Triple-negative breast cancer (TNBC) is a type of breast cancer that does not have receptors for the hormones estrogen or progesterone or for a protein called HER2. As such, TNBC does not respond to certain treatments for other types of breast cancer.
Although there are currently no set dietary recommendations for people with TNBC, studies show that diet may influence the development and progression of cancer. Moreover, a nutritious diet can help a person maintain their strength, energy levels, and overall health while undergoing cancer treatment.
This article outlines the nutrition needs of people living with TNBC. It also lists foods to eat and avoid, meal-planning tips, and recipe ideas for people living with cancer and those undergoing cancer treatment.
The National Cancer Institute (NCI) advises that good nutrition is important before, during, and after cancer treatment.
A registered dietitian or nutritionist can help a person with cancer make dietary changes that may assist with the following:
A doctor or dietitian can advise a person on how to consume enough calories, protein, vitamins, and minerals to support their overall health. They may suggest the following:
Certain foods contain compounds that can influence gene expression and cancer progression. However, cancer is a complex disease, and compounds that are beneficial in some cancers and for some people may not be beneficial in others.
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.
The American Cancer Society (ACS) advises that people consume the below foods to promote overall health and reduce the risk of certain diseases, including some cancers.
A 2019 meta-analysis concluded that a dietary pattern of consuming fruit, vegetables, and whole grains has a stronger link to a reduced risk of breast cancer than a dietary pattern of eating red and processed meats and animal fats. However, certain factors can influence these results, including whether a person is pre- or post-menopausal and whether their breast cancer is hormone-dependent.
Many studies have found a link between a Western dietary pattern high in ultra-processed foods and added sugars and an increased risk of certain cancers, including breast cancer.
Western dietary patterns also tend to be very high in calories, which can lead to weight gain and obesity. Females with excess weight or obesity are at an increased risk of developing breast cancer.
Additionally, a 2021 study found that obesity had correlations with shorter, disease-free survival and overall survival among TNBC patients.
Phytochemicals are chemical compounds that derive from plants. Research shows many phytochemical compounds have anticancer properties.
Epigenetics is the study of how external factors switch genes on or off. A 2020 review investigating epigenetic regulation and dietary control of TNBC indicated that the following phytochemicals could help manage the disease:
However, the authors acknowledge that the body may not absorb the active molecules in these compounds effectively. Additionally, scientists do not fully understand how these phytochemicals interact with one another.
Soy contains compounds called isoflavones that can act similarly to the hormone estrogen. But research into the effects of soy on breast cancer has yielded conflicting results. Since TNBC is not a hormone-responsive breast cancer, soy is unlikely to have any effect on its progression.
However, a 2017 study looked at gene expression in women with TNBC. The researchers found that those with high soy intake pre-diagnosis had more tumor suppressor genes and fewer cell growth-related genes. This suggests soy consumption may have some protective effects.
However, it is worth noting that this study only involved participants in China. Soy is much more prevalent in the diets of Chinese and Japanese populations than those of Western populations. As a result, these findings may not apply to people in different parts of the world.
The ACS advises people to limit or avoid the following foods and beverages:
A smaller 2016 study investigating TNBC in women with dense breasts found that people who ate the following foods had a higher risk of developing this type of cancer:
The ketogenic or keto diet is a high fat, very low carbohydrate, and moderate protein diet. This dietary approach induces a process called ketosis, a metabolic state where the body burns fats for fuel.
The NCI advises that although a keto diet is difficult to follow, it is generally safe. The organization explains that the purpose of the diet is to decrease the amount of glucose the tumor cells need in order to grow and reproduce.
A 2019 review of ketogenic diets in treating cancer suggests such diets may enhance the efficacy of treatments and increase patients quality of life. However, further studies are necessary to confirm these effects. Additionally, there is currently no research on the keto diet specifically for people with TNBC.
If a person with TNBC is interested in trying a ketogenic diet, they should discuss it with their medical team to check whether or not it is safe and appropriate for their specific health needs.
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:
Although these tips help promote overall health and can help ensure a person is getting the nutrients they need, it is not always possible for an individual with cancer to eat in a specific way. Often, cancer treatments take their toll on appetite and energy and could lead to symptoms such as nausea and taste changes.
Getting enough calories and protein and maintaining body weight and muscle mass are most important for people with cancer. If someone can only tolerate specific foods and textures, that is perfectly fine. The focus should be on eating whatever foods are tolerable, whether health experts consider them healthy or not.
If anyone has specific questions about diet and TNBC, or breast cancer in general, they can speak with their healthcare team. A healthcare team, including a registered dietitian specializing in cancer nutrition, can help people develop a plan to help them maintain their energy and support their overall health.
Research has not yet identified an ideal diet for people with TNBC. However, evidence suggests that a whole food diet rich in fruits and vegetables, whole grains, and legumes is beneficial to help prevent cancer and support health during cancer treatment.
Additionally, people living with cancer may benefit from avoiding or limiting their consumption of processed, high fat, and high sugar foods. Some may also consider increasing their intake of certain plant compounds. However, anyone who has a cancer diagnosis or is undergoing treatment for the disease should speak with their oncologist before making significant dietary changes.