Transcript: Cancer, Interrupted: Green Tea
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
More than 85% of breast cancers are sporadic, and attributable to long-term exposure to environmental carcinogens—such as those in the diet—through a multistep disease process progressing from non-cancerous to premalignant and malignant stages.
Now, we know that the chemical carcinogen, PhIP, is one of the most abundant heterocyclic amines found in high-temperature cooked meats, and is recognized as a breast carcinogen. However, the PhIP’s mechanism of action in breast cell carcinogenesis is not completely clear. How does it do it? Well, in this landmark new study they “demonstrated, for the first time, that cumulative exposures to PhIP” at the kind of concentrations one would expect just eating meat “effectively induced progressive carcinogenesis”—cancer transformation of normal “human breast…cells from a non-cancerous stage to premalignant and malignant stages in a dose- and exposure-dependent manner.”
They started out with normal human breast cells, and were able to transmute them completely into cancer cells just using that cooked meat carcinogen found predominantly in fried bacon, fish, and chicken. That’s all it took, and Jekyll becomes Hyde.
Now, PhIP was already established as a carcinogen. The reason they did this study was to develop a model of human breast cancer “carcinogenesis”—from beginning to end—so they could test various interventions to see if they could somehow stop this process of cancer formation.
For example, three recent meta-analyses reviewing all the epidemiological, or population-based, evidence concerning green tea consumption and breast cancer risk to date concluded that green tea consumption may be protective.
Okay, let’s put the plant to the test. Here’s how normal human breast cells rate against six different measures of cancer potential. Add some green tea to them, and nothing much happens. Add repeated exposure to the cooked meat carcinogen, PhIP, though, and all the cancer indicators go up. Okay, here’s the test. What happens if you now add the meat carcinogen with green tea phytonutrients? The transformation to breast cancer is blunted across the board, almost bringing cancer markers back to normal. Using a variety of measures, green tea phytonutrients were capable of suppressing PhIP-induced cellular cancer and tumor progression.
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