Breast Cancer Diet Basics

A quick-start guide to diet dos and don'ts for every stage of breast cancer treatment

Diana Torres: Diana is a board certified specialist in Oncology Nutrition with 14 years of experience providing nutrition guidance. Diana prioritizes knowledge over uncertainty and empowers individuals to choose what works for them. She attended the School of Public Health at Loma Linda University, earning her MPH in Nutrition.

Paige Herman-Axel has more than two decades of experience writing about beauty, skincare and wellness. A former editor for a variety of publications, Paige is now a freelance writer and consultant for skincare companies big and small, dermatologists and plastic surgeons, as well as a regular contributor to various websites. In the rare time spent away from her computer, Paige can be found on a tennis court, shuttling her 13-year-old son to and from basketball practice, or playing fetch with her Havanese, Nugget.

When you receive a breast cancer diagnosis, your entire world is turned upside down in an instant. Between doctors’ appointments, making decisions, and questioning what the coming months and perhaps the rest of your life are going to look like, those first weeks after you find out feel like you’re in the twilight zone. At some point, you’ll likely look for additional ways to get (and stay) healthy — and your diet can't be overlooked.

This is why your cancer care team may include a nutritionist. If this is the case, your first meeting will likely include reviewing your current diet, as well as any supplements you are taking. You’ll probably get lists of foods to eat and avoid. Remember, t’s OK if you don’t have the bandwidth to get started right away since you’re still processing your diagnosis, and the information you are given winds up in your ever-growing stack of medical reports, bills, and other breast cancer “stuff.”

It’s important to keep in mind that the advice you receive can vary depending on your nutritionist. There are a wide range of approaches that include those based on Western scientific research as well as more holistic views of diet as a path to overall health and wellness while navigating the cancer journey. 

Regardless of your nutritionist’s philosophy, these dietary approaches have a common thread: Inflammation. More specifically, incorporating anti-inflammatory foods (and skipping inflammation-causing ones) as a way to decrease the risk of recurrence and perhaps improve your prognosis.

Before you start freaking out about giving your diet a complete overhaul, an anti-inflammatory breast cancer diet essentially follows the same guidelines as the “healthy” diet most doctors and nutritionists recommend for everyone (including those who are cancer-free). If you’re still anxious, start by focusing on the “yes” foods, keeping an eye on the “maybes” and removing the “nos” from your daily go-to foods. 

Choose in abundance…

Healthy eating at every stage of breast cancer is actually simple. As a general rule, fill half of your plate with non-starchy vegetables, reserve one quarter for “good” proteins and use the remaining quarter for grains or starchy vegetables and a dash of healthy fats. Here are the main foods to focus on.

  • Cruciferous vegetables like broccoli, cauliflower and Brussels sprouts: These veggies feature a compound called 3,3-diindolylmethane (also known as DIM) that has been shown to play a protective role against breast cancer. 
  • Leafy greens: Chock-full of vitamins, minerals and fiber and low in calories, leafy greens are the OG superfoods. 
  • Brightly colored fruits and vegetables: A vibrant hue translates to beneficial antioxidants, and citrus and berries are bursting with them. If you’re going all in, steer away from high-sugar fruits like mango, grapes and pears.
  • Whole grains: Less-processed grains like brown rice, quinoa, oats and farro offer fiber and plant-based protein. (If you’re extremely sensitive to gluten, you may want to avoid oats as they are often processed around gluten-containing foods.) Quinoa is a winner because it’s a complete protein, which means it contains all essential amino acids.
  • Nuts and seeds: Consider nuts (think raw almonds, pecans, walnuts, macadamias and brazil nuts), seeds (like chia, flax, sunflower, sesame and pumpkin) and their associated unrefined butters your anti-inflammatory friends. They’re great for snacking and adding a little crunch to your leafy-green salads. 
  • “Good” oils: Extra virgin olive, coconut and avocado oils are ideal options for cooking, while flaxseed and walnut oils work wonderfully in cold dishes like salads. (Look for “cold-pressed” oils and choose the appropriate oil for the heat setting.)
  • Beans and legumes: These plant-based sources of protein (especially chickpeas,  lentils and black beans) offer a good amount of fiber to boot. If you want to level up your legume game, try mung or adzuki beans. These options have more proteins and tend to be less gassy.
  • Herbs and spices: In addition to providing extra flavor, garlic, ginger, basil, cumin, mint, rosemary, thyme, cinnamon, cayenne pepper and oregano are rich in inflammation-fighting antioxidants as well. (Turmeric is another beneficial spice for most, but it should be avoided while undergoing chemotherapy and radiation treatments.)
  • Organic, wild-caught fish: Fill your plate with these rather than farm-raised fish that are treated with antibiotics and more likely to be exposed to chemical waste.
  • Potato alternatives: Not only do Japanese yams, sweet potato and purple potatoes look better on your plate, but they also contain more nutrients and fiber than their pale, white counterparts. 

