Premenstrual Syndrome (PMS) is a recurrent condition of women, characterized by troublesome symptoms seven to fourteen days before menstruation.¹ Typical symptoms include: decreased energy level, tension, irritability, depression, headache, altered sex drive, breast pain, backache, abdominal bloating, and edema of the fingers and ankles. PMS is estimated to affect between thirty and forty percent of menstruating women, with peak occurrences among women in their thirties and forties. In most cases, symptoms are relatively mild. However, in about ten percent of all women, symptoms can be quite severe. Severe PMS, with depression, irritability, and extreme mood swings, is referred to as premenstrual dysphoric disorder.

Although PMS has been a well-defined clinical entity for over sixty years, many physicians still argue that it really does not exist.³ As a result, many women who suffer from PMS do not receive proper treatment. Instead, they are told that it is "all in your head." This view is gaining momentum, as large pharmaceutical companies have recognized the huge market potential. These companies have sponsored clinical trials using drugs to treat PMS symptoms (e.g., antidepressant drugs such as Prozac and Zoloft, anti-anxiety drugs related to Valium, and gonadotropin-releasing hormone), despite the fact that risks due to side effects appear to far outweigh the benefits.⁴

A more rational approach to the problem of PMS is identification of the causative factors and appropriate treatment using dietary therapy, nutritional supplementation, and exercise.

The Normal Menstrual Cycle

In order to appreciate the hormonal abnormalities that have been found in some women with PMS, it is important to briefly review the normal menstrual cycle. the menstrual cycle reflects the monthly rhythmic changes in the secretion rates of the female hormones and corresponding changes in the lining of the uterus and other female organs.

The menstrual cycle is controlled by the complex interactions of the hypothalamus, pituitary, and ovaries. Each month during the reproductive years, the secretion of various hormones is designed to accomplish two primary goals: (1) ensure that only a single egg is released by the ovaries each month, and (2) prepare the lining of the uterus (the endometrium) for implantation of the fertilized egg. To accomplish these goals, the concentrations of the primary female sexual hormones, estrogen and progesterone, fluctuate during the menstrual cycle.

The control center for the female hormonal system is the hypothalamus, a region of the brain roughly the size of a cherry, situated above the pituitary gland and below another area of the brain called the thalamus. The hypothalamus and pituitary gland are housed in the middle of the head just behind the eyes. The hypothalamus controls the female hormonal system by releasing hormones, such as gonadotropin-releasing hormone (GnRH) and follicle-stimulating-hormone-releasing hormone (FSH-RH), which stimulate the release of pituitary hormones.

In response to the hypothalamus, the pituitary gland releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH is the hormone primarily responsible for the maturation of the egg (ovum) during the first phase of the menstrual cycle. It is called "follicle-stimulating hormone" because each egg within the ovary is housed inside an individual follicle. LH is responsible for initiating ovulation—the release of the fully developed egg.

The release of LH is triggered by increased estrogen levels as a result of the growing follicle. After ovulation, the eggless follicle is transformed into the corpus luteum,which functions primarily to secrete progesterone and estrogen to help a fertilized egg become well-established in the uterine lining. If fertilization does not occur, the corpus luteum recedes, hormone production menstruation occurs approximately two weeks later, and the entire menstruation process begins anew.

The usual menstrual cycle is completed in about a month. It is divided into three phases, in order of occurrence: follicular, ovulatory, and luteal. The follicular phase lasts for ten to fourteen days, the ovulatory phase lasts for about thirty-six hours and involves the release of the egg, and the luteal phase lasts for fourteen days.

Other Hormones

Because of the complex interrelationships among the components of the endocrine system, disorder of any if the individual members of the system (pituitary, ovaries, adrenals, thyroid, parathyroids, and pancreas) can lead to menstrual abnormalities and/or PMS. For example, low thyroid function (hypothyroidism) and elevated cortisol (an adrenal hormone) levels are common in women with PMS.

Prolactin, another hormone produced by the pituitary, also plays an important role in PMS and female infertility. Prolactin's chief function is to regulate the development of the mammory gland and milk secretion during and after pregnancy. Increased production of prolactin in lactating women can inhibit the maturation of the follicles in the ovaries. In nonlactating women, elevated levels of prolactin are often linked to cases of PMS, menstrual abnormalities, absence of ovulation, ovarian cysts, and breast tenderness.

