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From the Townsend Letter for Doctors & Patients
December 2004



Women's Health Update
by Tori Hudson, N.D.

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Four Major Health Problems in Women

Depression in Women
Unipolar major depression is the most common psychiatric condition seen by primary care physicians, and most epidemiologic studies have shown that it is more prevalent in women than in men. Depressive disorders affect approximately 20 million American adults each year. They will affect one in eight individuals over the course of a lifetime, and are twice as common in women as in men. Depressive disorders can begin at any age, but they most commonly begin in the 20s and 30s. In this country, depression is diagnosed in two women for every man, on average.

(Blazer DG, Kessler RC, McGonagle KA, Swartz MS. The prevalence and distribution of major depression in a national community sample: the National Comorbidity Survey. Am J Psychiatry. 1994; 151: 979-986.) (Weissman MM, Olfson M. Depression in women: implications for healthcare research. Science. 1995; 269: 799-801.) (Weissman MM, Bland R, Joyce PR, Newman S, Wells JE, Wittchen H-U. Sex differences in rates of depression: cross-national perspectives. J Affect Disord. 1993; 29: 77-84.)

The sexual difference in rates of depressive disorders is not apparent in childhood but is evident by the age of 12 and is well established by the age of 15. The reason for this gender difference is not so clear. Some attribute the differences to women in our society having higher rates of victimization, role conflicts, internalization of stress, and a greater tendency toward low self-esteem. Others counter that it has its basis in neurobiologic and endocrinologic differences. Both schools of thought are probably at work, and we know that there are periods of hormonal change that tend to coincide with particularly vulnerable times for the occurrence of depressive disorders such as adolescence, premenstrual, pregnancy, postpartum, miscarriage, perimenopause and postmenopause.

1. Psychotherapy
Both interpersonal therapy and cognitive/behavioral therapy are effective against depression, although women with severe depression may not respond as well as men to cognitive-behavioral therapy.

2. Lifestyle changes
Cigarette smoking can be a significant factor in depression. Smokers have more symptoms of anxiety and depression than nonsmokers. Major depressive disorders are more common among smokers than nonsmokers. Conversely, for some susceptible women, nicotine functions as an antidepressant and nicotine withdrawal can produce depressive symptoms. Several studies have explored the connection between caffeine intake and depression. (Gilliand K and Bullick W. Caffeine: A potential drug of abuse. Adv Alcohol Subst Abuse 3:53-73, 1984.) People prone to depressive moods or anxiety states tend to be especially sensitive to caffeine.

Many studies have clearly indicated that exercise has significant antidepressive effects. There have been at least 100 studies where an exercise program has been used to treat depression. In an analysis of the 64 studies done prior to 1980, exercise was shown to relieve depression and improve self-esteem and work habits. (Folkins CH, Sime WE. Physical fitness training and mental health. Am Psychologist 36: 375-88, 1981.)

Subsequent studies since 1980 have further demonstrated, with even greater scientific confirmation, that regular exercise is an important antidepressant. Some of these studies concluded that exercise can be as effective as pharmaceutical antidepressants and psychotherapy. (Martinsen EW. The role of aerobic exercise in the treatment of depression. Stress Med 3:93-100, 1987.)

3. Folic acid
In studies of depressed patients, one third of them have been shown to be deficient in folic acid. (Crellin R, Bottiglieri T and Reynolds EH. Folates and psychiatric disorders. Clinical potential. Drugs 45: 623-36, 1993.)

Depression is also the most common symptom of a folic acid deficiency: 800 mcg per day of folic acid should be adequate to prevent deficiencies although much higher doses may be needed for a treatment dose.

4. S-Adenosylmethionine (SAM)
S-Adenosylmethionine (SAM) is formed in the body by combining the amino acid methionine with adenosyl-triphosphate (ATP). SAM is required for the manufacture of many neurotransmitters, including serotonin. It improves binding of neurotransmitters to receptor sites, which then will cause an increase in serotonin, resulting in significant improvement in depression, providing perhaps the most effective natural antidepressant to date. (Janicak P, et al. Parenteral S-adenosylmethionine in depression: A literature review and preliminary report. Psychopharmacology Bulletin 1989;25:238-241.)

