Breast cancer killed roughly 694,000 women worldwide in 2024, making it the most common cancer among women and the second leading cause of cancer death for women in the United States. Polyphenols, a group of plant compounds already known for their antioxidant properties, are emerging as one of the more promising dietary factors researchers are studying alongside conventional treatment. As the global toll from breast cancer has grown, so has interest in what people can control through their everyday food choices.
A study published in the British Journal of Nutrition adds weight to that idea. Researchers found that certain plant compounds called polyphenols, already known for their antioxidant properties, may lower the risk of dying from breast cancer or seeing it return.
What the polyphenol study found
Polyphenols show up naturally in a wide range of foods, including berries, cocoa, coffee, colorful vegetables, extra virgin olive oil, herbs and spices, legumes, nuts and seeds. For the study, researchers followed 95 women diagnosed with breast cancer for an average of 11.5 years, tracking how much of these compounds each woman consumed. Women who ate more total polyphenols, especially two subtypes called phenolic acids and lignans, had lower breast cancer specific mortality than those who ate less. Coffee turned out to be one of the biggest sources of polyphenols in participants’ diets, which surprised some of the researchers given its everyday reputation as just a caffeine habit.
How polyphenols may work inside the body
Registered dietitian nutritionist Monique Richard said polyphenols appear to touch several biological processes tied to cancer survival, including oxidative stress, chronic inflammation, insulin sensitivity, immune signaling, blood vessel growth and cell communication. In practical terms, these compounds may blunt the free radical damage and prolonged inflammation that can help cancer progress. There is also growing interest in how polyphenols interact with gut bacteria, since that relationship may influence estrogen activity in breast tissue, a pathway closely tied to how many breast cancers grow.
Why experts are still cautious
Dr. Tracy Crane of the Sylvester Comprehensive Cancer Center called the results encouraging but preliminary. She and other researchers want to see the findings replicated in larger and more diverse groups before drawing firm conclusions, and they note that variables like cancer subtype, how closely patients stuck to treatment and other lifestyle habits all need closer scrutiny in future work. A sample of 95 women, however carefully tracked, is not enough on its own to change clinical guidance.
Getting more polyphenols from real food
Richard and fellow nutritionist Meridan Zerner suggest building meals around a mix of colorful produce, leaning toward darker varieties such as blueberries, blackberries and red cabbage, along with dark leafy greens. A handful of walnuts or pistachios, a square of dark chocolate, or a spoonful of ground flaxseed stirred into oatmeal or yogurt can all add meaningful amounts of lignans and other polyphenols. Unsweetened green tea, black tea or coffee count too, along with everyday additions like extra virgin olive oil, legumes and spices such as cumin, cloves, ginger and cinnamon.
Both nutritionists point out that whole foods tend to outperform supplements here, since food delivers a broader mix of nutrients that helps the body absorb and use polyphenols more effectively.
The overall picture emerging from this research is that diet will not replace medical treatment for breast cancer, but it may be a meaningful piece of the puzzle alongside it. For anyone currently navigating a diagnosis, talking with an oncologist or registered dietitian before making major dietary changes remains the safest first step.
