The Encyclopedia of Natural Medicine, 3rd Ed.



• Painful inflammatory swelling of a hair follicle that forms an abscess; typically appears as a small rounded or conical nodule surrounded by redness, progressing to a localized pus pocket with a white center.

• There is tenderness and pain and, if the condition is severe, mild fever.

• Staphylococcus aureus can be cultured from the abscess.

A boil (furuncle) is a deep-seated infection (abscess) involving the entire hair follicle and adjacent tissue. The most commonly involved sites are hairy parts of the body that are exposed to friction, pressure, or moisture, such as the neck, armpits, and buttocks. Using petroleum-based skin lotions or creams can plug the hair follicles and increase the risk of boil formation. Since the infection can spread, several boils are often found at one location. When several furuncles join together, they are called a carbuncle.


There is no particular cause of boils, although occasionally they may indicate an underlying disease that is associated with poor immune function, such as diabetes, AIDS, or cancer. Most lesions will resolve within one to two weeks. Recurrent boils can indicate a highly infective form of bacteria, poor hygiene, industrial exposure to chemicals, or depression of the immune system.

Therapeutic Considerations

Recurrent attacks of boils can also indicate a depressed immune system, which may be caused by nutritional deficiencies, food allergies, and/or excessive consumption of sugar and other concentrated refined carbohydrates (see the chapter “Immune System Support,” for further discussion). The treatment goals are to address any underlying immune disorder, achieve higher skin levels of vitamin A and zinc, and disinfect the area with topical application of herbal antiseptics. However, in severe cases consult a physician immediately.

Botanical Medicines

The best herbal treatment for boils is the topical application of tea tree oil. The tea tree (Melaleuca alternifolia) is a small tree native to only one area of the world: the northeast coastal region of New South Wales, Australia. Tea tree oil possesses significant antiseptic properties and is regarded by many as the ideal skin disinfectant. It is effective against a wide range of organisms, penetrates the skin well, and does not cause irritation.1 Organisms inhibited by tea tree oil include:

• Candida albicans

• Propionibacterium acnes

• Pseudomonas aeruginosa

• Staphylococcus aureus

• Streptococcus pyrogenes

• Trichomonas vaginalis

• Trichophyton mentagrophytes

A clinical trial involving patients with boils demonstrated that tea tree oil encouraged more rapid healing without scarring, compared with matched controls.2 Presumably the positive clinical effects were due to the oil’s antibiotic activity against Staphylococcus aureus. The method of application included cleaning the site, followed by painting the surface of the boil freely with tea tree oil two or three times a day.

For boils and most skin infections, the most effective treatment appears to be direct application of full-strength, undiluted oil at the site of infection. If irritation occurs, try diluting the oil.


Various herbal poultices are commonly used in the treatment of abscesses. Folk healers have used burdock root, castor oil, chervil, licorice root, and others. Poultices, although quite simple, appear to be highly effective. Historically, naturopathic physicians commonly used a poultice made from a paste of goldenseal root powder. Its efficacy is probably due to berberine, the most active alkaloid in goldenseal. Berberine is well documented as an antimicrobial agent.3 It is toxic to the bacteria commonly associated with boils, particularly Staphylococcus aureus.4 It has also been found to stimulate immune system function and decrease inflammatory processes. An advantage of goldenseal poultices, as compared with hot packs and other types of poultices, is that they usually will not cause the boil to rupture.



• Recurrent attacks of boils can indicate a depressed immune system.

• Tea tree oil is an effective topical treatment for boils.

• If the boil is severe or does not resolve within two to three days, consult a physician.



Eliminate from the diet any foods that may suppress immune function (sugar, refined simple carbohydrates, and food allergens). If the boil is severe or does not resolve within two to three days, consult a physician, since the infection can spread under the skin, causing cellulitis (inflammation of the connective tissue), or into the bloodstream, causing bacteremia (bacteria in the blood). Cleanliness should be rigorously maintained. The infected area should be immobilized and not handled, except when necessary to change the poultice. If tea tree oil or goldenseal poultices are not available, a pack of hot Epsom salts (mix 2 tbsp Epsom salts in a cup of hot water, soak a washcloth in the solution, and apply to the boil) will bring an abscess to a head.

