow, through cell-to-cell communication, antioxidants tell the cancer cells “that
they better commit suicide or they’ll be murdered. So the cancer cells
make a decision and undergo” programmed cell death (Purdue, 1999).
And the Evidence?
After
all these explanation of how green tea kill cancer cells, you may wonder, “What proofs are there?” Researchers at the Tumor Biology Center in Sweden had the same inquiry.
To test the effectiveness of green tea effect in killing cancer cells, they conducted an experiment on mice that had
tumors. In the experiment, one group of mice drank nothing but water while the
other group drank only green tea. As the result, the tumors on the water-drinking
group increased as usual, and the mice eventually died. However, the tumors decreased
in size among the tea-drinking group; thus this group of mice were able to live longer and healthier than the non-tea drinkers. Even though the comparison between mice and humans is not exact, theses experimental
data do give a general idea of green tea’s benefits.
So Why Wait?
Now
that you have learned about the science behind green tea and cancer, why wait any longer?
If you still doubt because you are worried about getting too much Caffeine, then you’ll be happy to know that
green tea only contains about 1% to 4% of caffeine, as opposed to 60% of antioxidant.
Several cups of green tea a day have less caffeine than one cup of coffee in the morning. And unlike the strong, bitter
coffee (into which college students dumps a handful of sugar cubes that can lead to diabetes and unhealthy obesity at an early
age), green tea comes lighter and fresher. And if you prefer sweetened tea, only
a minimum addition of sugar will suffice to get the desired sweet taste.
For
those of you who value “health on a daily basis,” green tea is the perfect solution that satisfies your health
concerns and your drinking needs. Of course, nothing is a panacea, so
don’t think of green tea as a miraculous potion that will make you perfectly healthy, but as a better, healthier alternative
in time of thirst. Green tea may take away that guilt of consuming too much “junk
drink” while fulfilling the necessity to quench the thirst. And while you
are enjoying tea, you can feel the joy of knowing that you are taking a major step in preventing cancer. So next time you want to quench our thirst, you can pass the Coke section of the diner, and instead, get
a refreshing cup of green tea. So give it a try!
References
1. Farrukh Afaq, et al. “Inhibition of ultraviolet B-mediated activation
of nuclear factor kB in normal human epidermal keratinocytes by green tea Constituent (-)-epigallocatechin-3-gallate”.
Oncogene 2003; 22: 1035-1044
2. Jung, YD, et al. “EGCG, a
major component of green tea, inhibits tumour growth by inhibiting VEGF induction in human colon carcinoma cells”. 2001. British Journal of Cancer. 84 (6), 844-850.
3. University of California at Berkeley.
“Can Green Tea Help Prevent Cancer?” Wellness Letter.
1997; 14 (3): 1-2
4. Yang, CS, Wang, ZY. “Tea
and Cancer”. Journal of the national Cancer Institute. July 1993
5. Chen, Z.P., et al. “Green tea epigallocatechin gallate shows a pronounced
growth inhibitory effect on cancerous cells but not on their normal counterparts”. Cancer Letters. 1998; 129:173-179
6. Greenwell, Ivy. “Anti-carcinogenic properties of green tea”. LE
Magazine. 1999
7. Ahmad N. “Green tea constituent EGCG and induction of apoptosis and cell
cycle arrest in human carcinoma cells”. H National Cancer Institution 1997; 89: 1881-86
8. Ho C. “Antioxidant effect of polyphenol extract prepared from various
Chinese teas”. 1992; 21: 520-25
9. F Bertolini, et al. “Inhibition of Angiogenesis and Induction of Endothelial
and Tumor Cell Apoptosis”. Nature 2000; 14, 1477-1482
10. A G Dulloo, et al. “Green Tea and Thermogenesis: Interactions between
Catechin-Polyphenols, Caffeine and Sympathetic Activity”. International Journal of Obesity 2000; 24: 252-258
11. “Studies find how green tea may prevent cancer” by Purdue News
February, 1999. http://www.purdue.edu/UNS/html/ accessed 11-15-03
12. Spiridione
Gar'bisa. “Tumor invasion: molecular shears blunted by green tea”. Nature Medicine 1999; 5: 1216