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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.

Perimenopause

Perimenopause is the transition from the hormonal routine of a woman’s reproductive years to menopause. Perimenopause typically begins five to ten years before menopause, often in a woman’s early forties. Over the past two decades, clinicians and researchers, including me, have seen more women entering perimenopause earlier than was typical in previous generations. It is no longer unusual for women to enter perimenopause in their thirties, and for women in their late twenties to have estrogen deficiencies. This shift seems primarily due to both xenoestrogens and the widespread prescription and use of birth control pills, which interrupt the natural production of estrogen and are prescribed for reasons other than preventing pregnancy. For instance, the Pill is used to treat acne, anxiety, and sometimes even ADHD.

Perimenopause can be a time of great hormonal irregularity. Estrogen levels are declining overall—but not in a linear, even fashion. During perimenopause, estrogen seesaws up and down, fluctuating dramatically and erratically, without the same pattern of fluctuation that once occurred in younger years. The result? Unpredictable, variable monthly menstruation cycles, with irregular periods that change in their duration and in the amount of bleeding a woman experiences from one month to the next.

Women also experience symptoms of pronounced estrogen deficiency, including night sweats and hot flashes, mood swings, depleted energy, headaches, weight gain, and diminished interest in sex. I find that blood tests to measure estrogen levels as a clinical yardstick for menopause are useful, but to a limited degree. Women who fall in the wide range of “normal” estrogen levels indicated by blood tests can be firmly within perimenopause, as evidenced by their symptoms. And these symptoms can increase in severity. As you will see in chapter 4, it’s important to cue into any changes in your cycle and become familiar with signs of deficiency.

Progesterone in Perimenopause and Menopause

While estrogen rises and decreases dramatically even as it gradually declines over your lifetime, progesterone diminishes steadily starting in the early thirties, before declining markedly around age thirty-five. In previous generations, it was uncommon to enter menopause before fifty-five years old, but women today can enter menopause as young as thirty-eight or forty. Without a natural progesterone supply, you lose the balancing effect that progesterone provides to estrogen, as well as the protections against heart disease, breast cancer, cognitive decline, and other conditions. You will learn more about progesterone and its role in your overall hormonal health here.

Menopause

What is menopause? Is it the absence of a period? Is it a checklist of symptoms—night sweats, hot flashes, mood swings, weight gain? I regard menopause as a persistent state of estrogen deficiency. The cessation of menstruation and the range of symptoms that we associate with menopause are consequences of this underlying lack of estrogen.

Looking at menopause this way—as a deficiency of estrogen—you can see that menopause isn’t something that ends. Your hormonal life changes when menopause begins, but there is no end point at which you will be beyond estrogen deficiency. For this reason, I never talk about patients being “postmenopausal.” Women experience menopause and declining estrogen differently. Overall, early menopause involves larger and more frequent fluctuations and stronger reactions to estrogen deprivation, with more pronounced symptoms. As menopause progresses, some outward symptoms may quiet and recede—but the gradual dwindling of estrogen continues.

Let’s take a look at the phases of menopause and how estrogen behaves during each phase. It’s important to identify where you are in menopause when you’re working with your physician to design a bioidentical hormone replacement regimen that fits your individual needs. And remember, you experience the phases of estrogen in your own way, depending on your own particular hormonal identity. Many physicians refuse to prescribe estrogen until complete menopause; this is a mistake, causing many women to suffer unnecessarily for years. (See chapter 6 to take steps to understand your individual hormonal profile.) A significant factor in how you become menopausal is how much estrogen your body has produced throughout the course of your life since puberty. Other factors include how regular or irregular your cycle has been, if you experienced PMS, and how much you bled or didn’t bleed. Don’t be alarmed if your experience doesn’t exactly match the following, somewhat typical, descriptions. Variations are natural.

EARLY MENOPAUSE

Also known as early-onset menopause, this phase comprises approximately the first three years of menopause. By this point, women have stopped menstruating. Estrogen levels are still capable of frequent and strong fluctuations, but these rises and falls are less dramatic than they were during perimenopause. Because estrogen levels overall have declined significantly in early menopause, the symptoms of estrogen deficiency can be severe.