Nutritional Supplements

• In addition to the general recommendations given in the chapter “Supplementary Measures,” take:

  images Vitamin C: 500 to 1,000 mg three times per day

  images Vitamin A: 5,000 IU per day (do not use more than 3,000 IU per day of vitamin A if you are pregnant or may become pregnant)

  images Zinc: 30 to 45 mg per day for up to one month, then 20 to 30 mg per day

Botanical Medicines

• Tea tree oil (Melaleuca alternifolia): Apply undiluted oil to the affected area two to three times per day

• Goldenseal (Hydrastis canadensis) poultice: Mix 1 tbsp root powder with water to form a paste, then apply to abscess and cover with an absorbent bandage; use twice per day

Breast Cancer (Prevention)


• Breast cancer is most often discovered when a woman feels a lump in her breast.

• A mammogram can detect early breast cancer.

• Other than a lump, changes in breast size or shape such as skin dimpling, nipple inversion, or spontaneous single-nipple discharge may signal breast cancer.

Breast cancer is a cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas.

Although breast cancer can occur in men, it is over 100 times more common in women. It is currently estimated that one out of eight women in the United States will develop breast cancer in her lifetime. It is the second most common cancer (after skin cancer) and the most common cause of cancer death in women. Breast cancer causes more than 40,000 deaths in the United States each year.


Genetics is an important risk factor, but in most cases a genetic predisposition is strongly affected by dietary, lifestyle, and environmental factors. In other words, breast cancer risk is largely a result of diet and lifestyle. The rate of breast cancer is typically five times higher for women in the United States compared with women in many other parts of the world. It is interesting to note that in Japan the rate of breast cancer is about one-fifth the rate in the United States, but in second-or third-generation Japanese women living in America and eating the typical American diet, the rate of breast cancer is identical to that of other women living in the United States.

There are many risk factors associated with breast cancer. Here is a brief overview:

• Age. The risk of breast cancer increases as a woman gets older. Breast cancer is uncommon in women under age 35. Most breast cancers occur in women over the age of 50, and the risk is especially high for women over 60.

• Genetics. The presence of certain genes (BRCA1, BRCA2, and others) increases the risk of breast cancer, although this is mainly true if many women in your family have actually developed breast or ovarian cancer. A woman’s risk for developing breast cancer increases if her mother, sister, or daughter has had breast cancer, especially at a young age. Women of Ashkenazi (Central and Eastern European) Jewish ancestry also tend to have a higher than average rate of breast cancer.

• Race. Breast cancer occurs more often in white women than among black, Hispanic, or Asian women.

• Estrogen. The female hormone estrogen stimulates breast cells. The longer a woman is exposed to estrogen in any form (made by the body, taken as a drug, or delivered by a patch), the more likely she is to develop breast cancer. For example, risk is higher among women who began menstruation at an early age (before age 12), experienced menopause late (after age 55), never had children, or took hormone replacement therapy for long periods of time.

• Later childbearing. Women who have their first child after about age 30 have a greater chance of developing breast cancer than women who have a child at a younger age. The most protection comes from childbirth followed by breastfeeding.

• Breast density. Breast cancers nearly always develop in dense tissue (lobes and ducts), not in fatty tissue. That’s why cancer is more likely to occur in women who have dense breast tissue than in those with fattier breast tissue. Complicating the picture is that abnormal areas in dense breasts are harder to detect on a mammogram.

• Environmental factors. Among the factors that have been linked to breast cancer in varying degrees are exposure to xenoestrogens (synthetic compounds that mimic estrogen), secondhand smoke, pesticides, herbicides, power lines, electric blankets, and radiation, and lack of exposure to sunlight.

