Estrogen is the hormone that gives women their curves—hips and breasts. In the right amount, estrogen enables a woman to focus (no brain fog!) and contributes to balanced mood (no mood swings!), a timely (and pain-free) menstrual cycle and a healthy libido. Estrogen also positively affects the brain, skin, bones, liver and heart.

Progesterone keeps estrogen in check. These two hormones counterbalance each other. Estrogen causes you to retain salt and water; progesterone is a natural diuretic.  When it comes to the breast, estrogen stimulates breast cells to grow; progesterone prevents cysts from developing in painful breasts.18

Estrogen is a primary female sex hormone, and it is the hormone that defines women. However, estrogen can become problematic when it is high relative to progesterone; today, this is a very common hormone imbalance known as “estrogen dominance”.

Estrogen also plays a role in most breast cancers. About 80% of breast cancers are “ER-positive”, or “estrogen receptor-positive”. This means that the cancer cells in the breast are growing in response to estrogen.19

Two routes to estrogen dominance (for women):

  1. You have high estrogen relative to a normal progesterone level. This type of estrogen dominance is common in overweight women because, in addition to the ovaries making estrogen, fat cells also make estrogen. More fat cells means higher estrogen levels. Women of normal weight who have been exposed to xenoestrogens (synthetic chemicals that have estrogen-like effects) can also be estrogen dominant. Xenoestrogens are present in combination hormone birth control pills, skin care products, cosmetics, plastics, artificial food colorings, preservatives, insecticides, building materials, chlorine and chlorine by-products, among others.20
  1. You have high estrogen relative to low progesterone. This often happens, naturally, from age 35 as a woman’s fertility begins to diminish, and escalates during periods of hormonal transition, like perimenopause and menopause.

Men can also have high estrogen levels from:21, 22

» Being overweight or obese. Fat cells in the body convert male hormones (androgens) into estrogen, resulting in higher estrogen levels.

» Exposure to environmental estrogens. For example, regularly consuming conventionally raised meats.

» Heavy alcohol consumption.

» Liver disease. A malfunctioning liver upsets hormonal balance, causing lowered androgens (male hormones) and increased estrogen.

» Having Klinefelter syndrome. Men with this congenital condition have lower levels of androgens (male hormones) and higher levels of estrogen, and they often develop gynecomastia (male breast tissue). Men with Klinefelter syndrome can have a 20 to 60 times increased risk of breast cancer compared to other men.

» Radiation exposure, especially in the chest area.

Continue Reading About Breast Cancer Prevention (below):

Your Breasts: What You Need to Know  (Part 1)
Protect Your Breasts: Limit / Avoid the Big 3  (Part 3)
Better Breast Health: Eat These 3 Foods  (Part 4)

Sources

18  The Hormone Cure. Sara Gottfried, MD, Scribner. 2013. pp. 150-153
19  BreastCancer.org
20  WomeninBalance.org
21  BreastCancer.org
22  Cancer.org