Estrogen: Why it's Good AND Bad

Interviewer: Doctor, we hear a lot about estrogen these days and that being a bad thing in a lot of cases. Why is that? Why do we hear so much about that?

Dr. David Zava: Well estrogen has been associated with cancer. Excessive estrogen has been associated with cancer. But I always look at estrogen and what I said in the book, it's the angel of life and it could also be the angel of death. I always like to think of it as the angel of life. Estrogen is very important for your bones. It's very important for your brain, your skin, all tissues of your body. But it's really the balance of estrogen and keeping estrogen at a physiologic level that makes it the angel of life. It's when it gets out of balance just like cholesterol. Cholesterol is life giving. Estrogen is life giving. When cholesterol gets too high, when it gets oxidized it becomes dangerous. Estrogen is exactly the same thing. Estradiol, the molecule itself, is very life giving. When it's too high, when it's out of balance or it's oxidized and does certain kinds of metabolites it can cause cancer. It can cause cardiovascular issues, particularly in men. So it's good. It's bad. It's like water - too much, too little. Like electricity - too much, too little. Like fertilizer on your plants - too much, too little. So it's, you know, it's really about balance.

Interviewer: Mm-hmm. How does it get out of balance? And is it the same for men?

Dr. David Zava: It gets out of balance. Women need more estrogen than men because the reproductive tissues are dependent on estrogen for their function. Men also need estrogen. They need it for their bones. They need it for their brain. In fact, actually, most people don't realize it, but men have more estrogen in their brain than women because they have more testosterone, and testosterone is the precursor of the estradiol, so it converts an enzyme called aromatase, converts it into estradiol. So it's an important hormone.