• Exercise. Taking into account other established risk factors for breast cancer, women who exercise regularly have up to a 60% reduction in the risk of breast cancer compared with women with low levels of activity.

• Alcohol consumption. Women who have one drink a day have a 10% greater risk; those who drink two drinks have a 20% increased risk, and so on.

• Smoking. Like most other cancers, cigarette smoking increases the risk of developing breast cancer.

• Dietary factors. Important dietary factors include body weight (the more overweight you are, the greater the risk); increased intake of saturated fat; and decreased intakes of antioxidants, dietary fiber, omega-3 fatty acids (particularly alpha-linolenic acid), and dietary phytoestrogens (estrogen-like compounds found in foods such as legumes, nuts, and seeds).

Detecting Breast Cancer

Conventional wisdom dictates that early detection of breast cancer improves the chances of survival. Monthly breast self-exams have been stressed as important steps toward this goal. Mammography (a special type of breast X-ray) can detect breast cancer long before it can be felt. The National Cancer institute recommends that women age 40 and older have mammograms every one to two years.

Recently, however, this practice of routine mammography has come under fire. An increasing number of studies suggest that for women under 50 who have not yet gone through menopause, screening mammograms may not be a good idea. According to many experts in the field, screening mammograms don’t work very well for these women because:

• They have a high rate of false negatives (results that show no cancer when in fact cancer is present). The dense, healthy breast tissue of younger women can resemble or obscure tumors. Routine mammograms miss approximately 40% of the breast cancers that develop among women ages 40 to 49.

• Mammograms expose women to radiation that may cause breast cancer. With modern mammography equipment the risk is small (no more than 1 in 2,700). On the downside, the risk is cumulative, meaning that the chances increase with each subsequent mammogram.

• Screening mammography has not always been shown to increase the chances that premenopausal women will survive breast cancer.

• In women over the age of 50 it appears that mammography is best used to evaluate suspicious lumps, rather than screen for cancer (that is, to look for cancers when there is no sign the woman might have the disease).

• Results from a major study, the Canadian National Breast Screening Study 2, involving nearly 40,000 women, showed that yearly mammograms in women 50 to 59 did not lower breast cancer mortality compared with yearly physical examination alone. The authors of the study concluded that for women older than 50, thorough annual physical breast examinations, plus teaching of breast self-examination, may be a valid alternative to yearly mammography.1

• A Cochrane review in 2009 concluded that mammograms reduce mortality from breast cancer by 15% but also result in unnecessary surgery and anxiety.2

All of this information may be a bit confusing. There is no easy answers, as there are a lot of conflicting studies. Our recommendation is to get a baseline mammography after the age of 40, perform regular breast self-exam, get a yearly physical that includes a breast exam, and discuss the appropriateness of regular mammography with your physician.

Alternatives to a mammogram include thermography (computerized regulation thermography or thermal imaging thermography), which can help identify inflammation of the breast tissue and/or the existence of any breast tumors, but these techniques are still considered less reliable than a mammogram.

Therapeutic Considerations

The therapeutic goal is to reduce as many risk factors as possible while simultaneously maximizing dietary and lifestyle factors associated with breast cancer prevention. Most of the lifestyle factors linked to causing or preventing cancer in general, such as avoiding cigarette smoke and excessive intake of alcohol, also apply to breast cancer. The same is true for dietary factors. Therefore, we recommend strengthening the four cornerstones of good health detailed in Section II of this book. Focusing on these key foundations provides the strongest general protection against cancer:

• A positive mental attitude

• A health-promoting lifestyle

• A health-promoting diet

• Supplementary measures


One of the most interesting protective factors appears to be breastfeeding. Numerous scientific studies show that the longer a woman breastfeeds her child, the greater the degree of protection. The minimum amount of time required to see beneficial effects is three months. Breastfeeding may be protective because it will extend the period before a woman begins to ovulate again, thus reducing her overall total lifetime burden of estrogen exposure. The total number of ovulatory cycles experienced by women was much lower in preindustrial societies than in today’s society, in which women begin to have periods sooner, have children later, and have fewer children.

