Good and bad estrogens

So what happens when we consume the high levels of estrogen in dairy products? Our bodies have enzymes systems to eliminate or restore the estrogen levels to normal. These same enzymes are used to eliminate toxins from our body. In our bodies one of the most potent estrogens in dairy can be converted to another estrogen called estrone.

The enzymes we are interested in are known as CYP1A1 and CYP1B1. If estrone is acted upon by CYP1A1 an estrogen called 2-hydroxyestrone will be crreated (2OH). This would be considered a good estrogen because when it binds to the estrogen receptor alpha it does not stimulate cancer. If the estrone is acted upon by CYP1B1 then an estrogen called 16 alpha hydroxyestrone will be created. This would be considered a bad estrogen because when it attaches to the estrogen receptor alpha, it can stimulate cancer. This attachment of 16 alpha estrone to the estrogen receptor alpha is also almost permanent and unremitting stimulation of the estrogen receptor alpha can continue.

In areas of prostate tissue, increased levels of the CYP1B1 enzymes have been found. See Ragavan,N. et al. "CYP1B1 expression in prostate is higher in the peripheral than the transition zone," Cancer Letters 215 (2004):69-78.-R.Bibb,M.D.