A new observational study published in JAMA Network Open has found that people carrying the APOE4 genetic variant, the strongest known genetic risk factor for Alzheimer’s disease, may experience slower cognitive decline when they eat higher amounts of meat. The finding does not apply broadly to the general population and the researchers are careful to frame it as preliminary, but it introduces a meaningful complication to standard dietary guidance for people with elevated genetic risk.
The study was led by researchers at the Karolinska Institutet in Stockholm and drew on data from 2,157 adults over the age of 60. Participants were assessed every six years until age 78, then every three years after that, and reported their meat consumption throughout, including whether the meat they ate was processed or unprocessed.
The genetic piece that changes the picture
The APOE gene produces proteins involved in managing cholesterol in the body and exists in three variants: APOE2, APOE3 and APOE4. Carrying one copy of the APOE4 allele raises a person’s lifetime risk of developing Alzheimer’s disease significantly. Carrying two copies raises it further.
Among participants with the APOE3/4 and APOE4/4 genotypes, those who consumed the least meat had more than double the dementia risk compared to participants without those variants. Participants in the highest meat-consuming group ate roughly 870 grams of meat per week on average. That group, despite carrying the higher-risk genetic profile, did not show a significantly elevated risk of cognitive decline.
The pattern held specifically for unprocessed meat. A higher proportion of unprocessed meat in the diet was associated with lower all-cause mortality among APOE4 carriers, while a lower proportion of processed meat in the overall diet correlated with reduced dementia risk across genetic backgrounds.
Why this complicates standard advice
Conventional dietary guidance tends to emphasize plant-based eating for brain health, and that advice is broadly supported by existing research. What this study suggests is that the optimal dietary approach may not be universal, and that genetic profile could be a meaningful variable in how individuals respond to different patterns of protein consumption.
Jakob Norgren, the study’s lead author, noted that APOE3/4 and APOE4/4 carriers may have dietary needs that diverge from the general population. He framed the findings as a basis for future research rather than a reason to immediately revise clinical guidelines, but said the potential implications for dementia prevention could be substantial if the results are confirmed in larger studies.
How experts are reading the results
Dr. Steven Allder, a consultant neurologist, described the findings as a signal toward more personalized nutritional recommendations rather than a refutation of plant-forward eating. His position was that plant-focused diets remain broadly useful, but that the optimal balance of protein sources, including lean meats, may shift depending on a person’s genetics, cardiovascular profile and lifestyle factors.
That framing reflects how most nutrition researchers tend to approach observational findings of this kind. A single study, however well-designed, does not overturn established dietary science. What it can do is identify a subgroup worth studying more closely, and the APOE4 population represents exactly that.
What this means for people carrying the gene
Roughly 25% of people carry at least one copy of the APOE4 allele, making this a question with practical relevance for a significant share of the population. The researchers stopped short of prescribing specific dietary changes, and the observational design of the study means it cannot establish causation. What it can establish is an association strong enough to justify further investigation.
For people who know they carry the APOE4 variant, the study reinforces the case for discussing dietary choices directly with a physician or registered dietitian rather than relying on general population guidelines that may not account for their specific genetic risk profile.
