Diet and Breast Cancer Breast cancer is an unforgivable disease. It attacks a highly visible and sensitive organ. An organ that is closely associated with femininity and nurturing. When this disease strikes a breast, the risk is very great that it will strike again, either in the same breast, or at other sites such as bones or lungs. Once the disease has recurred, the only available treatments are drugs and radiation. An estimated 207, 000 women will be diagnosed with breast cancer this year (Lohr 42).
By the year 2000, it is expected that there will be 1. 5 million new cases of breast cancer in America, and the National Cancer Institute now estimates that 1 out of 8 women will develop breast cancer over her lifetime (Caste n 68). These finding have only added to women's anxieties concerning breast cancer. Unfortunately, most of the known risk factors for breast cancer are things women can do little or nothing about: being female, advancing age, strong family history of breast cancer, and problem reproductive history. Fortunately, however, current research is showing that outside environment and lifestyles can be key in determining cancer, too. According to many experts, diet holds the secret to preventing this disease that women fear most.
In the United States, breast cancer rates are 4 to 7 times higher than in Asia (93). But when Asian women move to the US, their breast cancer risk doubles in 10 years, and reaches our national rates in several generations, says nutritional epidemiologist Regina Ziegler, Ph. D. , MPH, of the National Cancer Institute (176). Why "Their diets and other lifestyle factors," Dr.
Ziegler says, "They start eating more calories, fat and meat, and stop eating many fruits, vegetables, and grains that they did in Asia." (177). According to Dr. Ziegler, genetics and family history may explain only a small fraction of breast cancer. The majority of cases are due to something in our daily environment-lik diet. In this paper I would like to focus on how a high fat diet is suspected to contribute greatly to this disfiguring disease. I will name 2 of the major contributing factors in predicating breast cancer, and will then suggest a few ways to reduce one's chances of getting breast cancer.
Finally, I will briefly cover some recent research done in this area. For breast cancer, the two major detergents for American women appear to be obesity and diet. Some experts rate the risk for an obese woman at around twice that of a normal woman, especially after menopause. Obesity is generally defined as being 20 percent or more above desirable body weight (Byrne 28). Since estrogen is produced in fat cells, obese women have higher circulating levels of estrogen. The most presumable culprit in the breast cancer mystery would seem to be diet.
The possibility that a high-calorie diet, with a particularly high consumption of fat, is connected to breast cancer and has been supported by the kinds of studies that I will be discussing. It has been supported by lab experiments with animals and epidemiological studies that compare large populations of people. A special communication from the Journal of the American Medical Association in 1989 said, "Data from animal experiments and human correlation studies strongly support the dietary fat-breast cancer hypothesis. Animals fed a higher-fat, higher-calorie diet have a substantially higher incidence of mammary tumors than animals fed a lower-fat and calorie-restricted diet" (Chan 65). The link between a high fat diet and breast cancer is still controversial, but many international population studies have found a strong association between high fat consumption and incidence of breast cancer. 3 out of 5 studies comparing breast cancer risk and fat intake have found a modest relationship between the two (68).
A study done in 1995 suggested that a high fat diet might affect growth of an existing breast cancer tumor also (Uzzle 29). Countless studies, including the one conducted at Tufts University School of Medicine and the New England Medical Center in Boston, support this conclusion. American's have far higher rates of breast cancer than women do in most other nations in the world. Based on available evidence, the differences appear to be caused by the two factors that I have mentioned.
By changing diet, women can significantly reduce the risk of breast cancer. Many experts believe that you can reduce your risk of this disease by as much as 50 percent by following a healthy diet plan (Ryder 69). Here are some key points to remember. The first thing that you need to do is cut your calorie intake.
Study after study confirms that the more overweight the woman, the higher her risk is. According to a brand new study of Asian-American women from Dr. Ziegler, women who gained 11 pounds within the previous 10 years had twice the risk of developing breast cancer compared with the women who had now weight change (76). In the same new study, losing weight in the previous decade was associated with a 30 percent decrease in the risk of developing breast cancer (77). The second thing that you need to do is eat more fruits and vegetables. A goal of 5 fruits and vegetables a day is a good start.
Many studies show that women who eat lots of fruits and vegetables are less likely to get breast cancer. In one recent study, women in New York State who ate more than 5 servings of vegetables a day had half of the risk of developing breast cancer than those who ate fewer than 5 servings (Journal of the National Cancer Institute, March 20, 1996). The same study showed that eating a wide variety of produce had the same effect. A third way to greatly reduce your risk of breast cancer is to eat more fiber. 30 grams or fiber a day is optimal. David Rose, MD, of the American Health Foundation in New York reported that 30 grams of fiber a day dropped women's estrogen levels by 20 percent, thus reducing the risk of breast cancer.
Finally, keeping fat intake to about 20 percent of your total calorie consumption will reduce your risk of developing breast cancer. There is new research that is reporting lower rates of breast cancer in countries around the world where fat consumption is lower. Even with the same country, take Japan for example, breast cancer risk rises as women consume a larger bulk of calories from fat. In one experiment that was conducted, Dr. Sherwood Gor bach and Dr.
David Zimmerman were researching the differences in estrogen levels between women who consumed a rich, typically American diet, and others that consumed less fat and more fiber. For the study they chose women between the ages of 20 and 30. The subjects could not take any drugs or have any illnesses that would affect their hormone levels. They also had to be very close to their ideal body weight and not be dieting. The aim was to find women with these characteristics who ate either a typical American diet, or were strict vegetarians. The non-vegetarians ate all major food groups of animal food.
The vegetarians followed a special diet that excluded meat but allowed milk, eggs, and fish. Ten omnivores and ten vegetarians were finally included in the study. The collection of data took 2 years. Analysis by nutritionists, biologists, and various specialists took and additional 2 years. The most important discovery was this: Diet has a major influence on estrogen levels. Higher levels of estrogen in the bloodstream lead to a greater exposure of breast tissue to these circulation hormones, which thereby increases the risk of breast cancer.
Vegetarian women excreted more estrogen than did omnivores. These findings were consistent during the 2-year period in which these women were observed. Besides learning about estrogen's importance in this experiment, they also learned a lot about the eating habits of American women. A typical American woman eats about 12 grams of fiber a day, and 40 percent of calories consumed are from fat. This study indicated that diet is a major factor in determining the estrogen levels in a woman's body. Another study similar to the one just mentioned was done in Hawaii.
It showed that a low-fat diet is associated with significantly lower levels of estrogen in the bloodstream also. Several theories have been developed to explain how diet influences these differences in the body's disposal of estrogen. One theory focuses on the high amount of fiber consumed by vegetarians and Asian women. Another possibility is that some properties of a vegetarian diet (probably the low fat content), slows down the metabolic activity of the intestinal bacteria. These bacteria act on estrogen in the small intestine to prepare it for reabsorption into the bloodstream.
Without this bacterial activity, the estrogen simply is excreted into the stool. Around this point in the study, things got very complex and scientific. I gleaned that the main finding of this study was that there is strong scientific evidence suggesting that the most protective step women can now take to prevent breast cancer is to eat less fat and more fiber. Study after study showed that a low-fat and high-fiber diet lowers the levels of estrogen in the bloodstream, and a woman can break the deadly chain of events linking estrogen to breast cancer by altering her pattern of eating. In conclusion, I would like to say that researching for this paper really opened my eyes to how our surrounding environment affects us. Article after article talked about all of the things you could do to reduce the risk of breast cancer-A low-fat diet being the major one.
My aunt died of this horrible disease, and I only wish that she had known all of the information in this paper back then. I am grateful that studies are being done on this women's health issue, because so much more that we can learn.