What is estrogen?

Estrogen is a group of sex hormone secreted primarily by the ovaries. It is responsible for female characteristics such as the development of breasts and female curves, as well as for menstruation. There are several types of estrogen and the main ones that we know are estradiol, estrone and estriol. These naturally occurring estrogens are found in the blood and in the body.

Too much estrogen in the body:

• Builds up uterine lining


• Stimulates breast tissue


• Increases body fat


• Salt and fluid retention


• Depression, headaches/migraines


• Interferes with thyroid hormone


• Increased blood clotting


• Decreases libido


• Impairs blood sugar control


• Increases risk of endometrial cancer


• Increases risk of breast cancer


• Slightly restrains bone loss


• Reduces vascular tone

What are estrogen receptors?

Like progesterone, it is the physical structures on the cell membrane that attract estrogen and respond to its effect. There are many estrogen receptors throughout the body.

There is only one progesterone receptor which means there is only one type of progesterone, but there are several types of estrogens.

Is estrogen dominance life-threatening?

We are now learning that many of these cancers are all known to be a result of hormonal imbalances. Specifically they are a result of excess estrogen or estrogen dominance.

Estrogen dominance is a term coined by the late Dr John Lee in his first book on natural progesterone. It describes a condition where a woman can have deficient, normal, or excessive estrogen but has little or no progesterone to balance its effects in the body. Even a woman with low estrogen levels can have estrogen-dominance symptoms if she doesn’t have any progesterone.

And how do we become ‘estrogen dominant’?

All too often our food chain is laced with toxic pesticides, herbicides and growth hormones ? a sea of endocrine-disrupting chemicals that mimic estrogen in our body. If we are overweight, our body?s store of excess fat can be converted into estrogen. Insulin resistance leads to estrogen dominance. A visit to our GP for the odd hot flash, missed period or PMS discomfort can result in a prescription of estrogen pills, patches or implants.

And yet unopposed estrogen in our bodies results in all sorts of hormone-related health problems such as PMS, endometriosis, uterine fibroids, infertility, weight gain, increased blood clotting, thyroid dysfunction, even cancer, in both men and women.

Our men-folk are equally at risk. Estrogen gradually rises as men age, while saliva levels of progesteorne and testosterone gradually falling. Thus, with aging, estrogen dominance occurs. A clear sign of estrogen dominance in aging men is their tendency to develop breasts. This indicates these men are low in progesterone and testosterone.

Where does progesterone fit in?

Estrogen is the hormone that stimulates cell proliferation, or the growing phase. In other words, estrogen causes cells to divide and multiply. Progesterone, on the other hand, is the hormone that stops growth and stimulates ripening. It induces cell maturation and programmed cell death (called apoptosis).

Although cells in different parts of the body may look and work differently, most repair and reproduce themselves in the same way. Normally, this division of cells takes place in an orderly and controlled manner. If, for some reason, the process gets out of control, the cells will continue to divide, developing into a lump which is called a tumour. Tumours can be either benign or malignant. Doctors can tell whether a tumour is benign or malignant by examining a small sample of cells under a microscope. This is called a biopsy.

Whilst not a cure for cancer, progesterone can dramatically decreases cell multiplication rates, providing women with a degree of protection against estrogen-driven cancers. Normal levels of progesterone in the body can, therefore, actually help protect you against some forms of cancer.

Uterine cancer, for example, is known to be caused by unopposed estrogen. That’s why women who have an intact uterus and take estrogen replacement therapy must also be given some form of progesterone to oppose estrogen and reduce this risk. This is generally given in the form of synthetic progestin which, incidentally, is not the same molecule as bioidentical progesterone, but is designed to block estrogen effects.

Testing your estrogen levels

Estrogen status is an important diagnostic tool for various symptoms and conditions in both men and women.

Testing facilities can assay the three naturally occurring estrogens to provide a more complete hormonal profile of you as a patients.

Estrone (E1) is the second most powerful human estrogen compared to E2, and is commonbly associated with an increased level of subcutaneous fat or the use of synthetic HRT i.e Premarin. (therefore it is a useful marker for monitoring patients taking Premarin or patients with significant subcutaneous fat).

Estradiol (E2) is the most potent human estrogen. It is easily converted to E1 sulphate. Together E1 + E2 contribute the bulk of estrogen activity.

Estriol (E3) is the least potent estrogen. E3 is important for protection against estrogen dominance because it competes for the same receptor as E1 and E2 but has lower activity.

Mr Colm Benson, Health Services Manager for Analytical Reference Laboratories (ARL), Melbourne kindly provided a sample of ARL’s new Salivary Hormone Test Report detailing reference and target ranges for the various hormones.