A HEALTHIER diet is linked to a lower dementia risk even in older adults whose blood already carries the biological hallmarks of Alzheimer’s, a 15-year Swedish study finds, with an anti-inflammatory eating pattern standing out for those most at risk.
Can Diet Blunt an Inherited Vulnerability?
Higher diet quality has been tied to less dementia, but whether it helps people who already carry Alzheimer’s pathology or broader signs of brain injury was unclear. Researchers set out to test whether diet could buffer dementia onset across differing levels of biological risk, moving beyond the general population studied before.
Tracking Diet and Blood Biomarkers Over Time
The population-based cohort study followed 1,865 dementia-free adults aged 60 or over from the Swedish National Study on Aging and Care in Kungsholmen, enrolled between 2001 and 2004 and examined up to six times through to 2019. Adherence to three dietary patterns was assessed over six years: the Alternate Mediterranean Diet, the Alternative Healthy Eating Index, and the reversed Empirical Dietary Inflammatory Index (rEDII), the last capturing lower inflammatory potential. Baseline blood levels of p-tau217, neurofilament light chain, and glial fibrillary acidic protein marked Alzheimer’s and neurodegenerative risk. The primary outcome was all-cause dementia; Alzheimer’s-related dementia was secondary, analysed with adjusted Cox regression.
Anti-Inflammatory Eating Stands Out
Over a mean 8.4 years of follow-up, 240 of the 1,865 participants (mean age 70.5 years; 60.3% female) developed dementia. Higher diet quality was linked to lower dementia risk, and crucially this held in those with elevated biomarkers. For the rEDII, each one-unit increase in adherence was associated with lower dementia risk among participants with raised p-tau217 (hazard ratio 0.71; 95% CI 0.58 to 0.88), neurofilament light chain (HR 0.79; 95% CI 0.66 to 0.95), and glial fibrillary acidic protein (HR 0.73; 95% CI 0.60 to 0.89). The Mediterranean and Healthy Eating patterns generally showed benefit only in those with lower biomarker levels. Findings were similar for Alzheimer’s-related dementia.
The authors concluded that an anti-inflammatory diet was associate
Targeting Prevention at Higher-Risk Groups
d with lower dementia risk even in people carrying Alzheimer’s pathology, suggesting diet may delay onset and prolong dementia-free years despite underlying disease. Because Alzheimer’s pathology raises risk without guaranteeing clinical dementia, they argued dietary prevention matters not just for the general population but for higher-risk individuals. Being observational, the study cannot prove cause, so trials would be needed to confirm the effect.
Reference
Mrhar A et al. Diet quality and dementia risk in older adults with alzheimer pathology. JAMA Netw Open. 2026;9(6):e2620254.
Featured image: ArTo on Adobe Stock
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