One of the best defenses against breast cancer may well be diet. A growing and impressive body of research reveals that what you eat and drink can help protect you from the disease. Below is a list of five foods that every woman should include in her regular diet—the sooner, the better. All of them are part of the anti-inflammatory diet I recommend for optimum health.
5 Foods to Eat
Breast cancer is estrogen driven and eating soy appears to ward off breast cancer by blocking estrogen receptors. Whole soy foods, like edamame, tofu, tempeh, and soy milk, contain weak plant estrogens that displace estradiol, your body’s more potent form of the hormone. Soy’s benefits get murkier when you consider that only about one-third of Americans can metabolize it into the form associated with greater risk reduction. And soy may be more protective when consumed before puberty, while breast tissue is forming.
“Among women with breast cancer, soy food consumption was significantly associated with decreased risk of death and recurrence.”
Bottom line? Soy’s potential benefits are too great to pass up—especially if you start eating it early in life (one study says protection begins in utero). I believe population studies support the consumption of soy even if you have or have had breast cancer, but this topic remains controversial, especially if your cancer is estrogen positive and you’re on tamoxifen. In this case, I suggest you consult your oncologist.
2. Fruits and vegetables.
Overwhelming evidence shows that a diet rich in fruits and vegetables helps prevent most types of cancer. Scientists suggest the protection may come from plant chemicals called polyphenols and carotenoids found in many fruits and vegetables. These compounds act as antioxidants and prevent damage to DNA that can trigger cancer growth. In fact, a recent study shows that breast cancer patients with the highest fruit and vegetable intake (and the highest blood levels of carotenoids) had a 43 percent lower risk of breast cancer recurrence compared to women with the lowest produce intake and the lowest carotenoid levels (Journal of Clinical Oncology).
“Our findings support that higher intake of fruits and vegetables, and specifically cruciferous and yellow/orange vegetables, may reduce the risk of breast cancer, especially those that are more likely to be aggressive tumors.”
I recommend that women eat at least nine daily servings of a variety of brightly colored fruits and vegetables. I also advise making one of those servings a cruciferous vegetable like broccoli, cauliflower, or cabbage; these not only provide antioxidant protection, but also help your body metabolize estrogen into a form associated with lower breast cancer risk, called 2-hydroxyestrone. Choose organic varieties when you can, especially for heavily treated produce.
3. Green tea.
It’s difficult to beat the antioxidant power of green tea. Although it comes from the same plant as black tea, the process of making green tea retains far more of the polyphenols that give the beverage its antioxidant potency. Most studies of green tea’s effect on breast cancer have been in test tubes. However, a recent analysis of epidemiological data found that drinking five cups of green tea a day reduces breast cancer risk by 22 percent (Carcinogenesis, July). I recommend everyone drink at least one cup a day.
Eating oily fish helps protect against breast cancer in two specific ways, says my colleague Victoria Maizes, MD, executive director of the Program in Integrative Medicine. First, it supplies plenty of omega-3 fatty acids, which help to metabolize the hormone into the safer 2-hydroxyestrone form. Second, oily fish contain vitamin D, which has been linked to a lower risk of breast cancer and many other malignancies (other vitamin D sources include fortified milk and soy milk, vitamin supplements, egg yolks, and liver).
Aim for two to three servings of oily fish a week, and choose Alaskan sockeye salmon, sardines, and black cod to avoid the mercury and PCBs found in other species. If you don’t eat seafood, supplement with 1 to 2 grams of fish oil a day. Fish oil might not offer all the benefits of eating fish, but supplies a convenient, contaminant-free source of omega-3s.
Flax also contains omega-3s that aid in blocking estrogen from binding to receptors and help break down estradiol into a safer form. Plant chemicals in flaxseed called lignans also seem to play a role in thwarting cancer. In one study, they were linked to slowed breast tumor growth, and there’s some evidence that lignans, and flax’s high-fiber content, can help to lower estrogen levels.
“Studies imply that flaxseed can have some protective effects in postmenopausal women“.
I suggest adding fresh ground flax seeds to your diet rather than supplementing with flax oil; the oil typically lacks the beneficial lignans and fiber. Sprinkle two tablespoons of ground seeds a day in breakfast shakes or on cereals, salads, or cooked vegetables.
5 Foods to Limit or Avoid
When it comes to breast cancer prevention, what you don’t eat and drink matters as much as what you do.
Refined foods containing sugar indirectly increase levels of insulin-like growth factor-1, which stimulates the growth of breast cancer cells.
2. Red meat.
Studies show that women who eat the most animal fat—which is rich in saturated fat—are more likely to develop breast cancer. Commercially raised beef also contains estrogen residues. If you eat red meat, choose organic, which at least has no added hormones (the same goes for all dairy products).
3. Charred meats.
Over-grilling transforms compounds in meat, poultry, and fish into cancer-causing chemicals called heterocyclic amines.
4. Partially hydrogenated oils.
These oils, used to extend the shelf life of many processed foods, contain trans fats, which have been linked in studies to an increased risk of breast cancer.
Consuming alcohol can increase levels of estrogen in the blood. But because moderate intake of alcohol also protects against heart disease, you have to weigh your risks. If you have breast cancer, eliminating alcohol makes sense. If you do drink, limit your intake to one drink a day, which a recent study suggests is all you need for cardiovascular benefits.