A Four-Part Series by Susan Silberstein, PhD, Center for Advancement in Cancer Education
Research has demonstrated that poor dietary choices in terms of fats, proteins and carbohydrates can definitely increase the risk for breast cancer. Fats are important in three ways: the amount of fat, the type of fat and the quality of fat. On a high fat diet, the breast-cancer promoting hormone estradiol increases; on a low-fat diet, it decreases (Journal of the National Cancer Institute, 1990). A high fat diet also promotes storage of xenoestrogens, synthetic chemicals that mimic estrogenic activity in breast tissue, from sources like pesticides, bleached paper products, plastic food containers, and especially bovine growth hormones added to meat and dairy products. These carcinogenic hormones and chemicals are lipophilic – that is, they love fat, they live in fat, and they
don’t metabolize out of fat; so if a woman has a high fat diet or a lot of fatty tissue on her body, she will store a lot of these dangerous compounds.
The type of fats is important as well. In general, saturated animal source fats are associated with increased risk for all cancers, while unsaturated plant source fats are more protective. However, there are differences in breast cancer risk among the unsaturated fats too. While omega-3 fats up-regulate immunity, omega-6 fats tend to suppress immune function. The latter are prevalent in soybean oil, safflower oil, sunflower oil, corn oil, and cottonseed oil, for example. Omega-6 fatty acids have a booster effect on breast cancer (Archives of Internal Medicine, 1998). Researchers studying 61,000 women noted that regular consumption of these fats increased breast cancer risk by 69%.
One final aspect of fats is their quality. Fats are very unstable and break down quickly when exposed to air, light or heat. When exposed, they oxidize, become rancid, and produce free radicals — dangerous compounds implicated in the aging and cancer-forming processes of all cells. Food manufacturers often add hydrogen to the omega-6 rich plant oils to make them solid at room temperature; that process produces carcinogenic transfats. In a European study of 700 post-menopausal women, researchers found a 40% increased risk of breast cancer among those women consuming a lot of hydrogenated fats in margarine, fried foods or baked goods (Cancer Epidemiology, Biomarkers, and Prevention, 1997).
Moving on to proteins, high animal protein is associated with risk for breast cancer. First, a diet high in animal protein often contains high animal fat. Second, a high protein diet raises the levels of prolactin, another hormone that can stimulate breast cancer growth (Cancer Research Journal, 1977, and Journal of Endocrinology, 1983). Of major concern is bovine growth hormone administered to western cattle beginning in the 1950’s, paralleling the rise of breast cancer in the United States. Among those consuming the most red meat, a New York study of 14,000 women found a 25% increased risk of breast cancer, and a study in Uruguay showed up to a 770% increase in risk. In a study of nearly 26,000 women, those who ate meat more than five times per week had 2.5 times greater risk for breast cancer than those who ate meat fewer than two meals per week (International Journal of Cancer, 1995).
Another source of animal protein is cow’s milk and dairy products like cheese. These foods often contain added growth hormones, but even organic milk products without added hormones contain insulin-like growth factors that will stimulate existing cancer cells to grow. Before the Berlin Wall came down, East Germany suffered dairy shortages – and shortages of breast cancer, while West Germany had plentiful dairy consumption – and plentiful rates of breast cancer. In general, countries that consume less dairy have lower rates of breast cancer than those that consume more dairy. The U.S. and the Netherlands, for example, have very high rates of both dairy consumption and breast cancer, whereas Singapore and Korea have very low rates of both.
Let us look at carbohydrates, especially refined carbohydrates like white sugar and flour. High sugar intake is a major risk factor for breast cancer in women over 45. Sugar increases insulin levels, and insulin is a strong promoter of cell growth. Since there are insulin receptors on the surface of breast cells, insulin can create the estrogen effect.
Scientists at the University of Toronto found a 283% increased risk of breast cancer in women with high insulin levels. According to some researchers, high levels of insulin and insulin-like growth factor are actually causative for cancer of the breast (Proceedings of the Nutrition Society of Australia, 2001)! High dietary sugar provides cancer cells their preferred food and reduces the body’s ability to mount an immune response.
The caffeine family also contributes to increased risk of breast cancer. Caffeine and related chemicals are found in coffee, tea, colas, orange soda, Mountain Dew, peanuts, cheese and – heaven forbid! – chocolate. Consumption of these foods and beverages promotes breast dysplasia, gradual cellular changes towards malignancy. Some surgeons restricting the caffeine family prior to biopsy have actually seen breast lumps shrink or even disappear within weeks.
The last negative dietary influence on breast cancer risk is alcohol. According to the U.S. National Cancer Institute, alcohol elevates serum estrogen levels, especially estradiol, in both pre- and post-menopausal women. In a study of nearly 16,000 females conducted at the University of California at Los Angeles, those women who averaged one drink per day (beer, wine or mixed drink) were 39% more likely to develop breast cancer than those who did not drink. Furthermore, a review of three separate studies published in the New England Journal of Medicine showed up to a 60% increase in breast cancer among women consuming one or more alcoholic beverages daily.
So alcohol is bad, coffee is bad, meat is bad, dairy is bad, sugar is bad – there’s nothing to eat!!! Stay tuned for the good news in part 3 of this series.