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What Estrogen Does for Your Body and Brain
In this chapter, I share with you specific information about how estrogen functions in your body and brain, so that you can become aware of how hormones are supposed to function in your body. Your hormonal system represents the pinnacle of how your body and brain work together. I like to think of this interaction as a symphony, with estrogen as lead conductor. It’s estrogen’s role to bring together all the other hormones and help them interact to ensure that you are healthy.
As you think about your own situation, and whether or not you feel ready to benefit from bioidentical hormone replacement therapy (HRT), it’s important to understand how estrogen is meant to function—both throughout your monthly cycle and over your lifetime so that you can fully appreciate and become more aware of the changes—subtle and not so subtle—that continue to occur.
Your Monthly Cycle
After the onset of puberty and before menopause, your estrogen levels fluctuate over the course of every month. A “typical” monthly cycle lasts approximately 28 days, though some women experience a brief 24-day cycle and others can have a 35-day cycle. A monthly cycle that is shorter or longer than 28 days is no less “normal” than a cycle that adheres precisely to a four-week schedule. What’s normal for you … may not be normal for another woman.
Week 1
The first day of menstruation is day 1 of your monthly cycle. This is the day the body begins its preparations to conceive in the upcoming month. Typically, menstruation lasts 5–7 days. During the first few days of menstruation, estrogen levels are very low, which is the main cause of the tiredness, lack of energy, low mood, trouble sleeping, cramping, and other symptoms that many women experience. By day 5 or so, estrogen levels begin to rise, and many women feel energized, centered, and even-keeled. That week after you’ve completed your period, when you feel as though you’re firing on all cylinders—rested, full of energy, enjoying the way you look and feel—you have estrogen to thank for that. This estrogen cycle is part of a network of brain–body signals that drive the body’s quest for reproduction.
Week 2
During days 7–14 of your monthly cycle, estrogen levels rise significantly. For many women, this week feels like a gift—they are energetic and productive. You may feel tremendously capable, sexy and sexually motivated, attractive and centered. During this week, estrogen is climbing toward its peak level, which comes just before ovulation. This rise in estrogen makes your skin look pretty, dewy, and clear. Women tend to feel most powerful and womanly during this phase of their cycle. The reason for this is no mystery: this is nature’s way of encouraging conception.
While you are feeling all the positive, vibrant, sexy effects of rising estrogen, that same estrogen surge is helping prepare your body to conceive. Estrogen increases production of cervical mucus, which will corral sperm that have entered the vagina and pull them through the cervix toward an egg waiting to be fertilized. Estrogen also promotes the thickening of the uterus’s lining, where an embryo will implant after the biologically hoped-for fertilization occurs.
Right before ovulation, estrogen levels drop briefly and precipitously, which is accompanied by a surge of testosterone. With this increase in testosterone, you might feel a more intense, urgent desire for sex than you do under the influence of the sensuality-promoting estrogen. On the cusp of ovulation, this is the body’s final push toward reaching its goal of conception.
Week 3
After that sharp drop just before ovulation, estrogen levels begin to rise again gradually during days 14–21 of a woman’s cycle, though not to the levels they reached just prior to ovulation. After having spent two weeks preparing to conceive, your body now functions as if it were pregnant. This can mean a continuation of the “feel-good” times of the pre-ovulation week, albeit slightly muted and without the same intensity of sexual energy. Immediately upon ovulation, the body began producing greater amounts of progesterone, which has a mood-balancing, calming effect. As women age, the estrogen rebound that occurs after ovulation often changes. The pre-ovulation drop in estrogen becomes steeper and estrogen levels fall further than when women were younger. The subsequent rise in estrogen also takes longer to occur, as many as several days or a week. Women in their thirties and forties may come to experience this week of their cycle very differently than they did when they were younger, with increasing symptoms of estrogen decline and deficiency.
Week 4
The week before menstruation, a woman’s body recognizes it is not pregnant. (Unless, of course, you are.) This biological moment of truth triggers estrogen to decline, leading to many of the symptoms associated with PMS: trouble sleeping, fatigue, mood swings, feelings of depression, forgetfulness, headaches. Progesterone, while still being produced by the ovaries, is also on the decline during this week, causing bloating, feelings of anxiousness, and breast fullness and tenderness. Testosterone levels rise during this premenstrual week, leading to feelings of irritability, as well as oily skin.
As women age, the decline in estrogen—as well as accompanying changes to levels of progesterone and testosterone—may begin earlier and earlier, cutting into the third week of the monthly cycle. The estrogen drop that ushers in the uncomfortable, painful, sometimes debilitating symptoms of estrogen deficiency and PMS can start as early as day 15 of a woman’s cycle, very shortly after ovulation itself. Estrogen reaches its lowest level just before a woman’s menstrual flow, and a new monthly cycle begins.
