Image Source: Freedigitalphotos.net / SOMMAI

Image Source: Freedigitalphotos.net / SOMMAI

A Natural Aromatase Inhibitor – the Common White Button Mushroom

I am always on the outlook for natural aromatase inhibitors, because of the fact that most of us can’t stand the hormone blocking drugs we are almost all prescribed after a diagnosis of hormone-driven breast cancer.  When I came across this interesting bit of research I knew I had to share it with you.

If you aren’t familiar with the lingo, the aromatase enzyme is responsible for a key step in the biosynthesis of estrogen, and the aromatase inhibiting (AI) drugs block that activity, the thinking being that less estrogen circulating in the body adds less fuel to the tumor.

The problem is, however, that these drugs all have fairly serious side effects, or at the very least can create so much havoc in your body that you feel utterly miserable.  I discuss some of those side effects in my article Why I Chose Against Hormone Blocking Drugs.

Lately I have been noting that women newly diagnosed with estrogen receptor positive breast cancer are being told by their oncologists that less than 5% of women taking the AI drugs will have these side effects, but in my experience it’s a MUCH HIGHER percentage.  I believe the drug companies are minimizing the data, but that’s a whole other story.

The Common White Button Mushroom (Agaricus bisporus)

It seems that the common white button mushroom (Agaricus bisporus) is involved with the suppression of the aromatase enzyme.  In a 2006 study done by Dr Shiuan Chen at the City of Hope in Duarte, California, researchers concluded that white button mushrooms effectively suppressed aromatase activity and estrogen biosynthesis in estrogen receptor-positive/aromatase-positive MCF-7aro breast cancer cells isolated from hamster ovaries. 1  Other mushrooms including shiitake, portabello and crimini also had an anti-aromatase effect when tested but Dr Chen’s efforts have mainly focused on the white button mushrooms as they are the most commonly available and easy to obtain.

I also located an older study from 2001 that indicated diets high in white button mushroom may “modulate the aromatase activity and function in chemoprevention in postmenopausal women by reducing the in situ production of estrogen.” 2

What Is An Effective Dose?

Far from conclusive, but the best study I have been able to locate so far is a 2011 study 3 to determine the optimal dose to effectively reduce aromatase and circulating estrogen.  The study followed 24 postmenopausal women diagnosed with breast cancer at least five years previously, all of whom were free of recurrences, and had completed all breast cancer treatment (including any aromatase inhibitors or tamoxifen) at least three months prior to enrolling in the trial.  The women were treated with 5, 8, 10, or 13 grams of white button mushroom extract per day for 12 weeks.  The researchers reported that white button mushroom extract up to 13g per day was found to be well tolerated, with no adverse side effects.  They were unable, however, to significantly reduce estrogen levels from baseline during the 12 week trial period.  Subtle reductions in aromatase activity were noted, but nothing like the 50% reduction the researchers had hoped for.

Was a 50% reduction too much to hope for?  Is a 50% reduction in aromatase activity even necessary?  Hard to say. This research begs for more research to be done.

Perhaps the anti-aromatase and anti-breast cancer effects are cumulative, and maybe they are partially reliant upon other foods – some sort of synergy happening there.  Other studies have indicated that eating mushrooms is associated with a reduced risk of cancer 4, 5. which I believe is a strong enough reason to be taking them.  I recommend them on my page Diet and Cancer.

I just know that I will take my chances with the white button mushrooms rather than the hormone blocking meds, together with a few other natural compounds like ground flaxseed, Belle Vie ® and grapeseed extract.  These things, along with quite a few other diet and lifestyle changes have been working for 11 years for me so far!  Contact me if you’d like more information about any of these.

References:
1.  Anti-aromatase activity of phytochemicals in white button mushrooms (Agaricus bisporus) –   http://cancerres.aacrjournals.org/content/66/24/12026.long

2.  White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation – http://www.ncbi.nlm.nih.gov/pubmed/11739882

3.  A dose-finding clinical trial of mushroom powder in postmenopausal breast cancer survivors for secondary breast cancer prevention – http://meetinglibrary.asco.org/content/83362-102

4.  White button mushroom (Agaricus bisporus) exhibits antiproliferative and proapoptotic properties and inhibits prostate tumor growth in athymic mice –  http://www.ncbi.nlm.nih.gov/pubmed/19005974

5.  Macrophage immunomodulating and antitumor activities of polysaccharides isolated from Agaricus bisporus white button mushrooms — http://www.ncbi.nlm.nih.gov/pubmed/22217303

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