Download How black tea could prevent cancer

NEW RESEARCH REVEALS YET MORE HEALTH BENEFITS FOR BLACK
TEA
New mechanisms by which black tea could help to prevent cancer have been
revealed in two recent studies.1,2 Black tea, the most widely consumed
beverage in the UK, and its components, has been associated in several in
vitro and in vivo studies with the potential to reduce the risk of cancer. As an
emerging field of study, it is only very recently beginning to show what the
mechanisms for this protective effect might be. These two recently published
studies provide intriguing new information in relation to these mechanisms.
Commenting on the studies, Dr Tim Bond of the Tea Advisory Panel notes: “In
the first study,1 researchers from New Jersey in the United States evaluated
theaflavin-2 (TF-2), a compound unique to black tea (and oolong), which has
been shown to kill cancer cells, a process known as apoptosis. This study set
out to explore the mechanisms by which theaflavin-2 might induce cancer cell
death, including effects on inflammation as inflammation is one contributory
mechanism in the development of cancer. This was a laboratory based study
that tested cancer cells.
“Theaflavin-2, the component of black tea extract, triggered cancer cell death
(apoptosis), inducing shrinkage of cancer cells within 3 hours of treatment.
When the researchers looked at a specific set of genes that kill cancer cells,
Theaflavin-2 was found to up-regulate or activate these genes. The study also
showed the ability of Theaflavin-2 to suppress the activity of a gene that
induces the inflammatory enzyme cyclooxygenase (COX) 2 while also
reducing the activity of other inflammatory molecules (such as TNF-α and
nuclear factor-kappa B (NF-KB). Theaflavin-2 was also shown to reduce
inflammation and also produced a pattern of gene regulation similar to that
found in the cancer cells. These results suggest that Theaflavin-2, a major
component of black tea has the capacity to help kill cancer cells through
mechanisms involving gene regulation and an anti-inflammatory effect.
“In the second study,2 researchers from India examined the effect of
polyphenols from both black and green tea on the development of breast
cancer (mammary tumours) in female rats. Both black and green tea
polyphenols significantly reduced the number of mammary tumours by 77%
and 92% respectively as well as reducing their growth. When the potential
mechanisms for these benefits were investigated, both black and green tea
polyphenols were found to scavenge reactive oxygen species by 69% and
1
Gosslau A, En Jao DL, Ho CT et al. Effects of the black tea polyphenol theaflavin-2 on
apoptotic and inflammatory pathways in vitro and in vivo. Mol Nutr Food Res 2011; 55(2)198208
2 Roy P, George J, Srivastava S et al. Inhibitory effects of tea polyphenols by targeting
cyclooxygenase-2 through regulation of nuclear factor kappa B, Akt and p53 in rat mammary
tumours. Invest New Drugs 2011; 29(2) 225-231.
72% respectively by inhibiting the inflammatory COX enzyme and inactivating
an inflammatory molecule, technically known as NF-KB.
“Taken together, these two studies have demonstrated that components of
black tea can help shrink and kill cancer cells and/or result in helping to
reduce the number of tumours. These studies indicate that these effects are
associated with the ability of black tea components to regulate genes, reduce
the activity of COX, an inflammatory enzyme, and reduce the activity of
inflammatory substances such as NF-KB.”
In summary, Dr Bond adds: “These findings suggest the need for clinical trials
to evaluate the effect of black tea and its components on the risk of cancer in
humans. In particular, new studies are needed to evaluate the bioavailability
of theaflavins and the clinical effects of their metabolic degradation products
to shed further light on both mechanisms of action and clinical applications of
black tea ingredients. In the meantime, drinking black tea, the UK’s most
popular beverage, can continue to be recommended for its many health
benefits including the possibility that it could contribute to reducing the risk of
cancer.”
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The Tea Advisory Panel: The Tea Advisory Panel is supported by an unrestricted
educational grant from the UK TEA COUNCIL, the trade association for the UK tea
industry. The Panel has been created to provide media with impartial information
regarding the health benefits of tea. Panel members include nutritionists; dieticians
and doctors. For further information please call 0207 7052 8989.
For more information please contact:
Emma Sanderson at [email protected] or 0207 052 8853
Amy Dowd at [email protected] or 0207 052 8856
Nicky Smith at [email protected] or 0207 808 9750 / 07867513361