Preliminary evidence suggests that breast-feeding an infant girl may also help protect her from developing breast cancer as an adult. This protection may be due to the hormones and immune factors present in breast milk. Of course, there are many other important health benefits associated with breastfeeding, for both mother and baby. Babies who are breastfed have a lower incidence or severity of several childhood illnesses, including diarrhea, lower respiratory infections, ear infections, and bacterial meningitis. Other possible protective effects have been reported against sudden death infant syndrome, allergic diseases, and chronic digestive diseases.3,4


Many studies have shown that exercise reduces the risk of breast cancer. Taking into account other established risk factors for breast cancer, women who regularly engage in exercise have up to a 60% lower risk of developing breast cancer compared with women with low levels of activity.5 Exercise is even helpful in women with breast cancer, both during and after conventional treatments such as surgery, chemotherapy, and radiation.68 In particular, women with breast cancer who exercised reported having higher self-esteem, improved body image, less nausea during chemotherapy treatment, and less fatigue, depression, and insomnia. Women who exercised also had improvements in physical performance and a higher quality of life. For example, in one study, women who walked at their own pace for 20 to 30 minutes four to five times per week reported feeling less fatigued and less emotionally distressed and had an improved level of physical performance.8 Also, weight gain is a troublesome and potentially serious problem for breast cancer patients undergoing chemotherapy. In one study, the patients who gained more weight during treatment were more likely to relapse and more likely to die of their breast cancer than patients who gained less weight.9 Breast cancer patients who exercise while undergoing treatment may gain less weight compared with patients who do not exercise.


Diet appears to be one of the most critical aspects in the prevention of breast cancer. Obesity is perhaps the most significant factor, as it carries with it at least a 30% increased risk for developing breast cancer. Just as with heart disease and other chronic degenerative disease, eating a traditional Mediterranean diet is associated with lower risk. This diet features a high intake of vegetables, fiber, fruit, and fish and unsaturated oils, particularly omega-3 fatty acids, while a typical Western diet features a high intake of total and saturated fat, refined carbohydrates, and processed and red meat, plus a low fiber intake.10

Research on specific dietary factors is a bit muddy because investigators often look only at dietary factors in the United States. For example, let’s take a look at the research on saturated fats and breast cancer. It is difficult to determine true risk in looking at women in the United States because what is considered a low intake of saturated fat in the United States often translates to a high intake in other countries. To gauge all dietary risk factors in breast cancer, it is extremely important to examine data from a global perspective. When these sorts of analyses have been done, the results provide some sound evidence as to which dietary factors appear to promote breast cancer and which appear to be preventive.11

Nutritional Factors in Breast Cancer

Factors that may increase risk


High total fat intake

Saturated fats


Refined sugar

Excess intake of total calories


Factors that may lower risk


Whole grains

Soy and other legumes


Other vegetables



It may not be simply that meat intake is associated with breast cancer; what may eventually be shown is that cooking method determines whether it is carcinogenic. Perhaps the most important foods to avoid are meats grilled or broiled at high temperatures, because this preparation produces many potent carcinogens, including lipid peroxides and heterocyclic amines.

Researchers from the University of South Carolina gave questionnaires to 273 women who were diagnosed with breast cancer between 1992 and 1994 as well as 657 women who were cancer-free. They found that women who routinely ate three meats—very well done hamburger and beefsteak, and bacon—had a 462% greater chance of developing breast cancer. Women who regularly consumed these meats individually had lower increases in risk for breast cancer compared with those that ate all three, but they still had an increase in breast cancer risk. The risk for very well done vs. rare or medium was 50 to 70% greater for hamburger and bacon, and 220% greater for beefsteak. These results, coupled with other evidence, suggest that avoiding well-done meats can dramatically reduce breast cancer risk.12

One of the most interesting aspects of the population study was the tremendous protective effect of fish consumption. Fish, particularly cold-water fish such as salmon, mackerel, halibut, and herring, are rich sources of omega-3 fatty acids. These fats have shown tremendous anticancer effects and are especially important in fighting breast cancer.1315 In contrast, the omega-6 fatty acids found in most animal products as well as common vegetable oils such as corn, safflower, and soy are associated with promoting breast cancer.

