Older adults with a genetic risk for Alzheimer's disease did not show the expected increase in cognitive decline and dementia risk if they consumed relatively large amounts of meat, according to a Mar. 19 study from Karolinska Institutet published in JAMA Network Open. The findings could help develop more personalized dietary advice for those at increased genetic risk.
The APOE gene is known to influence the likelihood of developing Alzheimer's disease. In Sweden, about 30 percent of people carry the APOE 3/4 or APOE 4/4 gene combinations, which account for nearly 70 percent of Alzheimer's cases in the country.
Researchers followed over 2,100 participants aged 60 or older from the Swedish National Study on Aging and Care, Kungsholmen (SNAC-K), for up to 15 years. None had dementia at the start of the study. The team analyzed self-reported diet and cognitive health measures while adjusting for age, sex, education, and lifestyle factors.
At lower levels of meat consumption, individuals with APOE 3/4 and 4/4 had more than double the risk of dementia compared to those without these gene variants. However, this increased risk was not observed among participants who ate the most meat—about 870 grams per week 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," said Jakob Norgren. He added: "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 type of meat also played a role in outcomes. "A lower proportion of processed meat in total meat consumption was associated with a lower risk of dementia regardless of APOE genotype," said Sara Garcia-Ptacek, assistant professor at Karolinska Institutet and co-author with senior lecturer Erika J Laukka.
Beyond brain health, researchers found that carriers of APOE 3/4 and 4/4 who consumed more unprocessed meat also experienced reduced all-cause mortality rates.
The authors caution that their study is observational and further intervention studies are needed to confirm causal relationships. "Clinical trials are now needed to develop dietary recommendations tailored to APOE genotype," said Norgren. He continued: "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."
