Triple-negative breast cancer (TNBC) presents unique challenges in treatment due to its lack of estrogen and progesterone receptors, as well as the HER2 protein. While there is no single, universally recommended diet for TNBC, emerging research suggests that dietary modifications can play a supportive role alongside conventional treatments. This article explores the potential benefits of specific dietary patterns and foods in managing TNBC, based on current scientific evidence.
Understanding Triple-Negative Breast Cancer
Triple-negative breast cancer accounts for 10-20% of all breast cancer cases. Unlike other types of breast cancer, TNBC does not express estrogen receptors (ER), progesterone receptors (PR), or the HER2 protein. This absence of receptors means that typical hormone therapies and HER2-targeted drugs are ineffective, often limiting treatment options to chemotherapy.
The Role of Diet in Managing TNBC
While diet is not a primary treatment for TNBC, it can influence the course of the disease. Diet appears to influence the risk of breast cancer in several ways. One of the most well-established relationships is between body weight and breast cancer risk. Being overweight or obese is a significant risk factor, and a healthy diet plays a crucial role in weight management. Fortunately, you can decrease your risk by losing weight and maintaining the loss. Eating a balanced, healthy diet also has other benefits, too.
General Nutritional Guidelines
There are no specific scientific guidelines for this type of breast cancer in terms of nutrition.
- Focus on Whole Foods: Emphasize minimally processed foods like fruits, vegetables, whole grains, and legumes. A diet rich in nutrient-dense foods, such as vegetables, fruits, and whole grains, helps provide the vitamins and minerals a person needs for their overall health.
- Limit Processed Foods, Added Sugars, and Red Meats: It’s best to avoid the typical western-style diet many Americans follow, which is high in processed grains, processed meats (bacon, hot dogs), and red meats-all foods associated with increased rates of breast risk and progression.
- Maintain a Healthy Weight: Obesity is a well-established risk factor for breast cancer, and eating healthfully plays an essential role in helping you lose weight (if needed) and keep your weight stable.
- Reduce Inflammation: A healthy lifestyle is linked with lower levels of inflammation, and studies suggest that certain nutrients, vitamins, and compounds have anti-cancer properties that may help lower your risk of breast cancer.
Foods to Incorporate into Your Diet
Several foods and dietary components have shown potential benefits in preclinical studies and observational research related to TNBC.
Read also: The Hoxsey Diet
Omega-3 Fatty Acids
At the 2013 American Association for Cancer Research conference, researchers presented findings that omega-3 fatty acids slow down triple-negative breast cancer. Foods rich in omega-3 fatty acids include sardines, tuna, trout, salmon, as well as flax and hemp, etc. Research showed that when omega-3 reaches triple negative breast cancer cells, it reduces their activity: it slows down their growth or even stops it altogether.
- Sources: Fatty fish (salmon, tuna, trout, sardines), flaxseeds, hemp seeds.
Asparagine Restriction
A new multicenter study published in the medical journal Nature found that by limiting an amino acid called asparagine in laboratory mice with triple-negative breast cancer, they could dramatically reduce the ability of the cancer to travel to distant sites in the body.
- Foods to Limit: Dairy, whey, beef, poultry, eggs, fish, seafood, asparagus, potatoes, legumes, nuts, seeds, soy, and whole grains.
- Foods Low in Asparagine: Most fruits and vegetables.
Mediterranean Diet
Several studies have focused on the Mediterranean diet, a pattern of eating that emphasizes whole, minimally processed foods. The Primary Prevention of Cardiovascular Disease with a Mediterranean Diet (PREDIMED) evaluated the effects of the Mediterranean diet on the prevention of cardiovascular disease (Estruch et al., 2018). The PREDIMED study reported that consumption of the Mediterranean diet supplement with extra virgin olive oil (EVOO) and tree nuts lowered the risk of postmenopausal breast cancer by 51%.
- Key Components: Olive oil, fish, vegetables, fruits, whole grains, and legumes.
Antioxidant-Rich Foods
Antioxidants neutralize free radicals-unstable molecules than can damage cells’ DNA, thereby supporting the development and progression of breast cancer. Studies suggest that vitamin D, calcium, and polyunsaturated fatty acids (PUFAs) such as omega-3 fatty acids may also have protective effects.
- Sources: Fruits (berries, grapes, cherries), vegetables (broccoli, spinach, kale), green tea, turmeric.
Fiber
Fiber may also play a significant role in breast cancer prevention. A review of studies published in the journal Cancer found that women who consumed the highest amounts of fiber were eight percent less likely to develop the disease compared to those who ate the least. Eating more fiber may also help prevent breast cancer by influencing the makeup of your gut microbiome-the balance of good and bad microorganisms that reside in the gastrointestinal tract. Studies suggest that the microbiome may impact the risk of breast cancer by altering estrogen metabolism.
Read also: Walnut Keto Guide
- Sources: Whole grains, legumes, fruits, and vegetables.