5. St. John's wort (Hypericum perforatum)
St. John's wort (Hypericum perforatum) is the most talked about herbal antidepressant to date: 25 controlled studies have investigated the antidepressive effectiveness of hypericum extracts for mild to moderate depression. A total of 1592 cases have been included in those 25 trials. (Harrer G and Schulz V. Clinical investigation of the antidepressant effectiveness of Hypericum. J Geriatr Psychiatry Neurol 7 (Suppl 1): S6-8, 1994.)

Generally, the German studies use a preparation of .3% hypericin with dosages from 300 to 900 mg of the standardized extract daily. The results are generally in the range of 65%-70% effectiveness for mild to moderate depression which is only slightly less than placebo controlled studies on fluoxetine hydrochloride (Prozac).

Obesity is characterized by an excess of body fat and is a serious and pervasive health problem in America today, particularly among women. The prevalence of overweight in women is defined as a body mass index (BMI) of 25 to 29.9 and obesity as a BMI equal to or greater than 30.

More than half of American women and men are overweight or obese. Although about 9% more men than women between the ages of 20 and 80 have a BMI of 25 or greater, more women than men are seriously overweight, qualifying as obese, having a BMI of 30 or greater; 25% of US women are obese with higher percentages for minority women, (36.7% non-Hispanic African American women and 33.3% Mexican American women). The prevalence of Caucasian women who are overweight or obese, ranges from 18% among 25 to 34 year olds to 35% among 55 to 64 year olds. Sixty percent of African American women aged 45 to 65 are either overweight or obese.

The incidence of obesity is increasing in America at a disturbing and alarming rate. Since 1980, obesity in both men and women has increased by over 50%. It is estimated that 33% to 40% of American women are trying to lose weight at any given time.

Overweight and obesity are linked to numerous health risks and consequences. Increasing weight is associated with increased mortality, diabetes, hypertension, high cholesterol, heart attacks, osteoarthritis and infertility. As the percentage of weight increases, mortality increases. Women who have the lowest mortality in the US are women who weigh at least 15% less than the average weight for other women her age.

1. Nutrition
The basic message is to improve the quality of food choices, and reduce the calories. Whether it's a lower carb and higher protein diet, or a lower fat and higher complex carbohydrate diet, it's important to find an approach that works for your physiology, one that you can live with, and one that is based on basic principles of healthier food choices. Support, coaching, counseling, education and the advice of a qualified and respectful practitioner are also often needed for success.

2. Exercise
Exercise is one of the most powerful lifestyle changes we have available to us. Regular exercise is needed to increase the metabolic rate, burn calories, increase muscle mass, improve fitness, and reduce the risk of many health problems associated with being overweight. Consult your physician if you are not currently on an exercise program to get medical clearance if you have health problems or are over 40. Keys to successful exercise programs are selecting an activity you enjoy, make it fun, do it at least 30 minutes four times weekly, stay motivated, and get some instruction on maximum heart rates and weight training. It also turns out that individuals who exercise in the morning are more successful with staying on their exercise program.

3. A mental shift
Understanding our relationship with food, body image issues, emotional and psychological life events that continue to have impact on our lives, and how we respond to stressors, are all potentially influential on our eating habits and patterns. Individual counseling, support groups, self-help programs, and organized programs are possible approaches to help us make a shift and truly create a holistic approach to weight management.

4. 5-HTP
Low serotonin levels and a decreased enzyme that converts our body's tryptophan to 5-hydroxytryptophan (5-HTP) and subsequently to serotonin may be related to overeating. Three studies using 5-HTP in overweight women have been conducted to assess its effects on weight loss. (Deci F, et al. The effects of oral 5-HTP administration on feeding behavior in obese adult female subjects. J Neural Transm 1989;76:109-117.) (Cangiano C, et al. Effects of 5-HTP on eating behavior and adherence to dietary prescriptions in obese adult subjects. Adv Exp Med Biol 1991;294:591-593.) (Cangiano C, et al. Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-HTP. Am J Clin Nutr 1992;56:863-867.)