Be sure to go organic when possible to avoid pesticides, and choose animal-based protein sources raised without hormones or antibiotics.

The hard no’s…

  • Unwashed fruits and vegetables: Make sure anything you put in your body is free of chemicals such as pesticides. It’s best to choose organic, especially when eating strawberries, blueberries, raspberries, spinach, kale (and similar greens), nectarines, apples, grapes, cherries, peaches, pears, peppers, plums, celery, tomatoes and anything else you don’t peel.
  • Nitrates: Research has established that the nitrates found in processed and cured meats (like cold cuts, bacon, and sausage) increase the risk of breast and other cancers.
  • Industrial oils: Canola, corn, soybean, sunflower, safflower, and grapeseed oils are highly processed, which leads to the ingestion of excess omega-6 fatty acids that may promote inflammation.
  • Barbequed meat: Cooking animal protein on an open flame creates carcinogenic compounds, so avoid anything with a charred flavor or appearance. (Lightly grilled vegetables or cooking fish wrapped in aluminum foil is OK.) 
  • Processed soy: “Whole” soy-based foods like soy milk, tofu, and edamame are OK, but avoid soy derivatives like soy isolate that are found in products like protein powders and other processed foods — as well as isoflavone supplements. (Read your labels.)
  • Refined sugars, pastries, and other sweets: The blood sugar spikes these foods cause play a significant role in inflammation throughout the body.
  • Artificial sweeteners: Skip the aspartame, sucralose, and saccharin and opt for naturally derived sweeteners like stevia and monk fruit instead.

The maybes…

  • Animal-based protein: Hard-liners may suggest avoiding all animal-derived foods, but many mainstream nutritionists are comfortable with cancer patients and survivors eating organic, hormone-free, and antibiotic-free chicken, turkey, and pork as well as low-mercury fish and shellfish. Red meat should be hormone- and antibiotic-free, and limited to once a week (although some oncologists and nutritionists recommend once-a-month consumption).
    • GMOs: Genetically modified organisms are in a gray zone when it comes to cancer (and other health effects) simply because of a lack of substantial research. However, these foods have been linked to potentially toxic effects on several systems throughout the body. 
    • Certain cheeses: You may be recommended to steer clear of soft cheeses and those with blue veins (including brie, camembert, Roquefort, stilton, gorgonzola, and blue) as well as any unpasteurized dairy during chemotherapy because they are more likely to be contaminated with bacteria. 
    • Eggs: A 2015 study showed a slightly elevated risk of breast cancer in those who eat more than five eggs per week. To play it safe, opt for organic, pasture-raised eggs and limit consumption to twice a week. To minimize the risk of salmonella, only eat yolks and whites that are cooked solid (and opt for organic and pasture-raised eggs).
    • Raw seafood: Uncooked seafood (i.e. oysters, sushi, and sashimi) may be another no-no while undergoing chemo - ask your doctor for clearance.
    • Chicken skin: When fried, grilled, and cooked at high temperatures, chicken skin (including the rotisserie variety) contains a high level of heterocyclic amines (or HCAs), which are carcinogenic compounds.
    • Raw sprouts: Broccoli sprouts are high in sulforophane, which has been shown to provide anti-carcinogenic benefits. However, it may be advised to avoid raw sprouts during chemotherapy because they have an elevated risk of bacterial contamination. However, they are a valuable addition to your diet once you’ve completed treatment.

    A note about lymphedema

    If lymph nodes are removed during your mastectomy or treated with radiation, it’s possible to experience a condition called lymphedema that causes ongoing swelling that may affect your arm or chest wall on the treated side(s). 

    In addition to the above recommendations, focus your diet on whole foods (mostly plants), including a wide variety of rainbow-colored vegetables and fruits. Try to incorporate fermented foods, and use antioxidant-rich, anti-inflammatory herbs and spices to provide your favorite flavors. 

    Those with lymphedema should avoid added sugars (especially fructose), refined grains (especially foods that contain gluten), and chemically modified fats. Limit animal products and high-salt foods, and avoid dairy (with the exception of kefir and yogurt).

    If you are experiencing lymphedema, speak to your doctor about the best ways to manage this condition — and stay tuned for more Stage information about this topic.

    Regardless of your nutritionist’s philosophy, these dietary approaches have a common thread: Inflammation. More specifically, incorporating anti-inflammatory foods (and skipping inflammation-causing ones) as a way to decrease the risk of recurrence and perhaps improve your prognosis.

    - Paige Herman-Axel


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