Avoid These Four Foods If You’re HER2-Positive

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Some research suggests diet may play a role in HER2-positive breast cancer. Although diet is only part of the consideration of risk for breast cancer, some types of food may increase the risk of breast cancer, while others may provide some protection.

When breast cancer is diagnosed, your healthcare team will test for a sample of the cancer cells to learn the type, which will help determine the best treatment plan. One of the common types of breast cancer is called HER2-positive.

Her-2 Positive Foods to Avoid - Illustration by Julie Bang

Verywell / Julie Bang

What Is HER2-Positive Breast Cancer?

HER2-positive breast cancer cells have a greatly increased amount of a protein called human epidermal growth factor receptor 2 (HER2). When growth factors bind to the HER2 receptor, it encourages the cancer cells to divide.

While HER2-positive tumors used to have a poorer prognosis, now there are treatments that target these cells specifically, such as Herceptin (trastuzumab). HER2-positive breast cancers account for 30% of all breast cancers.

Breast cancer continues to be the most commonly diagnosed type of cancer worldwide. There were about 2.26 million new cases of breast cancer worldwide in 2020. Although the number of new cases of breast cancer continues to rise, the risk of death decreased by 40% from 1989 to 2017.

This article will discuss what foods you may wish to avoid, as well as foods that may be helpful in reducing your risk for HER2-positive breast cancer.

Breast Cancer and Diet

Many factors impact breast cancer development, and it’s not fully in anyone’s control. Diet is one of the factors that may impact cancer. Some foods may slow or speed up the growth of HER2-positive breast cancer by impacting how much of the protein is made.

Foods to Avoid

Here are some foods and foods groups that may increase your risk for HER2-positive breast cancer.

Sugary Foods

Foods with high amounts of sugar may increase your risk of multiple health problems. A 2020 study found that higher total sugar intake was associated with a higher risk for not only breast cancer, but all types of cancer.

Simple and refined carbohydrates—like white bread, desserts, candy, and ice cream—are considered high-sugar foods. Check the label to look at the total amount of added sugar in the food.

Ingredients on food labels that are simple sugar sources often end in “ose.” Examples include:

  • Fructose
  • Sucrose
  • Glucose
  • Dextrose
  • Maltose
  • Levulose


Drinking one to two alcoholic drinks per day may increase your risk of breast cancer by 30% to 50%.

Alcohol intake can interfere with estrogen production and receptors. Research suggests moderate alcohol consumption is associated with the growth of estrogen receptor-positive tumors.

Red Meat

Research has been mixed on the effects of meat consumption on breast cancer risk. Some studies found no relationship between them. Another 2020 study found red meat may increase the risk of breast cancer, while poultry may reduce the risk of breast cancer.

Saturated Fats

A diet high in saturated fat may increase the risk for receptor-positive breast cancer, especially HER2-positive cancer. Saturated fat could also impact the progression of breast cancer, according to a 2017 meta-analysis.

Food’s high in saturated fat include:

  • Butter
  • Red meat
  • Sausage and bacon
  • Cheese and full-fat dairy
  • Coconut

Foods to Eat

Diet can also lower the risk of breast cancer or slow its progression. Here are some foods that may benefit HER2-positive breast cancer.

Omega-3 Fatty Acids

Omega-3 fatty acids are a type of unsaturated fat that helps to reduce inflammation and protect heart health. Some research suggests omega-3s help when treating breast cancer and reduce chemotherapy-related muscle loss.

The Mediterranean diet is known for its abundance of omega-3 fatty acids. Research suggests this type of diet significantly lowers the risk of breast cancer.

Foods with omega-3s include:

  • Salmon
  • Tuna
  • Mackerel
  • Trout
  • Walnuts
  • Flax seed
  • Olive oil

Citrus Fruits

Citrus fruits contain vitamins, minerals, and antioxidants beneficial for all areas of health. A type of antioxidant called flavonoids may help slow the development of breast cancer cells. A 2017 study found two types of flavonoids called naringenin and hesperetin may help stop HER2-positive cell growth.

Citrus fruits include:

  • Orange
  • Grapefruit
  • Lemon
  • Lime


The conversation around soy and breast cancer has been controversial over the years. Some studies suggest it increases the risk. However, more recent research shows no risk between soy consumption and breast cancer risk, and one 2020 study actually found that higher soy intake may help prevent breast cancer.

Vegetables With Flavones

Flavones, also called phytoestrogens, are a type of plant-based compound that may benefit people with breast cancer. Research suggests these compounds may help slow the growth of HER2 cancer cells and lower breast cancer risk.

Vegetables and herbs with flavones include:

  • Cabbage
  • Celery
  • Onion
  • Tomato
  • Parsley
  • Lettuce
  • Broccoli
  • Bell pepper


Turmeric is a spice used in making traditional Indian food. It contains the antioxidant curcumin. Curcumin has long been used for its anti-inflammatory properties and has reported anticancer effects.

A 2016 study found curcumin may help to stop cancer cell growth and promote cancer cell death, as seen in studies done in the laboratory. The pathway of these effects involves hormone receptors and the HER2 receptor.

Limited Role of Diet

While diet may play a role in cancer risk, diet alone cannot prevent or cure breast cancer.


HER2-positive breast cancer is a type where the HER2 receptor is over-expressed on the cancer cells. Research suggests foods like saturated fat, red meat, sugary foods, and alcohol may increase the risk for breast cancer. Some foods that may help lower cancer risk include citrus fruits, soy, omega-3s, and turmeric.

A Word From Verywell

Your diet plays a role in your overall health and cancer risk. However, you can’t fully control cancer development through diet alone. Still, diet and lifestyle are factors affecting cancer risk.

The good news is that the foods that may increase breast cancer risk are those that you usually reduce when adopting a healthier eating pattern. Meanwhile, foods that may reduce the risk are those that are recommended for a balanced, heart-healthy diet.

Frequently Asked Questions

  • What are the different types of breast cancer?

    Some of the types of breast cancer include invasive ductal carcinoma, inflammatory breast cancer, metastatic breast cancer, and ductal carcinoma in situ. Cancers may also be classified by whether they are positive or negative for estrogen receptors, progesterone receptors, or HER2 receptors.

  • Can diet lower the risk of breast cancer coming back?

    Diet can’t fully prevent breast cancer from coming back, but diet may help lower the risk of it returning. Antioxidants, omega-3 fatty acids, soy, and vegetables with flavones may help lower your risk of breast cancer.

  • What is the first sign of breast cancer?

    Early signs of breast cancer include itchy breasts, changes in color, dimples in breast skin, discharge from the nipple, swelling, or lumps.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Ashley Braun, MPH, RD
Ashley Braun, MPH, RD, is a registered dietitian and public health professional with over 5 years of experience educating people on health-related topics using evidence-based information. Her experience includes educating on a wide range of conditions, including diabetes, heart disease, HIV, neurological conditions, and more.