Ask the expert: Q & A on breast cancer, exercise and diet


Jennifer Ligibel, MDJennifer Ligibel, MD 

Dana-Farber Cancer Institute partnered with CancerConnect so that patients could ask Jennifer Ligibel, MD, their questions about breast cancer, exercise, and diet. Dr. Ligibel is a medical oncologist in the Susan F. Smith Center for Women's Cancers at Dana-Farber Cancer Institute. She is also an assistant professor of medicine at Harvard Medical School. Dr. Ligibel has authored several papers on the role of lifestyle factors and breast cancer, including a recent study on the impact of exercise on reducing drug-related joint pain. 

Lifestyle factors, breast cancer and depression

Q: Are there any 'lifestyle' factors — diet/nutrition — that might help with anxiety and depression? (I didn't seem to have these issues until after my breast cancer diagnosis.) 

Dr. Ligibel: There are many studies that show that exercise has a positive impact on anxiety and depression. Studies suggest that fairly modest amounts of exercise can improve mood. We generally recommend that women start slowly and check with their physicians before starting an exercise program, but research suggests that moderate physical activity, such as walking, is safe for most breast cancer survivors and can have many positive health effects.

Although information is more limited in cancer survivors, there is also evidence that weight loss can have a positive effect on depression in women.

Health benefits of green tea or turmeric

Q: What do you think of the health benefits of green tea, specifically Matcha green tea? Also, what about turmeric? 

Dr. Ligibel: There is a lot of interest in the health benefits of specific supplements, but not much evidence that these products have any benefits for cancer survivors. Green tea has been studied as a potential nausea-preventing intervention, but the results of these studies have been mixed. Some preliminary results from animal studies have suggested health benefits from turmeric, but it is too early to know whether either of these supplements will eventually be shown to be beneficial for cancer survivors.

It is important to note that green tea and turmeric, like most supplements, are foods rather than medications. This means that they are not regulated by the FDA. Companies that produce them can make all kinds of health claims as long as they include the statement that the claims are not supported by the FDA. This can be confusing for patients, as many of these products are marketed as "cancer-fighting."

Optimal types of fat

Q: I'm a 9-year breast cancer survivor. I've seen studies which favor a low-fat diet to reduce the risk of breast cancer and recurrence. These studies do not specify types of fat. Do they look at or compare trans fats; fat from meat, dairy, and processed foods; fats from nuts, seeds, olive oil, coconut oil, etc.? I am mostly vegetarian, and my diet is actually fairly high in fat since my protein comes from nuts, seeds, and some eggs. What is your sense about high fat vs low fat and if the types of fats consumed contribute to higher or lower risk? I'd like to believe that healthy fats are not risk factors! Thank you. 

Dr. Ligibel: The study that showed that eating a low-fat diet reduced the risk of breast cancer recurrence — called the Women's Interventional Nutrition Study or "WINS" — was largely conducted in the 1990's, when there was not as much of a focus on different types of fat. Thus, there is, unfortunately, not a lot of evidence to provide an answer for your question about the impact of different types of fat on breast cancer recurrence rates.

However, in the years since the WINS study, research in other diseases, such as heart disease, has shown that all fats are not equal in terms of the impact that they have on a person's risk of developing different diseases. There is also evidence from population studies to suggest that individuals who consume healthy fats seem to be at lower risk of some kinds of cancers, although we can't determine if there is a cause-and-effect relationship between the types of fats a person eats and their risk of cancer from this kind of study.

A number of ongoing studies are looking at whether there is a "best" diet for breast cancer survivors, but evidence is not conclusive at this point. Some evidence suggests that keeping weight in a good range might be more important than specific dietary ingredients. The National Heart, Lung and Blood Institute, a group that prepares many of the recommendations about weight and diet for the US population, currently supports the use of a number of diets to maintain a healthy weight.

Thus, there is no simple answer to your question, but if your diet is successful in keeping your weight in a good range, it is likely a reasonable plan for you to continuing following.

Exercise and health benefits

Q: I have a very physically demanding job where I move at a great clip outdoors for at least 3-4 hours each day. When I am done work I have no energy for formal exercise (especially since BC treatment and Tamoxifen), just stretching or a little yoga. Is this enough? 

Dr. Ligibel: Studies have shown that physical activity, no matter how it is achieved, is linked to better outcomes in breast cancer. Sometimes it is hard to know how much activity a person is doing as part of a work day, so one way to make sure that you are doing enough exercise is to wear a pedometer to track the distance you walk each day as part of your job and during your leisure time. You should aim for 10,000 steps per day. If you are accomplishing this much walking during your average work day, you are likely achieving enough physical activity to provide health benefits.

