Fiber intake and risk of cognitive decline

A study has examined the influence of dietary fiber intake on the level of risk of developing cognitive impairment in older people with the APOE-epsilon-4 genotype in the Apolipoprotein E gene, which is considered a genetic risk factor associated with the development of Alzheimer’s disease.

The study was carried out by the Biomarkers and Nutritional Metabolomics of Food Research Group of the Faculty of Pharmacy and Food Sciences of the University of Barcelona (UB) and the Biomedical Network Research Center for Frailty and Healthy Aging (CIBERFES ) in Spain.

The work is directed by Cristina Andrés-Lacueva, professor at the Faculty of Pharmacy and Food Sciences, professor at the Torribera Food Campus of the UB, at the Institute for Research in Nutrition and Food Safety (INSA, dependent on the UB) and CIBERFES. It is based on the InCHIANTI project, a prospective study conducted in 1,139 adults aged 65 and over in two regions of Italian Tuscany. Specifically, a total of 848 volunteers with an average age of 74 years and 56% of the individuals being women participated in the study. The diet of all these people, their cognitive state and other health parameters were studied every three years, for a total of fifteen years.

Apolipoprotein E: the different genetic variants

Apolipoprotein E (apo E) is a multifunctional protein that is synthesized and secreted by various cells (hepatocytes, adipocytes, etc.). The apo E gene, found on chromosome 19 in humans, is polymorphic with three codominant alleles — epsilon-2, epsilon-3, and epsilon-4 (giving rise to different haplotypes, or genetic variants).

“Cognitive impairment, a precursor to the development of dementia in the elderly, is currently a public health problem that lacks treatment. For this reason, it is crucial to detect modifiable risk factors that allow the development of prevention strategies, among which diet has proven to be one of the most effective”, explains Tomás Meroño (UB), one of the main authors of the study. “Evidence shows that healthy diets, characterized by a high intake of fiber-rich foods, have a positive impact on cognition, but the specific role that fiber intake plays on cognitive function is still uncertain.”

The Biomarkers and Nutritional Metabolomics of Food Research Group of the Faculty of Pharmacy and Food Sciences of the University of Barcelona. (Photo: UB. CC BY-NC-SA)

As detailed by Cristina Andrés-Lacueva, “in participants with the APOE-epsilon-4 haplotype, we observed that an increase of five grams per day in fiber intake is already significantly associated with a 30% lower risk of cognitive impairment. This shows us that manageable increases in daily fiber intake can have a significant impact.”

The researchers also point out that this protective association is restricted to people who carry the APOE-epsilon-4 haplotype. For participants with other genetic variants of the ApoE apolipoprotein (such as APOE-epsilon-2), higher fiber intake was not associated with lower risk of cognitive decline.

“These results indicate that older people with the APOE-epsilon-4 haplotype could benefit from a higher fiber intake, and also open the door to investigate the interaction between the APOE genotype and fiber intake, which has not been characterized to date,” he concludes. the researcher Andrea Unión (UB), co-author of the study.

The study is titled “Apolipoprotein E gene variants shape the association between dietary fiber intake and cognitive decline risk in community-dwelling older adults”. And it has been published in the academic journal Age and Aging. (Source: University of Barcelona)