Specific Foods with Potential Benefits
Research has identified specific foods that may inhibit triple negative or ER-/PR- cell growth or proliferation.
- Fruits: Apples, blackberries, blueberries, boysenberries, cranberries, currants, grapes (red, black, muscadine), purple grape juice, cherries (sweet or tart).
- Vegetables: Artichokes, arugula, asparagus, bell peppers, bok choy, broccoli, broccoli sprouts, Brussels sprouts, butternut squash, cabbage, carrots (orange or black), cauliflower, celery, chives, cilantro, collard greens, cucumbers, garlic, greens, lettuce, peas.
- Legumes: Black beans.
- Nuts and Seeds: Brazil nuts, flaxseed.
- Spices and Herbs: Basil, black cumin, black pepper, chili powder, celery seed, cilantro, ginger, turmeric.
- Other: Green tea, halibut, herring, honey.
Foods to Limit or Avoid
Certain foods and dietary components may potentially promote cancer growth or interfere with treatment.
Omega-6 Fatty Acids
New research in animals suggests that aggressive cancer cells may be using a specific omega-6 fatty acid to survive treatment. The study focused on how triple-negative breast cancer cells use arachidonic acid to possibly evade treatment and the body’s natural immune responses. Arachidonic acid is an omega-6 fatty acid commonly found in the fatty parts of red meat and fish.
Note: While omega-6 fatty acids are essential, excessive consumption may be problematic.
Alcohol
Experts know that drinking any type of alcohol (beer, wine, liquor) raises the risk of breast cancer, but alcohol may also have detrimental effects on breast cancer patients.
Read also: Weight Loss with Low-FODMAP
Saturated and Trans Fats
Foods high in saturated fat, particularly high-fat dairy products such as butter and cheese,may increase breast cancer mortality.
Added Sugars
The rumor that sugar “feeds” cancer isn’t true, but it is wise to limit foods high in added sugars like high-fructose corn syrup, because they’re typically high in calories and contribute to weight gain, insulin resistance, and inflammation.
Copper
Copper has been shown to promote angiogenesis and metastasis, especially in aggressive forms of breast cancer such as inflammatory (IBC), triple negative, and HER2+ breast cancer. Note that copper jewelry and jewelry made from copper alloys, such as red, rose or pink gold, are a potential source of copper exposure.
Fructose
Minimum Fructose has also been shown to induce changes in triple negative breast cancer cells that may increase their aggressiveness, suggesting that patients should avoid concentrated sources such as agave nectar and processed foods sweetened with fructose, including beverages.
Cadmium
Cadmium has been reported to promote the growth of triple negative cells.
Methionine
The University of Wisconsin team believes that their laboratory studies may pave the way for a clinical trial in breast cancer patients to examine the effectiveness of a low-methionine diet in combination with a TRAIL-R2 monoclonal antibody.
Practical Meal Planning Tips
Following specific dietary patterns may help reduce the risk of certain types of cancer, including breast cancer. They may also help support overall health and improve treatment outcomes in those undergoing treatment for TNBC. The following meal-planning tips derive from the research and recommendations above:
- Fill at least half the plate with different colored vegetables at every meal.
- When making a stir-fry, substitute meat for tofu and include leafy greens, such as kale, red peppers, and carrots.
- Swap meat for beans and pulses in curries, casseroles, and chilies.
- Opt for whole grain types of rice, bread, and pasta.
- Replace packaged breakfast cereals with oatmeal.
- Snack on fruits, such as berries, cherries, and grapes.
- Try out herbs and spices that may have therapeutic benefits, such as turmeric, ginger, and parsley.
- Swap sweet treats for dark chocolate and a handful of walnuts for anti-inflammatory and antioxidant benefits.
Importance of Personalized Approach
Each individual's response to dietary changes can vary. Factors such as genetics, treatment regimen, and overall health status can influence how the body responds to specific foods or diets. Consulting with a registered dietitian or nutritionist is crucial to develop a personalized nutrition plan that aligns with individual needs and treatment goals.
A registered dietitian or nutritionist can help a person with cancer make dietary changes that may assist with the following:
- maintaining a moderate body weight
- maintaining physical strength
- keeping body tissues healthy
- decreasing appetite-suppressing side effects of cancer treatment, which may include:
- altered sense of smell or taste
- nausea or vomiting
- mouth sores
- pain
- fatigue
- depression
- stress or anxiety
The Role of Supplements
There is no supplement or combination of supplements that has been proven to reliably reduce the risk of triple negative breast cancer recurrence in women. When a beneficial micronutrient is administered at low doses by consuming food, it is likely to have subtle chemopreventive effects, whereas when the same micronutrient is administered at a high dose in a supplement, it is more likely to have pharmacological effects, with mostly unknown results. It is best to obtain beneficial compounds by consuming food, if possible.
One study reported that breast cancer patients with suboptimal levels (under 30 ng/mL) of vitamin D were three times more likely to develop triple negative breast cancer than patients with optimal levels. Please consult your oncology team for advice concerning your situation and dosages.