The Mediterranean Diet (MD), known for its health benefits and sustainability, is now being explored for its potential positive impact on sleep quality. Rich in plant-derived foods like whole grains, fruits, vegetables, legumes, and nuts, the MD has demonstrated its adaptability beyond Mediterranean cultures and proven effective in reducing the risk of various health issues.
Numerous studies have highlighted the MD’s role in lowering the risk of cancers, neurodegenerative diseases, and cardiometabolic disorders. As MD adherence often aligns with other healthy lifestyle habits, researchers have investigated its potential influence on sleep quality, recognizing the link between a healthy diet and improved sleep as a means to reduce the risk of chronic non-communicable diseases.
To explore this connection, a systematic search across the EMBASE and PubMed databases was conducted, encompassing papers published until January 2023. The analysis focused on observational studies involving individuals aged 18 and above, excluding studies on pregnant women, children, adolescents, and those with late-stage degenerative conditions. A total of 23 publications were reviewed.
Benefits of MD on Sleep Quality
Thirteen studies from France, Greece, Spain, and Cyprus indicated that high MD adherence correlated positively with enhanced sleep quality and longer sleep duration. Conversely, adherence to MD showed a negative association with the risk of sleep duration changes, insomnia symptoms, and daytime sleepiness. Notably, these associations were observed in studies from both Mediterranean and non-Mediterranean regions, hinting at potential biological mechanisms influencing the relationship.
Eighteen studies focused on healthy adults, while the rest involved individuals with health conditions such as breast cancer, multiple sclerosis (MS), obstructive sleep apnea, and rheumatoid arthritis. The findings suggested that individuals with health conditions may experience improved sleep with MD adherence. For instance, MD was linked to reduced insomnia in women with breast cancer and individuals with sleep apnea, as well as less disturbed sleep in those with MS.
Potential Causal Impact and Study Limitations
While the study findings consistently support the positive association between MD adherence and improved sleep outcomes, it’s essential to acknowledge the limitations. The studies were predominantly observational and cross-sectional, preventing causal inference. Self-reported data on dietary adherence and sleep quality could be influenced by social desirability and recall biases.
Additionally, the diverse tools and instruments used across the 23 studies precluded the possibility of conducting meta-analyses. Despite these limitations, the evidence suggests that MD could be a promising intervention to enhance sleep quality for individuals both within and outside Mediterranean regions, as well as those dealing with various health conditions.
Conclusion and Future Directions
The Mediterranean Diet’s potential to positively impact sleep quality underscores the importance of further research to establish causation. While the current evidence is compelling, future studies should explore the causal impact of MD adherence on sleep outcomes. This investigation opens new avenues for understanding the holistic benefits of the MD, expanding its potential role in promoting overall well-being and addressing health conditions through dietary interventions.