The Mediterranean Diet Is Associated with a Reduced Risk of Breast Cancer, Especially in Postmenopausal Women
Recent research indicates that adhering to the Mediterranean diet may offer protective benefits against developing breast cancer, particularly among women after menopause. These findings are more pronounced in Asian populations and are based on comprehensive analysis.
A Wide-ranging Meta-Analysis Highlights Protective Effects
This conclusion comes from an extensive meta-analysis conducted primarily by researchers based in Iran, published in Health Science Reports. The scientists hypothesize that the beneficial impact of the Mediterranean diet stems from its anti-inflammatory properties. Since inflammation is known to play a significant role in cancer development—interacting with hormonal factors—the diet’s capacity to reduce inflammation might help lower breast cancer risk.
Understanding Breast Cancer’s Impact on Public Health
Breast cancer remains a leading health concern worldwide, with high incidence and prevalence rates, making it not only a medical challenge but also a major public health issue. Early detection and prevention are crucial strategies, emphasizing the importance of identifying lifestyle factors and dietary patterns that can influence risk. Among these strategies, diet stands out as an affordable, effective, and accessible approach to reducing the likelihood of developing various chronic diseases, including certain types of cancer.
The Inverse Relationship Between the Mediterranean Diet and Breast Cancer Risk
Interestingly, multiple studies suggest that greater adherence to the Mediterranean diet correlates with decreased breast cancer risk, although some inconsistencies still need clarification. This latest research analyzed data from selected case-control and cohort studies identified through reputable databases such as PubMed, Scopus, and Web of Science. The analysis included studies that specifically examined the link between dietary adherence and breast cancer risk, focusing on those with quantitative data. Studies lacking such data, reviews, or those examining other dietary patterns or with insufficient sample sizes were excluded.
Methodology and Quality Assessment
The quality of the included studies was evaluated using the Newcastle-Ottawa Scale (NOS). The meta-analysis combined risk estimates by comparing the lowest and highest levels of adherence to the Mediterranean diet. Subgroup analyses were performed based on study design, geographic region, menopausal status, and other factors to determine if these variables altered the observed associations. Sensitivity analyses were also conducted to confirm the robustness of the findings, particularly considering the potential influence of alcohol consumption—an element of the diet whose role in breast cancer risk remains debated.
This comprehensive review considered data from 2,189 women aged between 20 and 104 years, collected across 31 studies out of an initial 43 published from 2006 to 2023. Of these, 19 were case-control studies, and 12 were cohort studies.
Key Findings of the Meta-Analysis
The analysis revealed a statistically significant association: women who closely follow the Mediterranean diet have about a 13% lower risk of developing breast cancer compared to those with lower adherence (Hazard Ratio: 0.87; 95% Confidence Interval: 0.82-0.92; I²=70%). This protective effect was particularly notable among postmenopausal women, showing a 12% reduction in risk (HR: 0.88; 95% CI: 0.84-0.92). Conversely, in premenopausal women, no significant association was observed (HR: 0.98; 95% CI: 0.90-1.06).
Geographic Differences Highlight Variations in Risk Reduction
The impact of the Mediterranean diet on breast cancer risk appears to differ based on region. The strongest protective effect was observed in Asian populations, where the odds ratio was approximately 0.59 (95% CI: 0.50-0.68). In contrast, moderate associations were seen in North America (OR: 0.92; 95% CI: 0.82-1.02) and Europe (OR: 0.90; 95% CI: 0.83-0.97). These differences could reflect cultural, genetic, or dietary variations across populations.
Study Design and Lifestyle Factors Influence Results
Subgroup analyses suggest that case-control studies tend to report a stronger association (HR: 0.77; 95% CI: 0.70-0.85) compared to cohort studies (HR: 0.96; 95% CI: 0.90-1.02). Additionally, the inclusion or exclusion of alcohol consumption influenced the risk estimates in certain groups, notably among postmenopausal women. This raises questions about alcohol’s role as either a trigger or a correlated factor in breast cancer development. Sensitivity analyses, including leave-one-out tests, confirmed the stability of these findings, with no anomalous studies skewing the overall results.
Concluding Remarks
In summary, adherence to the Mediterranean diet appears to be associated with a meaningful reduction in breast cancer risk, especially among postmenopausal women and in certain regions such as Asia. This suggests that adopting this dietary pattern could serve as a practical, low-cost strategy in breast cancer prevention efforts.
However, further research is essential to validate these findings and address some limitations. Differences noted between cohort and case-control studies need clarification, as the latter often show stronger associations but are more prone to recall bias. Additionally, variations in how the Mediterranean diet is defined and implemented across different cultures may impact results. Future studies should also explore specific subtypes of breast cancer, considering hormonal receptor status, genetic predispositions, and lifestyle factors, to better understand the potential protective mechanisms of this diet.
Sources
Karimi M, Asbaghi O, Hooshmand F, et al. Adherence to Mediterranean Diet and Breast Cancer Risk: A Meta-Analysis of Prospective Observational Studies. Health Science Reports, 2025. doi: https://doi.org/10.1002/hsr2.70736
