Anti-Inflammatory Diets May Help Reduce Risk of Alzheimer Disease–Related Death

Higher dietary inflammatory index (DII) scores are significantly associated with an increased risk of Alzheimer disease–related death among American adults, according to a study published in Experimental Gerontology.¹

Although the exact mechanisms of Alzheimer disease remain unknown, accumulating evidence suggests that chronic inflammation plays a key role in its pathogenesis and progression.² In particular, past research shows that neuroinflammation accelerates neuronal damage, synaptic loss, and cognitive decline observed in patients with Alzheimer disease.³

Anti-inflammatory diets can alleviate neuroinflammation in patients with Alzheimer disease by reducing systemic inflammation through several immune pathways in the brain and indirectly through the gut microbiome and body circulation pathways.⁴ Therefore, the researchers emphasized that an anti-inflammatory diet may constitute a beneficial nutritional approach in Alzheimer disease management.¹

The DII quantifies individual diets and estimates their inflammatory potential. While several studies have linked higher DII scores with greater cognitive decline and an increased risk of developing dementia, few have specifically investigated the relationship between DII and mortality outcomes in patients with Alzheimer disease.

The researchers conducted a study to address this literature gap, hypothesizing that a higher DII was significantly associated with worse Alzheimer disease survival outcomes. The relationship was examined using data from the National Health and Nutrition Examination Survey (NHANES). This nationally representative, cross-sectional research survey assesses the health and nutritional status of the US population.

Specifically, they used data from NHANES III (1988-1994) and 10 consecutive cycles of NHANES conducted between 1999 and 2014. The researchers explained that the data sets provide a comprehensive evaluation of dietary intake, health status, and mortality outcomes among eligible participants between 18 and 90 years old. Data on Alzheimer disease–related mortality were identified within the National Death Index through December 2019 using the relevant International Classification of Diseases, Tenth Revision code.

Additionally, dietary intake was assessed using 24-hour dietary recall interviews. A DII score greater than 0 reflects a pro-inflammatory diet, while a score less than 0 indicates an anti-inflammatory diet. DII calculations typically incorporate 45 dietary components associated with inflammatory responses, but the researchers only used 27 due to data availability. For further analysis, they categorized the DII scores into quartiles to enable dose-response comparisons.

The study population consisted of 45,093 US adults with a mean age of 42.8 years. Of the patients, 47.7% were male and 68.3% identified as non-Hispanic White. When stratified by DII levels, those in the highest DII quartile (Q4) were more likely to be female (68.8% vs 38.9%), younger (mean age, 41.6 vs 44.0 years), and obese (37.6% vs 28.3%) than participants in the lowest quartile (Q1).

Over a median follow-up period of 14.3 years, 455 Alzheimer disease–related deaths occurred among the study population. In Cox proportional models, higher DII scores were associated with an increased risk for Alzheimer disease–related mortality when analyzed as a continuous variable. In the model fully adjusted for covariates, each 1-unit increment in DII corresponded to a 9% higher risk of Alzheimer disease–related mortality (HR, 1.09; 95% CI, 1.03-1.15; P = .003).

Therefore, participants with pro-inflammatory diets had significantly elevated risks of Alzheimer disease–related mortality vs those with anti-inflammatory diets. Specifically, in the fully adjusted model, participants with pro-inflammatory diets had a 44% increased risk (HR, 1.44; 95% CI, 1.14-1.81; P = .002).

The researchers also observed a dose-response relationship when analyzing DII by quartiles. Compared with Q1, Q4 exhibited a significantly elevated risk of Alzheimer disease–related mortality across all models (fully adjusted model: 1.50; 95% CI, 1.12-2.01; P = .007). Consequently, they found a significant linear trend across DII quartiles (P < .001).

In stratified analyses, the positive association between DII and Alzheimer disease–related mortality remained consistent across most demographic and clinical subgroups, supporting the consistency and robustness of the study’s results.

The researchers concluded by acknowledging their study’s limitations, including the focus on Alzheimer disease–related mortality rather than incidence; this limited insights into the role of dietary inflammation in the early stages of the disease. Still, they expressed confidence in their findings and highlighted opportunities for further research.

“Although further studies are necessary to clarify the observed association, these findings still have important implications for research on the role of dietary inflammation and Alzheimer disease,” the authors wrote. “They also emphasize the significance of adhering to an anti-inflammatory diet as a preventive strategy for managing this condition.”

References

1. Liao R, Yang J, Huang X, et al. Dietary inflammatory index and Alzheimer's disease mortality in a prospective cohort. Exp Gerontol. doi:10.1016/j.exger.2025.112770
2. Scheltens P, De Strooper B, Kivipelto M, et al. Alzheimer's disease. Lancet. 2021;397(10284):1577-1590. doi:10.1016/S0140-6736(20)32205-4
3. Heneka MT, van der Flier WM, Jessen F, et al. Neuroinflammation in Alzheimer disease. Nat Rev Immunol. 2025;25(5):321-352. doi:10.1038/s41577-024-01104-7
4. McGrattan AM, McGuinness B, McKinley MC, et al. Diet and inflammation in cognitive ageing and Alzheimer's disease. Curr Nutr Rep. 2019;8(2):53-65. doi:10.1007/s13668-019-0271-4