Results have shown that 5-HTP is able to reduce caloric intake, promote weight loss, and decrease appetite. Weight loss ranged from 3.5 to 10.3 pounds. Recommended doses are 50-100 mg 20 minutes before meals for the first two weeks, then double the dosage if weight loss is less than 1 pound.

5. Chromium
One of the goals for enhancing weight loss is to increase the sensitivity of our cells, especially our fat cells, to the hormone insulin. Insulin plays a key role in maintaining good blood sugar levels and stimulating thermogenesis (heat production and the burning of calories). Chromium plays a very important role in increasing the body's sensitivity to insulin, and thus adequate thermogenesis. Supplemental chromium has been shown to lower body weight and increase lean body mass. (McCarthy M. Hypothesis: Sensitization of insulin-dependent hypothalamic glucoreceptors may account for the fat-reducing effects of chromium picolinate. J Optimal Nutr 1993;21:36-53.)

Recommended doses are 200-400 mcg three times daily.

Chronic Fatigue Syndrome
Chronic fatigue syndrome (CFS) is a disorder without a clear etiology and poorly understood pathophysiology. It consists of prolonged or recurring fatigue with an array of other possible symptoms including flu-like symptoms, myalgia, muscle weakness, arthralgia, low grade fever, sore throat, headache, sleep problems, swollen lymph nodes, and cognitive dysfunction.

CFS appears to occur more frequently in women than in men. Most commonly, the onset is between 20 and 40 years old, the majority of patients are middle class and people in the helping professions such as nurses, doctors and teachers seem to be particularly at risk for acquiring CFS.

Since the etiology and pathophysiology are still poorly understood, we can offer only some insights, possible mechanisms and hypotheses. Sleep disturbance appears to be highly correlated with chronic fatigue syndrome. But other mechanisms include a dysfunction in the hypothalamus and pituitary glands, a deficiency of corticotropin releasing hormone resulting in adrenal insufficiency, immunologic dysfunction, exposure to the Epstein Barr virus, dysfunction of the mitochondria in cells, muscle dysfunction, or a mind/body disorder. Some have proposed chronic candidiasis, intestinal permeability and environmental sensititivities/toxicity as underlying causes as well. More likely, this is a multifactorial problem and no one cause accounts for all cases of CFS.

1. Rhodiola
The folklore surrounding rhodiola led to the first investigations in its phytochemistry in the early 1960s, when scientists identified adaptogenic compounds in its roots. These adaptogens, (believed to help the body adapt to stress by supporting the adrenal glands and endocrine system), as well as the antioxidant and stimulating compounds that were later discovered in rhodiola, are responsible for its medicinal properties.

This herb's effects on the levels and activity of serotonin, dopamine, and norepinephrine, neurotransmitters found in different structures in the brain, influences the central nervous system and helps the body adapt to stress. It may be that rhodiola inhibits the breakdown of these chemicals and facilitates the neurotransmitter transport within the brain.

(Stancheva S, Mosharrof A. Effect of the extract of Rhodiola rosea L. on the content of the brain biogenic monamines. Med Physiol 1987;40:85-87.)

In addition to its impact on the central nervous system, rhodiola appears to increase the chemicals that provide energy to the muscle of the heart and to prevent the depletion of adrenal hormones induced by acute stress. (Maslova L, Kondrat'ev B, Maslov L, Lishmanov I. The cardioprotective and antiadrenergic activity of an extract of Rhodiola rosea in stress. Eksp Klin Farmakol 1994;57:61-63. (Article in Russian.))

Historically, Rhodiola was observed to act in humans as a tonic, increase attention span, memory and work performance. Two human studies were able to show that individuals with fatigue, irritability, insomnia and decline in work capacity responded favorably to a Rhodiola dose of 50 mg three times a day. (Krasik E, Morozova E, Petrova K, et al. Therapy of asthenic conditions: clinical perspectives of application of Rhodiola rosea extract. In. Proceedings Modern problems in psycho-pharmacology. Kemerovo-city, Russia: Siberian Branch of Russian Academy of Sciences: 1970.p. 298-330.) (Krasik E, Petrova K, Rogulina G, et al. New data on the therapy of asthenic conditions (clinical prospects for the use of Rhodiola extract). Proceedings of All-Russia Conference: Urgent Problems in Psychopharmacology 1970 May 26-29. Sverdlovsk, Russia: Sverdlovsk Press; 1970.p. 215-7.)

