Does Diet Impact Risk Of Breast Cancer?

Archived Content

  • Print

Almost 200,000 women will be diagnosed with breast cancer this year in the U.S. and about 40,000 will die. October is National Breast Cancer Awareness Month and Friday is National Mammography Day. QUESTION: DOES DIET HAVE ANYTHING TO DO WITH BREAST CANCER? Diet does affect breast cancer, but not in the way most people think it does. A seven year government study involving 3,000 women found that a low fat, high fruit and vegetable diet does not prevent breast cancer. Researchers have analyzed dietary fat separately and found no correlation between high fat diets and breast cancer, but they found certain fats like trans fatty acids (hydrogenated fats and deep fried foods, bakery, chips and candy bars) and omega-6 polyunsaturated fats (corn oil and safflower oil) increase risk. A study with 7,000 women published earlier this year in the International Journal of Cancer found that women who eat meat and dairy foods may have a decreased risk of breast cancer. This study also found eating a high starch and vegetable protein diet increased breast cancer. Researchers at the Harvard School of Public Health also found an association between high carbohydrate intake and breast cancer due to elevated levels of insulin and insulin-like growth factors. Insulin contributes to higher circulating levels of biologically active estrogens. Ninety percent of breast tumors are insulin-receptor positive and over-express insulin-like growth factors. QUESTION: DOES THIS MEAN WOMEN SHOULD FOLLOW A LOW CARB DIET? Researchers found the strongest association between sucrose and fructose and breast cancer. The recommendation is to significantly reduce your consumption of sweets and refined carbohydrates while increasing fiber. Insoluble fiber intake may lower breast cancer risk because it slows carbohydrate absorption and lowers glycemic response and insulin levels. Eating foods like oatmeal, barley, quinoa and buckwheat plus squash and green vegetables may help, but researchers point to changing lifestyle factors to reduce breast cancer. QUESTION: WHICH LIFESTYLE FACTORS AFFECT BREAST CANCER? The risk of breast cancer increases with age. As you get older your risk increases, but there are certain lifestyle factors that affect breast cancer and you do have some control over them. BREAST CANCER RISKS: Weight gain – less than 10% Abdominal fat – waist below 31” Little or no exercise Too much alcohol – more than 1 drink daily Women with waist measurements greater than 34 inches were 30 percent more likely to develop postmenopausal breast cancer than women whose waists measured less than 28 inches. Breast cancer risk increased due to the estrogens produced by fat tissue in the abdomen. Women over 40 who weigh close to what they did in their 20s, are less likely to get breast cancer. Ideally gain no more than 10 percent of body weight during adulthood. If you weighed 120 pounds in college, you should weight no more than 132 pounds throughout adulthood. Women who gain more than 38 pounds during pregnancy had a 40 percent higher risk of developing breast cancer after menopause. The higher blood levels of estrogen during pregnancy fuel the growth of abnormal cells that become malignant years later. Physical activity protects women against breast cancer. Regular exercise reduces insulin levels which reduces the growth of abnormal cells, and exercise lowers circulating estrogen. The longer women breast feed, the more protection they have: one year cumulatively. Many, many studies have found a link between alcohol and breast cancer. Having just two drinks a day increases breast cancer risk by 40 percent, but American women who drink alcohol and also take the supplement folate, tend to have a lower risk for breast cancer. QUESTION: IS THERE ANYTHING ELSE TO PREVENT BREAST CANCER? Lack of vitamin D may double the risk of breast cancer. Women with the lowest vitamin D levels are at the greatest risk. Spend 10-15 minutes in the sun most days and eat vitamin D rich foods and supplements: eggs, salmon, herring, sardines, Swiss cheese, milk. Women who ate the most eggs when young had lowest risk. Fish oil inhibits mammary tumor cell growth.