Mediterranean Diet Preserves White Matter Integrity in Hispanic and Latino Adults

Dietary Interventions and the Aging Brain

As the global prevalence of dementia and age-related cognitive disorders continues to rise, identifying modifiable risk factors has become a clinical priority for primary care physicians and neurologists alike [1, 2]. While pharmacological options for neuroprotection remain limited, dietary patterns have emerged as a significant area of investigation for preserving cognitive function [3, 4]. The Mediterranean diet, characterized by high intake of plant-based foods and monounsaturated fats, is frequently cited in clinical guidelines for its systemic benefits [5, 6]. Evidence suggests that these nutritional choices may reduce the risk of Alzheimer's disease and mild cognitive impairment, potentially by mitigating vascular risk factors [1, 7]. However, the specific structural brain changes that underpin these cognitive benefits, particularly in diverse populations, require further clarification [8, 9]. A recent study now provides detailed insights into how these dietary habits influence white matter integrity and cardiovascular health in Hispanic and Latino adults.

Study Population and Longitudinal Assessment

The researchers conducted a secondary analysis of data from the Study of Latinos-Investigation of Neurocognitive Aging-MRI (SOL-INCA-MRI) Ancillary Study to examine the association between Mediterranean diet adherence and white matter integrity in community-dwelling Hispanic or Latino adults. The study included a total of 2,642 participants with a mean age of 64.3 years (95% CI 63.4 to 65.1), of whom 44% were male. By focusing on this specific demographic, the authors aimed to clarify how long-term dietary patterns influence neurological health in a population that often faces a high burden of cardiovascular and metabolic risk factors, which are known precursors to vascular cognitive impairment. Data collection followed a longitudinal timeline that allowed for the assessment of dietary habits years before neuroimaging. At the baseline visit between 2008 and 2011, researchers collected dietary intake data using 24-hour recalls. These reports were used to derive a Mediterranean diet score (MeDiS) ranging from 0 to 9, where higher scores indicate closer adherence to the dietary pattern. Following this baseline, global cognition was ascertained between 2015 and 2018 using a composite score derived from 4 standardized cognitive tests, providing a robust baseline of functional mental status prior to the final imaging phase. The final stage involved brain MRI scans obtained between 2017 and 2022 using diffusion tensor imaging (a specialized MRI technique that maps the diffusion of water molecules to assess the microstructural integrity of white matter tracts). By comparing baseline diet scores with these later imaging results, the study sought to identify whether nutritional choices in late middle age correlate with the preservation of white matter volume and the prevention of small vessel disease markers, offering clinicians a clearer picture of the potential neuroprotective window for dietary interventions.

Quantifying Diet and Cardiovascular Health

To evaluate the relationship between nutritional habits and neurological outcomes, the researchers utilized the Mediterranean diet score (MeDiS) as the primary exposure variable. Within this cohort of Hispanic and Latino adults, the average MeDiS was 5.0 (95% CI 4.9 to 5.1), reflecting a moderate level of adherence. This metric allowed the authors to categorize participants based on their intake of neuroprotective food groups such as vegetables, legumes, fruits, nuts, whole grains, and fish, relative to their consumption of red meats and poultry. The study also accounted for systemic vascular health by calculating a baseline cardiovascular health score using the Life's Essential 7 score (LE7, range 0-100), a modified version of the American Heart Association's framework. The researchers specifically excluded the diet component from the original Life's Essential 8 score to avoid collinearity (a statistical overlap where two independent variables are so highly correlated that it becomes difficult to determine the individual effect of each on the outcome). The average LE7 score among the participants was 66.6 (95% CI 65.6-67.6), providing a standardized measure of cardiovascular risk factors including blood pressure, cholesterol, and glucose levels. To isolate the specific impact of the Mediterranean diet on brain structure, the researchers employed linear regression models that controlled for age, sex, and socioeconomic factors. This adjustment ensures that the observed correlations were not merely the result of demographic differences or varying access to healthcare resources, but rather the independent association of dietary patterns with the preservation of white matter and the reduction of small vessel disease markers over the follow-up period.