To evaluate the hypothesis that omega-3 fatty acids protect against breast cancer and omega-6 fatty acids promote breast cancer, the fatty acid composition of breast fatty tissue (adipose tissue) was examined from 241 patients with breast cancer and compared with that of 88 patients with benign breast disease. Women with higher levels of omega-3 fatty acids (alpha-linolenic acid, DHA) had a risk for breast cancer that was 61 to 69% less than women with lower levels. And women with the highest ratio of the long-chain omega-3 fatty acids EPA + DHA to omega-6 fatty acids had a 67% reduced risk of breast cancer.16


In addition to a diet that features fish and fish oil supplementation, supplementing the diet with flaxseed oil and ground flaxseed appears to offer significant protection against breast cancer, for at least two reasons.

Flaxseed oil provides the short-chain omega-3 fatty acid alpha-linolenic acid. In addition to the study looking at alpha-linolenic acid (ALA) in breast fatty tissue described above, other studies have shown lower levels of ALA in breast cancer patients.17 And in another study, of 121 women with initially localized breast cancer, a low level of ALA was associated with the spread of the cancer into the lymph nodes of the armpit as well as tumor invasiveness.18Since the main cause of death in breast cancer patients is the development of cancer in other tissues, this finding is extremely important. We recommend supplementing with 1 tbsp flaxseed oil (approximately 58% ALA) per day.

Flaxseed oil can be used as a salad dressing, mixed with yogurt or cottage cheese, or used as a dip for bread. Because its fats can be damaged by high heat, never cook with flaxseed oil—use olive or canola oil instead. Flaxseed oil should be bought in small, opaque bottles and kept refrigerated at all times. Some manufacturers also add antioxidants such as vitamin E or rosemary to the oil to further protect it. If a bottle of flaxseed oil is not used up within three months, throw it out and replace it with a fresh bottle, Also dispose of any flaxseed oil that has a bitter or rancid taste.

Flaxseed is also the best source of lignans, one of a group of substances called phytoestrogens that are capable of binding to estrogen receptors and interfering with the cancer-promoting effects of estrogen on breast tissue. Other foods that contain phytoestrogens include soy and whole grains. In addition to competing with estrogen for binding sites on breast cells, lignans and other phytoestrogens increase the production of a compound known as sex hormone binding globulin, which regulates estrogen levels by escorting excess estrogen from the body. Population studies, as well as experimental studies involving humans and animals, have demonstrated that lignans exert significant anticancer effects, especially against breast cancer.19,20 For example, in one study researchers followed 28 postmenopausal nuns for a year and tracked blood levels of two cancer-related estrogens: estrone sulfate and estradiol. In addition to their normal diets, the nuns were assigned to receive supplements of either 5 or 10 g ground flaxseed per day or to a control group. Estrogen levels fell significantly among the women taking the ground flaxseed but remained stable in the control group.21

In another study, 50 women who had recently been diagnosed with breast cancer were divided into two groups. One group received a muffin containing 25 g ground flaxseed (about 2 tbsp) each day. The others were given ordinary muffins. When their tumors were removed a month later, the researchers examined them for signs of how fast the cancer cells had been growing. The women who had received the flaxseed muffins had slower-growing tumors than the others.22

Ground flaxseed provides more digestable nutritional benefits than whole seed. That’s because flaxseed is very hard, making it difficult to crack, even with careful chewing. Flaxseed is easily ground with a coffee grinder, food processor, or blender. We recommend 1 or 2 tbsp per day added to foods such as hot cereals, salads, or smoothies.

