Compounds found in green tea have long been recognized for having anti-cancer effects in the body. The
antioxidants contained in green tea can promote apoptosis, otherwise
known as programmed cell death, in cancer cells that have gone “out of
control”. Regular consumption of green tea has been linked
with a lowered risk for many types of cancers, including cancers of the
skin, breasts, lungs, colon, and more. A study published in Food and Function discusses the relationship between polyphenols (powerful plant compounds) in green tea and the flavonoid known as quercetin. Quercetin,
a constituent found in many types of fruits and vegetables, has been
found to work synergistically with green tea, as it apparently increases
levels of green tea polyphenols inside cancer cells. This ultimately helps components within green tea to act with a higher level of potency.
Quercetin is known for its ability to act as a methylation inhibitor in the body. Since
green tea catechins naturally become methylated upon ingestion,
rendering them less beneficial as anti-cancer compounds, scientists
observed the effects of giving quercetin with green tea. For
a period of two weeks, researchers gave mice known to have severe
immunodeficiency brewed green tea, a diet that included 0.4% quercetin,
or a combination of both. The group of mice given both
green tea and quercetin were noted to have 2-3-fold increased levels of
total and non-methylated green tea catechins (specifically the catechins
called EGCG or epigallocatechin gallate).
Overall,
study results showed that combining quercitin with green tea catechins
led to a dramatic improvement in cancer-fighting ability in vivo. The combination increased cellular adsorption of EGCG by four-fold in lung cancer cells and two-fold in kidney cancer cells.
The team of researchers, from Rutgers University, concluded that "in order to have a maximum anticancer effect, green tea or green tea extract should be used together with quercetin." They
also pointed out how catechins found within green tea show higher
antioxidant abilities when compared with vitamins C and E. Recommendations
of 3-5 cups of freshly brewed green tea daily in combination with
quercetin from either food or supplementation were made as a way of
maximizing cancer-prevention benefits.
Dr. Shana McQueen
