Research conducted by the Glenn Biggs Institute for Alzheimer’s & Neurodegenerative Diseases at UT Health San Antonio, Boston University School of Medicine, and the Framingham Heart Study has established a strong link between higher scores on the Dietary Inflammatory Index (DII) and an increased incidence of all-cause dementia, including Alzheimer’s disease (AD) dementia.
Dementia: A Growing Global Challenge
According to the World Health Organization, dementia cases are projected to rise to 152 million worldwide by 2050, imposing significant burdens on caregivers and healthcare systems. While advancements in drug therapies have improved treatment options, effective preventive measures remain scarce.
Diet has emerged as a promising avenue for mitigating dementia risk. Observational studies have shown that anti-inflammatory dietary patterns, such as the Mediterranean and MIND diets, are associated with slower cognitive decline and a reduced risk of dementia.
Understanding the Dietary Inflammatory Index (DII)
The DII is a validated tool that quantifies the inflammatory potential of dietary patterns by analyzing various nutrients, bioactive compounds, and food components. Diets with higher DII scores—indicating greater inflammatory potential—have been associated with increased systemic inflammation, a condition linked to neurodegenerative processes.
Study Design and Findings
The findings, published in Alzheimer’s & Dementia, are based on data from the Framingham Heart Study Offspring cohort, which included 1,487 participants aged 60 or older who were dementia-free at baseline. Participants were followed for a median of 13 years, during which dietary information was collected through food frequency questionnaires (FFQs) administered across three examination cycles (1991–2001).
The study categorized 36 dietary components as either anti-inflammatory (e.g., fiber, omega-3 fatty acids, vitamins A, C, D, E) or pro-inflammatory (e.g., saturated fats, total energy intake, refined carbohydrates). Higher DII scores indicated diets with greater inflammatory potential.
Key findings include:
- Increased Risk: Each one-unit increase in DII score was associated with a 21% higher risk of all-cause dementia and a 20% higher risk of Alzheimer’s disease.
- Dietary Impact: Participants with the most pro-inflammatory diets had an 84% greater likelihood of developing all-cause dementia compared to those consuming the most anti-inflammatory diets.
These results remained robust even after adjusting for age, sex, education, BMI, physical activity, smoking status, and total energy intake.
Mechanisms of Inflammatory Diets in Neurodegeneration
The findings support the hypothesis that dietary inflammation exacerbates neurodegenerative processes through systemic inflammation. Chronic consumption of pro-inflammatory foods, such as those high in saturated fats and refined carbohydrates, may contribute to brain inflammation and accelerate amyloid-beta plaque accumulation, a hallmark of Alzheimer’s disease.
Conversely, anti-inflammatory nutrients, including omega-3 fatty acids and flavonoids, may mitigate these effects by reducing cytokine production and supporting brain health. Clinical trials, such as PREDIMED, have demonstrated that anti-inflammatory dietary patterns like the Mediterranean diet can improve cognitive outcomes, likely by decreasing systemic inflammation.
Implications for Prevention
While causality cannot be established due to the observational nature of the study, the strong correlation between DII scores and dementia risk highlights the importance of dietary interventions. Incorporating anti-inflammatory foods into regular diets may serve as a viable long-term strategy for reducing dementia risk.
The study underscores the potential for integrating DII assessments into dietary guidelines to identify high-risk populations and inform targeted nutritional strategies at both individual and public health levels.
