I am not a total expert, but I have recently learned that my habit of eating lots of soy products (soy milk, soy meat, etc) mimics
estrogen in the body. I also found out that certain chemicals
in soft plastic water bottles (which I had drank out of every day for a year at work) 'leak' into the water and also 'mimic' estrogen. Even stress hormones can lead to further imbalances.