How Black Tea Fights Cancer
Due to the relatively small body of research, doctors and medical professionals are hesitant to make any definitive statements about black tea’s effects on cancer. However, between population studies, in-vitro studies, and scientific examinations of the mechanisms and effects of flavonoids on cancer, there is strong evidence that black tea reduces cancer risk and inhibits tumor growth naturally.
Black tea was proven to initiate cell death mechanisms in cancer cells in a groundbreaking study
Theaflavins and thearubigins, black tea’s antioxidant compounds, inhibit tumor growth
All cancer risks are reduced from drinking black tea by 9-13%
Antioxidants, like those found in tea, safely neutralize free radicals that would otherwise cause genetic damage. The genetic damage from free radicals when not stopped by antioxidants, can develop into cancer.
Black tea also contains green tea’s special anti-cancer compound, EGCG, shown to inhibit lung cancer, colon cancer, breast cancer, and more.
A black tea drink, when dehydrated, is composed of 71% cancer-fighting antioxidants, 10 times as much as the 7% portion of tea’s stimulant, caffeine
Caffeine might also have anticancer properties as it interferes with skin cancer formation
Because less than 10% of tea research focuses on black tea, limited scientific data is currently available, but the results are promising
Over 70% of the nutrient profile for black tea contains anticancer polyphenols
Black Tea Prevents Cancer Formation from Free Radical Damage
What are free radicals and how can they cause cancer? A free radical is an unpaired electron on an oxidizing chemical. These unpaired electrons are unstable without a partner and thus will steel a partner electron from wherever they can get one. By steeling electrons, these free radicals can damage cell structures, including causing DNA damage. When left unchecked, the DNA damage from free radicals can initiate cancer growth.
Antioxidants are nutrients that are stable with or without a given electron. As such, an antioxidant can safely give up an electron to neutralize a free radical before the free radical causes damage to a body’s cells. Fortunately, low calorie high antioxidant superfoods, like tea, provide a balance to the free radicals from junk food, chronic inflammation, and even the oxygen we breathe.
Black tea’s weight comes 60% from its unique antioxidants theaflavins and thearubigins and another 11% from the miracle antioxidant EGCG (found strongest in green tea at double the concentration as in black tea. Read more about the differences between black and green tea here.) All 3 of these types of antioxidants found in black tea have multiple cancer-fighting properties in addition to their antioxidant effects. This means that over 70% of black tea is full of cancer-fighting compounds!
Reduced Risk of all Cancers
Population studies in the UK and Russia (the world’s 3rd and 4th largest black tea consumers respectively) found black tea consumption reduces cancer risk. Population studies follow large groups over multiple years or even decades to identify health and medical trends. The UK study showed black tea drinkers had an average 11% decreased risk of all forms of cancer. The study in Russia focused specifically on rectal cancer and found similar results that black tea drinkers have lower risk of developing cancer.
Even though these studies only show correlation, they are still an excellent resource to guide further research. Fortunately, other research has been conducted showing the mechanisms by which black tea’s antioxidants reduce cancer risk, demonstrating the reported correlations of these population studies have underlying causation. Personally, as an engineer, knowing that black tea prevents cancer is more useful than knowing the exact biochemical mechanisms involved. The ‘why’ is just icing on the cake, or maybe, the honey in my tea.
Inhibits Cancer Growth
The theaflavins in black tea have been shown to slow new tumor development to a near stop and slowing the growth rate of existing tumors by over 80%. Further, black tea’s antioxidants block materialization (spreading) of tumor cells to other parts of the body.
Additionally, theaflavins were shown to block multiple pathways by which cancer initially forms. One example of these blocked cancer forming pathways is the downregulation of the nuclear factor kappa-B transcription process. NF kappa-B, when unregulated, propagates and copies cells out of control which has been linked to cancer development. Theaflavins keep NF kappa-B working at their proper rate and prevents copying of damaged or otherwise cancer-causing genetics.
A separate study looked specifically at theaflavins’ effects on breast cancer tumor growth. The study found that theaflavins slow the growth of breast cancer cells including slowing hormone-therapy resistant breast cancers.
Trigger Cancer Cell Death
In addition to blocking the initial growth of cancer cells and slowing cancer once it has started, black tea’s antioxidants have also shown the capability to kill cancer cells. Multiple scientific studies have shown the polyphenols found in teas (a type of antioxidant including theaflavins, thearubigins, and EGCG) will inhibit tumor growth and induce apoptosis (cell death) in cancer cells.
Cancer cells can invasively and aggressively grow because they “switch off” the cell’s natural “programmed cell death” apoptosis responses. This programmed cell death is how damaged cells are destroyed and replaced with healthy cells (such as shedding skin and replacing digestive track lining). Polyphenols, according to these studies, switch the natural cell death back on in cancer cells. As a side note, induced apoptosis is the same mechanism that chemo therapy and radiation therapy utilize to kill cancer.
In one study, theaflavins and thearubigins were found to cause apoptosis in melanoma cells. This cancer-killing effect of black tea is not limited to melanoma either. In another study, black tea has been scientifically demonstrated to initiate a “death cascade” in cancer cells, a mechanism in which pro-apoptotic Bax proteins stimulate the mitochondria to release chemicals that destroy the cell. This research was initially performed on lab mice with Ehrlich's Ascites Carcinoma [EAC]. EAC, a form of mouse breast cancer, is a widely used model for cancer research as it matches many other forms of cancer in both progression and response to treatment. A meta review of multiple studies later confirmed these findings that the antioxidants from black tea cause apoptosis, killing cancer cells.
Caffeine vs UVB radiation
In addition to the antioxidants in tea, caffeine may have its own anticancer effects. One study demonstrated that caffeine prevented melanoma formation from UVB radiation in mice. The caffeine also helped slow and even kill off patches of skin cancer on the tested mice. These effects were observed when the caffeine was applied directly to the skin cancer topically (which may lead to caffeine being added to sunscreens) and when the caffeine was ingested.
Unfortunately, this study, being an animal study on mice, needs further research to confirm these effects in humans. Other studies have also found caffeine to have cancer-fighting properties, but there are other studies that contradict these findings. A meta review of these various studies found more evidence for caffeine’s anticancer properties than against, but the results were still inconclusive. Until more research becomes available, caffeine may or may not be a helpful cancer-fighting compound.
Fight Cancer, Drink Tea
From the evidence, it is clear that black tea’s antioxidants fight cancer at every stage. These antioxidants prevent cancer from forming due to free radical damage, reduce risk of all cancers, inhibit cancer growth, and trigger cancer cell death. Never fear cancer again, drink tea!
About the author
As a chemical engineer, Spencer Lane, Chai Hous’ Chief Brewing Officer, is fascinated with the chemistry of health. Researching what causes sickness led him to understand how nutrition plays a critical role in every day health. Based on his research on chai spices, he feels he has discovered the alchemical elixir of life, or, as a sci fi fan, the Spice. “The most precious substance in the universe is the spice mélange… The spice extends life.” – Frank Herbert, Dune