STOCKHOLM — Older adults who consistently followed healthy dietary patterns were less likely to develop dementia, including those with biological signs associated with Alzheimer's disease, according to new research published in June that adds to growing evidence linking nutrition and brain health.
The study, published in JAMA Network Open, tracked 1,865 adults aged 60 and older in Sweden for an average of 8.4 years. Researchers found that greater adherence to healthy eating patterns was associated with a lower risk of developing dementia, with the strongest associations seen among people with elevated blood biomarkers linked to neurodegeneration.
Investigators evaluated participants' long-term adherence to three dietary patterns: the Alternate Mediterranean Diet, the Alternative Healthy Eating Index and a diet with lower inflammatory potential measured by the reversed Empirical Dietary Inflammatory Index. Dietary habits were assessed repeatedly over six years alongside blood tests measuring biomarkers including phosphorylated tau (p-tau217), neurofilament light chain and glial fibrillary acidic protein.
Among participants with higher levels of Alzheimer's-related biomarkers, stronger adherence to the lower-inflammatory dietary pattern was associated with a significantly lower risk of dementia. Researchers also found that people with elevated p-tau217 levels who more closely followed any of the three healthy dietary patterns spent more years free of dementia over a 10-year period.
The findings suggest that dietary improvements may remain beneficial even after biological changes associated with Alzheimer's disease have begun, although the researchers cautioned that the observational study cannot prove that diet directly prevented dementia. Other lifestyle and health factors may also have influenced outcomes despite statistical adjustments.
The results add to a broader body of evidence linking healthy eating with cognitive health. A systematic review and meta-analysis published in Nutrition Reviews in June concluded that greater adherence to Mediterranean, DASH and MIND dietary patterns was generally associated with a lower risk of dementia, although the authors said evidence across studies remained mixed and further research is needed.
The new research comes as scientists continue to investigate ways to reduce dementia risk through lifestyle interventions. Experts say factors including regular physical activity, adequate sleep, control of cardiovascular risk factors and a balanced diet all appear to contribute to maintaining brain health, though no single measure can eliminate dementia risk.
Researchers said additional studies, including clinical trials, will be needed to determine whether targeted dietary interventions can help delay or prevent dementia among people identified as being at elevated biological risk.
