Moderate Soy Consumption OK for Breast Cancer Survivors

From Medscape Medical News > Oncology Sandra Yin November 7, 2011 (Washington, DC) — It is all right for breast cancer survivors to consume moderate amounts of soy foods, Bette Caan, PhD, a senior research scientist who specializes in nutritional epidemiology at the Division of Research at Kaiser Permanente Northern California in Oakland told attendees here at the American Institute for Cancer Research (AICR) Annual Research Conference 2011 on Food, Nutrition, Physical Activity and Cancer in a session on cancer treatment and survivorship. Dr. Caan sought to clarify the highly charged topic of whether soy is safe for breast cancer survivors by reviewing the epidemiologic literature. Soy has been touted in the mainstream media as "the miracle bean" and laypeople read about everything from the "joy of soy" to the "dark side of soy." It is not surprising that the public and experts are confused, Dr. Caan acknowledged. Part of the problem is conflicting data. Soy foods can either increase the risk for breast cancer progression or decrease the risk, she observed. Evidence suggests that lifetime endogenous estrogen exposure increases the risk for breast cancer. So people were afraid to tell breast cancer survivors that it was okay to eat soy. Clinicians have several options based on the epidemiologic literature, and some routinely advise against soy in the diet of patients with breast cancer, Dr. Caan noted, "and I don't think the current science supports that at all." No Evidence of Harm After reviewing the 7 epidemiologic studies, Dr. Caan said there was no evidence that soy is harmful for women with breast cancer, and pointed out that 6 of the 7 studies demonstrate some type of benefit. On the basis of the lack of harm and the benefits reported in the studies she cited, clinicians might want to recommend that patients with breast cancer begin eating whole soy foods to treat breast cancer, but she cautioned that she doesn't think existing data were strong enough to justify that. "What I do think is that they could adopt a stance of permitting use in patients who want to begin eating reasonable amounts of soy foods or for whom soy foods already represent a normal part of their diet," Dr. Caan said. The data support this option, and she said they were consistent with the American Cancer Society (ACS) position. The ACS is in the process of rewording its guidelines. The old ones said that up to 3 servings of traditional soy foods per day are unlikely to be harmful. According to Dr. Caan, those guidelines may be revised to state that women with breast cancer can eat moderate amounts of soy foods. She added 1 caveat: to avoid concentrated sources of soy, such as pills, powders, or supplements containing high amounts of isoflavones, because data are lacking on the risks and benefits. "We still need to proceed with caution," she said. The discussion heated up during the session's Q&A when another presenter, Leena Hilakivi-Clarke, PhD, professor of oncology at Georgetown School of Medicine, Washington, DC, whose talk focused primarily on animal research, shared her advice on soy consumption. If a woman had been consuming soy before diagnosis, it would be perfectly safe to eat the same amount or maybe increase it a little bit, she said. But her recommendation was more cautious for another subgroup. "If she had not eaten any soy beforehand, my opinion is that she shouldn't start before we know whether it's safe or not," she said. A member of the audience took issue with the latter advice. "First, when human data exists, it should surpass animal data," said Mary L. Hardy, MD, medical director at the Simms/Mann University of California at Los Angeles Center for Integrative Oncology. Nor was she convinced that models using a vectorized mouse or rat were an appropriate model for humans. "Third, If we're moving people toward a plant-based diet, and we take out a really good source of plant-based nutrition, how are we taking with one hand and giving with another?" Because her patients have heard from the media or uninformed physicians that soy is bad, Dr. Hardy said they "freak out" because they see soy in everything, as it is used as an emulsifier and a flow agent. "They'll think they can't eat anything, which can be confusing and demoralizing," she said. "I'm very hesitant for that advice to be promulgated, when I think it's going to cause at many levels more harm than good." Later Dr. Hardy told Medscape Medical News that she agreed with Dr. Caan's recommendations. But she had another concern about Dr. Hilakivi-Clarke's advice. In her practice, she actively encourages people to eat a plant-based diet and reduce their dependence on red meats. Taking away meat and then soy would confuse patients who want to identify a good-quality protein source, she said. What's more, the average breast cancer patient whose tumor was caught early and is responsive is probably many times more likely to face risk for heart disease than breast cancer, so it wouldn't make sense to take away a heart-healthy food that lowers cholesterol, she said. "I think inappropriately discouraging soy use is going to cause problems." Dr. Caan told Medscape Medical News that either you eat soy or you don't. If you enjoy soy as part of your diet, you can continue to eat it because more evidence suggests that it's beneficial. Referring to the other speaker's advice that patients with breast cancer who have never eaten soy should not start to eat it to treat their cancer, she said, "Who are those people? You're giving a warning to people who don't exist." Dr. Caan and Dr. Hilakivi-Clarke have disclosed no relevant financial relationships. Dr. Hardy serves on the scientific advisory board of Dean Foods, which makes soy milk. American Institute for Cancer Research (AICR) 2011Annual Research Conference on Food, Nutrition, Physical Activity and Cancer. Presented November 3, 2011.

