The Mediating Role of Gut Microbiota on the Association Between Dietary Quality and Cancer-Related Fatigue Among Breast Cancer Patients: A Cross-Sectional Study.

OBJECTIVES

Cancer-related fatigue (CRF) is highly prevalent in patients with breast cancer, resulting in undesirable outcomes and even reduced survival rates. This cross-sectional study investigated the relationship between dietary quality and CRF in patients with breast cancer, and the potential role of gut microbiota (GM) in this association.

METHODS

Dietary intake and CRF were evaluated in 342 patients, with 64 fecal samples collected for 16sRNA sequencing and 106 plasma samples for tryptophan (TRP) metabolite determination.

RESULTS

A total of 149 (43.6%) patients experienced CRF, which was significantly associated with low intakes of protein, vitamin A, vitamin E, dietary fiber, phosphorus, magnesium, potassium, iron, and copper ( < 0.05), and a remarkably low Chinese Healthy Eating Index (CHEI) score ( < 0.05). CRF patients had decreased GM diversity, an unhealthier GM composition, lower TRP concentrations, and a higher kynurenine (KYN)/TRP ratio ( < 0.05). Mediation analyses revealed that both the Sobs index (ACME = -0.0005; 95% CI -0.0051, -0.0001; = 0.034) and the Chao index (ACME = -0.0005; 95% CI -0.0050, -0.0001; = 0.033) were significant mediators of the correlation between total CHEI score and CRF.

CONCLUSIONS

The presence of CRF in patients with breast cancer might be correlated with inadequate nutrient intake and low dietary quality via GM-dependent pathways.