Not All Natural Estrogens Are The Same

by Dr. Cynthia Horner

Estrogen refers to a group of 20 hormones with similar molecular structure and similar names. Three estrogens –  estradiol, estrone and estriol –  are found in larger quantities in females and are considered the most important of the estrogens. Although similar in name and structure there is a major difference in how various estrogens work in the body.

More than fifteen years ago it was shown that estradiol and to a lesser degree estrone were capable of causing cancer, especially if given at times when the body did not deem them needed and when not ‘opposed’ by another hormone called progesterone. The hormones administered to women going through menopause are primarily unopposed estradiol and estrone. Birth control pills have one or both of these estrogens in them. These two estrogens are naturally found more abundant in females going through puberty and they appear again, rising only slightly in all females after ovulation. When the body produces these estrogens at just the right time in just the right quantity and with the ‘opposing’ hormone progesterone in its correct quantity there is no threat of inducing cancer.

Estone and estridiol produce more female reproductive tissue

The job of these two hormones (estradiol and estrone) are to tell the body to produce more female reproductive tissue. This is more breast tissue, more uterine tissue obviously necessary at puberty and also necessary after ovulation to prepare the breasts and uterus for the coming egg and possible pregnancy. Progesterone regulates estrogen or calms the effects of estrogen; this is referred to as ‘opposing’ estrogen.

A study reported in the Journal of the American Medical Association showed estrone to be the principle component in endometrial carcinoma and edometetriosis. Breast cancer increased 52% between 1950 and 1990. The large amounts of estradiol and estrone in birth control pills were partly responsible. It is interesting to note the average bra cup size increased from a B to C cup four years after the birth control pill was introduced.

Estriol is the helpful estrogen

Estriol was once thought to be a weak hormone with less importance and less influence in a woman’s body than than estrone and estradiol. Estriol accounts for 60 to 80% of circulating estrogen.  New research has shown estriol to be associated with reduced incidence of cancer. It is a much safer hormone for the symptoms women experience in menopause. Research suggests that estriol has benefits for bone density, heart health, multiple sclerosis, and postmenopausal urinary tract health.

When buying bio-identical hormones look at the label to see what kind of hormones you are buying. What is also important is that replacement hormones in the form of transdermal (skin) cream do not have to be as strong as hormones in the form of a pill.

What my patients have taught me.  “When you really listen without judging, things become a lot clearer.”