Green Tea Effects on Chemotherapy are Mixed, Research Suggest

Green tea and chemotherapy have long been viewed in various spheres as potential weapons against cancer. While green tea’s prospective abilities in preventing and even combating cancer have gained a certain traction among practitioners of natural and herbal healing, the effectiveness of chemotherapy against cancer has long gained the acceptance and approval of the scientific medical healing field.

But can these two seemingly diverse agents possess points of convergence that may make the war against malignant neoplasm even more potent and effective? Or do they essentially operate in their own respective areas, working their so-called magic independently of each other?

Green tea comes from the lightly fermented leaves of the tea plant camellia sinensis. It is known to possess high levels of powerful antioxidants called polyphenols. Antioxidants are materials that help fight free radicals - compounds in the body that alter cells, damage DNA, and give rise to abnormal growth of tumors that lead to cancer. EGCG or epigallocatechin-gallate is the most important green tea polyphenol and is believed to help protect against cancer development by aiding the self-destruction of these cells, and by affecting enzymes and the communications between cells, thereby slowing the growth and multiplication of cancerous cells.

On the other hand, chemotherapy refers to a standardized regimen of cancer treatment involving either a single neo-plastic drug or a combination or cocktail of such drugs. Active agents in these drugs act by killing cells that divide and replicate rapidly. However, this method also involves harming cells that divide rapidly even under normal circumstances. This results in the most common side effects of chemotherapy: the decreased production of blood cells, the weakened state of the immune system, the inflammation of the lining of the digestive tract, and the loss of hair.

Taken hand-in-hand, do green tea and chemotherapy complement each other in the crusade against their common enemy? Well, the findings have decidedly been mixed.

A study conducted on mice by the School of Pharmaceutical Sciences at the University of Shizuoka in Japan showed that the effectiveness of the chemotherapy drug doxorubicin against carcinoma tumors appeared to have more than doubled when green tea was used as an adjunct. The tumors showed a higher concentration of the doxorubicin in the tumor tissue when the mice ingested green tea.

Interestingly, only the cancerous tissue reflected a higher concentration of the drug as a result of the addition of the green tea and not the normal ones. This may suggest promising implications on the issue of side effects as it implies that the drug’s side effects may not increase when used in tandem with the green tea.

Another study showed that the chemotherapy drug adriamycin was likewise found to be more effective at treating ovarian sarcoma when it was paired with green tea. The mice in this study became very responsive to the treatment when they were given green tea alongside the adriamycin while another group of mice not given the green tea proved unresponsive.

However, another research study involving a different chemotherapy drug yielded a different result.

Laboratory and live mice experiments undertaken by the University of Southern Califo
ia’s Keck School of Medicine found that taking green tea alongside the chemotherapy drug bortezomib against multiple myeloma and the malignant brain tumor glioblastoma showed that the antioxidants in the green tea may possibly negate and cancel out the therapeutic effects of the bortezomib.

The scientists subsequently found that the boronic acid component in bortezomib allowed the EGCG to latch on directly to the drug's molecules, thereby inhibiting the anti-cancer actions of both the chemotherapy agent and the green tea compound. The effect of this is that instead of killing more cancer cells, the treatment allowed almost all of them to survive and multiply.
The researchers in this study consequently concluded that “the current evidence is sufficient enough to strongly urge patients undergoing bortezomib therapy to abstain from consuming green tea products, in particular the widely available, highly concentrated green tea and EGCG products that are sold in liquid or capsule form."

There have likewise been reports of green tea extracts affecting a gene in prostate cancer cells that may make them less responsive to chemotherapy drugs.

However, the same scientists hastened to add that the same adverse reaction did not occur when EGCG was combined with several other non-boronic, acid-based proteasome inhibitors, including the HIV treatment nelfinavir or Viracept.

It is worthwhile to note that these studies have so far only been conducted on mice and in laboratory experiments. These results have not yet been confirmed in studies on people. As with many other early results, further research is warranted.

It may be gleaned from these divergent findings that green tea appears to have different interactive effects with certain specific chemotherapy drugs. Green tea appears to complement the therapeutic effects of some anti-cancer drugs while negating and being adverse to those of other anti-cancer medication. It is for this very reason that individuals undergoing chemotherapy treatment ought to talk to their physicians before drinking green tea or taking tea extracts.