Cancer-Fighting Impact
of Black Tea
Preclinical data show
that black tea theaflavins block cancer
development and progression. Human studies are
urgently needed to evaluate these findings in
the clinical setting.
Scientifically reviewed by: Dr. Gary
Gonzalez, MD, in September 2022. Written
by: Bruce Edwards.
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It has been observed that people with
higher intake of black tea have reduced
rates of cancers.1
That may be due to a compound found in
black tea called theaflavins.
In cell culture and animal models,
theaflavins have demonstrated
anti-cancer effects, working in multiple
ways to slow the spread and progression
of many types of cancer.1-5
One group of scientists has dubbed black
tea “the future panacea for cancer.”2
Systemic Effects of Theaflavins
When green tea leaves are fermented to
make black tea, compounds called
theaflavins are formed.6
These black tea polyphenols (theaflavins)
have shown body-wide health benefits.
In particular, research has uncovered
specific ways that theaflavins play a
role in fighting cancer.
By interacting with cellular pathways
and processes critical to cancer
development and progression, theaflavins
beat back cancer cells and make it hard
for them to survive and spread.
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One review paper noted that an ideal
cancer therapy would: 2
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Shrink tumors by inducing cancer cell
death, blocking the growth of new blood
vessels in tumors, and slowing or
stopping the spread of cancer in the
body,
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Boost immune system function to aid in
the fight against cancer, and
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Reduce the systemic toxic effects that
cancer creates.
These scientists believe that black tea
theaflavins accomplish all these
actions. Several reviews of the
anti-cancer actions of theaflavins
provide evidence to support this belief.
1-5
A “Guardian Angel” Against Cancer
A gene is critically involved in halting
the progress of a wide range of human
cancers.
Known as p53, this gene has long been
recognized as a tumor suppressor,
inhibiting both the formation and
progression of tumors. In fact, p53 has
earned the nickname “the guardian of the
genome.” 7,8
Tumor suppressor genes are parts of the
genetic code that prevent and interrupt
malignant changes in cells.
In approximately half of all human
malignancies, the p53 gene is mutated,
thus impairing the cell protective role
of p53.9
When p53 is functional, it defends the
health of cells by repairing damage to
DNA that can cause mutations that
contribute to cancer.9
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The p53 gene also acts as a master
regulator of cell pathways that are
involved in cancer development. Active
p53 helps starve cancer cells of fuel,
prevent new blood vessel formation, halt
spread and metastasis, block cancer cell
proliferation, and induce cancer cell
death.3
It even helps improve the success of
chemotherapy and radiation in attacking
existing cancer cells.
In many tumors, however, p53 is mutated.
This is a driver of cancer risk and
progression.3
Research on theaflavins suggests the
activation of p53 as an important
mechanism in inducing many of its
anti-cancer actions.3
Additional Anti-Cancer Action
Theaflavins regulate a protein called
mTOR, which can cause cells to
excessively propagate.
Theaflavins also inhibit an
inflammation-inducing complex called NF-kB
that is involved in cancer development
and progression.1,4,7,10
In cell cultures and animal models,
theaflavins have demonstrated the
ability to impair cancer by:1-5
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Reducing the initial development of
cancers,
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Arresting the cancer cell cycle, halting
cancer cells’ ability to grow and
proliferate,
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Reducing cancer cell viability, making
them less robust and resilient,
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Inducing the death of cancer cells,
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Inhibiting the formation of new blood
vessels in the tumor, starving the
cancer of oxygen and nutrients,
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Impairing the ability of cancer cells to
spread and metastasize, and
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Boosting the immune system to join the
fight against cancer.
WHAT YOU NEED TO KNOW
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Anti-Cancer Activity of Theaflavins
Theaflavins are nutrients found in black
tea. These compounds work in different
ways to prevent cancer development,
block its ability to grow and spread,
and directly kill cancer cells.
These anti-cancer effects of theaflavins
have been demonstrated for many forms of
cancer in both cell cultures and animal
models.
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A wealth of pre-clinical data has found
that theaflavins offer protection
against mechanisms involved in cancer
development and progression.11-15
These beneficial actions have been seen
in cancers of the breast, prostate,
lung, ovaries, cervix, skin, colon,
liver, esophagus, stomach, and
hematological malignancies like
leukemia.1-5
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Human Studies
There are human data to support this.
One study recruited men with prostate
cancer who were scheduled for surgery.16
Some consumed black tea for five days
prior to surgery while others received a
placebo drink.
After surgery, levels of tea polyphenols
were significantly higher in the removed
tumor tissues of men who received black
tea.
Scientists then attempted to grow the
prostate cancer cells in a cell culture
containing blood serum from the
patients. In these cultures, cancer cell
growth was significantly reduced in
those who drank black tea five days
prior to surgery.
Summary
Preclinical studies have found that
theaflavins from black tea exert
anti-cancer effects.
Cell culture and animal models have
demonstrated multiple ways that
theaflavins block cancer development and
progression, and epidemiological studies
show that people with higher intake of
black tea theaflavins have reduced rates
of cancers.
We hope the data presented in this
article will motivate oncology
researchers to initiate clinical trials
to assess whether adding theaflavins to
conventional cancer treatments improves
patient outcomes.
THEAFLAVINS FIGHT CANCER BY SOME OF THE
SAME MECHANISMS AS STATIN DRUGS
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Recent research has found that some
common medications possess anti-cancer
activity. For example, the statin drugs
used to treat abnormal cholesterol
levels have been found in some studies
to reduce risk for cancer. This effect
is believed to be attributable to
various mechanisms including modulation
of mTOR and associated PI3K/Akt.
These cellular signaling pathways are
intertwined with many other mechanisms
of cancer development and progression.
Theaflavins have been found to share
many of these mechanistic
targets.1,4,5,17
Theaflavins are not a substitute for
conventional cancer treatment. They may
later demonstrate efficacy as an
adjuvant nutrient analogous to doctors
who recommend vitamin D to patients with
diseases like type II diabetes and
cancers today.
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References
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Black Tea: Chemical and Pharmacological
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Das T, Sa G, Chattopadhyay S, et al.
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Anti-Cancer Properties of Theaflavins.
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Kaur S, Greaves P, Cooke DN, et al.
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