Breast Cancer

The quality of the food we consume can impact our risk of developing breast cancer. Research has shown that consuming more healthful plant-based foods, such as whole grains, fruits, and vegetables, is associated with a lower risk of developing breast cancer.1 Fruits and vegetables have been found to be protective against developing breast cancer and dying from breast cancer.2 Researchers have suggested the antioxidants found in fruits and vegetables protect against breast cancer by reducing DNA damage in breast cells.

One study of nearly 10,000 women found that those who consume low-fat diets have a 23% lower risk for breast cancer recurrence.3 They also have a 17% lower risk of dying from the disease.

In overweight women with metastatic breast cancer, a whole food, plant-based diet can improve health markers. Research published in 2024 found that after just eight weeks on the diet, women in the intervention group had reduced fasting insulin, reduced insulin resistance, reduced total and LDL cholesterol, an improved hormonal profile, and experienced a 6.6% weight loss on average.4 While this study was not long enough to assess cancer-related outcomes, previous research has found that diets high in plant-based foods, especially fruit, vegetables, and soy, are associated with a lower risk of dying from cancer.5

Soy has been found to be protective against developing breast cancer, particularly when consumed during adolescence. This may be because phytoestrogens affect the developing breast tissue during puberty, resulting in a reduced risk of breast cancer later in life.⁶ After a diagnosis of breast cancer, women who eat more soy-based foods actually have a better chance at a long, healthy life. They are less likely to have a recurrence and less likely to die from breast cancer than women who skip soy or eat less soy.^7-8 The notion that soy products are associated with increased recurrence is a myth that has been widely and mistakenly promoted. Research findings show that eating soy foods like tofu, tempeh, and soy milk seems to have a protective effect.⁹

The BRCA gene mutation is the most significant genetic risk factor for developing breast cancer. One study found that the protective effect of soy was stronger in women with the BRCA mutation than those without.¹⁰ Soy intake was associated with only a 27% breast cancer risk reduction in people without the BRCA mutation, but a 73% risk reduction in carriers of BRCA gene mutation.

The research on the link between dairy and breast cancer is less clear. The Life After Cancer Epidemiology study found that, among women previously diagnosed with breast cancer, those consuming one or more servings of high-fat dairy products (e.g., cheese, ice cream, whole milk) daily had a 49% higher breast cancer mortality, compared with those consuming less than one-half serving daily, while low-fat dairy products were not associated with an increased risk.¹¹

Research funded by the National Cancer Institute, the National Institutes of Health, and the World Cancer Research Fund, found that women who consumed 1/4 to 1/3 cup of cow’s milk per day had a 30% increased chance for breast cancer, while there was no change in risk associated with cheese or yogurt.¹²

Another long-term study called the China Kadoorie Biobank study followed 300,911 pre- and postmenopausal women for 11 years.¹³ In this population where dairy consumption is relatively lower than in a Western population, researchers found a positive association between dairy consumption and breast cancer, with a 17% increased risk for each 50 grams of dairy products consumed per day above the average intake of 37.9 grams.

Studies, such as the UK Women’s Cohort Study, show that red and processed meat, like hot dogs and bacon, can increase breast cancer risk.¹⁴ The Nurses’ Health Study II found that premenopausal women who ate the most red meat had a 97% higher risk of a common type of breast cancer.¹⁵ The NIH-AARP Study involving nearly 200,000 women found a 25% higher risk for breast cancer in those eating the most red meat, compared to those eating the least.¹⁶

The Let’s Beat Breast Cancer campaign is an annual campaign pioneered by the Physicians Committee to show how a healthful diet and lifestyle can help reduce your breast cancer risk. This campaign centers around four steps:

1. Choose Plant-Based Foods
2. Exercise Regularly
3. Limit Alcohol
4. Maintain a Healthy Weight