"Taking estrogen is dangerous." How many women have you heard say this? If we could single out the most damaging consequence of the controversy over HRT, it would be that estrogen--this essential life-enhancing friend to your body--has become for many women a dirty word.

What Is "Estrogen"?
Since the first hormone replacement drugs were put on the market over fifty years ago, it has become an ingrained practice to use the word "estrogen" indiscriminately for both the estrogen your body produces and a wide range of diverse hormonal preparations. Drug companies with hormone replacement products have contributed significantly to the confusion by continually referring to their products as simply "estrogen."

A woman will tell a friend that she is taking estrogen, thinking she is ingesting a single substance called estrogen that conforms to the hormone produced in her own body. But estrogen is, in fact, not a single hormone but a family of hormones, consisting principally of estrone (E1), estradiol (E2), and estriol (E3). Along with these three principal estrogens, we know that there are at least two dozen(1) identified estrogens produced in a woman's body, and researchers may well discover others. Premarin contains 48 percent estrone (natural to humans) and 52 percent horse estrogens (natural to horses). It also contains additives that are foreign to a woman's body. None of the American drug products contain estriol (E3), which has been used widely in Europe for over fifty years, and which new studies have shown to be cancer preventive.(2) Estriol, the estrogen most dominant during pregnancy, has particular benefit for women who are at risk for breast cancer and need hormone balancing and replenishment. In Europe, it is particularly favored for use in vaginal preparations, such as Oevestin. The reasons for its being completely ignored in the United States until recently will be discussed at greater length in chapter 6.

Most media reporting contributes to the confusion over "estrogen" by failing to make clear which estrogen they are referring to or to make distinctions as to what specific products are being discussed or tested. None of the mainstream media articles reporting the recent studies of increased incidence of breast cancer in women on HRT mentioned the fact that the subjects had used Premarin. Of the three principal estrogens circulating in a woman's body, the one predominantly implicated in increased cancer risk is estradiol. Premarin, as noted, is formulated with estrone, which converts to estradiol. Estriol, as we have just mentioned, has cancer-preventive properties. So when the results of studies are announced that show increased risk of breast cancer in those women on HRT, it is unfortunately estrogen that is
demonized and not the specific products tested.

The fact is, you cannot live without estrogen. Estrogen is not merely a "sex" hormone, as there are presently three hundred known functions for estrogen in the body and we are only beginning to understand all its interactions. Every cell in your body has receptors--what you might think of as little landing docks--that receive the complex hormonal messages circulating through your blood. There are estrogen receptors in all your vital organs--such as your brain, your heart, and your liver--and all through your body. Estrogen spurs the production of an important enzyme in the brain that helps the connections between brain cells to flourish. It is estrogen that helps maintain verbal learning and enhances a woman's capacity for new learning.(3) Indeed, estrogen supports you from birth until death.