Weight gain/weight loss

Q1: I am taking anastrozole. It is very difficult to lose weight. Do you have any suggestions as to offsetting the effects of this medication on weight loss? What should the majority of the diet include, and what should be omitted in order to lose weight? 

Dr. Ligibel: There are many reasons why woman with breast cancer gain weight or have difficulty in losing it after breast cancer diagnosis. Some women go through menopause as a result of chemotherapy or other cancer treatments. The average woman who undergoes a "normal" menopause (not due to cancer treatment) will gain 5-10 pounds in the years after her menstrual cycles stop. This weight gain can be even greater when it occurs suddenly as a result of breast cancer treatment. Many women also feel fatigued as a result of their breast cancer therapy and become less physically active. Studies have shown that weight gain is not increased in women taking tamoxifen or anastrozole, but it is harder to study the effects of these drugs on a woman's ability to lose weight.

Regardless of the reasons for weight gain, weight loss requires calorie reduction. This can be accomplished in many ways. A diet that is low in fat and high in fruits and vegetables has been a standard for weight loss for many years, but low-carbohydrate, vegetarian, low-glycemic index, and Mediterranean diets can also be used to lose weight. Many people find keeping a journal of what you eat and drink is a first step to understanding your eating patterns. You might be surprised by "hidden" calories you are consuming. Some people also find a structured meal plan to be helpful when starting a weight loss program. Commercial programs can also be useful to teach you how to recognize where your calories are coming from and create new eating patterns.

Q2: I was diagnosed with Stage 4 inflammatory breast cancer last July at the age of 31. I am currently on maintenance treatment and need to lose about 40-50 pounds. I lost a lot of my strength during treatment, and I am a pretty picker eater who hates to cook. The thought of having to lose that much weight is so overwhelming, even though I know it will help to decrease recurrence. Can you tell me what 2 or 3 things (whether nutrition- or exercise-related or both) I can start with? 

Dr. Ligibel: It can be daunting to know where to to start when you would like to lose a lot of weight. We find that people are most successful when they start with an attainable goal. Studies have shown that smaller amount of weight loss, 5-10% of your starting body weight, can have many benefits, even if people can't lose 50 pounds.

I would recommend that you start with keeping track of what you eat for a week. Look for "hidden" calories like soft drinks, alcoholic beverages, or juices, which are high in calories and not filling. Processed foods and sweets are also very high in calories with less nutritional value. Try to limit the amount of these you consume.

Start slowly with exercise if you have not been active. Make a plan to start with walking at a moderate pace for 10-15 minutes three times per week and gradually increase to every day, and then for longer periods of time.

Joining a group program (like Weight Watchers) can also be helpful for some people, or working with a weight loss "buddy," a person with whom you can explore low-calorie recipes and exercise, works for some people.

Soy

Q: My question concerns tamoxifen, nutrition, and products that contain soy. I was diagnosed 1/19/12 with invasive ductal carcinoma PR+ ER+ HER2+ and received bilateral lumpectomies, no lymph node involvement either side, 16 taxol/herceptin weekly infusions, 33 radiation rounds, 4 A/C, and the year's course of herceptin. I have been taking tamoxifen for the last year and a half and have read conflicting information about soy products. 

Although my hot flashes have subsided a bit, they do keep waking me up at night. I realized that many protein-rich yogurts and nutrition bars have traces of soy in them. I considered soy as a supplement initially but decided against it, since the research appeared to be "out" on the final word (soy mimics estrogen but does it tend to promote my type of estrogen-driven cancer?). What are your thoughts on how much soy is good or harmful in contributing to recurrence? 

Dr. Ligibel: There is a lot that we do not know about the relationship between soy and estrogen-driven breast cancers. Early studies showed that high doses of soy led to breast cancer formation in lab experiments, but it is not clear whether this amount of soy was remotely similar to what a woman could consume through diet. A number of recent reports looking at the diet patterns of women in Asia and the US suggested that the risk of breast cancer recurrence was not increased by soy intake. Although there are some difficulties in using this information to completely conclude that soy intake is "safe" for breast cancer survivors, most experts at this point feel fairly confident that some soy intake in the diet is unlikely to be dangerous for breast cancer survivors. This means that it is likely not necessary to be reading food labels to avoid products containing soy, but I would personally stop short of endorsing soy as a supplement for a breast cancer survivor.

Foods to avoid

Q: Are there any specific foods we should stay away from specifically if you are positive to estrogen? 

Dr. Ligibel: There is a lot of debate regarding the use of soy products in women with an estrogen-positive breast cancer (see question above regarding soy). Other foods also contain phytoestrogens, which are plant-based substances that are similar in structure to hormonal estrogen but come from plant sources. There is not a lot of definitive evidence about the risks or benefits of any of these products in women with breast cancer, but as a general rule, the moderate amounts of most of these substances in foods are considered safe.

