Older adults carrying high-risk APOE4 gene variants experienced slower cognitive decline and lower dementia risk with higher meat consumption, according to a Karolinska Institutet study of over 2,100 participants tracked for up to 15 years. Findings suggest diet's effects on brain health vary by genetics, challenging one-size-fits-all advice.
A study from Karolinska Institutet, published in JAMA Network Open, analyzed data from more than 2,100 dementia-free individuals aged 60 and older in the Swedish National Study on Aging and Care, Kungsholmen (SNAC-K), followed for up to 15 years. Researchers adjusted for age, sex, education, and lifestyle factors while evaluating self-reported diets and cognitive outcomes. About 30% of Swedes carry the APOE 3/4 or 4/4 variants, which raise Alzheimer's risk—nearly 70% of diagnosed patients have these genotypes.
High-risk carriers (APOE 3/4 or 4/4) in the highest meat consumption quintile—median 870 grams per week, scaled to 2,000 daily calories—showed no elevated dementia risk or faster cognitive decline compared to lower consumers, defying expectations. Jakob Norgren, first author from Karolinska's Department of Neurobiology, Care Sciences and Society, noted this tests an evolutionary hypothesis linked to ancestors' animal-based diets. "Those who ate more meat overall had significantly better cognitive development and lower dementia risk, but only if they had the gene variants APOE 3/4 or 4/4," Norgren said.
Unprocessed meat appeared key: a lower proportion of processed meat correlated with reduced dementia risk across all genotypes, per assistant professor Sara Garcia-Ptacek. High-risk gene carriers eating more unprocessed meat also had lower all-cause mortality.
As an observational study, it cannot prove causation. Norgren called for clinical trials tailoring advice by APOE genotype, suggesting Nordic countries—with higher APOE4 prevalence—lead such efforts. Results underscore personalized nutrition for brain health.