Impact on White Matter Microstructure

The researchers utilized diffusion tensor imaging to evaluate white matter integrity through four distinct metrics, providing a comprehensive view of both macrostructural and microstructural brain health. These measures included total white matter volume (tWM) and white matter hyperintensity (WMH) volume, the latter of which serves as a critical clinical marker of small vessel disease and chronic ischemia. At the microscopic level, the study measured fractional anisotropy (FA), a metric that reflects axonal integrity and the organization of white matter fibers by measuring the directionality of water diffusion, and free water (FW), which indicates the presence of extracellular fluid and often serves as a marker for neuroinflammation or edema. The analysis determined that higher adherence to the Mediterranean diet is linked to better white matter structural integrity across all these domains. Quantitative results revealed that for every point increase in the dietary score, there was a correlated lower white matter hyperintensity volume (β = -0.08, 95% CI -0.11 to -0.04) and a higher total white matter volume (β = 0.05, 95% CI 0.005-0.09). These findings suggest that the dietary pattern may mitigate the progression of small vessel disease and help preserve overall white matter mass. Furthermore, higher diet scores were associated with lower free water (β = -0.04, 95% CI -0.08 to -0.002) and higher fractional anisotropy (β = 0.09, 95% CI 0.05-0.13). For the practicing clinician, these results indicate that patients with high dietary adherence maintain better axonal organization and lower levels of extracellular fluid, potentially reflecting reduced neuroinflammation and superior structural preservation of the brain's communication pathways.

The Cardiovascular-Cognitive Pathway

The researchers conducted a secondary analysis to determine whether cardiovascular health and white matter integrity functioned as pathway variables, or intermediate biological steps, between Mediterranean diet adherence and global cognition. To explore these relationships, the authors performed a mediation analysis (a statistical method used to identify the specific mechanism through which an exposure, such as diet, affects an outcome, such as cognition). The results confirmed that white matter hyperintensity volume, total white matter volume, and fractional anisotropy mediated the association between Mediterranean diet scores and global cognition. These findings suggest that the cognitive benefits of the diet are at least partially realized through the physical preservation of the brain's white matter. Beyond simple mediation, the study identified a serial mediation effect (a sequential chain of events where one factor influences another in a specific order). Specifically, the analysis showed that higher Mediterranean diet scores influenced global cognition through a pathway starting with the Life's Essential 7 score, which then impacted white matter hyperintensity volume, total white matter volume, and fractional anisotropy. This indicates that the diet first improves systemic cardiovascular health, which in turn protects the structural integrity of the brain, ultimately leading to better cognitive performance. For the practicing clinician, these results clarify that white matter structural integrity and cardiovascular health together mediate the association between the Mediterranean diet and global cognition, providing a robust physiological rationale for dietary counseling as a primary preventive strategy for cognitive health in Hispanic and Latino populations.

References

1. Zuliani G, Gianfredi V, Veronese N, et al. Efficacy of Mediterranean diet for the prevention of neurological diseases: A systematic review and meta-analysis featured in the Italian National Guidelines "La Dieta Mediterranea".. Nutrition (Burbank, Los Angeles County, Calif.). 2026. doi:10.1016/j.nut.2025.112990

2. Fu J, Tan L, Lee JE, Shin S. Association between the mediterranean diet and cognitive health among healthy adults: A systematic review and meta-analysis.. Frontiers in nutrition. 2022. doi:10.3389/fnut.2022.946361

3. Gutiérrez-Tordera L, Folch A, Rojas M, et al. Effects of Nutrition on Cognitive Function in Adults with or without Cognitive Impairment: A Systematic Review of Randomized Controlled Clinical Trials. Nutrients. 2021. doi:10.3390/nu13113728

4. Christodoulou CC, Pitsillides M, Hadjisavvas A, Zamba-Papanicolaou E. Dietary Intake, Mediterranean and Nordic Diet Adherence in Alzheimer's Disease and Dementia: A Systematic Review.. Nutrients. 2025. doi:10.3390/nu17020336

5. Visseren FL, Mach F, Smulders YM, et al. 2021 ESC Guidelines on cardiovascular disease prevention in clinical practice. European Heart Journal. 2021. doi:10.1093/eurheartj/ehab484

6. Chen X, Maguire B, Brodaty H, O'Leary F. Dietary Patterns and Cognitive Health in Older Adults: A Systematic Review.. Journal of Alzheimer's disease : JAD. 2019. doi:10.3233/JAD-180468

7. Joshi S, Jabade M, Nadaf H, Salve P. Evidence-Based Pathways to Healthy Aging: A Systematic Review and Meta-analysis of Lifestyle Interventions for Longevity and Well-Being.. Investigacion y educacion en enfermeria. 2025. doi:10.17533/udea.iee.v43n3e06

8. Townsend RF, Logan D, O'Neill RF, Prinelli F, Woodside JV, McEvoy CT. Whole Dietary Patterns, Cognitive Decline and Cognitive Disorders: A Systematic Review of Prospective and Intervention Studies.. Nutrients. 2023. doi:10.3390/nu15020333

9. Soest AMVV, Beers S, Rest OVD, Groot LDD. The Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) Diet for the Aging Brain: A Systematic Review. Advances in Nutrition. 2024. doi:10.1016/j.advnut.2024.100184