Elderly individuals with genetic variants associated with an increased risk of Alzheimer's disease may not experience accelerated cognitive decline if they consume relatively high amounts of meat. This conclusion was drawn from a study conducted by specialists at the Karolinska Institute and published in JAMA Network Open. The findings suggest the potential for more precise dietary recommendations tailored to individual genetic profiles.

The Role of the APOE Gene

The APOE gene significantly influences the likelihood of developing Alzheimer's disease. In Sweden, about 30% of the population carries the APOE 3/4 or 4/4 genotypes, while among patients with the disease, these variants are found in nearly 70%. In 2023, the Swedish Food Agency recommended further research to better understand the impact of meat products on dementia risk.

Study Design

The study involved more than 2,100 adults from the Swedish National Study on Aging and Care (SNAC-K). All participants were over 60 years old and did not have dementia at the start of the observation period, which lasted up to 15 years. Researchers analyzed dietary data provided by participants, as well as cognitive health indicators, taking into account age, gender, education, and lifestyle factors.

Main Findings

Among APOE 3/4 and 4/4 carriers who ate less meat, the risk of developing dementia was more than twice as high compared to people without these genetic variants. However, among those who consumed more meat (median intake—about 870 grams per week with a daily caloric intake of 2,000 kcal), this increased risk was not observed.

Participants with APOE 3/4 or 4/4 genotypes who ate more meat showed a slower decline in cognitive function and a lower risk of dementia. The study notes that traditional dietary recommendations may not be optimal for certain genetic subgroups. For individuals aware of their risk group, the results indicate that lifestyle changes can influence the likelihood of developing dementia.

Impact of Meat Type

A lower proportion of processed meat in the diet was associated with a reduced risk of dementia, regardless of APOE genotype.

Additional Observations

Further analysis showed that APOE 3/4 and 4/4 carriers who consumed more unprocessed meat had a significantly lower risk of death from any cause.

Limitations and Future Directions

This study is observational and does not establish a causal relationship. To confirm the effects of dietary changes on dementia risk, more rigorous interventional studies and clinical trials are needed, especially considering APOE genotype. Since the prevalence of APOE4 is about twice as high in Northern European countries compared to Mediterranean countries, individualized recommendations for risk groups are particularly relevant in these regions.

About the APOE Gene

Apolipoprotein E is involved in the transport of cholesterol and fats in the brain and bloodstream. The APOE gene exists in three main forms: ε2, ε3, and ε4. Each person inherits two copies of the gene—one from each parent—resulting in six possible genotypes: 2/2, 2/3, 2/4, 3/3, 3/4, and 4/4. Compared to the most common 3/3 genotype, having one copy of the ε4 variant increases the risk of Alzheimer's disease by about 3–4 times, while two copies raise the risk by 10–15 times. The ε2 variant is associated with a lower risk. Risk levels may vary depending on ethnic background.