In another human study, Rhodiola alleviated fatigue, irritability, distractibility, headache and weakness in 64% of the cases. (Krasik E, Petrova K, Rogulina G, et al. New data on the therapy of asthenic conditions (clinical prospects for the use of Rhodiola extract). Proceedings of All-Russia Conference: Urgent Problems in Psychopharmacology 1970 May 26-29. Sverdlovsk, Russia: Sverdlovsk Press; 1970.p. 215-7.)

In a study of students, physicians and scientists, Rhodiola was given for 2-3 weeks beginning several days before intense intellectual work such as final exams. (Spasov A, Wikman G, Mandrikov V, et al. A double-blind, placebo-controlled pilot study of the stimulating and adaptogenic effect of Rhodiola rosea SHR-% extract on the fatigue of students caused by stress during an examination period with a repeated low-dose regimen. Phytomedicine 2000;7(2):85-89.)

The extract improved the amount and quality of work and prevented decreased performance due to fatigue.

Several studies have shown that Rhodiola increased physical work capacity and significantly shortened the recovery time between bouts of intense exercise. In one study, work capacity was increased by 9% and the pulse slowed to normal much more quickly. (Saratikov A, Krasnov E. Chapter III: Stimulative properties of Rhodiola roseas. In: Saratikov A, Krasnov E, editors. Rhodiola rosea is a valuable medicinal plant (Golden Root). Tomsk, Russia: Tomsk State University; 198.p. 69-90.)

Biathlon athletes given Rhodiola also have shown statistically significant increased shooting accuracy, less arm tremor and better coordination. Improved recovery time, strength, endurance and cardiovascular measures were also significantly better in those who took Rhodiola. We're not really sure what is responsible for these effects, but animal studies suggest that Rhodiola increases essential energy metabolites in the muscle and brain cells. It may also increase metabolism of fats.

Many individuals may see an improvement in their mood, energy level, mental capacity, memory, stamina and/or endurance within two to six weeks.

2. Licorice
The properties of licorice that may have some bearing in CFS are its immunomodulatory activity, antiviral activity, influence on steroid metabolism, and anti-inflammatory activity. A brief summary of some key findings are helpful to understand the role of licorice in CFS: Glycyrrhizin (GL) and glycyrrhetinic acid (GA) are active constituents of licorice. Licorice and GA helped the recovery of total leucocyte count, lymphocyte count and cellular immunity in irradiated mice. (Lin I, Hau D, Chen K, et al. Chin Med J 1996;109(2):138-142.)

GL has been shown to be particularly active against several viruses, including human immunodeficiency virus. (Nakashima H, Matsui T, Yoshida O et al. Jpn J Cancer Res 1987;78(8):767-771.) (Ito M, Nakashima H, Baba M et al. Antiviral Res 1987;7:127-137.)

Glycyrrhizin also induces interferon production but GA only has weak activity. (Abe N, Ebina T, Ishida N. Microbiol Immunol 1982;26(6):535-539) Both GL and GA exert influence on human steroid hormone function even though their intrinsic hormonal activities are low. GL inhibits the metabolism of corticosteroids and thus potentiates the effect of cortisone and adrenocorticotrophin hormone. (Kumagai A, Yano S, Otomo M et al. Endocrinol Jpn 1957;4(1):17-27.) Many other specific effects may have a viable role in treating CFS through its aldosterone-like effects, potentiating the activity of cortisol – and increasing the anti-inflammatory activity of cortisol.

3. Siberian ginseng
The actions of Siberian ginseng can be summarized as an adaptogen (assisting the body to counteract and adapt to stress), immunomodulator, and tonic. The majority of animal studies have demonstrated the ability of Siberian ginseng to act as an adaptogen under many different stressful conditions. In the original animal research, Siberian ginseng increased stamina in rats by up to 70%. (Fulder S. The root of being: ginseng and the pharmacology of harmony. Hutchinson, London, 1980. pg 137.)

