Up to 20 percent of invasive breast cancers are classified as triple negative, which refers to the fact that the cancer is estrogen receptor negative (ER-), progesterone receptor negative (ER-), and HER2/neu negative (ER-/PR-/HER2-). In other words, triple negative breast cancers do not express receptors for estrogen or progesterone and do not overexpress HER2. Triple negative breast cancer is also classified as basal-like breast cancer by some researchers.
Women diagnosed with triple negative breast cancer are more likely to be premenopausal than women with hormone receptor positive breast cancer. Treatments or foods that reduce the production of estrogen or block its effects in the body are not useful for this type of breast cancer.
Women with metabolic syndrome are more likely to have triple negative breast cancer upon diagnosis than women without it. A high cholesterol diet has been shown to induce angiogenesis and accelerate mammary tumor growth in a mouse model of triple negative breast cancer. On the other hand, use of lipophilic statins such as Zocor might reduce recurrence. The type 2 diabetes drug metformin has been shown to reduce the metastatic potential of triple negative breast cancer cells.
The studies concerning diet or specific foods that relate to triple negative cancer focus on hormone receptor status; HER2/neu status tends to be studied separately. However, the information concerning ER-/PR- breast cancer and diet is likely to be relevant to triple negative breast cancer since HER2- is the normal state (see also our web page on HER2+ breast cancer if you have ER-/PR-/HER2+ breast cancer). There are specific foods that have been found to be associated with lower risk of this type of breast cancer and some that are associated with higher risk.

Foods that reduce the risk of triple negative or ER-/PR- breast cancer

Foods and supplements that increase the risk of ER-/PR- breast cancer

The following foods have the potential to increase the risk of ER-/PR- breast cancer or its progression:
Apricots, dried, non-US — potential for high cadmium levels
Bacon and other processed meats
Beef and veal, especially liver
Copper supplements, including multivitamins
Corn oil
Genistein supplements
High fructose corn syrup
Indian mustard or black mustard
Lamb, especially lamb liver
Milk, full-fat
Peanuts and peanut oil
Pork and lard
Resveratrol supplements
Rice from Louisiana, Thailand or India — potential for high cadmium levels
Safflower oil
Highly salty foods
Products made from defatted soy flour, such as soy protein isolate & textured soy protein
Soybean oil
Sunflower seeds and sunflower oil
Vitamin E supplements, alpha-tocopherol
Vitamin K supplements
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. Exposure to bisphenol A (BPA) has also been shown to increase proliferation of triple negative breast cancer cells.
Cadmium has been shown to promote the growth of triple negative cells. Copper has been shown to contribute to angiogenesis and metastasis of breast cancer, especialy in women with triple negative disease. Copper jewelry and jewelry made from copper alloys, such as red gold and pink gold, are another potential source of copper exposure. Cigarette smoking is associated with significantly poorer outcomes for triple negative patients.

Foods that can help reduce or regulate blood sugar and insulin levels

The foods below have been shown to help regulate glucose, increase insulin sensitivity and/or reduce circulating insulin levels while also protecting against breast cancer. Consuming such foods may help reduce the likelihood or extent of metabolic syndrome.
Beans, dry
Flaxseed oil
Hot peppers
Olives & olive oil
Brown rice, U.S. grown
Walnuts & walnut oil

Additional comments

It is important for triple negative breast cancer patients and survivors to eat a wide variety of the foods on our recommended food list and limit or avoid those on our avoid list, in addition to paying particular attention to the foods on the lists above. See also our article on how to optimize your breast cancer diet for information on what to eat during all stages of treatment and recovery.
Below are links to recent studies on this topic. For a more complete list of studies, please click on triple negative diet.

Food for Breast Cancer triple negative breast cancer articles

Below are links to all of the other articles concerning triple negative breast cancer.
To see all of the news stories and studies concerning triple negative breast cancer, click on the tripleNegative tag in the list of tags directly below.