A diagnosis of HER2-positive breast cancer brings many new considerations, and diet is a significant part of managing your overall health during and after treatment. While no food can cure or cause cancer, certain dietary choices can influence inflammation, hormone levels, and cell growth. Working with your healthcare team and a registered dietitian is always recommended to create a personalized nutrition plan.
Refined Sugar and Simple Carbohydrates
Research has consistently linked high sugar intake to worse health outcomes in breast cancer patients. Sugary foods may increase inflammation and promote faster cancer cell growth. The World Health Organization recommends limiting added sugars to less than 10% of daily calories.
Why to avoid sugar
Cancer cells thrive on sugar, and high sugar consumption can fuel their growth. It also increases systemic inflammation, which can negatively impact treatment and recovery. Refined carbohydrates are quickly converted to sugar in the body and should be limited as well.
What to limit
- Added Sugars: Read food labels carefully and avoid ingredients ending in “-ose,” such as fructose, sucrose, and maltose.
- Sugary Beverages: This includes soda, sweet tea, energy drinks, and fruit juices with added sugar.
- Refined Grains: White bread, white pasta, and white rice break down quickly into sugar.
- Baked Goods: Packaged cookies, cakes, pastries, and frostings are often high in both sugar and unhealthy fats.
Unhealthy Fats: Saturated and Trans Fats
Diets high in saturated and trans fats can elevate low-density lipoprotein (LDL) cholesterol levels, which some researchers believe helps cancer cells make proteins needed for growth. Avoiding these fats supports cardiovascular health, which is especially important during treatment.
Sources of unhealthy fats to avoid
- Saturated Fats: Primarily found in fatty red and processed meats, butter, and full-fat dairy products.
- Trans Fats: Often listed as “partially hydrogenated oils” on ingredient labels. These are common in fried foods, packaged snacks, and baked goods.
- Deep-Fried Foods: This includes fries, fried chicken, and other heavily processed items.
Alcohol
Alcohol consumption has been linked to an increased risk of breast cancer and can negatively impact treatment outcomes. It may increase circulating estrogen levels, which can promote the growth of cancerous cells, even in HER2-positive cases. Some studies also suggest it may interfere with the effectiveness of certain treatments like trastuzumab. The safest approach is to avoid alcohol entirely during treatment and recovery.
Red and Processed Meats
High consumption of red and processed meats is associated with an increased risk of breast cancer. These meats can be high in saturated fat and may promote inflammation. Processed meats, such as bacon, hot dogs, and ham, contain preservatives that can have carcinogenic properties.
Caution with Certain Minerals and Soy
Some evidence suggests that certain minerals and components of soy deserve careful consideration for HER2-positive individuals.
Copper
While an essential nutrient, high copper intake has been reported to potentially promote angiogenesis (the formation of new blood vessels that feed tumors) and metastasis in HER2-positive breast cancer. It is important not to exceed the recommended dietary allowance (RDA) of around 0.9 mg. Foods high in copper include beef and calf liver, as well as chocolate and most nuts and seeds.
Soy
For many years, there was concern about soy's impact due to its phytoestrogen content. However, research findings are mixed and require careful interpretation. Some studies suggest that overall soy food intake does not increase recurrence risk, but one small study indicated high intake of soy isoflavones might increase risk in HER2-positive patients. Meanwhile, other research suggests whole soy foods may have protective effects. It is crucial to discuss soy intake with your care team, as recommendations may vary based on your specific hormone receptor status.
Food Choices Comparison
To help navigate your dietary choices, this table offers simple comparisons between items to limit and healthier alternatives.
| Foods to Limit / Avoid | Healthier Alternatives |
|---|---|
| Sugary drinks (soda, fruit juice) | Water, herbal tea, unsweetened soy milk |
| White bread, pasta, and rice | Whole-grain bread, brown rice, quinoa, and oats |
| Processed and red meats | Lean protein like fish, skinless chicken, beans, and lentils |
| Saturated & trans fats (butter, margarine) | Olive oil, avocado, nuts, and flaxseed |
| Deep-fried and fast foods | Steamed, baked, or grilled foods |
| High-copper nuts (e.g., peanuts) | Copper-free walnuts or smaller portions of other nuts |
| Alcohol (beer, wine, liquor) | Sparkling water with fruit or non-alcoholic beverages |
The Role of a Healthy Diet
Focusing on a balanced, plant-forward diet is a recommended strategy for managing breast cancer. Research shows that diets high in fruits, vegetables, whole grains, and healthy fats can help reduce inflammation and improve outcomes. Including fiber-rich foods like beans, lentils, and nuts is also beneficial. A comprehensive nutrition plan, designed in consultation with oncology dietitians, is the best approach.
Lifestyle and Treatment
Beyond diet, other lifestyle factors also play a critical role. Maintaining a healthy weight through balanced nutrition and regular physical activity is important for reducing cancer risk and recurrence. During treatment, some patients may experience side effects like nausea or appetite changes, which can impact food choices. In these cases, it is especially important to work with a dietitian to ensure adequate nutrient intake and manage symptoms. Addressing dietary concerns as part of a holistic treatment plan helps patients feel empowered and proactive in their health journey.
Conclusion
While a diet cannot cure HER2-positive breast cancer, limiting certain foods can significantly support treatment and overall health. Key items to avoid or restrict include refined sugars and simple carbohydrates, saturated and trans fats, alcohol, red and processed meats, and high levels of copper. A diet rich in plant-based foods, healthy fats, and lean protein can provide essential nutrients and help reduce inflammation. By making informed food choices in consultation with your medical team, you can take proactive steps to improve your well-being throughout your treatment and beyond.
For more detailed information on nutrition during cancer treatment, consider exploring resources from the National Comprehensive Cancer Network (NCCN).