Prenatal health and your baby

Did you know that having a healthy pregnancy and baby actually starts before you get pregnant? Taking care of yourself when you’re thinking about becoming pregnant is important. This includes: Eating healthy foods and getting regular exercise. Canada’s Food Guide offers tips and advice for healthy eating at all stages of life. Aiming for at least 30 minutes of moderate exercise, 5 days a week. Making sure your vaccines are up-to-date. Check with your doctor to ensure you are properly protected against illnesses like rubella, chickenpox and influenza. Getting these vaccines will help protect your baby. Talking to your doctor about any prescription drugs you are taking to find out whether they are safe during pregnancy. Vitamins before pregnancy: If you are planning to get pregnant, you should be taking folic acid. Folic acid (also called folate or folacin) is a vitamin that helps a baby’s neural tube develop properly during pregnancy. The neural tube becomes your baby’s brain and spinal cord. Neural tube defects (NTD) result from openings in the spinal cord that do not close properly during early pregnancy, causing spina bifida and anencephaly. Folic acid protects against NTDs and can also lessen the risk of other problems at birth, such as cleft palates or heart, genital and urinary defects. Although certain foods (fortified grains, spinach, lentils, chick peas, asparagus, broccoli, peas, Brussels sprouts, corn, and oranges) have folic acid, it can be hard to get enough from diet alone. Most healthy women should take a daily multivitamin with 0.4-1.0 mg of folic acid, for at least 2 to 3 months before getting pregnant, throughout pregnancy, and then after birth for as long as they breastfeed. Women who have diabetes or epilepsy, and women with a family history of NTDs (a sibling, parent or cousin with the condition), or who have already had a baby with an NTD need a higher dosage, and should supplement their diet with between 0.8 and 4 mg of folic acid daily. Talk to your health care professional if you aren’t sure how much you should take. Vitamins during pregnancy: You should take a multivitamin during pregnancy that includes between 16 and 20 mg of iron. You should also take vitamin D. Your doctor may recommend up to 2000 IU/day. Not getting enough vitamin D during pregnancy will affect how much vitamin D your baby has at birth. A baby born to a mother who is vitamin D deficient is more likely to have vitamin D deficiency rickets. Cow’s milk, margarine and some soy beverages produced in Canada are fortified with vitamin D. If you don't use these products, if you do not have much exposure to sunlight or your skin is covered much of the time outside—especially if you do not take vitamin D supplements—then you are more likely to be vitamin D deficient. How much weight should I gain during my pregnancy? Weight gain is an important part of supporting your growing baby and placenta, which provides your baby with the nutrients he needs. Women who gain the recommended amount of weight during pregnancy have fewer complications that can lead to things like caesarean section, high blood pressure, and low or high birth weight for your baby. How much should I eat during pregnancy? Your baby is counting on you to provide all the nutrients she needs to grow healthy and strong. Making smart choices about food will help you both stay healthy during and after pregnancy. Also, be sure to prepare food carefully so that you avoid illnesses such as listeriosis or salmonella infection. Canada’s Food Guide suggests how much you should eat from each food group: Vegetables and fruit are a source of vitamins, minerals and fibre. 7-8 servings/day Choose at least one dark green and one orange vegetable or fruit every day. Grain products are an important source of energy from carbohydrates. 