A low-fat diet can reduce your risk of breast cancer

Breast cancer in the United States is increasing at an alarming rate. One out of eight women will develop this potentially fatal disease and approximately 90 percent of women diagnosed as having breast cancer will die. The American Cancer Society reports an estimated 180,000 new breast cancer cases in 1993, with an estimated 45,000 deaths.

By now, however, most women know that early detection--through self breast examination and regular mammograms is the key in treating and conquering this disease. But what many don't understand is what causes breast cancer and what they can do to reduce or even prevent the risk of ever getting it.

Prevention is the key in conquering breast cancer, and to prevent it one must understand what causes it. There are essentially nine risk factors of developing the disease:

* Excessive fat in the diet.
* Obesity.
* Higher than normal levels of estrogen in the body.
* Lack of exercise.
* Alcohol consumption.
* Family history.
* Early age of menarche (one's first menstrual period).
* Late age of first pregnancy or no pregnancy.
* Late age at menopause.

Breast cancer is uncommon before the age of 30, but the incidence rate increases dramatically between the ages of 30 to 50. After 50, the incidence continues to rise, but at a slower rate.

Although several of these risk factors cannot be controlled, it's the conclusion of much research that the main reason for breast cancer is excessive fat in the diet. And the amount of dietary fat you consume is entirely under your control.

Research has shown that a high-fat diet is the major factor in most breast cancers in the United States. Dietary fat is believed to act primarily as a "promoter" of tumor growth. Thus, a high-fat diet provides the necessary environment for malignant (cancer) cells to flourish. [2]

Women living in countries where fat intake is low tend to experience a much lower incidence of breast cancer. Breast cancer rates in Thailand are about one-sixth that of the U.S. and women in Thailand eat an average of 21 grams of fat per day. The traditional Japanese diet has about one-fourth as much fat as the typical American diet. Consequently, the breast cancer rate in Japan is about one-fifth of that in the U.S.

At one time this difference was attributed to genetic factors; but when Japanese women move to the U.S. and adopt American eating habits, their breast cancer incidence rises until it's similar to the American rate.

Studies have not yet identified the stages of life when the amount of fat in the diet is most harmful. But excessive dietary fat consumed early in life might influence the development of breast cancer later in life, so, even children and teenagers should reduce the amount of fat in their diets.

Each type of dietary fat has been positively associated with breast cancer. The substitution of one type for another--eating unsaturated fat rather than saturated, for example--does not reduce one's risk. [3]

High levels of estrogen in the body also increases one's risk of developing breast cancer in a number of ways. [1] Reasons why a woman might have elevated levels of estrogen include obesity and a high-fat diet.

Elevated levels of estrogen cause women to menstruate about four years longer than they would if they kept a low-fat diet. The average age of menopause should be about 46. A prolonged menstrual life is associated with a much higher risk of breast and uterine cancer because of longer stimulation of vulnerable cells by cancer-promoting estrogens.

Often, the cause of late menopause is obesity. Obesity causes the female body to produce more estrogens. The more obese a women is, the higher her estrogen level. Does fat distribution affect cancer risk? One study has found that women who gain weight in areas of the upper body (such as the abdomen, shoulders and nape of neck) appear to be at a significantly higher risk than those who gain weight in the lower body (such as the buttocks and thighs).

In addition, over-stimulation of the breast tissues by higher than normal levels of estrogen causes the breast to swell and become tender. Eventually, after repeated bouts of inflammation, the breast develop scar tissue in many places. Some milk ducts become plugged and form cysts. This is called Fibrocystic Breast Disease and is associated with a higher risk of breast cancer.

Studies suggest that exercise may reduce breast cancer. One study published in the British Journal of Cancer 4 shows that exercise in college female athletes reduced their incidence of breast and reproductive organ cancer. It also shows that a sedentary lifestyle was associated with an increased risk of cancer in these areas. Regular aerobic exercise, therefore, is an important factor in preventing breast cancer.