A preparation of Siberian ginseng has been shown to increase the phagocytosis of Candida albicans by 30%-45%. (Wildfeuer A, Mayerhofer D. Arzneim-Forsch 1994;44(3):361-366.) Given the possible involvement of Candida in CFS, this may be an important issue in at least some patients. In relationship to general immune function, Siberian ginseng has shown in one clinical trial significant improvements in a variety of immune system parameters including an increase in helper T cells and an increase in natural killer cell activity. (Bohn B, Neve C, Birr C. Flow-cytometric studies with Eleutherococcus senticosus extract as an immunomodulatory agent. Arzneimittel-Forsch 1987;1193-1196.)

Perhaps most significantly, Siberian ginseng has been used in Traditional Chinese Medicine for centuries. They believed that its regular use increased longevity, improved general health and restored memory.

4. Panax ginseng
Panax ginseng, also called Korean or Chinese ginseng is perhaps the most famous medicinal plant of China. It has been used in traditional Chinese folk medicine for a vast array of problems and syndromes that includes fatigue, memory problems, insomnia, as a stimulant, and the promotion of longevity. The mental and physical anti-fatigue properties of ginseng have been demonstrated in both animal studies and randomized clinical trials in humans. (Hikino H. Traditional remedies and modern assessment: The case of ginseng. In: The Medicinal Plant Industry. CRC Press, Boca Raton, Fl, 1991:149-166.) (Shibata S, et al. Chemistry and pharmacology of Panax. Econ Med Plant Res 1985;1:217-284.) (Hallstrom C, Fulder S, Carruthers M. Effect of ginseng on the performance of nurses on night duty. Comp Med East West 1982;277-282.) (D'Angelo L, et al. A double-blind, placebo controlled clinical study on the effect of a standardized ginseng extract on psychomotor performance in healthy volunteers. J Ethnopharmacol 1986;16:15-22.)

Effects include increasing physical and mental performance, increasing the time to exhaustion under tests of exertion, improving energy metabolism and sparing glycogen utilization in exercising muscle. Ginseng also possesses immunostimulating activity and has the ability to enhance antibody responses, cell-mediated immnity, natural killer cell activity, the production of interferon, and phagocytic functions. (Jie Y, Cammisuli S, Baggiolini M. Immunomodulatory effects of Panax ginseng C.A. Meyer in the mouse. Agents Actions 1984;15:386-391.) (Gupta S, et al. Panax: A new mitogen and interferon producer. Clin Res 1980;28:504A.)

Ginseng's ability to treat fatigue and stress has been well documented in students, nurses and athletes. While improving the mental and physical performance in these individuals is different than treating patients with CFS who are hypofunctioning at baseline, it is none the less indicated as a general tonic in debilitated and weakened individuals.

5. Stress, sleep, rest
The four plants discussed are key ingredients to an overall strategy but their success is most likely influenced by attention to reducing stressors, increasing coping behaviors, rest, enhancing sleep, supporting moods and the nervous system, exercise that does not exacerbate the symptoms, and other immune modulating, adrenal supportive and symptom-specific therapies. Recovering from CFS will require time, compassion, diligent efforts and patience.

Breast Cancer Prevention
Breast cancer prevention is important for all women, and more assertive prevention strategies become of vital importance for women with family history of a mother, daughter or sister with breast cancer, are significantly overweight, or who drink more than one drink of alcohol per day. This may include adopting dietary habits that have been scientifically associated with lower rates of breast cancer, changes in lifestyle habits that reduce the risk (less alcohol, more exercise, less stress), reducing body weight, reducing exposure to estrogens (hormone replacement therapy, pesticides, some plastics, chlorinated organic compounds) and radiation, anti-estrogen pharmaceutical options and surgical options. Although more research is needed, there are meaningful dietary considerations, nutrients and herbs in supplement form that can reduce the risk of breast cancer: fiber, dietary fat, fish, fruits, vegetables, soy, green tea, fish oils, flax seeds, vitamin C and D.

