Drinking coffee linked to lower breast cancer death risk: Here’s why

For this study, researchers followed 95 women diagnosed with breast cancer for an average of 11.5 years. Scientists assessed their polyphenol intake.

At the study’s conclusion, they found that a higher intake of total polyphenols and two types of polyphenols, phenolic acids and lignans, linked with lower breast cancer-specific mortality.

A greater consumption of phenolic acid itself was associated with lower breast cancer recurrence, and the total intake of polyphenols was correlated with longer survival when breast cancer mortality was considered.

In the study, researchers noted that coffee was the major contributor to total polyphenol, phenolic acid, and lignan intake for study participants.

According to Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight who was not involved in this study, polyphenols are a large family of naturally occurring plant compounds found in foods like:

• berries
• cocoa
• coffee
• colorful vegetables
• extra virgin olive oil
• herbs and spices
• legumes
• nuts and seeds.

“Polyphenols don’t exist in isolation in nature — they come packaged with fiber, vitamins, minerals, healthy fats, and thousands of other phytochemicals that likely work together,” Richard told Medical News Today.

“Polyphenols work through a variety of mechanisms. They appear to influence multiple biological pathways that are relevant to cancer survivorship, including oxidative stress, chronic inflammation, insulin sensitivity, immune signaling, angiogenesis, and cellular communication.”

–Monique Richard, MS, RDN, LDN

“Polyphenols also influence free radical damage and can participate in calming an intense inflammatory response, which is exactly the kind of chronic stress that can allow cancer cells to progress,” added Meridan Zerner, MS, RDN, CSSD, LD, CHWC, founder of Meridan Zerner Nutrition in Dallas, TX, who was also not involved in this study.

“Polyphenols influence our gut bacteria and lignans, a category of polyphenols mentioned in this study, support the gut bacteria which, in turn, could dial down estrogen-driven growth in breast tissue,” Zerner explained.

“More research would be needed to identify the impact, but there could be a hormone mechanism at play here,” she added.

MNT also had the opportunity to speak with Tracy Crane, PhD, RDN, co-lead of the Cancer Control Program and director of lifestyle medicine, prevention and digital health at the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine.

Crane commented she found this study’s findings encouraging and biologically plausible, but they should be viewed as hypothesis-generating rather than definitive.

“This study identifies an important signal, but it does not establish that increasing polyphenol intake will prevent recurrence or extend survival,” Crane, who was not involved in this study, explained. “The findings also do not prove that women should begin drinking large amounts of coffee or consume alcohol as a source of polyphenols.”

Crane suggested the next steps for this research first be replication in much larger and more diverse populations, using repeated dietary assessments before and after diagnosis.

“Studies should carefully account for breast cancer subtype, stage, contemporary treatments, treatment adherence, body weight, physical activity, comorbidities and socioeconomic factors,” she detailed. “Future research should also evaluate dose-response relationships. Researchers also need to separate the effects of individual food sources, particularly coffee, from those of the broader dietary pattern.”

“Ultimately, I would like to see randomized, food-based interventions that test whether increasing a diverse range of polyphenol-rich whole foods changes relevant metabolism, inflammatory and tumor related pathways and, if sufficiently powered and followed long enough, recurrence and survival,” Crane added. “Importantly, I would not jump from this study directly to trials of concentrated polyphenol supplements.”

For readers who may wish to consume more polyphenols, Richard and Zerner offered these tips:

• eat the rainbow — foods that have darker colors have higher polyphenol count so eat more blueberries, blackberries, raspberries, and dark red/purple foods like red grapes, plums, red cabbage, and pomegranates
• increase the consumption of dark leafy greens
• snack on walnuts, pistachios, with a small piece of dark chocolate
• flaxseed is a rich source of lignans which mixes nicely into oatmeal or yogurt
• drink unsweetened green tea, black tea, or coffee, if tolerated
• use extra virgin olive oil for dressings, marinades, sauteing or as a flavor enhancer to top roasted vegetables or grilled fruits
• include legumes several times each week in grain bowls burritos, salads, and pasta
• Spices like cumin, cloves, ginger, and cinnamon are considered polyphenol powerhouses as well.

“Many of my clients ask about getting polyphenols through supplements, but right now the research indicates that getting polyphenols from whole foods is more effective than taking supplements because whole foods provide balanced nutrient combinations and synergistic compounds that maximize absorption,” Zerner added.

“I encourage clients and patients to think about color, variety, and consistency versus any particular ‘superfood,’ or ‘nutrient hack,’” Richard said. “Every meal is an opportunity to include another source of polyphenols.”

“Polyphenols are an important part of an orchestra of nutrients needed to support harmony within our body,” she continued. “Our entire dietary pattern, and lifestyle choices, can support long-term health and resilience — like a maestro, if you will — conducting the symphony playing within our internal environment.”