Soy Products

Since the 1970s, there has been a marked increase in the consumption of both traditional soy foods (such as tofu, tempeh, and miso) and “second-generation” soy foods that simulate traditional meat and dairy products (such as soy milk, soy hot dogs, soy sausage, soy cheese, and soy frozen desserts). One of the big reasons for the increase in soy consumption is that there is now considerable evidence from test tube, animal, and population studies that soy may have an anticancer effect, particularly in hormone-sensitive cancers such as breast and prostate cancer.

Much of the latest research on soy has focused on the soy isoflavone compounds daidzein and genistein. These substances are often classified as phytoestrogens, which bind to estrogen receptor sites. However, other factors beyond isoflavones appear to contribute to soy’s anticancer properties. Researchers at the University of Illinois tested the effects of purified isoflavones against soy protein mixes with and without isoflavones in female rats. Although all the compounds studied reduced the incidence of mammary gland tumors, the soy protein mix without isoflavones was the most effective in decreasing the number of tumors.

Anticancer Effects of Soy Isoflavonoids

• They act as antioxidants.

• They reduce estrogen levels, particularly free estrogen. Lower levels of estrogen have been associated with a decreased risk of breast cancer.

• They have anti-angiogenesis effects (that is, they prevent the formation of new blood vessels). This prevents tumors from obtaining the increased blood supply necessary for their continued growth.

• They prevent tumor cells from dividing and growing by inhibiting certain enzymes required during cellular replication.

• They replace animal-based protein in the diet, thus reducing intake of saturated fats, which are a known risk factor.

Population studies have offered clear evidence that soy offers some protection against breast cancer. Women in Asian countries, such as China and Japan, who traditionally consume more soy products than most women in Western countries, have a lower risk of breast cancer. There are also a growing number of clinical and experimental studies offering support for the contention that soy consumption reduces the risk for breast cancer. When healthy women add soy products to their diets, the change leads to lower levels of estrogen and other hormones in their bodies.2325

The most protective benefit of soy consumption may occur before and during adolescence. Animal studies appear to show that intake of soy before adulthood enhances the maturation (differentiation) of breast cells. These more mature cells are less susceptible to carcinogens. Population-based studies seem to support the importance of intake during adolescence. Soy eaten after adolescence appears to have a more significant protective effect against premenopausal breast cancer compared with postmenopausal breast cancer.24

The amount and frequency of soy intake are also important. The amount necessary to protect against the development of breast cancer is thought to be 25–100 mg of isoflavones per day. We strongly recommend getting this amount from food rather than taking a dietary supplement containing purified isoflavones. Labels on any soy foods now state the level of isoflavones per serving. As the table below shows, you do not need to consume huge amounts of soy foods to get the recommended levels.

Vegetables in the Brassica Family

Vegetables in the brassica family, such as broccoli, cauliflower, cabbage, and kale, contain anticancer phytochemicals known as glucosinolates. The chief glucosinolate is indole-3-carbinol (I3C), a compound formed whenever cruciferous vegetables are crushed, chewed, or cut. (Crushing, chewing, or cutting the cells in cruciferous vegetables activates the enzyme that makes the I3C.) I3C and other glucosinolates are antioxidants and potent stimulators of natural detoxifying enzymes in the body. I3C is converted in the stomach to several other compounds, including diindolylmethane (DIM). Both IC3 and DIM are especially protective against breast and cervical cancer (see the chapter “Cervical Dysplasia”) because of a number of actions, including an ability to accelerate the breakdown of estrogen. Studies have shown that increasing the intake of brassica vegetables or taking I3C or DIM as a dietary supplement significantly increased the conversion of estrogen from cancer-producing forms to nontoxic breakdown products.2629

Soy Foods and Their Isoflavone Content




Cooked soybeans

1/2 cup


Roasted soybeans (soy nuts)

