A recent Kaiser Permanente study found that women who had a heart-healthy diet at the time of their breast cancer diagnosis were less likely to go on to develop heart disease. This finding can help all breast cancer survivors make dietary choices that may lower their heart disease risk.

In the U.S., breast cancer is the most common cancer in women. But heart disease is the most common cause of death. Both diseases share similar risk factors, such as poor diet, obesity, and smoking. Also, some cancer therapies can cause heart damage.

“Many people are not aware that breast cancer survivors have a higher risk of developing heart disease than women who have not had breast cancer,” said Isaac Ergas, PhD, MPH, MFA, a staff scientist at the Kaiser Permanente Division of Research who led the study. “Since diet can improve heart health, we felt it was important to see if diet quality was related to future risk of heart disease in women diagnosed with breast cancer.”

The study, published in JNCI Cancer Spectrum, included 3,415 women with breast cancer who are enrolled in the Kaiser Permanente Northern California Pathways Study. Pathways is one of the largest U.S. studies to follow breast cancer survivors from the time of their diagnosis.

The study found that women whose food choices at the time of their breast cancer diagnosis were most similar to those recommended by the Dietary Approaches to Stop Hypertension (DASH) Eating Plan were least likely to develop heart disease and other heart problems. These women had a 47% lower risk of heart failure, a 23% lower risk of arrhythmia (an irregular heartbeat), a 23% lower risk of cardiac arrest, a 21% lower risk of valvular heart disease, and a 25% lower risk of developing a blood clot than women whose food choices were least like those recommended by DASH.

“Our study is one of the few studies that has taken a deep dive into the effect of diet on cardiovascular disease risk in breast cancer survivors,” said senior author Marilyn Kwan, PhD, a research scientist at the Division of Research. “Our findings highlight how important it is that doctors continue to talk to breast cancer survivors about diet quality.”

The DASH Eating Plan recommends eating vegetables, fruits, and whole grains as well as limiting sugar-sweetened beverages, sweets, and foods high in saturated fats. The diet also includes fish, poultry, beans, nuts, vegetable oils, and fat-free or low-fat dairy products.

“It is exciting to see the results of this excellent work that empowers our oncologists to recommend evidence-based lifestyle medicine recommendations,” said Tatjana Kolveska, MD, chair of The Permanente Medical Group Medical Oncology and Hematology.

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