The Role of the Mediterranean Diet in Breast Cancer Survivorship: A Systematic Review and Meta-Analysis of Observational Studies and Randomised Controlled Trials

Ge Chen; Sam Leary; Jizhao Niu; Rachel Perry; Angeliki Papadaki

doi:10.3390/nu15092099

The Role of the Mediterranean Diet in Breast Cancer Survivorship: A Systematic Review and Meta-Analysis of Observational Studies and Randomised Controlled Trials

Nutrients. 2023 Apr 27;15(9):2099. doi: 10.3390/nu15092099.

Authors

Ge Chen^{1

2}, Sam Leary^{1

2}, Jizhao Niu³, Rachel Perry⁴, Angeliki Papadaki³

Affiliations

¹ Bristol Dental School, University of Bristol, Bristol BS2 8AE, UK.
² National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol BS8 2BN, UK.
³ Centre for Exercise, Nutrition and Health Sciences, School for Policy Studies, University of Bristol, Bristol BS8 1TZ, UK.
⁴ Bristol Medical School (Cardiovascular Surgery and Vascular Biology), University of Bristol, Bristol BS2 8HW, UK.

Abstract

Female breast cancer is the most frequently diagnosed cancer. The long-term survival rates for this disease have increased; however, the unique demand for high-quality healthcare to improve breast-cancer survivorship are commonly unmet. The Mediterranean diet (MD) is associated with reduced breast-cancer risk and various health-related benefits in the general population, but its effect on breast-cancer survivors remains uncertain. The objective of this systematic review and meta-analysis was to assess current evidence from randomised controlled trials (RCTs) and observational studies (cohort, cross-sectional and case-control) regarding the effect of the MD on survival, quality of life (QoL) and health-related outcomes in female breast-cancer survivors. MEDLINE, EMBASE, Web of Science and the Cochrane library were searched for studies published before and including April 2022. Two reviewers independently screened the literature and completed the data extraction and risk-of-bias assessment. Eleven studies (fifteen reports) were included, including two RCTs, four cohort and five cross-sectional studies. The meta-analysis of the cohort studies showed strong evidence of an inverse association between high adherence to the MD and all-cause mortality (hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.66-0.93, I²: 0%, Grading of Recommendations Assessment, Development and Evaluation (GRADE) = low certainty of evidence) and non-breast-cancer mortality (HR 0.67, 95% CI 0.50-0.90, I²: 0%, GRADE = very low certainty of evidence). The associations between high adherence to the MD and QoL and health-related parameters were not consistent. These findings highlight the potential of adherence to the MD to reduce the risk of mortality. Future research with better study designs, as well as more consistent measurements of QoL and MD adherence, taking into account changes in MD adherence over time and population subgroups, is needed to provide more robust evidence on the survival, QoL and health-related outcomes in BC survivors.

Keywords: Mediterranean diet; breast cancer; mortality; quality of life; survivorship; systematic review.

Publication types

Meta-Analysis
Systematic Review
Review

MeSH terms

Breast
Breast Neoplasms*
Cancer Survivors*
Diet, Mediterranean*
Female
Humans
Observational Studies as Topic
Randomized Controlled Trials as Topic
Research Design

Grants and funding

This research received no external funding.