Breast Care
There are three important methods used to detect breast changes: breast self exam, mammography and thermography, and regular examinations by a health professional. No one method of detection is perfect, but the three work together. Each method has advantages and weaknesses. As science and medicine move forward, new methods of breast cancer detection will evolve and improvements will be made. Consult with your health care practitioner about frequency of mammograms.

Dietary fat has been the attention of much controversy in regard to its impact on breast cancer. A review of some of the pertinent findings will be helpful. About 30 years ago, the fat intake of many countries was plotted on a graph against breast cancer rates.
(Carroll K, et al. Dietary fat and mammary cancer. Can Med Assoc J 1968;98:590-593.) With few exceptions, the more dietary fat that individuals in that society consumed, the higher the risk of breast cancer. Ten out of ten international studies looking at large differences in fat intake from one country to another continued to confirm this relationship between higher dietary fat levels and higher rates of breast cancer. By and large, the women who live in cultures with the lowest fat intake like Japan and Thailand, have the lowest rates of breast cancer. Women in the Middle East who have medium rates of breast cancer have medium amounts of fat in the diet. Women in Europe and North America with the highest intake of dietary fat have the highest rates of breast cancer. However, there have been conflicting reports and in 1992, the Nurses' Health Study group found no such link. (Willett W, et al. Dietary fat and fiber in relation to risk of breast cancer. JAMA 1992;268:2037-2044.)

A follow-up in 1999 also found no protective benefit from lower fat diets. (Holmes M, Hunter D, Colditz G, et al. Association of dietary intake of fat and fatty acids with risk of breast cancer. JAMA 1999;281:914-920.) Surprising to many, they saw no increased risk of breast cancer with increased intake of animal fat, polyunsaturated fat, saturated fat, or trans-unsaturated fats. They also found no evidence of decreased risk of breast cancer with increased intake of vegetable fat or monounsaturated fats. However, the capacity to examine breast cancer risk at the extremes of fat intake is limited by the small proportion of women in those groups and a greater probability of misclassification of dietary intake in these categories.

Increased olive oil consumption was associated with a lowered risk of breast cancer in Greek women by 25%. (Trichopoulou An, Katsouyanni K, Stuver S, et al. Consumption of olive oil and specific food groups in relation to breat cancer risk in Greece. J NCI 1995;87(2):110-115.) A recent survey was completed in Sweden studying 61,471 women from 1987 to 1990. (Wolk A, et al. A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer. Arch Intern Med 1998;158(1):41-45.) They reported that monounsaturated fat reduced the risk of breast cancer by 45 percent. They credited the effects of canola oil and olive oil, the oils highest in oleic acid. To achieve optimum protection, 2 tablespoons per day is recommended.

It is still thought by most nutrition experts that one of the best ways to reduce the risk of breast cancer is to consume more omega-3 fatty acids. The protective effect of omega-3 fatty acids was first observed in Greenland Eskimo women who seemed to have a strikingly low rate of breast cancer. These women have a diet that is probably the highest in omega 3 fats of any women to date. Laboratory, animal and epidemiological studies almost universally show reductions in breast cancer associated with high omega 3 fish oils. Fish that are generally available and contain high amounts of omega 3 oils include salmon, tuna, halibut, mackerel, sardines and herring.

Fiber has been underrated as a breast cancer prevention strategy. A low fat diet, rich in insoluble fiber, has been shown to decrease the circulation of estrogens between the intestines and the liver and decrease plasma estrogen levels, thereby potentially reducing the risk of hormone-related cancers. Seeds and whole grains contain significant amounts of lignans. Once lignans are absorbed, they interfere with estrogenic activity and have a weak estrogen blocking effect on the breast. Vegetarians eat more fiber and more lignans, than do non-vegetarians and vegetarians excrete a high level of lignans. Vegetarians with a high lignan diet do in fact appear to have lower rates of breast cancer.

Cabbage family foods
There are some specific vegetables that may have a very important role in reducing the risk of breast cancer. Cabbage family foods (broccoli, cauliflower, cabbage, Brussel sprouts), are high in compounds called indoles, or specifically indole-3-carbinol (I3C). I3C has been reported to affect the metabolism of estrogen in a way that might protect against breast cancer. (Michnovicz J, Bradlow H. Altered estrogen metabolism and excretion in humans following consumption of indole-3-carbinol. Nutr Cancer 1991;16:59-66.)

