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November 2012 Ask the Expert: Diet and Nutrition After Breast Cancer

During the month of November 2012, Living Beyond Breast Cancer expert Suzanne Dixon, MPH, MS, answered your questions about diet and nutrition after breast cancer.

When you are either constipated or have diarrhea (no in between), is there a certain food that can control both?

I love soy products, but I was told not to eat them. What are your thoughts?

I hear conflicting guidance on wine consumption. Is it better to limit consumption to one a day, two a week or eliminate it entirely?

Does gluten play a significant role in breast cancer recurrence?

What are the effects of alcohol on triple-negative breast cancer survivorship?

What are the effects of caffeine on triple-negative breast cancer survivorship?

How do you feel about beef and breast cancer? Should you only eat free-range, organic beef?

Question: When you are either constipated or have diarrhea (no in between), is there a certain food that can control both?

 Ms. Dixon: Digestive issues are a common complaint for people who are being treated for cancer. Some of the medications used to treat cancer tend to cause loose stools, or diarrhea. Other medications used to control treatment side effects such as nausea, vomiting or pain tend to lead to the opposite problem—constipation.

Put all of this together and you end up swinging back and forth between these two extremes. This can make having a normal bowel movement difficult.

Talk to your nurse or doctor about this problem. They may be able to adjust some of your medications to help lessen these episodes of diarrhea and constipation. Fiber is great for normalizing bowel function; you just need to make sure you get the right type of fiber.

There are two types of fiber: soluble and insoluble. Soluble fiber becomes “sticky” when it gets wet. Oats, which are rich in soluble fiber, are a great example of this. They thicken up and absorb liquid. Insoluble fiber does not absorb much water,so it doesn’t change when liquid is added to it.

Think of what celery would look like if you dropped it into a glass of water. A few hours later, it would still look like that same piece of celery. That’s insoluble fiber.

For both diarrhea and constipation, you want to get more soluble fiber. For constipation only, you can add in some insoluble fiber as well. Many people find that simply taking a daily fiber supplement made up mostly of soluble fiber will lessen both diarrhea and constipation.

Ask your doctor or nurse if it is OK to add more fiber before you try a supplement. These products are considered safe for most people; however, some digestive problems may worsen with the addition of fiber.

Once you get the OK from your medical team, you can pick up a fiber supplement, such as Metamucil Clear & Natural or Benefiber powder,at any pharmacy or supermarket. Start with half a serving and plenty of water to see how your body tolerates the product.

Over several days, slowly add more fiber as tolerated to help normalize your bowel function. You can experiment with taking the supplement in the morning, the evening or both to determine what works best for you.

If you want to focus on food to get more soluble fiber, try oats and oatmeal, natural applesauce (no added sugar), lentils, pears, finely ground flaxseeds, barley and white rice. For insoluble fiber, try whole wheat and wheat bran, nuts, seeds and raw vegetables. Beans and peas contain significant amounts of both soluble and insoluble fiber. Just remember that soluble fiber is good for both diarrhea and constipation. Foods that are high in in soluble fiber are best for constipation only.

Question: I love soy products, but I was told not to eat them. What are your thoughts?

Ms. Dixon: I believe one reason so many women have concerns about soy arises from the term “phytoestrogens.” Some soy nutrients—the isoflavones—have chemical structures that look a bit like the estrogen found in a woman’s body. This is where the term phytoestrogen originated. However, it’s important to note that phytoestrogens are not the same thing as female estrogens, and soy foods do not contain estrogen.

I also believe it’s unfortunate that people think of soy in relation to its so-called “estrogenic” effects. This gives the impression that the only actions of soy are related to soy’s impact on estrogen or estrogen receptors, but this simply isn’t true.

Health experts who study soy note that it has many beneficial effects in the body, including antioxidant activity and the ability to alter cell behavior down to the molecular level. Soy foods seem to enhance a cell’s ability to withstand damage. Soy nutrients also can encourage damaged cells to die, in a process called apoptosis, before they can go on to become cancerous.

Soy can turn up the production of cell proteins that dampen cell growth and are linked with lower cancer risk. Soy can turn down the production of proteins that spur cell growth and are linked with higher risk of cancer­. Soy appears to have anti-inflammatory activities as well. The list of soy’s potential beneficial effects is impressive indeed. And none of these actions I’ve described have anything to do with estrogen.