1/2 cup



4 oz



4 oz


Soy protein

1/2 cup


Soy milk

1 cup



WARNING: For women with estrogen-receptor-positive breast cancer, we recommend no more than one serving of soy per day, providing no more than 40 mg isoflavones. In test tube and animal studies, genistein has been shown to inhibit breast cancer cells that do not have estrogen receptors, but in certain situations it may actually encourage growth of breast cancer cells with estrogen receptors. Exactly how all of this research in test tubes relates to human consumption is not clear, but given the potential for harm, we recommend that until this issue is clarified, women with a history of estrogen-receptor-positive breast cancer should restrict soy intake and definitely avoid soy isoflavone supplements.

Soy consumption is also contraindicated for women who are taking the anticancer drug tamoxifen. Genistein and tamoxifen have a similar affinity for estrogen receptors. In test tube studies, when isolated human breast cells are exposed to both genistein and tamoxifen at the same time, genistein can stimulate cell growth and override the growth-inhibition effect of tamoxifen. Until researchers show us what happens when tamoxifen, genistein, and naturally occurring estrogen are all together at the same time in the human body, it is prudent to restrict soy intake while on tamoxifen.


Specifically, the body can break down estrogen into either 16-alpha-hydroxyestrone, a compound that promotes the growth of breast tumors; or 2-hydroxyestrone, which does not stimulate breast cancer cells. Adding 500 g per day of broccoli to the diet or taking IC3 (400 mg per day) or DIM (a daily dose of 2 mg/kg) improves the ratio of good to bad estrogen breakdown products, as determined by measuring these compounds in the urine. In high-risk women, we recommend either making sure to eat large amounts of vegetables in the brassica family or supplementing the diet with IC3 or DIM. Broccoli sprouts have been reported to have the highest levels of these compounds, with 1 lb of broccoli sprouts being equivalent to 40 lbs of fresh broccoli.


One of the key ways in which the body gets rid of estrogen is by attaching glucuronic acid to estrogen in the liver and then excreting this complex in the bile. Glucuronidase is a bacterial enzyme that breaks the bond between estrogen and glucuronic acid, leading to less excretion of estrogen. Thus it is not surprising that excessive glucuronidase activity is associated with an increased cancer risk, particularly for estrogen-dependent breast cancer. The activity of this enzyme is increased when the diet is high in fat and low in fiber. The level of glucuronidase activity may be one of the factors explaining why certain dietary factors cause breast cancer and why other dietary factors are preventive.



• The rate of breast cancer is typically five times higher for women in the United States than for women in many other parts of the world.

• Genetics is an important risk factor, but in most cases a genetic predisposition is secondary to dietary, lifestyle, and environmental factors.

• Early detection of breast cancer improves the likelihood of survival.

• The therapeutic goal is to reduce as many risk factors as possible while simultaneously incorporating dietary and lifestyle factors associated with breast cancer prevention.

• Women who exercise regularly have a statistically significant lower risk of developing breast cancer.

• Obesity is perhaps the most significant dietary factor, as it carries with it at least a 30% increased risk for developing breast cancer.

• Women with the highest ratio of omega-3 fatty acids to omega-6 fatty acids have a 67% reduced risk of breast cancer.

• Flaxseed and flaxseed oil provide the omega-3 fatty acid alpha-linolenic acid and anticancer compounds known as lignans.

• There is a growing amount of evidence that soy consumption reduces the risk for breast cancer.

• Increasing the intake of vegetables in the brassica family or taking I3C or DIM as a dietary supplement significantly increases the conversion of estrogen from cancer-producing forms to nontoxic breakdown products.

• Women working the graveyard shift have an increased risk of developing breast cancer.

• Studies suggest that green tea offers a protective effect against breast cancer.

