Current Evidence on the Impact of Diet, Food, and Supplement Intake on Breast Cancer Health Outcomes in Patients Undergoing Endocrine Therapy

Background/Objectives: The most common type of breast cancer (BRC) in women is estrogen/progesterone receptor positive. First-line treatment includes endocrine therapy, either with aromatase inhibitors or tamoxifen to reduce estrogen levels. Among the side effects produced by this treatment, aromatase inhibitor-induced arthralgia is the most common, affecting the patients' overall health and quality of life (QoL). The objectives here were to evaluate interventions examining the impact of modified diets, supplements, and/or some food components on health outcomes in BRC patients undergoing endocrine therapy. Methods: The literature search was performed in PubMed, Scopus, and Web of Science from June 2024, as well as manually, through the end of November 2024. The search was limited to studies of women diagnosed with estrogen/progesterone-receptor-positive BRC with selected articles reporting interventions with diet, food, or supplement intake and examining the relevant health outcomes. Studies not focusing on BRC patients undergoing endocrine therapy or not including specific health outcomes were excluded. Results: The search uncovered 1028 studies; after the removal of duplicates, abstracts, and irrelevant studies, 53 were closely examined, with 26 evaluated and presented here. The outcomes were changes in bone and body composition, cardiovascular disease risks, inflammation, and QoL. Conclusions: The examined evidence suggests that adherence to dietary patterns such as the Mediterranean or a low-fat diet, and a higher intake of fruits and vegetables were beneficial for various outcomes. Additionally, supplementation with some foods/components (dried plum, red clover) contributed to improving/maintaining bone and body composition, especially in overweight/obese patients. Supplementation with vitamin D or omega-3 improved lipid and angiogenic parameters and QoL. Although these results are promising, the effects of each supplement/food cannot be summarized due to the diverse nature of study designs, patients, and supplement dosages. Further studies are needed to explore the effects of specific nutritional interventions (including the newest, like fasting-mimicking diets and whole-grain cereal diets) on various health outcomes in BRC survivors during endocrine therapy, and to derive universal recommendations.