Question: Is there any evidence that avoiding dairy products might lessen the chance of breast cancer recurrence?
Ms. Barkai: The relationship between an initial breast cancer and dairy consumption has been examined in many studies. Some researchers have hypothesized that the fat content and possible hormone residue in dairy foods could increase risk for breast cancer, while others have speculated that the vitamin D that is added to some dairy foods could have a protective effect. However, dairy food consumption has not been consistently associated with breast cancer risk or progression in either pre- or postmenopausal women in the studies.
Question: What are your recommendations on total calcium daily intake after breast cancer treatment? Please specify how much calcium in foods vs. in supplements. Is there a difference in your recommendations based on whether one had chemo or not?
Ms.Barkai: Women diagnosed with breast cancer are at increased risk for osteoporosis and should consume 1,200 mg of calcium per day. Ideally the calcium will come from foods such as low-fat dairy products, dark leafy greens and fortified products, because these foods provide other nutrients as well.
A serving of low-fat dairy product (one cup of low-fat milk or yogurt or one ounce of cheese) will supply about 300 mg of calcium. Following the recommendation of three dairy food servings per day and increased vegetable intake will thus result in adequate calcium consumption.
Vitamin D is important for absorbing calcium, and since many dairy products are fortified with vitamin D, consumption of low-fat dairy foods will help by providing vitamin D as well. Dark leafy greens (such as kale, spinach, collards and others) are also rich in magnesium and vitamin K which are important for bone health.
Nevertheless, if you know you are not getting 1,200 mg of calcium from foods, you can benefit by taking a supplement. The maximum safe level for calcium consumption is 2,000 mg, so it’s important not to go over that level. Calcium absorption is best at levels of up to 500 mg at a time, so if you need to take more than that, split the dose and take it twice a day.
Both calcium carbonate and calcium citrate are effective. Calcium carbonate products should be taken with food, while calcium citrate can be taken on an empty stomach. When choosing a supplement, look for a brand-name supplements with proven reliability. Look for labels that have the USP (United States Pharmacopeia) symbol.
Chemotherapy has some adverse effects on bone. Because women who have been diagnosed with breast cancer are at increased risk for fragile bones for multiple reasons in addition to chemotherapy, they should consume 1,200 mg of calcium per day.
Question: If being overweight can give you cancer and you had a mastectomy, is this still true or is your risk lower because you don't have breasts any longer and you don't have to worry about the extra weight? Or can you get cancer elsewhere?
Ms.Barkai: Breast cancer can come back as a local recurrence (since you had a mastectomy, it can come back at the mastectomy scar area, for example) or somewhere else in the body (most often in the lymph nodes, bones, liver, lungs or brain). Body fat increases estrogen levels, insulin levels and inflammation that promotes cancer cell growth regardless of the site. We don’t know yet if weight loss will reduce breast cancer recurrence rate (this is what current studies are testing), but there is a good reason to believe it could.
Regardless, if you are overweight or obese, losing 5-10 percent of your body weight reduces risk for other diseases such as heart disease and diabetes. Thus, losing this weight is recommended.
Question: I am bombarded by information suggesting that if I eat or had eaten a healthier diet, I would not have breast cancer. I have been told that weight correlates to breast cancer, and the implication is that if I have a BMI of 18, I am less likely to relapse than if I have a BMI of 23. Is there any medical evidence to sustain this? What is your opinion?
Ms.Barkai: Postmenopausal women with a healthy body mass index (BMI) of 18.5–24.9 are less likely to get breast cancer than overweight or obese women. Some of the possible mechanisms in which fat increases cancer cell growth are elevated estrogen, insulin and inflammation levels that result from extra body fat.
BMI below 18.5 is considered underweight and is not necessarily indicative of good health. Most studies do not differentiate the healthy BMI range of 18.5–24.9 to subcategories when looking at breast cancer and recurrence rates, so there is no evidence on which to base conclusions about different degrees of risk across that range.
Question: There is conflicting information about soy in the diet of breast cancer survivors. What is most prudent?
Ms. Barkai: For women diagnosed with breast cancer, current research finds no harmful effects from eating soy foods. However, soy or isoflavone supplements are not recommended because there is not sufficient research data on whether high dose concentrated supplements influence risk for cancer recurrence or progression.
Question: As a lifelong tai chi practitioner I get daily range-of-motion exercise. However, this does not elevate my heart rate. I do it because I love practicing the forms, but is this kind of exercise also helpful for breast cancer survivors?
Ms. Barkai: Tai chi is an excellent mind-body practice that reduces stress, improves range of motion and balance and, to some degree, also improves muscle strength. However, in order to improve your aerobic fitness and help with fat loss (if needed), incorporating a daily aerobic workout (such as walking, biking or swimming) will be beneficial. Enjoyment is a big part of a keeping a healthy lifestyle, so please keep enjoying tai chi and add an aerobic workout to your daily routine.
Question: Is it best to buy all organic fruits and vegetables? I have triple-negative breast cancer.
Ms. Barkai: Vegetables and fruits provide healthy bioactive food components such as phytochemicals, vitamins and fiber and are a big part of a healthy diet. When measuring the nutritional content, studies have generally found that organically grown vegetables and fruits are no different than those that are conventionally grown. Currently there are no studies that show any risk in eating conventionally grown vegetables and fruit. Taste and budget should lead your choice.
However, if you are concerned about pesticides and herbicides, purchase organic produce if the conventional ones might possibly have higher levels of pesticides. (The Environmental Working Group maintains a list of such fruits and vegetables.) Whether organically grown or not, it is important to always wash your fruits and vegetables before consuming them.
Question: I spoke with a nutritionist when I was first diagnosed with metastatic breast cancer. She advised no alcohol at all. Would you agree with that? I know other stage IV patients have an occasional glass of wine.
Ms. Barkai: Although alcohol consumption has been consistently linked with modestly higher risk of incident (first) breast cancer, the evidence that it might contribute to recurrence or affect survival is mixed. Unless there is a contraindication with medications or a specific medical condition (such as liver insufficiency), enjoying a glass of wine occasionally is unlikely to pose adverse effects or affect survival.
Question: I am getting ready to start chemo for triple-negative breast cancer and I'm in Germany, which can at times be a different world. The gynecologists here deal with female cancers. I asked about nutrition and what to eat last week when I met my chemo gyno. I'm already vegetarian. His response was that I should eat what I want and should eat meat. Can you generally outline what you consider a healthy diet for chemo and after?
Ms. Barkai: The American Cancer Society Nutrition and Physical Activity Guidelines for Cancer Survivors working group of experts thoroughly review diet and exercise through cancer treatment and after. The summary of evidence and recommendations is available at http://www.cancer.org/cancer/news/news/guidelinesaddress-diet-exercise-and-weight-control-for-cancer-survivors.