MID-MENOPAUSE

The next five years of menopause are considered mid-menopause. At this point, the body has been producing estrogen levels that are for the most part consistently low, with occasional fluctuations. Many women during mid-menopause experience fewer hot flashes and night sweats, symptoms associated with estrogen deficiency. This quieting of symptoms can lead women to believe they have moved beyond menopause, which doesn’t happen. In mid-menopause, women continue to experience the effects of estrogen deficiency, even as their bodies and minds make adjustments to cope with the symptoms. But their underlying estrogen deprivation remains, until or unless they are supplementing with bioidentical estrogen.

LATE MENOPAUSE

Most women over the age of fifty-eight have entered the late phase of menopause, which on average has been going on for at least ten years. Estrogen levels in this phase of menopause are low but constant, with virtually no fluctuation. Late menopause is the “phase” in which women will remain for the rest of their lives. Late menopause—or any stage of menopause—should not be equated with giving up or giving in to the effects of estrogen deficiency. This need not be a time for settling or learning to live with less—less energy, less sex, less mental and intellectual sharpness, less joy and fulfillment. Last year, Irene, a seventy-five-year-old patient of mine who had not been sexually active for twenty years, began to enjoy a new romance. She became sexually active with her new partner and even experienced an orgasm. The ability of the vagina lining to become lubricated can always be improved with HRT and supplements. Unfortunately, men’s plumbing issues—whether related to incontinence or sexual functioning—can’t be restored, but women are lucky!

Up until around age fifty-eight—most women after fifty-eight can no longer produce estrogen—adult women who have low estrogen can benefit from bioidentical estrogen, tailored to meet their individual hormonal needs. This is true for young women, for women in the throes of perimenopausal estrogen decline, and for women who have been in menopause for many years. As I tell my patients, what’s good for women at twenty is still good for them at seventy! If you think you might be estrogen deficient, keep in mind that getting such HRT can help bone to regrow and help improve skin health. Receiving bioidentical HRT can also wake up the vagina, which will enhance your ability to experience sexual pleasure.

The Problems with Excessive Estrogen

Though excess estrogen rarely occurs on its own, in today’s world, our bodies are assaulted by an array of toxic chemicals that permeate our environment and appear in the food we eat, the water we drink, the air we breathe, and the products we use in our homes and workplaces. Many chemicals, once inside the body, mimic the functions and effects of estrogen and raise risks of developing breast cancer and other cancers. Known as xenoestrogens, these chemicals affect girls and even babies in the womb, and this early-in-life exposure to toxins and chemicals increases the risk of breast cancer throughout their lifetime. These estrogenic chemicals also wreak havoc on women’s bodies. In addition, excess estrogen is frequently and inaccurately used by practitioners as a marker to determine how much estrogen a woman needs; often resulting in women receiving a sub-optimal amount.

Xenoestrogens are found in numerous products, from shampoo and deodorant to canned goods and plastic containers. Xenoestrogens wreak havoc with natural hormone levels, trigger inflammation throughout the body, damage genes, and distort gene function—all of which also raises the risk for cancers. Some of the chemicals most abundantly present in the environment that are associated with breast cancer risk include the following:

Dioxins. Dioxins are a group of highly toxic chemicals that act as xenoestrogens and specifically affect hormonal health. By-products of a wide range of manufacturing processes, including smelting, chlorine bleaching of paper pulp, and the manufacturing of some herbicides and pesticides, dioxins are released into the environment, with the highest levels of these compounds found in some soils, sediments, and food, especially nonorganic dairy products, meat, fish, and shellfish. They are among the “dirty dozen,” a list of the most dangerous and widespread persistent organic pollutants, or POPs, we are unwittingly exposed to through the foods we eat. Dioxins have long been identified as a serious health hazard, and efforts to reduce their levels in food and at large have been under way for years. Federal restrictions on dioxin production limit the amount of the chemical that can be generated, and screenings exist for dioxin levels in food, both within the United States and outside it. But dioxins, like other POPs, don’t just disappear—they remain lodged in the cells and tissues of plants and animals, in the water, and in the air. Because of so many years of accumulated dioxins, exposure to this group of toxins remains widespread and, to a real degree, unavoidable.