Hormonal Patterns in Women with PMS

Although there is a wide spectrum of symptoms, there are common hormonal patterns among PMS patients compared to women who have no symptoms of PMS. The primary finding is that estrogen levels are elevated and plasma progesterone levels are reduced five to ten days before menses, or the ratio of estrogen to progesterone is increased. In addition to this hormonal abnormality, hypothyroidism and/or elevated prolactin levels are common, FSH levels are typically elevated six to nine days prior the onset of menses, and aldosterone (a hormone produced by the adrenal glands that leads to sodium and water retention) levels are marginally elevated two to eight days prior the onset of menses.^1,5,6

Corpus Luteum Insufficiency and PMS

PMS symptoms occur during the luteal phase of the menstrual cycle. This phase signifies the important role that the corpus luteum plays in the production of primarily of progesterone, but also of estrogen. Many researchers theorize that PMS reflects corpus luteum insufficiency. Corpus luteum insufficiency is usually diagnosed by measuring the level of progesterone in the blood three weeks after onset of menstruation. If the level is below 10 to 12 ng/ml, corpus luteal insufficiency is a strong possibility.

In addition ot PMS, corpus luteal insufficiency has been linked to abnormal menstruation (excessive blood loss; absent, persistent, or more frequent menstruation), elevations in prolactin level, and low thyroid function.⁷

Diagnosis and Classification

Diagnosis of PMS is usually made by observation of the symptoms attributed to PMS and their occurrence during the luteal phase of the menstrual cycle. To aid in the diagnosis, symptom questionnaires are often used. Since recalled information loses accuracy, it is a good idea for women with PMS to begin keeping a menstrual symptom diary in addition to answering a symptom questionnaire. The diary will help document improvement and further clarify the symptom pattern. Both a questionnaire and diary are provided in this chapter.

PMS Classification

In an attempt to bring some order the clinically and metabolically confusing picture of PMS, several experts have created classification systems that sort PMS sufferers into subgroups.⁸ The system with which we have the most experience was developed by Dr. Guy Abraham; it divides PMS into four distinct subgroups.⁹ Each subgroup is linked to specific symptoms, hormonal patterns, and metabolic abnormalities. Following is a sample menstrual symptom questionnaire based on Dr. Abraham's classifications, followed by a brief discussion of the individual subgroups. Please note that women rarely experience a particular subgroup in a pure form; usually a woman with PMS experiences aspects of two or more subgroups.

PMS-A

PMS-C

PMS-C (C = carbohydrate craving) is associated with increased appetite, craving for sweets, headache, fatigue, fainting spells, and heart palpitations. Glucose tolerance tests (GTT) performed on PMS-C patients during the five to ten days before their menses show a flattening of the early part of the curve (which usually implies excessive secretion of insulin in response to sugar consumption), whereas during other parts of the menstrual cycle their GTT is normal.² Currently, there is no clear explanation for this phenomenon, although an increased cellular capacity to bind insulin has been postulated. This increased binding capacity for insulin appears to be hormonally regulated, but other factors may also be involved, such as a high salt intake or decreased magnesium or prostaglandin levels.

PMS-D

PMS-D (D = depression) is the least common type and is relatively rare in its pure form. Its key symptom is depression, which is usually associated with low levels of neurotransmitters in the central nervous system. In PMS-D patients, this is probably due to increased breakdown of the neurotransmitters as a result of decreased levels of estrogen (in contrast to PMS-A which shows the opposite results). The decreased ovarian estrogen output has been attributed to a stress-induced increase in adrenal androgen and/or progesterone secretion.

PMS-H

PMS-H (H = hyperhydration) is characterized by weight gain (greater than three pounds), abdominal bloating and discomfort, breast tenderness and congestion, and occasional swelling of the face, hands, and ankles. These symptoms are due to an increased fluid volume, secondary to an excess of the hormone aldosterone which causes an increased fluid retention. Aldosterone excess during the premenstrual phase of PMS-H patients may arise due to stress, estrogen excess, magnesium deficiency, or excess salt intake.

Estrogen and Progesterone in PMS

Estrogen Excess and Liver Function

In the early 1940's, Dr. Morton Biskind observed an apparent relationship between B vitamin deficiency and PMS.^15,16 He postulated that PMS, as well as excessive menstruation and fibrocystic breast disease, was due to an excess in estrogen levels caused by decreased detoxification and elimination in the liver due to B vitamin deficiency. The liver utilizes various B vitamins to detoxify estrogen and excrete it in the bile.

