Can diet help with advanced breast cancer? Indications look positive, researchers say

According to a study by researchers at the University of Rochester Medical Center and Wilmot Cancer Institute, women with breast cancer who exclusively ate a whole-foods, plant-based diet lost weight, improved cholesterol levels and other key metabolic factors, had less fatigue, and perceived that they felt sharper mentally and generally more well.

The results were published in the journal Breast Cancer Research and Treatment.

While many anti-cancer treatments lead to weight loss, breast cancer treatment often results in weight gain. A 1997 review found that 50% to 96% of women undergoing chemotherapy for early-stage BC gained between five and 13.6 pounds. This weight gain is linked to elevated insulin, insulin resistance, blood glucose, cholesterol, sex hormones, and IGF-1, all of which can worsen BC progression, increase mortality risk, and reduce quality of life.

Dietary therapy can affect both obesity and its related cardiometabolic and hormonal risk factors. A plant-predominant dietary pattern, lower in processed foods, is commonly recommended by many organizations, including the American Institute for Cancer Research and the American Cancer Society.

In the study, 30 patients on stable treatment were randomly divided into two groups. One group received standard care, while the other followed an eight-week diet of fruits, vegetables, whole grains, legumes, potatoes, nuts, and seeds, avoiding animal-based foods, oils, and added fats. Participants also took a daily multivitamin.

Researchers observed that starting with an average BMI of 29.7, the whole-foods plant-based group lost one to two pounds per week without mandated exercise. They also noticed a reduction in blood samples of IGF-1, a growth factor that has been associated with many common cancers, as well as less inflammation.

“Although we cannot say anything yet about whether the diet can stop cancer progression from this small study, we saw preliminary results that suggest favourable changes within the body, which is very positive. Patients should first consult with their oncologists or healthcare providers before making major dietary changes and this is especially important for people who take blood thinners or insulin medications,” said research leader Thomas M. Campbell, an assistant professor of Family Medicine at URMC.

Reference: Campbell, T.M., Campbell, E.K., Culakova, E. et al. A whole-food, plant-based randomized controlled trial in metastatic breast cancer: weight, cardiometabolic, and hormonal outcomes. Breast Cancer Res Treat 205, 257–266 (2024). https://doi.org/10.1007/s10549-024-07266-1