  • Dioxin is a xenoestrogen; it functions like estrogen in the body, disrupting hormone balance and raising risks for cancer.
  • Dioxin raises risks for cancers in the general population.
  • Dioxin elevates the risk for breast cancer and other cancers.
  • Dioxin exposure in utero affects that unborn child’s risk for breast cancer throughout her lifetime.
  • Dioxin exposure can cause reproductive problems and fertility issues.
  • Dioxin damages the immune system.
  • Dioxin exposure is especially harmful in people who eat high-fat diets.

BPA (bisphenol A). BPA is found in plastics and epoxy resins used to coat metal, including cans for food. Humans are widely exposed to BPA in food, in water and air, and through everyday products found at home and work. This toxin is also found in many consumer plastics, including cans for food, plastic food storage bags, plastic utensils for eating and drinking, water bottles, other plastic containers such as CD or DVD cases, and electronic equipment. Work has been done in recent years to remove BPA from consumer products, and it’s common now to see plastics and cans used for consumer products, including food products and products for children and babies, labeled BPA-free. We must ask ourselves, however, whether what’s being used in place of BPA is truly safer (see below on BBPs). Like other persistent organic pollutants, BPA cannot simply be removed from circulation; this dangerous xenoestrogen remains throughout the environment—in our water supplies and in our food chain.

  • BPA is a xenoestrogen, and exposure to this toxin—especially during youth—raises risks for breast cancer and other cancers.
  • BPA triggers changes to normal cell growth and alters apoptosis (orderly cell death), increasing cancer risk.
  • BPA is linked to cardiovascular problems in men and women.
  • BPA elevates risks for cancers, diabetes, cognitive dysfunction, and asthma.

BBP (benzyl butyl phthalate). This chemical, used in plastics manufacturing, is another xenoestrogen to which humans are broadly exposed. Significantly disruptive not only to estrogen but also to testosterone, BBP and other phthalates are found in vinyl, PVC, and plastics used in commercial and consumer products. Exposure to BBP comes through food and water sources, as well as through direct contact with plastics. BBP exposure in utero is linked to elevated lifetime breast cancer risk. Exposure during a woman’s lifetime also raises her risk.

  • BBP spurs the growth of breast cancer cells.
  • Exposure to BBP in utero leads to changes in gene expression that make a woman more vulnerable to breast cancer (and other cancers) throughout her lifetime.
  • BBP increases incidence of polycystic ovary syndrome (PCOS)
  • BBP contributes to fertility problems in men and women.
  • BBP is linked to developmental delays in children.
  • BBP may contribute to obesity.
  • BBP triggers, aggravates, and causes asthma.

DDT (dichlorodiphenyltricholoroethane). Another of the dirty dozen POPs, DDT is a pesticide that was widely used in commercial and industrial agriculture before its ban in the United States in 1972. But it persists in the environment and is still used in other parts of the world, primarily to kill mosquitoes that spread disease.

  • DDT exposure at a young age dramatically increases a woman’s risk for breast cancer throughout her lifetime.
  • Maternal exposure to DDT is highly predictive of daughters’ breast cancer, raising this next generation’s breast cancer risk by 370 percent.
  • DDT may contribute to other cancers.
  • DDT contributes to fertility and reproductive problems.
  • DDT can damage the nervous system.

PAH (polycyclic aromatic hydrocarbons). PAH are chemicals produced from burning fossil fuels and the burning of other substances, including wood, garbage, and tobacco. Cigarette smoke contains high levels of PAH. PAH are absorbed by the human body through air, food, and water. Many PAH are xenoestrogens.

  • Early-in-life exposure to PAH elevates risk of breast cancer throughout a woman’s lifetime.
  • A woman’s PAH exposure at the time of her first pregnancy may affect her risk of breast cancer later in life, after she has transitioned to menopause.
  • PAH elevate risks for other cancers in women and in men.
  • PAH contribute to disorders and diseases of lungs, gastrointestinal system, kidneys, and skin.

Ethanol. Ethanol is touted as a “green” alternative to gasoline and is often used as an additive to it. Scientists have found that ethanol and its by-products create ground-level ozone pollution, adding toxicity to our air and water. Exposure to ethanol raises risks for breast cancer.

