On the board there is a post discussing flax oil and its estrogen binding capacity. Rather than post my response there, I thought Id post this here for everyone to read because it has implications for much more than flax supplementation.
The question refers to the fact that flax (or componenets of flax seeds/oil) can bind the estrogen receptor (ER). This is true. But before you freak out and start eating lard again in stead of drinking flax, there is an important distinction that must be made when discussing receptor binding. This is important when looking at any compound that binds receptors.
First, there are several types of ligand (binding agent) activity. 1)Agonism means that the ligand (estradiol for example) binds to its receptor and exerts full ER mediated effects. 2)Partial Agonism means that a compound will bind the receptor and only exert a small % of the effects the Agonist would at the same concentration. 3)And then there are Antagonists. a)There are several types. Competitive Antagonists bind the same location and “compete” with the Agonist for the receptor. They prevent Agonist binding. b)There are other types of Antagonists (they are called uncompetitive or noncompetitive) that bind other locations on the receptor to inactivate receptor function so that Agonist can bind but cannot promote any function.
My Point? Well, several things (like flax) can bind the ER and actually have beneficial effects because of either Partial Agonism or Antagonism.
Alone, flax is a Partial Agonist and it can promote very weak estrogenic effects at the receptor. But in the presence of strong estrogens, it prevents binding of the estrogens and and acts as an Antagonist to prevent the full ER mediated effecs.
Ok, enough pharmacology. Practically speaking, from the research, flax does tend to increase LH and T levels. It also may tend to raise estrogen levels in the blood but fortunately there are 2 mechanism that protect us from the estrogen’s effects. First, the flax antagonizes the effects of this raised estrogen level at the receptor. And second, flax tends to increase urinary estrogens (therefore estrogens leave the body faster).
The moral of this story…in the future, remember that just because something binds to a receptor doesnt mean that it promotes the effect of that receptor. It might just do the opposite.