If progesterone drops, you spot before your period, and if progesterone falls too soon, you don’t reach the usual 28th day of a normal cycle and don’t bleed at all.
The Subtypes of Estrogen
Estrogen is often discussed as though it were a single hormone. In fact, there are several estrogens, including one estrogen compound—esterol, or E4—that is made only during pregnancy. The three most important estrogen compounds that all women’s bodies produce are estradiol (E2), estrone (E1), and estriol (E3). The ovaries, the primary place of estrogen production in the body, make these three different versions of the hormone.
Estradiol (E2)—The most potent and efficient of the estrogens, estradiol is responsible for many of the protective health benefits for which estrogen is known. With receptors on every cell in your body, estradiol affects most of your body’s systems—from reproduction to digestion and everything in between.
Estrone (E1)—A weaker version of estrogen, estrone is produced by the ovaries and liver before menopause; after menopause, estrone is produced by your fat cells. It is thought to help retain bone strength.
Estriol (E3)—This estrogen compound is markedly weaker than both estradiol and estrone. Ninety-nine percent weaker than E2, estriol is a gentle version of estrogen that plays a critical role in balancing the other estrogens. It mainly functions during pregnancy (when it increases a thousandfold), and is often an indication of the health of a pregnancy. When it comes to HRT, estriol is very important to balancing the way the other estrogens work. Most significant among its functions is that estriol protects against breast cancer. It also supports vaginal health, maintaining lubrication, encouraging production of good bacteria (which means fewer vaginal and urinary infections), and restoring the tissues of the vaginal wall. Estriol helps skin remain youthful, full, and elastic, and it reduces inflammation.
Each of these estrogen compounds produced by the body has its own role in creating health, sexual function, and mental and emotional well-being. Working in collaboration, estrogens protect cardiovascular health, regulate appetite and weight, boost energy, keep the brain and bones healthy and strong, balance mood, and protect against depression and anxiety. Together, these three estrogens keep you feeling like your best self: healthy, capable, energized, and focused. So my question to you is this: why not live a long life enjoying their many benefits?
The Life Cycle of Estrogen
Puberty
Estrogen drives much of the development from girlhood to womanhood—it fosters breast development, inaugurates and supports reproductive capabilities, and facilitates the gravitation of fat to a girl’s hips, legs, and breasts. Prepubescent girls have consistently low levels of estrogen in their bodies. At the onset of puberty, the ovaries begin to ramp up estrogen production. It’s at this time that estrogen—along with progesterone and testosterone—begins to rise and to fluctuate significantly. Estrogen is the driving force behind the development of a maturing girl’s curves, the onset of her menses and her ability to conceive, and the dawning of her sexuality. Estrogen also contributes to distinct changes to her emotional and psychological life and experiences, both as an individual and in her relationships with others. As you read the stories of my patients, you will come to recognize the connections between estrogen and a woman’s sense of self.
As puberty progresses, estrogen and other hormones often behave erratically, working to come into balance. Irregular menstrual cycles, cramping, mood swings, and other symptoms associated with PMS are commonly experienced among girls moving through puberty.
The typical age of puberty has lowered significantly over the past twenty years. While it was once common for puberty to begin somewhere in mid-adolescence, around the ages of 14–17, today the onset of puberty happens much earlier, with an average age of menarche, the beginning of menstruation, between ages 11–13. The reasons behind this shift are complicated. A significant root cause for early puberty is exposure to the chemicals in household products, including cosmetics and hygiene products. These chemicals mimic estrogen and give a young girl’s body and hormonal system the false impression that she has a lot of estrogen, and so the body responds by beginning puberty earlier than it would if she did not have daily exposure to chemicals.
Food also plays a role in the early onset of puberty. Researchers believe that girls who eat a diet high in nonorganic or processed/packaged foods high in fat and sugar mature earlier than did girls in the past. In addition, some researchers believe that early menarche is tied to fat mass: the heavier the girl, the more likely she will start her period at a younger age. And many girls are heavier today than in previous generations.
Getting your period early in life is not necessarily a health concern. However, it is a signal that a girl’s body is responding to environmental triggers that may not be good for her. (See chapters 2 and 10 on how to avoid these triggers and protect a young woman’s reproductive health.)
Young Adulthood
Estrogen levels, rising throughout puberty, typically reach their peak in your midtwenties. This peak is also the time when women generally are most fertile. Often, the irregularity of estrogen’s monthly rise and fall—as well as the rise and fall of other hormones, including testosterone and progesterone—evens out by young adulthood. During their twenties and early thirties, women generally have consistent month-to-month estrogen fluctuations and predictable symptoms from the normal rise and fall of estrogen and other hormones. Yet for many women today, biological fertility does not align easily with social, professional, and relationship pressures. In other words, young women have many competing goals during this fertile period.
Copyright © 2020 by Uzzi Reiss