Researchers have identified a possible connection between genetics, meat intake, and brain health in older adults. The results raise new questions about whether future dietary recommendations for dementia prevention could be more personalized. Credit: Stock

A long-term Swedish study suggests that the relationship between diet and dementia may be more complex than previously understood.

Older adults with a genetic predisposition to Alzheimer’s disease did not show the expected rise in cognitive decline and dementia risk when they ate relatively high amounts of meat. That is the conclusion of a new study from Karolinska Institutet published in JAMA Network Open. The findings could help support more personalized dietary guidance.

APOE is a gene linked to Alzheimer’s disease risk. In Sweden, about 30 percent of the population carries the APOE 3/4 or APOE 4/4 genotype. Among people with Alzheimer’s disease, nearly 70 percent have one of these genotypes.

Last year, the Swedish Food Agency released a research overview on diet and dementia and called for more studies on whether meat intake may be connected to dementia development.

“This study tested the hypothesis that people with APOE 3/4 and 4/4 would have a reduced risk of cognitive decline and dementia with higher meat intake, based on the fact that APOE4 is the evolutionarily oldest variant of the APOE gene and may have arisen during a period when our evolutionary ancestors ate a more animal-based diet,” says first author Jakob Norgren, a researcher at the Department of Neurobiology, Care Sciences and Society at Karolinska Institutet.

Jakob Norgren. Credit: Ulf Sirborn

The study tracked more than 2,100 participants in the Swedish National Study on Aging and Care, Kungsholmen (SNAC-K) for up to 15 years. All participants were age 60 or older and had no dementia diagnosis at the start of the study. Researchers analyzed the link between self-reported diet and measures of cognitive health while adjusting for age, sex, education, and lifestyle factors.

Testing a new hypothesis

Among people with lower meat intake, those with APOE 3/4 and 4/4 had more than double the risk of dementia compared with people who did not carry those gene variants. But that elevated risk of cognitive decline and dementia was not seen in the one-fifth of participants who consumed the most meat. Their median intake was estimated at about 870 grams of meat per week (about 30.7 ounces, or 1.9 pounds), standardized to a daily energy intake of 2,000 calories.

“Those who ate more meat overall had significantly slower cognitive decline and a lower risk of dementia, but only if they had the APOE 3/4 or 4/4 gene variants,” says Jakob Norgren. He continues:

“There is a lack of dietary research into brain health, and our findings suggest that conventional dietary advice may be unfavourable to a genetically defined subgroup of the population. For those who are aware that they belong to this genetic risk group, the findings offer hope; the risk may be modifiable through lifestyle changes. ”

The study also found that the kind of meat may matter.

“A lower proportion of processed meat in total meat consumption was associated with a lower risk of dementia regardless of APOE genotype,” says Sara Garcia-Ptacek, assistant professor at the same department, who together with senior lecturer Erika J Laukka is the study’s last author.

The results may also have implications beyond brain health. In a follow-up analysis, the researchers found a significant reduction in all-cause mortality in carriers of APOE 3/4 and 4/4 who consumed more unprocessed meat.

More research is needed

However, the study was observational, so it cannot prove cause and effect. Intervention studies are needed to better determine whether the relationship is causal.

“Clinical trials are now needed to develop dietary recommendations tailored to APOE genotype,” says Jakob Norgren. He continues:

“Since the prevalence of APOE4 is about twice as high in the Nordic countries as in the Mediterranean countries, we are particularly well suited to conduct research on tailored dietary recommendations for this risk group.”

Reference: “Meat Consumption and Cognitive Health by APOE Genotype” by Jakob Norgren, Adrián Carballo-Casla, Giulia Grande, Anne Börjesson-Hanson, Hong Xu, Maria Eriksdotter, Erika J. Laukka and Sara Garcia-Ptacek, 19 March 2026, JAMA Network Open.
DOI: 10.1001/jamanetworkopen.2026.6489

The research was funded by, among others, the Swedish Alzheimer’s Foundation, the Swedish Dementia Foundation, the Emil and Wera Cornell Foundation, the Leif Lundblad family and other philanthropists, the Swedish Research Council and FORTE. The researchers state that they have no related conflicts of interest.

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