Cholestasis can be caused by a great number of factors besides estrogen excess (see DETOXIFICATION). Presence of cholestasis may be a predisposing factor PMS, as with cholestasis there is reduced estrogen detoxification and clearance. Hence, a positive feedback scenario is produced. It is obvious that many American women suffer from cholestasis. All one has to do is look at the tremendous frequency of gallstones.

Effects of Estrogen on Neurotransmitters

Another possible result of the increase in the estrogen-to-progesterone ratio is impairment of neurotransmitter synthesis and endorphin activity. Neurotransmitters are compounds that transmit the nerve impulse. A group of neurotransmitters know as monoamines are made from dietary amino acids—the building-block molecules of protein. For example, the amino acid tryptophan serves as the precursor to serotonin and melatonin, while phenylalanine and tyrosine are precursors to dopamine, epinephrine, and norepinephrine.

According to the dominant medical view, depression is characterized by imbalances of monoamines. In addition to estrogen-induced alterations, environmental, nutritional, psychological, and genetic factors can all lead to an imbalance in the monoamines, which might result in depression. Different antidepressant drugs act by increasing levels of different monoamines in the brain via blocking either the reuptake or the break-down, or enhancing the effect of, a specific monoamine.

Antidepressant drug therapy for PMS is gaining popularity among many M.D.s. However, there are other ways to address the alterations in neurotransmitters; chief among them is normalizing estrogen-to-progesterone ratios. It is interesting to note that the majority of the over twelve million patients who take Prozac are women between the ages of twenty-five and fifty—the same population that has a high frequency of PMS. Alternatives to Prozac and other antidepressant drugs are given in the chapter on DEPRESSION.

Estrogen Excess and Endorphin Levels

Estrogen excess during the luteal phase also negatively affects endorphin levels. Endorphins are the body's own mood-elevating and pain-relieving substances. One study found a direct correlation between an increased estrogen-to-progesterone ratio and endorphin activity in the brain.¹¹ In essence, when the estrogen-to-progesterone ratio was increased, there was a decline in endorphin levels. This reduction is significant, considering the known ability of endorphins to normalize or improve mood. Other studies have shown that low endorphin levels during the luteal phase are common among women with PMS.¹⁷ Endorphin levels are lowered by stress and raised by exercise. The role of endorphins is further discussed in Stress, Endorphins, and Exercise in PMS, later in this chapter.

Estrogen Impairs Vitamin B6 Function

The negative impact of estrogen excess on neurotransmitter and endorphin levels during the luteal phase may be secondary to impairment of vitamin B6 action. Vitamin B6 (pyridoxine) is extremely important B vitamin involved in the formation of body proteins and structural compounds, chemical transmitters in the nervous system, red blood ells, and hormone-like compounds known as prostaglandins. Vitamin B6 is critical to maintaining hormonal balance.

It is well known that estrogens negatively affect vitamin B6 function. Vitamin B6 levels are typically quite low in depressed patients, especially women taking estrogens (birth-control pills or Premarin).^18,19 Vitamin B6 supplementation has been shown to exert positive effects on all PMS symptoms (particularly depression) in many women. The improvement is achieved via a combined reduction in mid-luteal estrogen levels and increase in mid-luteal progesterone levels.

Estrogen's Effects on Aldosterone

As stated previously, aldosterone is a hormone produced by the adrenal glands that leads to retention of sodium and water. In many cases of PMS, aldosterone levels are marginally elevated two to eight days prior to the onset of menses. This elevation may be a result of estrogen excess increasing the secretion of aldosterone.

Estrogen and Prolaction Secretion

Excessive levels of prolactin are implicated in many cases of PMS, expecially in women experiencing breast pain or fibrocystic breast disease (discussed in FIBROCYSTIC BREAST DISEASE).^20,21 Estrogens, both internally produced and ingested as birth-control pills or Premarin, are known to increase prolactin secretion by the pituitary gland. Following the recommendations (given in the following section, entitled Reducing Estrogen-to-Progesterone Ratio) for lowering the luteal-phase estrogen-to-progesterone ratio may be all that is necessary to lower prolactin levels. In particular, the herb Vitex agnus-castus (chasteberry) may prove to be useful in cases of high prolactin levels due to corpus luteum insufficiency (discussed later in Herbal Recommendations for PMS). Vitamin B6 and zinc supplementation also lower prolactin levels and are discussed in subsequent sections of this chapter. Prolactin levels also tend to be elevated in cases of low thyroid function.