The activity of glucuronidase can be reduced by making sure you have a good balance of health-promoting intestinal bacteria. Eat a diet high in plant foods and supplement it with the “friendly” bacteria Lactobacillus acidophilusand Bifidobacterium bifidum. Another dietary factor that can dramatically reduce the activity of this enzyme is the consumption of onion, garlic, and foods high in glucaric acid such as apples, brussels sprouts, broccoli, cabbage, and lettuce.

Calcium D-glucarate is a dietary supplement used to inhibit glucuronidase. Researchers at M. D. Anderson Cancer Center, Memorial Sloan-Kettering Cancer Center, and other major cancer centers have conducted preliminary research with calcium D-glucarate in the prevention and treatment of breast cancer, and the results have been quite encouraging. The recommended daily dosage for prevention is 200 to 400 mg. Higher dosages (i.e., 400 to 1,200 mg) may be necessary for individuals with existing cancer. There are no known side effects or drug interactions.30,31

The Night Shift–Melatonin–Breast Cancer Connection

Several studies have shown quite dramatically that women working the so-called graveyard shift have an increased risk of developing breast cancer.3234 In fact, in one study graveyard shift work was associated with a 60% increased breast cancer risk.33 The risk seems to rise with the amount of time spent working this shift.

The explanation given for this link is that exposure to artificial light at night appears to suppress the normal nighttime production of melatonin, a hormone secreted by the pineal gland (a small pea-sized gland at the base of the brain). Melatonin is critically involved in regulating the natural biorhythm of hormone secretion, and it has significant anticancer effects, especially against breast cancer. To offset the increased risk of breast cancer that comes with night shift work, we recommend taking 3 mg melatonin at bedtime for night shift workers (regardless of when that bedtime might be).

Green Tea

Population studies have shown that increasing green tea (Camellia sinensis) consumption reduces the risk of breast cancer. For example, studies have suggested that breast cancer rates are lower in Japan in part because, per day, people there typically drink about three cups of green tea, which provide roughly 240 to 320 mg polyphenols, substances that have an anticancer effect. To achieve the same degree of protection from supplements containing green tea extract, standardized for 80% total polyphenol content, takes 300 to 400 mg per day.35



Focus on reducing risk factors and incorporating dietary and lifestyle factors associated with breast cancer prevention.


• Follow the recommendations in the chapter “A Health-Promoting Lifestyle.”


• Follow the dietary guidelines in the chapter “A Health-Promoting Diet.” In particular, apply the principles of the Mediterranean-style diet: increase consumption of whole food products, including fish, cereals, vegetables, and monounsaturated fats; eat soy foods and vegetables in the brassica family on a regular basis; avoid high-glycemic foods and unhealthy fats; and achieve and maintain ideal body weight. Take 1 or 2 tbsp ground flaxseed per day.

Nutritional Supplements

• A high-potency multiple vitamin and mineral formula as described in the chapter “Supplementary Measures”

• Key individual nutrients:

  images Vitamin D: 2,000 to 4,000 IU per day

  images Selenium: 200 mcg per day

• Fish oils: 1,000 to 3,000 mg EPA + DHA per day

• Flaxseed oil: 1 tbsp per day (in addition to the 1 tbsp of ground flaxseeds)

• One of the following:

  images Grape seed extract (>95% procyanidolic oligomers): 100 to 300 mg per day

  images Pine bark extract (>95% procyanidolic oligomers): 100 to 300 mg per day

  images Some other flavonoid-rich extract with a similar flavonoid content, super greens formula, or another plant-based antioxidant that can provide an oxygen radical absorption capacity (ORAC) of 3,000 to 6,000 units or higher per day

• Probiotic supplement (active lactobacillus and bifidobacteria cultures): a minimum of 5 billion to 10 billion colony-forming units per day

• For night shift workers: melatonin, 3 mg at bedtime

• In high-risk cases, one of the following:

  images I3C: 200 to 400 mg per day

  images DIM: 150 to 200 mg per day

  images Calcium-D-glucarate: 200 to 400 mg per day

Botanical Medicines

• Green tea extract (>80% total polyphenol content): 300 to 400 mg per day