6-7 servings/day Make at least half of the grain products whole grain. Milk and alternatives are nutritious sources of calories, as well as calcium and vitamin D. Some alternatives (such as fortified soy beverage) have vitamin D added. Check labels for calcium and vitamin D content. 2 servings/day Drink skim, 1% or 2% cow’s milk or fortified soy beverage each day. Meat and alternatives are important sources of iron and protein. 2 servings/day Choose a variety of lean meat, poultry, and de-boned fish, eggs, tofu, dried peas, beans and lentils. At least 2 servings of fish /week are recommended. Oils and fats 2-3 tbsp a day Canada’s Food Guide also recommends an extra 2-3 servings from any one of the 4 food groups every day. Be sure to drink plenty of water throughout the day. Is there anything I should avoid consuming while pregnant? Fish with higher levels of mercury (such as shark, swordfish and fresh tuna) should be avoided, because mercury can harm a developing baby. Canned, chunk light tuna generally has a lower amount of mercury than other tuna, but should still be eaten in moderation, with no more than 150 g a month. Avoid raw fish, which may contain bacteria or parasites that can make you sick. Limit caffeine, and consider cutting it out of your diet completely while pregnant. Certain medications can also be dangerous to your baby during pregnancy. If you are on any medications, talk to your doctor about whether you should keep taking them when pregnant. How can I stay active during pregnancy? Staying active during your pregnancy will help ease your aches and pains and may help with your mood. It’s also a good way to ensure you have the energy you need for your pregnancy and delivery. Some suggestions for physical activity include: regular walking, swimming, low-impact aerobics, prenatal exercise classes, and yoga. If you weren’t already active before your pregnancy, start slowly and speak to your health care provider before starting a new exercise routine. Can I drink alcohol while I am pregnant? If you drink alcohol during your pregnancy, the alcohol goes to the baby through your bloodstream. Drinking alcohol during pregnancy can cause fetal alcohol spectrum disorder (FASD, a serious condition that can affect a child for life. If you are thinking about getting pregnant, it’s best to stop drinking alcohol now. Then you’ll know for sure that your baby will be safe from FASD. Women who find it hard to stop drinking, or who already have a child with FASD, should get help before getting pregnant. Can I smoke or take recreational drugs while I am pregnant? Avoid smoking and drug use during pregnancy. These can be dangerous to your growing baby and increase the risk of Sudden Infant Death Syndrome. If you are thinking about getting pregnant, it’s best to stop drinking alcohol, smoking or doing recreational drugs now. Then you’ll know for sure that your baby will be safe. If you are already pregnant, you should stop drinking alcohol, smoking or doing recreational drugs completely. For more information: Fetal alcohol spectrum disorder: What you should know about drinking during pregnancy Depression in pregnant women and mothers: How it affects your child Prenatal nutrition, a resource by Health Canada Healthy pregnancy, a resource by Health Canada Healthy Beginnings, a book on pregnancy from the Society of Obstetricians and Gynaecologists of Canada (SOGC). Healthy eating, exercise and weight gain: Before and during pregnancy, from SOGC. Pregnancy and breastfeeding resources, Motherisk Reviewed by the CPS Public Education Advisory Committee Posted: August 2011 This information should not be used as a substitute for the medical care and advice of your physician. There may be variations in treatment that your physician may recommend based on individual facts and circumstances. Canadian Paediatric Society 2305 St. Laurent Blvd., Ottawa, Ont. K1G 4J8 Phone: 613-526-9397, fax: 613-526-3332