It’s also reassuring that several large, human studies—in which thousands of women have been followed for many years—consistently show that compared with women who do not eat soy, women who regularly consume soy foods have lower breast cancer risk. Some of these studies even show that women diagnosed with breast cancer who consume soy foods have a lower risk of breast cancer recurrence than those who avoid soy. These studies have been conducted in both Asian and US populations. This is important because soy has long been a part of many Asian cuisines, but it is a relatively new introduction to the American diet.

These studies are observational, which means researchers collect diet information from women then follow them for many years to see who gets what diseases. Researchers look at a particular disease such as breast cancer and try to determine if it is related to whether or not a woman eats soy or some other food. In an observational study, it is always possible that the true connection with better breast health is not soy, but something else that is related to eating soy.

For example, suppose that women who eat soy foods also eat less fried food. Maybe they also happen to eat more vegetables, are thinner and exercise more. Any one of these factors could be the reason why soy-eating women have lower breast cancer risk.

This means that large, observational studies can’t conclusively prove that soy protects against breast cancer. However, these studies are reassuring in affirming that soy foods do not increase breast cancer risk. And they do point toward a protective effect of soy on breast health, regardless of other lifestyle and diet choices.

Because these studies are observational, I don’t believe the research evidence is strong enough to recommend that all women with a history of breast cancer eat more soy. But I am confident that soy foods are safe for women who want to eat them.

Remember that soy foods are a healthy option, while soy supplements may not be. The research on soy and breast health has looked at soy foods, not supplements.

If you are concerned about breast health, stick to healthy, whole soy foods such as tofu, tempeh, soy milk and edamame. Don’t rely on powders and pills. The occasional soy protein bar or snack food is fine, but as with all plant foods, less processed is better.

In the end, feel confident in whatever choice you make about soy foods. Eat these foods if you enjoy them, or skip them altogether if soy isn’t your cup of tea!

Question: I hear conflicting guidance on wine consumption. Is it better to limit consumption to one a day, two a week or eliminate it entirely?

Ms. Dixon: The conflicting information on alcohol consumption arises from the fact that alcohol can protect against some health conditions, but it has also been linked with increasing risk of other diseases. For example, up to one drink per day for women, or two per day for men, may lower the risk of heart disease. When it comes to cancer, however, alcohol is not helpful.

When a woman drinks alcohol, the level of estrogen circulating in her body increases. Through this pathway, alcohol can increase the risk of estrogen sensitive cancers, including estrogen-receptor positive (ER positive) breast cancer. This applies to wine, beer and hard liquor.

This matters for women diagnosed with breast cancer, too; studies suggest, at least for ER positive breast cancer, risk of recurrence increases when a woman has more than one or two drinks per week. This is far below the standard health recommendation that women consume no more than one drink per day. Beyond the estrogen connection, alcohol itself is known to be carcinogenic, or cancer-causing.

Also, keep in mind that one drink may be smaller than most people realize. A single drink is five ounces of wine, 12 ounces of beer, or 1 1/2 ounces of hard liquor. A typical large glass of wine often contains eight, or even 10 ounces. This would be two servings.

If you have a history of breast cancer and truly enjoy a glass of wine or a cocktail, I suggest that alcohol be saved for special occasions or enjoyed once per week with a nice dinner. If completely avoiding alcohol is not difficult for you, then you should avoid it.

But don’t focus only on alcohol. Regular exercise and eating at least five servings of vegetables and fruit per day have been shown to lower breast cancer recurrence risk. Healthcare providers rarely tell a woman she’s increasing her risk of recurrence by not exercising, but they don’t hesitate to tell a woman alcohol is off limits. I think it’s important to keep this in perspective.

However, the bottom line is that even a few drinks per week on a regular basis can increase breast cancer risk.

Question: Does gluten play a significant role in breast cancer recurrence?

Ms. Dixon: There is no connection between gluten and risk of breast cancer or its recurrence. In fact, numerous observational studies show that the more whole grains a woman eats, the lower her risk of breast cancer. This includes gluten-containing grains such as wheat, rye, barley and triticale, a wheat/rye hybrid.

As I’ve pointed out in some of my other Ask the Expert answers, observational studies cannot prove cause and effect. There are other health-related behaviors that may go along with eating whole grains that explain part of the connection between these foods and decreased cancer risk.

