Associations between dietary fiber, the gut microbiota, and health outcomes in breast cancer survivors: A scoping review

Background

Breast cancer (BC) is the most frequently identified malignancy in women and a major cause of female mortality. Its progression is influenced by a range of factors, including genetic, environmental, lifestyle, and hormonal elements. Recently, the gut microbiota (GM) has emerged as an important factor impacting BC. Dietary factors, particularly dietary fibers, may play a significant role in BC survivorship. These nondigestible carbohydrates serve as nutrients for gut microorganisms, promoting GM diversity and production of beneficial short-chain fatty acids (SCFAs), which possess anti-inflammatory and antiproliferative properties, influencing estrogen metabolism through the gut estrobolome, which modulates estrogen exposure and BC risk. This review synthesizes current literature on the effects of dietary fibers on GM in BC patients, exploring underlying mechanisms and clinical implications.

Method

Studies from PubMed/Medline and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were identified up to June 2024, including quantitative designs targeting BC cases with performed GM analyses.

Results

Ten studies met the inclusion criteria, revealing that dietary fibers consistently correlate with beneficial changes in GM, such as increased diversity and beneficial bacterial abundance while reducing harmful bacteria linked to estrogen reabsorption. Dietary fibers influence GM by serving as fermentation substrates and producing SCFAs.

Conclusions

The review highlights the necessity of standardizing microbiota analysis and dietary assessment methods and calls for long-term studies across diverse populations. Personalized nutritional interventions based on individual GM microbiota hold promise to improve BC outcomes and quality of life.