Background and Disease Burden
Dementia represents a growing global health challenge, with substantial disability and dependency burdens among older adults. Despite advances in identifying modifiable risk factors such as physical inactivity and cardiovascular health, diet has often been sidelined due to inconsistent evidence linking specific dietary patterns to dementia risk. Given the increasing prevalence of dementia worldwide and limited therapeutic options, prevention strategies—including nutritional modifications—have garnered interest. This study specifically evaluates the associations of four established dietary indices with the incidence of all-cause and cause-specific dementia within a large prospective cohort.
Study Design and Methods
This investigation utilized data from the UK Biobank encompassing 121,521 participants with a mean age of 55.7 years at baseline, of whom 53.5% were women. Dietary intake was repeatedly assessed via up to five self-reported 24-hour recalls, which were averaged to estimate habitual dietary consumption. Four dietary indices were computed to quantify adherence to healthy eating patterns: the Recommended Food Score (RFS), the Healthy Diet Indicator (HDI), the Mediterranean Diet Score (MDS), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) score.
The primary outcomes included incident all-cause dementia, Alzheimer’s disease, vascular dementia, and non-vascular dementia identified through ICD-10 codes from hospital and primary care records over a median follow-up of 10.9 years. Censored Cox proportional hazards models adjusted for age, sex, education, and several lifestyle and health factors assessed hazard ratios (HRs) with 95% confidence intervals (CIs) to evaluate dementia risk.
Key Findings
During follow-up, 621 participants developed dementia. Compared to the lowest adherence quartile (Quartile 1), participants with highest dietary adherence (Quartile 4) displayed significantly lower risks of all-cause dementia for the Mediterranean Diet Score (HR 0.53; 95% CI: 0.45-0.63), the MIND diet (HR 0.61; 95% CI: 0.48-0.78), and Recommended Food Score (HR 0.66; 95% CI: 0.53-0.85). In contrast, the Healthy Diet Indicator showed no significant associations.
For Alzheimer’s disease specifically, similar risk reductions were evident with MDS (HR 0.55; 95% CI: 0.46-0.67), RFS (HR 0.61; 95% CI: 0.47-0.80), and MIND (HR 0.66; 95% CI: 0.51-0.87). Vascular dementia risk was notably diminished only in those adhering to MDS (HR 0.46; 95% CI: 0.31-0.68) and MIND (HR 0.68; 95% CI: 0.40-0.97). Importantly, sensitivity analyses using a 5-year landmark methodology reinforced these associations, signaling robustness against reverse causation.
Expert Commentary
This large-scale prospective cohort analysis strengthens the evidence base linking specific healthy dietary patterns—particularly the Mediterranean and MIND diets—to reduced risk of both all-cause and Alzheimer’s dementia. The Mediterranean diet’s dominant effect likely derives from its emphasis on plant-based foods, healthy fats, antioxidants, and anti-inflammatory nutrients, which may collectively mitigate neurodegeneration and vascular pathology.
The lack of association with the Healthy Diet Indicator may reflect its focus on less dementia-specific dietary components or insufficient sensitivity in capturing neuroprotective dietary elements. The use of repeated 24-hour recalls enhances dietary exposure assessment accuracy relative to single baseline measures, improving reliability.
Nonetheless, limitations include potential residual confounding and reliance on self-reported dietary data except for hospitalization diagnoses. Generalizability to non-UK populations and older individuals beyond the mean baseline age warrants further study. The study advances dietary recommendations by suggesting that adherence to Mediterranean and MIND dietary patterns could be promising strategies for preserving cognitive health among middle-aged and older adults.
Conclusion
This study from the UK Biobank cohort highlights that higher adherence to the Mediterranean diet, MIND diet, and Recommended Food Score associates independently with substantially lower risk of all-cause and Alzheimer’s dementia. These findings reinforce the role of healthy dietary patterns as modifiable lifestyle factors capable of improving brain health and preventing dementia. Integrating such dietary guidance into clinical practice and public health interventions could have meaningful impacts on the future dementia burden.
Funding and Trial Registration
The study was supported by grants acknowledged in the original publication. UK Biobank’s data access and usage were conducted under approved ethical guidelines. No specific clinical trial registration applies to this observational analysis.
References
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Morris MC, Tangney CC, Wang Y, Sacks FM, Barnes LL, Bennett DA, Aggarwal NT. MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimers Dement. 2015 Sep;11(9):1007-14.