Estrogen Excess and Uterine Fibroids

Fibroid tumors are benign (nonmalignant) tumors that consist of uterine muscle cells. Fibroids are one of the most common type of tumor and are thought to be the result of estrogen excess. Most often, fibroids grow silently and cause no problems, especially if they are small. If a fibroid is large (the largest fibroid ever reported weighed an incredible 303 pounds!), it can lead to excessive menstruation (menorrhagia), pain, or inability to maintain a pregnancy. The treatment and prevention of uterine fibroids involves the same approach outlined in the next section for reducing the estrogen-to-progesterone ratio.

Reducing Estrogen-to-Progesterone Ratio

Central to effective treatment in most cases of PMS is lowering the luteal-phase estrogen-to-progesterone ratio. An elevation of this ratio may be the underlying factor in the hormonal, neurotransmitter, endorphin, and other physiological disturbances in most cases of PMS. Effective treatment usually involves the following steps:

Step 1: Follow These Dietary Recommendations A number of dietary factors are known to reduce circulating estrogen levels or block the attachment of estrogen to receptor sites. The primary dietary recommendations are:

- Increase consumption of plant foods (vegetables, fruits, legumes, whole grains, nuts, and seed)

- Consume small-to-moderate quantities of meat and dairy products

- Reduce fat and sugar intake

- Increase consumption of soy foods

In addition, it is important to reduce the load of environmental estrogens by avoiding foods sprayed with pesticides and herbicides.

Step 2: Establish Proper Gastrointestinal Flora One of the key ways in which the liver detoxifies cancer-causing chemicals, as well as the body's hormones such as estrogen, is by attaching glucuronic acid to the toxin and excreting it in the bile. Beta-glucuronidase is a bacterial enzyme that uncouples (breaks) the bond between excreted toxins and glucuronic acid. Not surprisingly, excess beta-glucuronidase activity is associated with an increased risk of getting cancer, particularly estrogen-dependent breast cancer, and presumably PMS.

The activity of this enzyme can be reduced by establishing proper bacertial flora.²² The dietary guidelines given in Step 1 go a long way toward this goal. In addition, initial supplementation with probiotics is recommended. Probiotics (literally translated, "for life") is a term used to signify the health-promoting benefits of "friendly bacteria." The most important friendly bacteria are Lactobacillus acidophilus and Bifidobacterium bifidum.

Step 3: Take the Recommended Nutritional Supplements Estrogen excess is known to increase nutritional needs for B vitamins, magnesium, an dpossibly other nutrients. B vitamins and magnesium are also necessary for the proper detoxification of estrogens. Recommended levels of supplementation are given in Micronutrients and PMS, later in this chapter.

Step 4: Enhance Liver detoxification Supporting liver function focuses on protecting th eliver by following the dietary guidelines listed in Step 1 and the nutritional supplement recommendations mentioned in Step 3. In addition, most naturopathic physicians use formulas that contain lipotropic factors. Lipotropic factors are substances that hasten the removal or decrease the depositition of fat and bile in the liver through their interaction with fat metabolism. In essence, they produce a "decongesting" effect on the liver and promote improved liver function and fat metabolism. Compounds commonly employed as lipotropic agents include choline, methionine, betaine, folic acid, and vitamin B12, along with herbal cholagogues and choleretics. Most major manufacturers of nutritional supplements offer lipotropic formulas. The important thing, when taking a lipotropic formula, is to take enough of the formula to provide a daily dose of 1,000 mg of choline and 500 mg of methionine and/or cysteine.

Step 5: Use Chasteberry or Phytoestrogen-Containing Formulas Chasteberry (Vitex agnus-castus) and phytoestrogen-containing herbs, such as dong quai, black cohosh, and licorice, are popular herbal recommendations for treating PMS. Their appropriate use is described later in this chapter, in Herbal Recommendations for PMS.