Therefore, I would not say that there is good evidence that any food needs to be avoided for women with breast cancer, but soy products, flax seed, and alcoholic beverages (which also increase estrogen in some situations) should be taken in moderation.

Diet/exercise resources

Q: Do you have any recommendations for books or resources that would be a good guide to helping with navigating the best things to do for nutrition/exercise after breast cancer 

Dr. Ligibel: The American Cancer Society has developed a set of diet and nutrition guidelines for cancer survivors that is available on its web site.

The American Society of Clinical Oncology has also made "Obesity and Cancer" one of its primary initiatives this year and will be releasing a set of materials about weight, nutrition, and diet for cancer survivors in the next few weeks. These materials will be available in print and online through their website, www.cancer.net.

Neuropathy

Q: Can diet or exercise help neuropathy from chemo? 

Dr. Ligibel: There is not a lot of evidence that diet or exercise can help neuropathy from chemotherapy. There are studies looking at glutamine, a supplement, but this product seems to work best while an individual is receiving chemotherapy treatments. Ongoing studies are looking at acupuncture as a potential treatment for chemotherapy-induced neuropathy.

Prevention

Q: What should we tell our daughters, sisters, mothers, wives, girlfriends about diet/exercise to help them prevent breast cancer? 

Dr. Ligibel: There is a lot of evidence that a "healthy" lifestyle — keeping your weight in a healthy range, exercising regularly, and consuming a diet that is higher in fruits and vegetables and lower in fat — could reduce the risk of developing breast and other cancers. This doesn't mean that these behaviors are 100% effective in preventing breast cancer or that people who don't do any of these things will necessarily develop breast cancer, but the evidence does suggest that maintaining a healthy lifestyle should be part of a cancer prevention strategy.

General nutrition and physical activity recommendations from the American Cancer Society for Cancer Prevention include the following:

  1. Stay active: perform at least 150 minutes of moderate-intensity aerobic exercise each week, such as walking at a brisk pace.
  2. Consume a healthy diet that is low in fat and high in fruits, vegetables, and fiber.
  3. Maintain your weight in a healthy range, and attempt weight loss if you are overweight or obese.
  4. Limit alcohol to no more than 1 drink per day for women and 2 drinks per day for men.

Immune system

Q: My questions are: 1) Does boosting the immune system help prevent breast cancer? 2) Is there a diet that boosts the immune system (I am a vegetarian)? 3) I just read something about a study showing that a vegetarian diet is linked to poor health — what does this mean to me as a breast cancer survivor? 

Dr. Ligibel: There is a lot that we do not know about the biology that links nutrition and exercise to breast cancer. Some scientists have hypothesized that the immune system may play a role in this connection, but there is little conclusive evidence. Similarly there is not much known about how specific foods or supplements affect the immune system, so I would not recommend a particular diet to enhance the immune system.

Finally, vegetarian diets can be very healthy, as long as they contain a good balance of essential nutrients. It can be hard to consume enough protein, for example, for individuals who maintain a vegetarian diet. As long as you ensure that you consume a balanced diet, there is no reason why a vegetarian diet would be unhealthy. If you have specific concerns regarding your diet, I would recommend meeting with an oncology nutrition specialist.

Diet/exercise to help with fatigue

Q: I have metastatic breast cancer — have been on multiple treatments for what seems like forever. I am grateful to be alive but am beginning to feel what I assume are the cumulative effects of all of my treatments. Are there any recommendations for food or exercise that might help with my fatigue? 

Dr. Ligibel: There is, unfortunately, very little information about the role of diet and exercise in patients with advanced breast cancer. However, exercise has been shown to be an effective way to reduce fatigue in many studies performed in women with early-stage cancer undergoing chemotherapy. There have been a few small studies of moderate-intensity exercise in women with advanced cancer that suggest that exercise is safe and may have benefits. I would recommend asking your doctor about starting an exercise program. As long as he or she is supportive, I would recommend slowly starting to exercise. It is important to set reasonable goals, and begin slowly. If you have not been exercising at all, even just walking around the block once per day can be a good start. Build up the time that you spend exercising each week, and you will likely begin to see some benefits in terms of your energy level.

Maca

Q: I am taking femara for ER & PR + stage III breast cancer. Is it safe to take maca to help manage side effects of the AI? 

Dr. Ligibel: There is unfortunately no safety data for this supplement for women with breast cancer.

Please note: The information above is general in nature and is not intended as a guide to self-medication by consumers or to substitute for advice provided by your own physician or other medical professional. 


 
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