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Breast cancer isn’t just one disease, it comes in many variations. One of the main factors in determining the type of breast cancer is the sensitivity of the tumor cells to estrogen. If a breast tumor is hormone sensitive—or estrogen positive—it means there are specific estrogen receptors on the tumor cells, and when estrogen binds with these receptors, it transfers a message to the cancer cells. Like a lock and key effect, the breast tumor cells are stimulated by estrogen to grow and reproduce. Therefore, one of the main goals of therapy or intervention with hormone-positive cancer is to reduce hormonal stimulation as much as possible. Here are some key strategies:
Maintain a Healthy Weight
The ovaries make estrogen during the years before menopause, but it’s also made in fat cells where enzymes convert other hormones to estrogens. After menopause, fat is the primary source of estrogen production in the body. This means that weight is a critical factor in determining estrogen levels, for both pre- and post-menopausal women. Dietary choices and activities that promote a healthy weight are essential to any estrogen-reducing program.
Research has shown that cholesterol byproducts are able to bind to estrogen receptors and stimulate tumor growth. Elevated cholesterol levels are associated with breast cancer.
Minimize Exposure to Heavy Metals
Heavy metals including copper, cobalt, arsenic, cadmium, mercury, and lead have been found to stimulate estrogen receptors. Sources of arsenic include some brands of rice, seafood, and well water. Cadmium is high in cigarettes and can be found in some soils. Mercury is mainly prevalent in larger fish and old dental amalgams. And lead contamination is a component of air pollution, paint and dyes, and ceramic glazes, among other sources.
Heavy metal and toxin exposure is difficult to completely avoid, even with careful choices. Because of this, I advise my patients to use compounds that provide safe, gentle detoxification of heavy metals and other contaminants.
Modified citrus pectin, (MCP) has been shown in human studies to remove harmful heavy metals and reduce toxic body burden over time. MCP is able to cross the intestinal barrier and circulate in the bloodstream, where it binds to toxins and heavy metals and helps safely excrete them-without removing essential minerals. I also recommend alpha lipoic acid, N-acetyl cysteine, garlic, cilantro, and other herbs and nutrients that provide support for the body’s complex detoxification systems.
Many chemicals used in agriculture, body care products, food packaging, and plastic water bottles are estrogenic, called “xenoestrogens” or “estrogen mimics.” In addition to binding with estrogen receptors, these toxins are fat soluble, so they tend to accumulate in fat cells. We know that breast tissue has a high concentration of fat, particularly after menopause. Studies have shown that breast milk often contains dangerous levels of these chemicals. Reduce exposure by avoiding plastic food and beverage containers, canned foods, and body products that contain these toxins. For a list of chemicals to watch out for, visit the Environmental Working Group.
Diet and Estrogen Levels
Determining the effects that specific foods have on breast cancer risk and protection is an active area of research, with a number of controversies still unresolved. What we do know is this:
- Regular alcohol use increases breast cancer risk. An excellent literature review noted that even moderate alcohol consumption led to a 30–50 percent increase in breast cancer risk.
- Fatty red meat has been associated with increased breast cancer, especially meats cooked at high temperature.
- A 2008 study of more than 15,000 women found that high-fat food choices were significantly associated with increased cancer risk. Among other negative effects, fat intake increases estrogen levels.
- A 2013 study found that intake of high-fat dairy, but not low-fat dairy, was related to a higher risk of mortality after breast cancer diagnosis.
- Cruciferous vegetables, such as broccoli, cauliflower, kale, and collards, contain a wealth of beneficial compounds, including diindolylmethane (DIM), which promotes healthy estrogen metabolism. The botanical breast health supplement BreastDefend contains DIM, and has been shown in multiple studies to strategically support breast health.
- A high fiber diet promotes the binding of estrogens in the colon, and has been shown to reduce the risk of breast cancer.
- Green tea is a true star in terms of its anticancer properties, with many studies on its multiple anticancer mechanisms.
Phytoestrogens and Soy: the Debate
Phytoestrogens are compounds that have a mild estrogenic effect and are found in whole grains, nuts, and seeds, as well as many other botanicals, fruits, and vegetables. These foods are associated with a reduced risk of breast cancer as well as reduced cancer recurrence.
The controversy becomes heated in the debate over soy-containing foods. This issue is complex, with some studies showing that eating soy early in life can reduce breast cancer risk. On the other hand, consumption of concentrated soy extracts showed increased proliferation of breast cancer cells. Finally, other studies show a protective or neutral effect from whole soy foods.
My recommendation for soy is to eat whole soy foods in moderation—no more than a few servings per week, preferably fermented soy foods such as miso or tempeh. Avoid soy protein isolates and supplements containing concentrated soy isoflavones.
Other Dietary Tips
Keep your vitamin D levels in the high normal range with some sun exposure and appropriate supplementation. Vitamin D beneficially influences a large number of genes involved in the regulation of cell growth and metabolism.
Use olive oil and foods high in omega-3 fats including wild-caught Alaskan salmon and sardines, flax seeds, and walnuts. And diversify your diet to minimize your reliance on animal protein sources. Any animal protein you do eat should be lean, organic, and grass fed to avoid potential chemical and hormonal additives. And completely avoid sugar and processed foods.
By understanding the ways that estrogen levels increase, and other ways in which these receptors can be stimulated, we can make wise choices and engage in activities that will minimize activation of estrogen receptors in breast cells. We can also boost overall vitality in the process-a win/win situation.