For example, suppose that women who eat lots of whole grains also eat plenty of vegetables and fruit, exercise more and don’t smoke or drink alcohol. Any of these other behaviors could be the reason why whole grain-eating women have lower breast cancer risk. Despite this, many health experts do believe that whole grains themselves have anti-cancer properties.

Whole grains contain fiber, which can help balance and lower estrogen levels in the body and stabilize blood sugar levels; they help women stay full, thereby helping them maintain a lower, healthier body weight. Whole grains contain hundreds of nutrients that appear to prevent damage in the body that can lead to cancer and its progression. For all of these reasons, whole grains—those with gluten and without—should be a regular part of the diet.

There is one situation in which gluten must be completely avoided. If a person has celiac disease, which is true gluten intolerance, then his or her diet must be completely free of gluten. In this situation, exposure to gluten can lead to a host of health problems, including increased risk of intestinal cancer. However, even in women with celiac disease, gluten is not associated with increased risk of breast cancer.

In fact, a study published just this year (2012) suggests that women with celiac disease have a lower risk of breast and ovarian cancers compared with the general population. No one really knows why this would be the case, but it’s reassuring to know that celiac disease itself and exposure to gluten are not in any way associated with breast cancer or its recurrence.

But for woman or men with celiac disease, gluten must be avoided in order to limit the risk of other devastating health effects. For someone with celiac disease, eating gluten triggers a systemic (whole body) immune reaction that can lead the body to attack its own tissues. In a person with celiac, any tissue can be damaged when he or she eats gluten.

Studies suggest that well over half of all people following a gluten-free diet do not have gluten intolerance. This means people may be needlessly avoiding healthy foods that are linked with lower risk of many chronic diseases, including heart disease, diabetes and cancer. If you suspect you have gluten intolerance, talk to your doctor.

If you do not have celiac disease but gluten-containing grains simply do not agree with you, try cutting back. You may not need to eliminate them completely.

If you still find these foods cause you problems, make an appointment with a dietitian. A registered dietitian can help you sort out your digestive issues and design a healthy, cancer-risk reduction diet that helps you feel your best.

Question: What are the effects of alcohol on triple-negative breast cancer survivorship?

Ms. Dixon: Several large observational studies show an association between drinking alcohol and increased risk of breast cancer and breast cancer recurrence. Alcohol is most strongly linked with increased risk of estrogen receptor-positive breast cancer. This connection is not surprising, because health experts note that when a woman drinks alcohol, the level of estrogen circulating in her body increases.

There haven’t been enough studies to know with certainty whether or not alcohol increases risk of triple-negative breast cancer recurrence. However, it is a good idea to limit alcohol consumption anyway, because alcohol itself is known to be carcinogenic, or cancer-causing.

Studies suggest, at least for ER-positive breast cancer, that risk of recurrence increases when a woman has more than one or two drinks per week. This is far below the standard health recommendation that women consume no more than one drink per day.

Also, keep in mind that one drink may be smaller than most people realize. A single drink is five ounces of wine, 12 ounces of beer or 1½ ounces of hard liquor. A typical large glass of wine often contains eight or even 10 ounces. This would be two servings.

If you have a history of breast cancer and truly enjoy a glass of wine or a cocktail, I suggest that alcohol be saved for special occasions or enjoyed once per week with a nice dinner. If completely avoiding alcohol is not difficult for you, then you should avoid it.

I believe it’s important to consider all of the things you can do to take care of yourself. For example, even for women who are overweight or obese, the combination of five or more servings of vegetables and fruit per day and 30 minutes per day of moderately vigorous exercise has been shown to reduce the risk of recurrence by nearly 50 percent.

Despite this, many women are strongly advised not to consume alcohol but are never told the importance of healthy eating and regular exercise. This focuses only on the negative—“don’t drink”—but fails to empower women with the positive things they can do to reduce risk, such as eat well and exercise regularly.

All women with a history of breast cancer, but especially ER-positive breast cancer, should limit alcohol intake or eliminate it altogether. However, it would be a mistake to focus only on one thing, such as alcohol. If all of the other healthy lifestyle choices are in place—a good diet, regular physical activity, avoiding tobacco, getting adequate sleep, managing stress,and so forth—an occasional alcoholic beverage is unlikely to have measurable impact on risk of recurrence. Just remember that “occasional” means special occasions, not every day.