Additional studies indicate that a diet including high-fiber foods, fruits and vegetables has a protective effect against breast cancer. [1-5] Statistically, risk of breast cancer decreases for all women who include dietary fiber, vitamin A, beta-carotene and vitamin C in their diets. [4] Many studies have shown that fiber decreases the amount of estrogen in the body. Thus, increasing dietary fiber can have a preventive effect on the disease.

A dietary approach to breast cancer prevention should include weight control, a reduction in dietary fat and an increase in fiber. Women should eat no more than 20 percent of their daily calories as fat and should eat at least 30 grams of fiber every day. (See Fig. 1 for a list of high-fiber and low-fat foods.) Women who have never smoked and do not drink are at less risk of breast cancer, while women who do are at a greater risk. When the effects of alcoholic beverages--beer, wine and spirits--were examined, the risk of breast cancer increased at intermediate to high levels of intake of these beverages. Additional evidence suggests an interaction between alcohol consumption and cigarette smoking/

It's never too late to change your lifestyle and reduce your risk. Even women with breast cancer can increase their survival rate by making a low-fat, high-fiber diet part of their lives.

Follow these guidelines for breast cancer prevention, and start today:

1. Eat no more than 20 grams of fat per day.
2. Eat at least 30 grams of fiber every day.
3. Eat fruits and vegetables that contain vitamins A, C, D and beta-carotene.
4. Drink no alcohol or as little as possible.
5. Exercise daily for at least 30 minutes.
6. Do not smoke.




Thailand 2 21
Japan 4 38
EL Salvador 2.2 40
Taiwan 4.6 42
Ceylon 3 44
Yugo 6 72
Panama 7 57
Bulgaria 8.5 65
Portugal 13 66
Poland 11 85
Hungary 13.6 97
Czechoslavkia 15 91
Austria 16 118
Germany 16.5 137
Australia 18.5 129
United States 21 146
Switzerland 22 137
Canada 23 140
Netherlands 26 155

Fig. 1 Cut the Fat, Add the Fiber

Here's a list of common foods you can easily include in your diet to increase fiber and reduce fat:

* Whole wheat pasta
* All kinds of grains
* Popcorn
* Corn
* Pretzels
* Peas
* Rice (except white)
* Legumes
* Potatoes with the skin
* Lentils
* Oats and bran
* All fruits and vegetables

The following are high-fat foods your should avoid:

* Dairy products.
* Red meat (also limit consumption of chicken and fish).
* Foods cooked with or containing oil, such as: cookies, pastries, fried foods, etc.

GRAPH: Breast Cancer vs Fat Consumption Worldwide


1. "Breast cancer and nutrition: the hidden link," Ladies Home Journal, July 1990
2. "Dietary fat and the risk of breast cancer," International Journal of Epidemiology, Vol. 19, #I, 1990
3. Lower prevalence of breast cancer and cancer of reproductive system among former college athletes compared to non-athletes. British Journal of Cancer, 52:885-891, 1985
4. Dietary prevention of breast cancer," Medical Oncology and Tumor Pharmacotherapy, Vol. 7, #2/3, 1990
5. "Screening as prevention for breast cancer," Allen T. Cohen, D.O., Journal of Osteopathic Medicine, March
6. "Abdominal Obesity and Breast Cancer," Annals of Internal Medicine, Vol. 112, No. 3
7. "Alcohol Consumption and Risk of Breast Cancer," International Journal of Cancer, 41, 695-699, 1988


By Bruce Scott Sobel, D.O.

Bruce Scott Sobel, D.O. is a physician based in Phoenix, Arizona. He is medical director of the Diabetes Obesity Cholesterol Clinic and a partner in Sobel Family Medicine. After being diagnosed with dangerously high blood pressure at the age of 18, he healthfully lost 38 pounds and vowed to maintain a personal program allowing him the security and energy that comes with wellness. Dr. Sobel's areas of interest are in nutrition, high risk management and preventive medicine.

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