Aluminum. This abundant metal is used widely in commercial, industrial, and consumer activities, production, and products. Aluminum is also a common ingredient in personal care products, including deodorants, makeup, toothpaste, and sunscreen, as well as in medications such as antacids and some aspirins. Aluminum is sometimes used as an additive to food.

A hormone- and estrogen-disrupting metal, aluminum exposure is linked to

  • Neurodegenerative disease, including Alzheimer’s disease
  • Nervous system damage
  • Alterations to DNA
  • Cancers, including breast cancer

Cadmium. This heavy metal is created as a by-product of industrial production and the burning of fossil fuels. It is also released in tobacco smoke. Cadmium is a widespread contaminant in soil and water and so makes its way into our food. Cadmium is used in chemical fertilizers, chemical dyes, plastics, and batteries. A hormone disruptor, cadmium exposure results in imbalance to estrogen and overall hormone balance.

  • Chronic exposure to cadmium has been shown to elevate breast cancer risk.
  • Cadmium exposure can be damaging to kidneys and kidney function.
  • Exposure to cadmium can cause lung disease.
  • Cadmium is associated with cardiovascular disease risk.
  • Cadmium contributes to developmental defects.

Endocrine-disrupting chemicals can be found anywhere in your home—from the laundry room and kitchen to the bathroom, living room, and bedroom. Essentially, any piece of furniture, rug or carpet, cosmetic, or cleaning product can contain a dangerous chemical. Absorbed into the body through air, water, and food, as well as direct contact with chemicals and the products they generate, environmental toxins gather and lodge in fatty tissues, like the tissue of the breast. A toxic environment poses profound health hazards that our preindustrial ancestors did not face. Science and medicine have barely begun to understand these modern problems, and of the tens of thousands of chemicals found in consumer and industrial products, very few have been subjected to rigorous scientific study. We know very little about the chemical toxins that surround us, but one thing we do know: cancer rates have soared alongside the industrial and technological development of the last century. We also know that you can take proactive steps to protect yourself and your family. First, make it a habit to look at the labels of all household, cosmetic, and personal health products you consider purchasing. Many times, the chemicals or their derivatives are identified. Safe products are typically labeled as such with language such as “Non-GMO” or “No parabens or other harmful chemicals.” In my experience, the Environmental Working Group (EWG) is a reliable source for learning more about individual chemicals as well as safer products you can use on your body and in your home.

The youngest and the eldest among us are more vulnerable to these chemicals because their immune systems are not as strong or protective. In some cases, metals, for instance, can be removed from the body. In other cases, you can take steps to “detoxify” your body and lessen or remove the chemicals that have accumulated. A very first step is to reduce exposure; then the body will naturally and automatically use its own detox strategies to get rid of foreign agents—through sweat, excretion, and sleep.

Environmental Hazards

Chemical toxins elevate the risk for breast and other cancers through several different pathways:

Oxidative stress. The process of oxidative stress in the body generates free radicals. These are molecules broken away from whole, stable cells that damage tissues and healthy cells and promote the initial development and growth of cancer cells.

Inflammation. Environmental toxins can trigger unhealthy levels of inflammation in the body. The presence of inflammation promotes aromatization—the conversion of testosterone to estrogen in the breast, which elevates risk for breast cancer. Inflammation increases the aggressiveness of breast cancer, and the likelihood of metastasis, as well as the risks for other cancers and disease.

Damage to DNA and genetic function. Many of the chemicals we are exposed to are genotoxic, which means they directly affect genes and DNA. The accumulation of chemicals in breast tissue and other tissues of the body causes damage to genes and to their ideal, intended function and expression. Mutations and alterations to normal gene structure and function lead to disease, including breast cancer.

Hormone disruption. Many environmental chemicals and toxins disrupt endocrine function, upending the delicate balance of hormones in the body. A great many of the most toxic and widespread chemicals found in our environment are xenoestrogens, chemicals that can both mimic and disrupt estrogen when absorbed into the body, leading to estrogen imbalance and elevating risks for breast cancer, metabolic disorders, cardiovascular problems, cognitive decline, and a broad range of illness and disease.

