Contrary to Tinfoil Hat Philosophy, researchers are rather intensely studying green tea and potential good health effects it may have.
The bad news is that an early study shows green tea inhibits the effects of one of the common treatments for multiple myeloma, Bortezomib. Bortezomib (BZM) causes tumor cells to die, but some elements in green tea inhibit that effect. Does the tea keep the cancer cells alive, or interfere with the cancer-killing drug? Not sure.
It’s clear that cancer patients undergoing treatment that includes drug or chemo therapy need to inform their physicians if they are using green tea or other alternative treatments in addition.
Is this such a surprise? We’ve known for years that grapefruit juice multiplies the effects of some blood pressure medicines, which means that grapefruit is one fruit blood pressure and cardiac patients probably need to avoid. Foods that have medicinal effects may also have effects that counteract the medicines physicians provide.
“Green Tea Polyphenols Block the Anticancer Effects of Bortezomib and Other Boronic Acid–Based Proteasome Inhibitors”
Blood. 2009 Jun 4;113(23):5927-5937, EB Golden, PY Lam, A Kardosh, KJ Gaffney, E Cadenas, SG Louie, NA Petasis, TC Chen, AH Schönthal
The anticancer potency of green tea and its individual components is being intensely investigated, and some cancer patients already self-medicate with this “miracle herb” in hopes of augmenting the anticancer outcome of their chemotherapy. Bortezomib (BZM) is a proteasome inhibitor in clinical use for multiple myeloma. Here, we investigated whether the combination of these compounds would yield increased antitumor efficacy in multiple myeloma and glioblastoma cell lines in vitro and in vivo. Unexpectedly, we discovered that various green tea constituents, in particular (-)-epigallocatechin gallate (EGCG) and other polyphenols with 1,2-benzenediol moieties, effectively prevented tumor cell death induced by BZM in vitro and in vivo. This pronounced antagonistic function of EGCG was evident only with boronic acid–based proteasome inhibitors (BZM, MG-262, PS-IX), but not with several non–boronic acid proteasome inhibitors (MG-132, PS-I, nelfinavir). EGCG directly reacted with BZM and blocked its proteasome inhibitory function; as a consequence, BZM could not trigger endoplasmic reticulum stress or caspase-7 activation, and did not induce tumor cell death. Taken together, our results indicate that green tea polyphenols may have the potential to negate the therapeutic efficacy of BZM and suggest that consumption of green tea products may be contraindicated during cancer therapy with BZM.
Watch. The crank science sites will pick up on this study and argue that it’s just one more demonstration that scientists can’t get the story right. Reading just the abstract, however, you can see that the paper talks about a specific chemical action of specific components of green tea against a specific type of cancer treatment. This paper could just as easily be read to say that green tea helps prevent senescence in cells, and it does the same thing it tumor cells, which isn’t at all what we want.
It will be very, very interesting to see how this research gets covered in the popular, mass and internet press.
Posted by Ed Darrell 
Millard Fillmore's Bathtub 