A recent study in Sweden, compared the diets of 2,832 postmenopausal women aged 50-74 years diagnosed with invasive breast cancer with 2,650 postmenopausal women of the same age with no history of breast cancer. Women who consumed an average of 1-1/2 servings of cabbage family vegetables each day had a 25% decreased risk of breast cancer. (Terry P, Wolk A, Persson I, et al. Brassica vegetables and breast cancer risk. JAMA 2001;285:2975-7.)

Perhaps no other food has been surrounded by as much controversy as soy, especially for the woman who has or has had breast cancer. Part of the confusion is that women and often even their physicians, think that there is estrogen in soy. However, there is not. Soy does contain a group of compounds called phytoestrogens. The phytoestrogens in soy are called isoflavones and the dominant isoflavones are genistein and daidzein. These are not estrogen, but have the ability to selectively function in some tissues in a weak estrogenic type manner, while in other tissues, actually block the effects of estrogen. What has been confusing is how do the soy isoflavones function in the breast? It may be different in different hormonal environments. Perhaps differently in premenopausal women than in post-menopausal women.

The clearest data shows that women who eat soy starting at a young age in adolescence can clearly reduce the risk of breast cancer later in life. Adult women may be able to reduce their risk by adding soy to the diet both before or after menopause but not all studies show this. The reassuring part is that no studies show that eating soy can increase the risk of breast cancer. What is confusing is what to do if you are a breast cancer survivor. Most the evidence points to the safety of soy, even for those women who have had breast cancer, however one can find some conflicting reports. For example, perhaps low dose is stimulatory to breast cancer cells whereas higher doses are inhibitory. Practically speaking, a higher dose would be greater than 70 mg of soy isoflavones per day.

There are many important mechanisms by which soy foods would appear to lower the risk of breast cancer. Women who are given high soy diets have lower blood levels of estrogen. Soy foods also contain antioxidants and enzyme inhibitors that can inhibit malignant cell formation and division. The genistein in soy also is anti-angiogenic which means that it can limit the blood supply to a tumor.

The most respected expert researchers on soy, advise breast cancer patients that a moderate amount of soy in the diet that is consistent with the Asian diet is probably safe. However, for those women on Tamoxifen, soy should be avoided. The reason is that there has been conflicting research: some show that soy interferes with the anti-estrogenic effect of estrogen and others show that soy augments the anti-estrogenic effect of Tamoxifen in women with ER + breast cancers. I would add that women who are on aromatase inhibitors should also avoid soy until we have further information.

I know that there is much information out there on the pros and cons of soy and not all of it is either accurate or helpful, let alone conflicting. I encourage women to look for reliable sources of information with scientific citations and resources. The best review of the scientific literature I have seen on the subject can be found in the (Journal of Nutrition 2001; 131:3095S-3108S. Authors Mark Messina and Charles Loprinzi)

Most but not all studies report women who drink alcohol have a higher risk of breast cancer compared with women who do not drink. In 1988, researchers conducted a meta-analysis of 16 previous studies. Researchers found that two drinks per day were associated with a 40% increased risk of breast cancer in retrospective studies. When they looked at prospective studies, they found that two drinks per day were associated with a 70% increase in risk. They also found that in the prospective studies, the more the women drank, the higher their risk. A 20% increase was found in women who averaged half a drink per day.

Individual dietary nutrients may be associated with a reduced risk of pre and postmenopausal breast cancer. Dietary sources of vitamin C, carotenes, selenium and vitamin D may be important nutrients to consider in prevention strategies. If you collect the results together of 12 breast cancer/nutrition studies, the women consuming the most vitamin C were found to have a 16% reduction in risk of premenopausal and a 37% reduction in the risk of postmenopausal breast cancer. (Howe G, et al. Dietary factors and risk of breast cancer: combined analysis of 12 case-control studies. J Natl Cancer Inst 1990;82:561-569.)