Step 6: Consider Progesterone Therapy You may be asking, "If one of the primary features of PMS for most women is an elevated estrogen-to-progesterone ratio, why not simply take progesterone?" Although progesterone administration is a popular recommendation by many physicians (M.D.s and N.D.s alike), we have some reservations. First of all, although progesterone administration has been the most common prescription for PMS by the medical community, controlled clinical trials have failed to consistently demonstrate the superiority of progesterone therapy over a placebo (there is a significant placebo response in PMS, by the way).^23-28

The studies that demonstrate a beneficial effect of progesterone therapy have used dosages that far exceed the normal levels for progesterone and for the estrogen-to-progesterone ratio (200 to 400 mg twice daily as a vaginal or rectal suppository, from fourteen days before the expected onset of menstruation until the onset of vaginal bleeding).^27,28 Side effects, although generally mind, are common. In one of the more recent double-blind studies that did show a positive effect of progesterone therapy (400 mg twice a day by vaginal or rectal administration), adverse events were reported by fifty-one percent of patients in the progesterone treatment group, compared to forty-three percent in the placebo group.²⁸ Irregularity of mentruation, vaginal itching, and headache were reported more frequently by the women who took the progesterone.

Secondly, philosophically we would rather help the body naturally improve the estrogen-to-progesterone ratio by addressing the underlying causative factors, such as reduced detoxification or clearance of estrogen, along with reduced corpus luteum function, rather than artificially and drastically tipping the ratio in favor or progesterone.

We do not recommend unsupervided use of progesterone creams as the first step in treating PMS, but rather as a possible last choice after other natural meansures have failed. Here are some guidelines if you elect to give progesterone-containing cream a try:

1. First, make sure that the level (in milligrams) of progesterone per dosage unit is provided so that you can calculate how much of the cream is required to achieve the high dosage required (200 to 400 mg applied twice daily into the vagina). A distinction must be made between prescription progesterone preparations and some over-the-counter progesterone-containing creams, including those misrepresented as "yam-concentrates." Mexican yam is a source of a compound known as diosgenin that can be converted in a laboratory environment to progesterone and to the hormone DHEA. There is no evidence that such a conversion occurs in the human body. Some companies label a progesterone-containing cream as a yam concentrate, as a marketing ploy, while other companies market a true yam concentrate without any significant levels of progesterone, yet promote it as providing the same benefit as a progesterone-containing cream. In both cases, these representations are wrong.

2. Apply the cream intravaginally; this is more effective than simply applying the cream to the skin. In fact, applying progesterone to the skin (nonmucous membranes) results in poor absorption.

3. Monitor your progesterone levels by ordering a saliva test for progesterone from Aeron Life Cycles Laboratories (800-631-7900) after one month of use, and adjust your dosage accordingly.

Low Thyroid Function and PMS

Low thyroid function (hypothyroidism) has been shown to affect a large percentage of women who have PMS.^29,30 For example, in one study published in the pretigious New England Journal of Medicine, fifty-one out of fity-four PMS subjects demonstrated low thyroid status compared to zero out of twelve in the control group.²⁹ In another study, it was seven out of ten in the PMS group and zero out of nine in the control group.³⁰ Other studies have also shown hypothyroidism to be only slightly more common in women with PMS than in controls.^31,32 Many women who have both PMS and confirmed hypothyroidism and who are given thyroid hormone experience complete relief of symptoms.²⁹ For more information, see HYPOTHYROIDISM.

Stress, Endorphins, and Exercise in PMS

Like many common conditions associated with "mondern" living, stress playes a role in PMS. When stress is extreme, unusual, or long-lasting, it triggers biological changes in the brain, largely as a result of altered adrenal gland function and endorphin secretion or action. These changes produce a domino effect that leads to alterations in normal physiology. Effective treatment of PMS must include stress management (see STRESS, STRESS MANAGEMENT, and ADRENAL SUPPORT).

Exercise and PMS

Several studies have shown that women who are engaged in a regular exercise program do not suffer from PMS nearly as often as sedentary women.^33-35 In one of the more thorough studies, mood and physical symptoms during the mentrual cycle were assessed in ninety-seven women who exercised regularly, and in a second group of 159 female nonexercisers.³³ Mood scores and physical symptoms assessed throughout the mentrual cycle revealed that exercise had signifiant effects on negative mood states and physical symptoms. The regular exercisers obtained significantly lower scores on impaired concentration, negative mood, behavior change, and pain.