Women Vary

Just as a woman’s estrogen levels fluctuate throughout each month and over the course of her lifetime, every woman’s estrogen “identity” is different—both in the patterns of estrogen’s rise and fall and in how much estrogen her body naturally produces. Consider the situation of fifty-two-year-old fraternal twin sisters whom I treat. Mary, a mother of three teenage daughters, is five foot five and athletic and has thick brown and gray hair. She has fairly high muscle mass, experiences severe PMS, and bleeds heavily and regularly every month. Her sister Megan is five foot four, slightly built, and weighs twenty pounds less than her sister. Megan no longer gets her period (she went into menopause at forty-nine) and has never given birth.

Although the two women resemble each other, they have markedly different hormonal identities, due to many factors, most important of which are their differing levels of estrogen, progesterone, and testosterone. Mary has high levels of testosterone, very low levels of progesterone, and uneven estrogen levels—in other words, they vary throughout the month. Megan is low in all three hormones, in part because she never got pregnant and has a slight build. (It’s also important to note that testosterone levels are often inaccurate, as this hormone can exist intra-cellularly as well.)

Although Mary and Megan share a tremendous amount of DNA and were raised in the same household, their life experiences (pregnancy versus no pregnancy) set them apart, as do their body types. The fact that Megan is in menopause and Mary is not (she is in perimenopause, four to eight years prior to the cessation of menstruation) is probably the biggest marker setting the twins’ health profiles apart. Megan’s hormonal levels are lower than those of her sister, who is still menstruating. Neither woman is less or more healthy than the other—they just need different amounts and combinations of hormonal supplements.

Women’s bodies naturally produce different levels of estrogen. Some women naturally produce high levels of estrogen, while others produce barely a sufficient amount to enable fertility. Women who have high levels of estrogen are typically short in stature, full breasted, and curvy. Women who naturally produce less estrogen tend to be tall, thin, and small breasted. Estrogen speeds up development and maturation, which includes helping bones to “close,” which in turn signals the body to stop growing. The great majority of women fall somewhere in between these highest and lowest estrogen producers. However, how consistently a woman produces estrogen over the course of her life, especially during her main reproductive years, reflects and predicts her body’s ability to protect itself from degeneration. In general, women who make sufficient estrogen, live a healthy lifestyle, and stay away from environmental toxins that interfere with hormonal balance will be in a better position to protect their overall health and well-being.

So how do you know what is a sufficient amount of estrogen for your health? It’s very difficult to define a “normal” hormone level for any one woman, because what is a so-called normal or healthy amount for one woman is not right for another. Patients and doctors all need to be aware of this essential variation so that, once you begin a regimen, you can continue to talk to your physician about your symptoms—which ones have resolved and which are persistent—and have the physician adjust your dose to the amount that works best for you. For instance, many doctors insist that a level of 50 picograms (pg/ML) is “enough,” despite the variation in individuals’ blood hormone levels. Often this is the amount delivered by an estrogen patch, which is minimally efficient and effective.

However, in my experience 50 pg/ML is not at all sufficient for most women. Doctors used to be mainly concerned about night sweats, which is how they originally came up with 50 pg/ML as a sufficient level. However, if a woman has always shown a blood level over 200 pg/ML, receiving only 50 pg/ML once she is in menopause will not be nearly sufficient to solve her mood, sleep, or fatigue issues or let her feel like herself again. All these numbers and measurements will make more sense after you read the successive chapters and begin to assemble your own hormonal profile.

Even though each woman experiences the ebb and flow of estrogen differently, there are common symptoms that indicate when you are in a state of high estrogen or low estrogen. Learning to recognize these symptoms can help you better weather hormonal shifts and help you anticipate and manage symptoms amid your daily life. You can develop a sense of what to expect physically, mentally, and emotionally rather than feeling broadsided by fatigue, irritability, or memory problems. Understanding when and why these and other symptoms occur makes them much easier to deal with—and allows you to make decisions about whether, and when, to use supplemental estrogen and other hormones.

There is no more valuable information than your understanding and awareness of your own body—how you feel, under what conditions you function at your best, and how you respond to changes in your estrogen levels. These are the truest guides to health and wellness as you age. The most important insights—about estrogen, and more broadly about hormone balance—can’t be read on a chart or gleaned from a lab result. They come from you, your deep capacity for self-awareness, and your thoughtful attention to your mental and physical feelings.

