Estrogens are often thought of as "female hormones," and in fact, they are responsible for common female physical characteristics, such as increased subcutaneous body fat (fat just under the skin), breasts, and the wider hips on women that provide the curvacious appearance that attracts men. But just as women synthesize androgens such as testosterone in their bodies, men also produce much smaller amounts of estrogen (compared to women) in their bodies. The precise role of estrogen in men is still a matter of scientific speculation. What is known is that among other effects, estrogen tends to promote increased levels of a cholesterol-carrier in the blood (HDL) that is considered protective against cardiovascular disease onset. Estrogen adds another layer of CVD protection through its ability to maintain the nitric oxide system in blood vessels that keeps arteries supple and helps to prevent atherosclerosis. These factors explain why heart attacks and strokes are relatively rare in young women prior to menopause. Other studies show that estrogen may help to prevent Alzheimer's disease, maintain bone density (A drop in estrogen is a primary risk factor for osteoporosis, which is more common in women than men), and do other beneficial things in both females and males bodies. In short, having an optimal level of estrogen is essential for health in both sexes.
On the flip side, estrogen is the only endogenous hormone officially listed as a carcinogen. It is linked to cancers of the breast and endometrium in women, prostate cancer in men. Indeed, emerging studies suggest that it may be that having excess estrogen coupled with a lack of normal testosterone levels may be a primary risk factor for the promotion of prostate cancer. In men, an imbalance of estrogen over testosterone leads to pronounced estrogenic side effects. These can include gynecomastia, or excess breast tissue in men; increased subcutaneous body fat storage; and possible blunting of libido. A recent study found that higher than normal levels of estrogen are related to sudden death heart attacks. Testosterone was not implicated in this process. Excess estrogen also increases the risk of internal blood clot formation, which in turn is associated with a higher rate of heart attacks and strokes.
Recent studies suggest that various compounds existing in the environment known as endocrine disruptors (ED) can interfere with normal hormonal reactions in the body. Many of these EDs are not actual hormones, but rather compounds that can mimic the effect of hormones in the body through interacting with hormonal cell receptors. Estrogen has two cell receptors, ER-A and ER-B, while androgens such as testosterone, have only one. These various EDs can lock on to hormone receptors and block the effects of actual hormones. This usually results in negative effects on both . . .