In another study, 143 women were monitored for five days in each of the three phases of the cycle (mid-cycle, premenstrual, and menstrual).³⁴ The women were thirty-five competitive athletes, two groups of exercisers (thirty-three high exercisers and thirty-six low exercisers), and thirty-nine sedentary women. The high exercisers experienced the greatest positive-mood scores, and the sedentary women the least. The high exercisers also reported the least depression and anxiety. The differences were most apparent during the premenstrual and menstrual phases. These results are consistent with the belief that women who frequently exercise (but not competitive athletes) are protected from PMS symptoms. In particular, regular exercise protects against the deterioration of mood before and during menstruation.

Coping Style and PMS

Whether you are currently aware of it or not, you have a pattern for coping with stress. Unfortunately, most women with PMS tend to employ "negative" coping styles.³⁶ We term them negative because they ultimately do not support good health. If you are to be truly successful in coping with stress, negative coping patterns must be identified and replaced with positive ways of coping. Try to identify from the following list any negative or destructive coping patterns you may have developed:

- Feelings of helplessness

- Overeating

- Watching too much television

- Emotional outbursts

- Overspending

- Excessive behavior

- Dependence on chemicals

drugs, legal or illicit

alcohol

smoking

For some tips on ways to improve coping strategies, see A POSITIVE MENTAL ATTITUDE.

Psychotherapy

Various psychotherapy methods have been used successfully to improve the psychological aspects of PMS. In particular, psychotherapy in the form of biofeedback or short-term individual counseling (especially cognitive therapy, which is further discussed in the chapter DEPRESSION) have documented clinical efficacy.^37,38 One of the advantages of cognitive therapy in the treatment of PMS over antidepressant drug therapy is that learning techniques such as cognitive-behavioral coping skills can produce excellent results that will be maintained over time.

Depression, Low Serotonin Levels, and PMS

There are some important relationships between PMS and depression. Depression is a common feature in many cases of PMS, and PMS symptoms are typically more severe in depressed women.¹ ^The cause appears to be a decrease in the brain level of various neurotransmitters, with serotonin and gamma-amino-butyric acid (GABA) being the most significant.^39-41 Use of antidepressant drugs such as Prozac is quickly becoming the dominant medical treatment for PMS.¹ As stated previously, eight percent of the twelve million Americans taking Prozan are women between the ages of twenty-five and fifty-the age range with the highest frequency of PMS.

Diet and PMS

Women who suffer from PMS typically have a diet that is even worse than the standard American diet. Guy Abraham, M.D., reports that, compared to symptom-free women, PMS patients consume:62 percent more refined carbohydrates, 275 percent more refined sugar, 79 percent more dairy products, 78 percent more sodium, 53 percent less iron, 77 percent less manganese, and 52 percent less zinc.⁹

In addition to providing benefits in treating PMS symptoms, the following dietary recommendations provide significant protection against the development of breast cancer, other cancers, heart disease, strokes, osteoporosis, diabetes, and virtually every other chronic degenerative disease.

The seven most important dietary recommendations for relieving PMS are:

1. Follow a vegetarian or predominantly vegetarian diet

2. Reduce your intake of fat

3. Eliminate sugar intake

4. Reduce dietary exposure to environmental estrogens

5. Increase your intake of soy foods

6. Eliminate caffeine consumption

7. Keep your salt intake low

Vegetarian Diet and Estrogen Metabolism

Vegetarian women have been shown to excrete two to three times more estrogen in their feces and have fifty-percent-lower levels of free estrogen in their blood than omnivores.^43,43 These differences are thought to be a result of the lower fat and higher fiber intake of the vegetarian women. These dietary differences also may explain the lower incidence of breat cancer, heart disease, and menopausal symptoms in vegetarian women.

At the very least, eat less saturated fat and cholesterol by reducing or eliminating the amounts of animal products in your diet, and increase consumption of fiber-rich plant foods (fruits, vegetables, grains, and legumes). Limit intake of animal protein sources to 4 to 6 ounces per day, and choose fish, skinless poultry, and lean cuts rather than fatladen meats.

It appears that many of the effects of a vegetarian diet on lowering circulating estrogen levels are related to a higher intake of dietary fiber. The fiber promotes the excretion of estrogens directly and indirectly by promoting a more favorable bacterial flora with lower levels of beta-glucuronidase activity.