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I have breast cancer. Should I change my diet? 

– Catherine Noulard, dietician-nutritionist at Hôtel-Dieu Hospital in Montréal, gives more information on this subject.

Eating a well-balanced diet that includes a variety of foods is Ms. Noulard’s number one recommendation to everyone, regardless of their state of health. Following a healthy diet means eating three well-balanced meals a day, that include at least one serving from three of the four major food groups, specifically vegetables and fruits, grain products, milk and alternatives and lastly, meat and alternatives. Eating well is especially important for women with breast cancer, as they need to absorb their daily intake of vitamins, minerals and other nutrients to better handle their treatment.

Chemotherapy and Surgery

While undergoing chemotherapy or preparing for an operation, it is recommended that patients consume enough calories and proteins. Eating meat, legumes, dairy, nuts and eggs, for example, will help accelerate healing after surgery and also reduce the risk of infection. Moreover, proteins are an excellent source of energy for rebuilding strength and boosting the immune system when undergoing any treatment. Nutritious drinks like milk, fruit juice or Ensure-type nutritional supplements can also help boost energy levels. You should also make sure you stay properly hydrated.

If you experience a loss of appetite, eat several smaller meals throughout the day instead of three big meals, and don’t hesitate to load up on high-protein and high-calorie foods. This will help you absorb the nutrients you need to fight the disease. If you lose weight during treatment, it is important to consult a nutritionist. Nutritionists specializing in oncology are available in many hospitals; ask your nurse navigator to help you get in touch with one to obtain the advice you need.

What Foods Should I Avoid?

While no foods are completely off-limits here are a few suggestions:

Since chemotherapy can weaken your immune system, you may become more sensitive to bacteria that are otherwise well tolerated, as well as susceptible to food poisoning. Women having chemotherapy should, as much as possible, avoid foods containing a lot of bacteria, such as Bio-K+ and probiotic yogurt, as well as unpasteurized foods (like raw milk cheese) or raw or undercooked meats (tartare, sushi, etc.).

Whatever the treatment (chemotherapy, radiotherapy, hormonotherapy, etc.), it is best to avoid taking vitamins and natural supplements as they may interfere with the absorption of prescription medications. It is recommended to meet one’s nutritional needs by getting nutrients directly from food, rather than absorbing them in an isolated form derived from high doses of food supplements.

What About Phytoestrogens?

Phytoestrogens are a hot topic associated with breast cancer. They are plant-derived molecules that affect our organism in much the same way as do the body’s own natural female hormones, estrogens. Phytoestrogens include isoflavones from soybeans and their derivatives (the beans themselves, soy drinks, tofu, tempeh, roasted soy nuts) and lignans (from flaxseed, for example). One of the underlying mechanisms of the hormone-dependent type of breast cancer is the ability of the human body’s natural estrogens to stimulate cell division and, consequently, stimulate the cancer’s progression. However, it is worth noting that the phytoestrogens affinity for the body’s estrogen receptors is 100 to 1,000 times weaker than that of natural and synthetic hormones.

Studies on the effects of the consumption of phytoestrogens have been carried out in children, teens, women with breast cancer and women at high risk of developing breast cancer. In women with hormone-dependent breast cancer (2/3 of patients), the effects of phytoestrogens are not conclusive. According to some studies phytoestrogens in food (especially isoflavones) may promote the division of cancerous cells, while no harmful interactions have been revealed from other studies. Notwithstanding, the fact remains that there is no consensus among these studies. According to Ms. Noulard, based on what we know, a moderate consumption of soy and soy-based foods should not put these women at risk. However, it is best to refrain from taking isoflavone or phytoestrogen supplements.

To learn what is most pertinent to your situation or to obtain more information, we recommend that you talk to your doctor or to a clinical nutritionist.

Consumption of Alcohol

When it comes to the consumption of alcohol, it is recommended not to have more than 1 or 2 drinks a week or to abstain from consuming altogether. Alcohol can increase the estrogen level in the blood, while in breast cancer patients the level should in fact be reduced.

Suggestions for Recipes During and After Breast Cancer

If you would like to try some recipes, designed specifically for treatment or post-treatment period, Ms. Noulard recommends these two books:

  • Healthy Eating During Chemotherapy, by Jose Van Mil and Christine Archer-Mackenzie.
  • Bien manger pendant et après un cancer, by Geneviève Nadeau. (French only)