It is difficult to know if the protective association is the result of other properties and ingredients found in the fruits and vegetables, which are high in vitamin C, or the vitamin C specifically. Fruit, the best dietary source of vitamin C, by itself has been found to have a link with breast cancer protection. However, The Nurses' Health Study could not find a link between vitamin C in food or supplements and breast cancer prevention.
Another valuable antioxidant is vitamin A, which occurs as retinol and beta-carotene. There is evidence that women who eat more beta-carotene (Rohan T, et al. A population-based case-control study of diet and breast cancer in Australia. Am J Epidemiol 1988;128:478-479.) or retinol (Graham S, et al. Diet in the epidemiology of breast cancer. Am J Epidemiol 1982;116:68-75.) have a lower risk of breast cancer. Both may be potentially able to reduce cancer risk, but most evidence suggests that beta-carotene is more protective. Women who eat the most vegetables in their diet, the best dietary source of beta-carotene, have a lowered risk of breast cancer; maybe as much as a 90% lower risk than that of women with the lowest vegetable intake.

Selenium has significant antioxidant properties by activating glutathione peroxidase. Numerous observations have been made regarding selenium and breast cancer. Areas of the United States with low levels of selenium in the soil have higher rates of breast cancer. In some but not all studies, American breast cancer patients have been reported to have lower blood levels of selenium than do healthy women. A more recent study cast serious doubt on the protective relationship between selenium and breast cancer and did not find a protective effect. (Clark L, Combs G, Turnbull B, et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. JAMA 1996;276:1957-1963.)

Vitamin D
Vitamin D has been used to prevent mammary cancer in rats, inhibit breast cancer cell growth in the laboratory, and may have antiestrogenic activity. Women who live in sunnier parts of the country or in the Southern hemisphere leading to increased levels of sun exposure, correlate with reduced risk of breast cancer. When we look at dietary vitamin D though, there may be some correlation with an increased risk of breast cancer. Since dietary sources of vitamin D are high in saturated animal fat, it would seem logical to acquire vitamin D through exposure to sunlight.

Green Tea
While this article is not attempting to deal with treatment of breast cancer, one study that would be remiss not to mention is of Green tea helping to reduce recurrence rates in women who had stage I and II breast cancers. In stage I and II patients, there was a 16.7% recurrence rate for those consuming 5 cups or more of green tea (average 8 cups) per day. For those who consumed 4 or less cups per day (average of 2), there was a 24.3% recurrence rate. Disease-free survival was also significantly improved in stage I and stage II breast cancer patients with a greater consumption of green tea. Of all the predictors, green tea was the most statistically significant predictor for a decreased rate of recurrence in the stage I and II patients. No improvement in prognosis was seen in stage III patients. (Nakachi K, Suemaso K, Suga K, et al. Influence of drinking green tea on breast cancer malignancy in Japanese patients. Japan Journal of Cancer Research 1998; 89: 254-261.)

In the spirit of common sense, it would seem that your average woman who does not have breast cancer and women at higher risk for breast cancer, should drink green tea as a preventive measure. It is estimated that one cup of green tea contains 30 to 40 mg of EGCG.

Breast Cancer Prevention Summary
Vegetarian diet (even Vegan diet) plus fish
Lower fat in the diet to 20% or less
Olive oil: 1-2 tbsp/day
Fish (salmon, tuna, halibut, sardines, mackerel): twice weekly or more
Maximize all fruits and vegetables (5 or more servings per day)
Cabbage family foods: 1-2 cups per day
High fiber diet: whole grains plus fruits and vegetables
Ground flax seeds: 1 tbsp per day
High legumes: especially soy foods- one serving per day
Green tea: 3-5 cups per day
Reduce dairy, beef, chicken, turkey, lamb, pork
Reduce saturated fats, hydrogenated oils
Reduce sugar, white flour products
Reduce alcohol intake (less than one drink per day)


Subscriptions are available for Townsend Letter for Doctors & Patients,
the magazine, which is published 10 times each year.

Search our pre-2001 archives for further information. Older issues of the printed magazine are also indexed for your convenience.
1983-2001 indices ; recent indices

Once you find the magazines you'd like to order, please use our convenient form, e-mail, or call 360.385.6021 (PST).


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July 12, 2005