Clearing the Air: The Difference Between Chemical and Bioidentical Hormones

For too long, bioidentical hormones—estrogen and others—have been lumped together with chemicalized (or synthetic) hormones and have been regarded as essentially the same, with the same risks and benefits. However, bioidentical hormones have far fewer risks than synthetics do. By and large, physicians recommending HRT default to prescribing chemicalized estrogen and progesterone supplements because they are easier to access, are more often covered by insurance, and remain part of our culture’s outsize trust in big pharma. I believe that the benefits of using bioidentical hormones far outweigh their downsides—namely, inconvenience, since obtaining them requires that you see a health practitioner who works individually with a compounding pharmacy. Of course, this decision is up to you—at the end of the day, I’d prefer that you receive some supplementation to none.

All bioidentical hormones are created through an enzymatic process that takes specific molecules in plants, such as organic yams and soy, and makes the hormone identical in structure to the hormones created by the human body. Down to the molecule, bioidentical estrogen is the same as human estrogen. For this reason, I believe that bioidentical estrogen is a safer, effective way to replace diminishing estrogen levels as you age and move through perimenopause and menopause.

On the other hand, chemicalized estrogen is the synthetic or chemicalized estrogen in medications, such as Premarin and Provera, often prescribed by physicians who do not use bioidenticals. Pharmaceutical corporations generate the vast majority of estrogen that women use in hormone replacement therapy. The estrogens made by pharmaceutical manufacturers from animal and plant sources are synthesized to their own proprietary, patented versions of estrogen—which, of course, is the key to their profitability. Many chemicalized estrogen substitutes are what’s known as conjugated equine estrogens, or CEEs. To my knowledge, there is no scientific basis for preferring estrogen supplements for women that are created from horse urine. Horse urine contains several different estrogens (twelve, to be exact), and all but one are biochemically distinct from a human female’s estrogen. Horse urine is used, it appears, out of ease and economy. Horses have long gestation periods and large bladders, and they can be constantly catheterized to draw urine that winds up in medication used by millions of women each year. Most women have no idea where their estrogen comes from or what animals go through for them to get it. I believe that these CEEs are inferior estrogen that may actually cause harm to the women they purport to help.

Other, newer forms of chemicalized estrogen are synthesized from plants, primarily from soy. That might sound like a step in the right direction, but the final estrogen compounds made from these plant sources are synthesized to be biochemical matches to the CEEs of earlier generations, not to a woman’s own estrogen. This approach may protect the proprietary nature of the product, but it does nothing advantageous for women who need estrogen that matches their own. Nevertheless, these plant-derived estrogens are marketed as “natural,” despite the fact that they’re closer biochemically to the natural estrogen of a horse than that of a woman.

Chemicalized estrogens often use a version of only one of the three estrogen compounds—estradiol, E2, the strongest of the estrogens found naturally in women. Estradiol delivers powerful benefits, but those benefits are maximized—and its risks minimized—when E2 exists in balance with estriol. That’s how a woman’s body uses estrogen, and there is no superior model. By using E2 only, women are missing out on the benefits conferred by other estrogen compounds, particularly the potent health protections that E3 delivers.

The pharmaceutical companies and their supporters want you to believe all hormone replacement is the same, that the risks associated with chemicalized estrogen are risks that extend to bioidentical estrogen as well. In my experience, this is simply not true.

A Reminder: Always Pair Estrogen with Progesterone

No estrogen—chemicalized or bioidentical—is safe to use on its own for long-term hormone replacement. The balance that progesterone provides to estrogen is critical. Without progesterone—or, unbalanced by progesterone—estrogen over time will increase the likelihood of developing uterine cancer. To be used safely, supplemental estrogen must be accompanied by progesterone.

The Benefits and Safety of Bioidentical Hormones

I believe that bioidentical hormones are safe and beneficial for women who are suffering from a loss of estrogen. I know this from the testimony and medical results of thousands of patients. As my patient Irene told me, “I feel so good now. I finally sleep at night. I no longer need three glasses of wine to destress. And my vagina feels like celebrating.” Theresa, who’d been reluctant to commit to HRT treatment, said, after three months of taking it, “I know this is working. I feel so good, so healthy.”

