Hormones and Performance Part 3
Estrogens and Your Diet
A woman's body produces three natural estrogens. Estradiol, the most potent, is associated with a healthy menstrual cycle and drops off at menopause as cycles cease. Estrone is produced mainly by fat cells and can be converted into estradiol. Both estrone and estradiol have been linked to, an increased risk of breast cancer. The third estrogen, estriol, is a weak estrogen that rises dramatically during pregnancy but, otherwise, remains at a steady, low level.
The source of estrogens in men is actually testosterone that is converted to all three estrogens though male levels are much lower than those of a premenopausal woman. It has been shown that as a man ages his testosterone converts to estradiol at a faster rate. This increase in male estradiol levels can have two effects.
In several controlled studies, a diet high in fiber has been shown to lower serum levels of estradiol and estrone in both pre- and postmenopausal women. It is not known how fiber works to lower estradiol levels, but studies with flaxseed and wheat bran demonstrated that it could be the way and speed at which the hormone is broken down by the body during the disposal process.
Why is how estradiol disposed of important?
Asian women who consume a traditional diet containing high fiber have lower estradiol and estrone levels before and after menopause. These women also have substantially lower rates of breast cancer compared with Western women - in fact, lower by 80%. But, these women also consume high levels of soy products and much lower levels of fat, so there may be multiple contributing factors to lower estrogen levels.
However, when Asian women immigrate to a Western country, typically the U.S., and convert to a more Western diet, their estradiol levels increase as they begin losing their protection against breast cancer.
The idea of having breast cancer is a very scary and emotional proposition. The truth is that many, many more women will die of heart disease, but breast cancer usually strikes younger women and carries with it vivid images of pain. In one study, 11,000 women in Iowa were followed for 11 years and those whose diet contained the most whole grains, and or nutrient rich fiber had nearly a 20% lower risk for breast cancer. Other studies have looked at the risk of endometrial and colon cancer and found that fiber-eaters had a decreased risk for each. No study, to date, has found that fiber can drop estradiol levels too low and interfere with normal menstrual cycles.
The American Dietetic Association suggests 20-25 grams of fiber daily - about two times higher than the average intake in the U.S.
It has been shown that a daily intake of over 30-40 grams is appropriate for active individuals.
A vegetable food group that causes a drop is estradiol levels and can effect how estradiol is broken down by the body is cruciferous vegetables such as cauliflower, broccoli, kale, brussel sprouts, rutabaga, cabbage and turnips. Incorporating some of these vegetables into your diet is always GREAT idea.
Food recently talked about as affecting low estrogen-related symptoms, curing everything from menopausal hot flashes to heart disease as well as decreasing breast cancer risk, is soy.
Soybeans contain a variety of substances that can positively impact our health:
It is the isoflavones that are important to our discussion of diet and estrogen levels. Some soy isoflavones look very much like (similar chemical structure) our body's estradiol, so much so that when we eat large amounts of isoflavones our body can be fooled into thinking that these plant estrogens are our own.
What is the advantage of this you ask? For midlife women who, for one reason or another, do not want to take an estrogen supplement, dietary soy can soften menopausal symptoms. It is still unknown whether in the long term high dietary soy can replace estradiol's protection of the heart and bones of menopausal women. Preliminary scientific evidence suggests that 15 ounces of soy milk or 2 ounces of tofu daily might be all a woman needs to decrease hot flashes.
Hope you found this little write up educational!
Thomas Sampson CFL-3, USAW-2, Sports Nutritionist
International sports science association. Sports nutrition. 5th edition. 2018 carpinteria CA
Nancy Clarks Sports Nutrition Guidebook. 4th edition. 2008 champaign IL
Hormones and performance. Sports Science Association. 2020