White mushrooms have been shown to be a natural aromatase inhibitors, with the stuffing variety (Agaricus bisporus) exhibiting the most potent aromatase inhibition (Baiba et al. 2001).
However it wasn't established from this study what component of the mushroom extract provided the aromatase inhibition and what form it should be eaten in to provide the greatest benefit.
A later study by Chen et al. (2006) has shown that the aromatase inhibition is likely to be rooted in the high concentrations of essential fatty acids, linoleic acid and conjugated linoleic acid (CLA), providing a transient anti-inflammatory effect and reducing aromatase activity. These anti-aromatase effects of CLA have been confirmed previously (Chen et al. 2004) as well as modulation of oestrogen receptor function (Durgam et al. 1997) and even suppression of aromatase mRNA expression (Chen et al. 2006).
So...while the humble mushroom isn't as potent as pharmaceutical compounds like exemestane, aromasin or letrozole at regulating the aromatase enzyme, it could be a nice, easy addition one's diet to help keep oestrogen at bay
Still wondering...the dosage of common CLA needed to elicit significant inhibition of aromatase enzyme, and whether the naturally-occurring CLA in the mushroom extract works synergistically with other compounds present to make the effect stronger?