Estrogen: An Unlikely Player
As most men approach middle age, the seemingly inevitable starts to occur: we gain weight around the waistline, sexual desire starts to wane, we’re unable to lift as much weight at the gym, and we seem to simply have a harder time keeping up with the younger guys.
And most of us – doctors included – think that loss of testosterone is the main culprit. Not totally true. We’re learning that another hormone plays a key role in the development of some of these symptoms of aging in men. And it’s an unlikely player. That hormone is estrogen.
When most of us think of estrogen, we think of women. That’s because estrogen is a key hormone in women’s health. And the loss of estrogen in women at menopause causes big physiological changes. Weight gain, skin dryness, wrinkles, heart attacks, bone loss and osteoporosis, loss of sexual sensation and dementia are just some of the effects of loss of estrogen in women.
Yet estrogen is proving to play a serious role in the aging of men, too. A study published in the New England Journal of Medicine demonstrated that in men, while low testosterone is the main culprit in loss of muscle strength, loss of estrogen is a big cause of that mid-section weight gain, the infamous “pot-belly.” And it seems that loss of both testosterone and estrogen together contributes to diminished sex drive and sexual function in men.
But Wait….Isn’t Estrogen Harmful to Men?
The answer to this question seems to be related to where the estrogen comes from. So let’s talk about that for a moment.
In healthy men, estrogen, specifically estradiol (a form of estrogen), comes from testosterone. There is an enzyme, aromatase, that converts a certain amount of a man’s testosterone to estradiol. So as a healthy man’s testosterone levels rise or fall, estradiol levels tend to rise and fall as well. The average estradiol level of an adult male is about 75 pg/mL. But men can make estrogen another way as well. In obese men, there is an increased concentration of a different form of estrogen, estrone. This estrone gets converted to estradiol (as opposed to conversion of testosterone to estradiol). So high estrogen in obese men is due to another reason than high estrogen in healthy men. It is important to not confuse two, because they play out very differently with regard to our health.
The Protective Effect of Estrogen in Men
High endogenous estrogen levels in “normal ” men is protective against coronary artery disease, Type 2 Diabetes, and prostate cancer. (This is not true, however, in obese men with high estrogen levels because the estrogen produced in visceral fat is estrone, which then converts to estradiol versus the aromatization of testosterone to estradiol.)
As men age, testosterone levels fall, and so do estrogen levels. This contributes to the accumulation of excess fat in men and their lack of sex drive and sexual function. They also begin to lose the protection against heart disease, Type 2 Diabetes, and prostate cancer that estrogen provides.
Estrogen deficiency has also been implicated in the pathogenesis of osteoporosis in men. A study published in Osteoporosis Int. demonstrated that 38% of men with osteoporosis had undetectable serum estradiol levels. This as well as more recent studies show that estrogen deficiency, not androgen (e.g. testosterone) deficiency is much more prevalent in male osteoporosis.
Additionally, estradiol levels in men are inversely correlated with sperm DNA damage, suggesting that estradiol may have a protective effect on sperm DNA.
So How Do Men Maintain Optimal Estrogen Levels as They Age?
One of the goals of hormone replacement therapy (HRT) is to restore hormone levels back to the optimal levels of a young adult. For estrogen in men, this means restoring levels to about 75 pg/mL. The best way to achieve this in men is by optimizing testosterone levels. Some of the testosterone will be converted to estrogen, therefore maintaining adequate levels.
To get started, you should have your testosterone and estrogen levels checked by a physician who specializes in hormone optimization. It’s a simple blood test. Once you know if you’re deficient, you can discuss options to optimize your levels so you can look and feel as good as possible while at the same time significantly decreasing your risk for chronic degenerative diseases.