Breast cancer can take decades to develop, so "early" detection via mammogram may be too late. The breast cancer you may feel one day as a lump in the shower, may have started 20 years ago. We now suspect that all the epithelial cancers: breast, colon, lung, pancreas, prostate, ovarian—the ones that cause the vast majority of cancer deaths—take up to 20 years or more to manifest. By the time it’s picked up it may have already been growing, maturing, scheming for years, acquiring hundreds of new survival-of-the-fittest mutations to grow even quicker and better undermine our immune system. Early detection may in effect be really, really late detection.
People are considered “healthy” until they show symptoms, so if we’ve been harboring a malignancy for 20 years we may feel all right, but we haven’t been. Thus, many people who do the right thing and improve their diet in hopes of preventing cancer may, at that very moment, be treating it as well. In this way, cancer prevention and treatment may sometimes be the same thing.
What new developments are there are in the battle against breast cancer? Well, most breast tumors are estrogen receptor positive, meaning they respond to estrogen; estrogen makes them grow. The problem for tumors in postmenopausal women is that there isn’t much estrogen around—unless of course you take it in a drug like Premarin (so-named because it’s made from pregnant mare urine). Premarin appears to increase the risk of breast cancer (as well as strokes, heart attacks, and blood clots). Unfortunately, the plant-based bioidentical hormone replacement therapies don’t appear any safer (see my 4-min. video Plant-Based Bioidentical Hormones).
Thankfully millions of women stopped taking Premarin in 2002, and we saw a nice dip in breast cancer rates. Unfortunately, those rates have since stagnated. Hundreds of thousands of American women continue to get the dreaded diagnosis every year. So what next?
Well, with no estrogen around, many breast tumors devise a nefarious plan—they’ll just make their own! Seventy percent of breast cancer cells synthesize estrogen themselves using an enzyme called aromatase. In response, drug companies have produced a number of aromatase inhibitor drugs that are used as chemotherapy agents. Of course by the time you’re on chemo it can be too late, so researchers started screening hundreds of natural dietary components in hopes of finding something that targets this enzyme.
To do this you need a lot of human tissue. Where are you going to get it from? To study skin, for example, researchers use discarded human foreskins from circumcision. They’re just being thrown away–might as well use them! Where are you going to get discarded female tissue? Placentas. They got a bunch of women to donate their placentas after giving birth to further this critical line of research.
After years of searching, they found seven vegetables with significant anti-aromatase activity. You can see the graph in my video Vegetables Versus Breast Cancer. Bell peppers, broccoli, carrots, celery, green onions, and spinach dropped aromatase activity by about 20%, but mushrooms forced down the estrogen-producing enzyme more than 60%.
Which mushroom worked best? Woodear, crimini, oyster, Italian brown, enoki, button, stuffing, shiitake, chanterelle, or Portobello mushrooms? Don’t even try to guess—you won’t get it! Check out my 2-min video Breast Cancer Prevention: Which Mushroom Is Best? for the answer.
-Michael Greger, M.D.