Fiber intake associated with lower risk of cognitive decline in old people with ApoE ε4 genotype

Reviewed by Emily Henderson, B.Sc.Mar 22 2023

Fiber intake is associated with a lower risk of developing cognitive decline in those old people with the Apolipoprotein E ApoE ε4 genotype, regarded as a genetic risk factor linked to the development of Alzheimer's disease. This is stated in a study conducted by the Research Group on Biomarkers and Nutritional and Food Metabolomics of the Faculty of Pharmacy and Health Sciences of the University of Barcelona and the CIBER on Fragility and Ageing (CIBERFES).

The study, published in the journal Age and Ageing, is led by Professor Cristina Andrés-Lacueva, from the Institute on Nutrition and Food Safety Research (INSA-UB), the Food and Nutrition Torribera Campus of the UB and CIBERFES. It is based on the InCHIANTI project, a study carried out in 1,139 adults aged over 65 in two areas of Tuscany. In particular, the study included 848 volunteers (56% were women), of an average age of 74, to study their diet, cognitive state and other health parameters every three years, for fifteen years.

Apolipoprotein E: different genetic variants

Apolipoprotein E (ApoE) is a multifunctional protein synthesized and secreted by several cells (hepatocytes, adipocytes, etc.). the ApoE gene, which in humans is found in the chromosome 19, is a polymorphic one and has three codominant alleles (ε2, ε3 i ε4) which lead to different haplotypes or genetic variants.

Cognitive decline, precursor of the development of dementia in old people, is currently a public health problem without treatment. This is why it is crucial to detect modifiable risk factors that allow us to develop prevention strategies, among which the diet has proved to be one of the most efficient. Evidence shows that healthy diets, characterized by a high consumption of fibre-rich foods, have a positive impact on cognition, but the specific role of fibre intake plays on the cognitive function is still unknown".

Tomàs Meroño (UB-INSA-CIBERFES), one of the authors of the study

Cristina Andrés-Lacueva notes that "in participants with the ApoE ε4 haplotype, we see that an increase of five grams per day in the fibre intake is already associated with a 30% lower risk of cognitive decline. This shows that an acceptable increase in the daily fibre intake can have an impact".

Moreover, the researchers note that this protecting association is limited to people who carry the ApoE ε4 haplotype. Regarding the participants with other genetic variants of the Apolipoprotein E (ApoE ε2 and Apoe ε3), a higher fibre intake was not associated with a lower risk of cognitive decline.

"These results show that old people with the ApoE ε4 haplotype could benefit from a higher fibre intake, and it opens the door to study the interaction between the ApoE genotype and consumption, which has not been characterized to date", concludes the researcher Andrea Unión (UB-INSA-CIBERFES), first author of the study.