An Investigation of the Effects of Dietary and/or Nutraceutical Modulation of Insulin Resistance on Survival in Female Breast Cancer Patients: A Systematised Review of the Evidence
By Patricia Daly - Online MSc - Advanced Nutrition
Abstract
Background
Evidence shows how dysregulated insulin feedback in breast cancer patients has several negative implications for cancer treatment effects and survival. Modulation of insulin resistance with dietary and/or nutraceutical interventions may become a relevant and safe therapeutic approach to enhance outcomes in breast cancer.
Aims and objectives
The primary aim of this study was to document the evidence base for dietary and/or nutraceutical modulation of insulin resistance and its impact on survival in female breast cancer patients. A secondary aim was to establish the quality of this evidence. Objectives included the provision of an evidence tool for nutrition professionals and discussion of future study design.
Methodology
A systematised review of randomised controlled and observational studies was conducted by one researcher. MEDLINE, Embase, AMED and CENTRAL databases and other sources containing unpublished literature were searched up until July 8, 2020. Study selection followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, employing pre-defined criteria. The study quality of the five studies identified for inclusion in the review was assessed using the Critical Appraisal Skills Programme (CASP).
Findings
The effects of dietary and/or nutraceutical interventions were strongest for recurrence-free survival, which was significantly reduced by a pre-surgery spike in insulin (+357%) via carbohydrate loading. Overnight fasting of <13 hours or elevated Haemoglobin A1c (HbA1c) of ≥ 5.6% combined with increased dietary acid load also negatively affected survival. Moderate evidence for improved overall survival was provided for using a ketogenic diet during treatment of neoadjuvant patients. Survival was negatively affected by high C-reactive protein (CRP) levels (>10mg/L).
Conclusion
Modulation of insulin resistance with dietary and/or nutraceutical interventions in women with breast cancer requires strong consideration. Patients with dysregulated insulin metabolism versus those without this diagnosis and regardless of body mass index (BMI), can expect shorter recurrence-free survival. Once insulin resistance is established, this review indicates that addressing and monitoring of such is a high priority to improve outcomes.