Question: What are the effects of caffeine on triple-negative breast cancer survivorship?

Ms. Dixon: Regarding caffeine, you’re in the clear in terms of breast cancer risk. This applies to both estrogen receptor-positive and triple-negative breast cancer subtypes.

Studies do not show a measurable link between caffeine consumption and risk of breast cancer or recurrence. Even in countries with very high intake of caffeine from coffee and tea, such as the Scandinavian countries, research does not support a link between caffeine and breast cancer.

However, I do believe the source of caffeine matters. If your caffeine comes from coffee and tea that is fine, as long as you are not having so much that you experience negative side effects such as insomnia or anxiety. Also, if you have high blood pressure, a rapid heart rate or other cardiovascular issues, you should keep caffeine intake moderate. Talk to your doctor about how much caffeine is safe for you to have.

Caffeine from soda, however, should not be a regular part of anyone’s diet. If you enjoy soda, you should have it as an occasional treat, but drinking soda daily is not a healthy habit. With both coffee and tea, you get some added benefit in the form of antioxidants and other nutrients that are linked with better health.  You get excessive amounts of sugar if you drink regular soda or synthetic sweeteners if you drink diet, neither of which are linked with good health.

Question: How do you feel about beef and breast cancer? Should you only eat free-range,organic beef?

Ms. Dixon: Observational studies are mixed regarding the impact of red meat on breast cancer risk. Some studies suggest that too much beef is linked with an increased risk of breast cancer, but other studies do not show such a link. And in all of these cases, the studies are not controlled trials, which means they cannot prove cause and effect. They only show an association (correlation) between two things, not that one thing caused the other.

To understand why this matters, consider all of the other habits that may go along with eating more red meat. For example, maybe women who eat a lot of red meat also drink more alcohol, exercise less, eat fewer vegetables and fruit and are more overweight. Any of these things could increase breast cancer risk. In this way, it might appear that red meat causes breast cancer. However, it may be something else that goes along with eating beef that is the true problem.

A controlled trial would be the only way to prove that beef causes or doesn’t cause breast cancer. Unfortunately, we don’t have controlled trials to consider. For obvious reasons, it would be difficult to assign some women to eat beef and other women to avoid beef completely, and then follow them for decades to see who develops breast cancer.

However, based on the observational studies we do have, moderate beef consumption—a three-ounce serving a couple of times per week—does not appear to increase breast cancer risk. Eating beef daily, while not proven to cause breast cancer, is more strongly linked with increased risk. For this reason, I believe beef should not be consumed daily.

As with most things related to health, moderation is key. If you like beef, enjoy it one to two times weekly. The rest of the time rely on beans, lentils, chickpeas, fish, chicken, nuts and seeds for your protein. Contrary to popular opinion, humans do not need meat for good health. Plants can provide all of the protein a person needs.

Also keep in mind that what I’ve mentioned applies to freshly-prepared red meat. Many people do not realize that processed meat does have negative effects on health and may increase risk of developing colon cancer. This includes ham, cold cuts, lunch meats, hot dogs, sausage and any smoked and cured meat. Because having a prior diagnosis of breast cancer is linked with an increased risk of developing colon cancer, anything that increases colon cancer risk should be minimized or avoided. Keep processed meat to a minimum in your diet.

Regarding the type of beef, there aren’t any studies to prove that organic or free-range beef are nutritionally superior to conventionally raised beef, in terms of health. However, I believe that if you care about the quality of the meat you eat, how that meat was produced and whether the animals were treated humanely, organic and/or free-range beef may be a better choice.

You should ask what “free-range” means—for example, how often do these animals have access to pasture— and whether “organic” means the animals were treated any differently than conventionally raised beef. If you’re paying extra, you should know what you’re getting for your money. And while it’s true that these types of beef are more expensive, if you only eat beef once or twice per week, the expense becomes less of an issue.

When it comes to nutrition and any type of cancer, the strongest evidence supports that a plant-based diet is the healthiest eating pattern. This doesn’t mean you should never eat beef or other animal foods. It does mean you should start figuring out ways to get more whole plant foods—including vegetables, fruit, legumes, nuts, seeds and whole grains—into your nutrition plan.

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