I can go on and on sharing success stories from my patients. Yes, my happy, healthy patients are proof of both the benefits and the safety of bioidentical HRT. The growing collection of peer-reviewed research studies also points to its efficacy and safety. In one large, significant study (called the E3N cohort study) of more than fifty thousand Frenchwomen, researchers compared different groups of women over an eight-year period: women who were not using any form of HRT, women who were using chemicalized progestin, and those who were using bioidentical progesterone. The group using the chemical HRT showed an increase in breast cancer, whereas those women who used bioidentical HRT had a 10 percent decrease in breast cancer. The researchers then tested the use of estrogen plus progesterone, in both chemical and bioidentical forms. The same relative results were found. The most startling finding, however, was that women who used no hormones at all experienced a sixfold higher incidence of breast cancer compared with the women who received bioidentical hormone treatment, emphasizing again that it’s better to take some HRT than none at all.

The research is solid and ever growing: bioidentical estrogen and other bioidentical hormones have not been shown to increase risks for breast cancer—and researchers have actually seen evidence that they decrease risk for the disease. Bioidentical hormones can help to protect heart health, not jeopardize it.

Bioidentical hormones are my standard for “natural” hormone replacement therapy. I wish they were the pharmaceutical industry standard, too, but they are not. The big drug manufacturers do not appear to be set up to produce or profit from bioidentical hormones. Although there are a few brand-name bioidentical supplements on the market, such as Vivelle, Estrace, or Alora, I do not believe that these pharmaceutical products contain all types of estrogen a woman needs. Typically they contain estradiol but not estriol (used to balance the effect of estradiol). The patches that are offered don’t meet the minimum amount of hormone for proper absorption; in other words, no one prescription product will deliver all the estrogen that you need.

Of course, you need to know your own hormonal profile and learn how to help your health care provider determine your specific hormonal and supplement needs. I will cover that in chapter 6. The “right” dosage is always about what you require as an individual; a one-size-fits-all approach will rarely if ever meet your specific needs.

YOUR HEALTH JOURNAL

As you become more familiar with the factors underlying your hormonal health, it’s crucial that you pay attention to yourself, to your moods and physical symptoms. I recommend keeping an almost daily record. This can be in a journal, a notes section on your smartphone, an audio recording—whatever works for you. Think of your journal as a place where you can record your thoughts and feelings, questions you might have, and any notes about yourself. I encourage all my patients to keep this kind of log so they can begin to cue in to their bodies and moods; patterns will begin to emerge over the course of a month or so. These records will become a vital source of information when you connect with a physician for treatment.

Take some time to reflect on where you are now by responding to the following questions.

  • If you are still getting your period, is it regular or erratic?
  • Do you notice an increased interest in sex at time of ovulation?
  • Do you notice a lull right before you bleed?
  • If you no longer get your period, when did it stop?
  • Are you experiencing night sweats?
  • Are you experiencing hot flashes during the day?
  • Are you more irritable or anxious than usual, or have these feelings become your new normal?
  • Has your sleep pattern changed? Is your sleep disrupted? If so, how?

Next, review signs of estrogen deficiency and excessive estrogen and note in your journal any that may apply to you.

Signs of Estrogen Deficiency

Mental fogginess

Forgetfulness

Difficulty staying focused

Depression

Anxiety

Mood swings

Difficulty falling asleep

Waking up in the middle of the night and inability to go back to sleep

Hot flashes

Night sweats

Temperature swings

Extreme fatigue

Reduced energy or stamina

Decreased interest in sex

Dry eyes

Dry skin

Dry vagina

Erratic monthly cycle

Sagging breasts

Pain with sex

Weight gain, especially around the middle

Increase in joint pain—knees and hips especially

Increase in headaches

Episodes of rapid heartbeat

Frequent bloating

Feeling invisible

Signs of Excess Estrogen

Breast tenderness or pain, especially around the nipple

Increase in breast size

Water retention (edema in fingers and ankles)

Pelvic cramps

Nausea

Cold hands and feet

Weight gain

Change to your monthly cycle (more frequent bleeding)

Keep in mind that these symptoms can have multiple causes, not all related to estrogen or other hormonal deficiency. However, as a general, easy rule to follow, start by understanding your own estrogen levels. If you are deficient, then you know these symptoms have a hormonal component.