The American Cancer Society has a detailed description of factors that are known to increase a woman’s risk of breast cancer. Many of them relate to estrogen:
- Being a woman
- Beginning menses before age 12
- Going through menopause after age 55
- Using oral contraceptives
- Using hormone replacement therapy
- Being overweight
There are additional factors that reduce a woman’s risk of breast cancer, that again relate to estrogen:
- Breast feeding
- Having children
And a simplistic view, might say that estrogen is “bad” for cancer. If we’re willing to look a little deeper, an interesting trend about estrogens appears, specifically one that opens up a whole avenue of breast cancer treatment and prevention.
When we talk about estrogen, we’re actually talking about a group of related hormones, each with a slightly different origin and different effect. A standard lab test, can tell a woman about the three main forms of estrogen, which are conveniently known as E1, E2 and E3.
E1 (Estrone) is the estrogen that is produced by fat cells – yes, fat cells produce estrogen. E1 is also the backbone for pharmaceutical forms of estrogen that are found in oral contraceptives and standard hormone replacement therapy. After menopause, E1 is the dominant estrogen in women. E1 is also considered a strong estrogen, because of it’s ability to strongly stimulate cell growth
E2 (Estradiol) is the form of estrogen that is produced by the ovaries. With progesterone, E2 controls the menstrual cycle. E2 serves as the baseline for other estrogens, in terms of being considered strong or weak. Bioidentical hormone replacement typically uses E2.
E3 (Estriol) is typically associated with pregnancy. The placenta churns out this relatively weak estrogen throughout pregnancy, and during that time E3 is the dominant form of estrogen in a woman’s body. Outside of pregnancy, the liver produces smaller amounts of E3 as the liver process the other forms of estrogen.
Let’s take a second look at those risk factors, and how they relate to the different forms of estrogen
| Increased Risk | Beginning menses before age 12 | Increased E2 |
| Increased Risk | Going through menopause after age 55 | Increased E2 |
| Increased Risk | Using oral contraceptives | Increased E1 |
| Increased Risk | Using hormone replacement therapy | Increased E1 |
| Increased Risk | Being overweight | Increased E1 |
| Decreased Risk | Breast feeding | Decreased E2 |
| Decreased Risk | Having children | Increased E3 |
The trend that starts to emerge suggests that lowering a woman’s E1 and E2, while raising E3 can be an effective intervention for reducing the risk of breast cancer. Admittedly, medicine has yet to prove this approach with the classical multi-center randomized, double-blind study, but there are 40 years of supportive preclinical research.
Most labs, can now report an Estrogen Quotient, a simple number that quantifies the ratio between the different estrogens. A ratio greater than 1, more E3 than E2 and E1, is considered to reduce a woman’s risk of breast cancer. A ratio less than 1, more E1 and E2 than E3, suggests an increased risk of breast cancer.
Republished with permission from Green Tea and Melatonin.
