In a significant stride towards understanding Alzheimer’s disease, researchers have discovered that higher levels of certain fatty acids in the blood are associated with a lower risk of brain changes typical of the disease. This finding, published in The Journals of Gerontology: Series A, could pave the way for more effective early detection and management strategies for Alzheimer’s, a condition that affects millions worldwide.
Alzheimer’s disease is a progressive neurological disorder that primarily affects older adults, leading to memory loss, impaired reasoning, and changes in personality and behavior. It is the most common form of dementia, characterized by the accumulation of amyloid-beta proteins in the brain, forming plaques that disrupt cell function. Despite extensive research, Alzheimer’s remains incurable, and its exact cause is still not fully understood, making early detection and management strategies critical.
“The incidence of dementia is increasing over time, impacting the persons affected, as well as their families and loved ones,” said study author Natasha A. Grande de França. “An earlier and more accurate diagnosis can help to prolong the quality of life; however, the diagnosis of dementia is still plenty biased and hard to do. For this reason, we were interested in finding blood biomarkers that could be used to help clinicians in the diagnosis of dementia, especially Alzheimer’s disease (the most common dementia).”
To carry out the study, the researchers employed a cross-sectional design, utilizing baseline measurements from a larger ongoing study named COGFRAIL. This study involved 317 older adults, aged 70 and above, who exhibited mild cognitive impairment but not severe dementia. The participants were chosen based on specific cognitive scores and were either prefrail or frail, meaning they showed signs of physical decline but were not entirely dependent on others for daily living.
The study excluded individuals with severe psychological conditions or high dependency on others for basic activities. The final sample included a total of 177 individuals.
França and her colleagues employed several measures to gather data. They used positron emission tomography (PET) scans to measure the levels of amyloid-beta, a protein that forms clumps in the brains of people with Alzheimer’s, in various brain regions. Blood samples were also collected and analyzed for various nutrients, including different types of fatty acids, vitamins, and an amino acid called homocysteine. The analysis of fatty acids was particularly comprehensive, examining their composition in red blood cell membranes.
Over half of the participants (57.6%) were identified as having high amyloid-beta levels in their brains. The researchers found that higher concentrations of a fatty acid called clupanodonic acid were consistently associated with lower amyloid-beta load in the brain. This association was observed in almost all regions of the brain, except for the thalamus.
“I was expecting that if any association would be significant, that would arise from the fatty acids omega-3 EPA and DHA,” França told PsyPost. “However, a more consistent result was observed with a metabolite of EPA, the clupanodonic acid. This suggests we should expand the look and the research to less well-known fatty acids, in particular the metabolites of the EPA and DHA as potential more precise biomarkers.”
Furthermore, the study noted that linoleic acid showed a positive association with amyloid-beta load, while mead acid and adrenic acid were negatively associated, though less consistently than clupanodonic acid. Interestingly, the study did not find any significant associations between amyloid-beta load and blood vitamins or homocysteine, a common amino acid in the blood.
“Our study found potential blood biomarkers to be used in the diagnosis of dementias associated with the aggregation of amyloid-beta in the brain – a peptide associated with the development of Alzheimer’s disease,” França told PsyPost. “However, this is just the first step that needs to be confirmed with other studies in other populations.”
Like all scientific research, this study comes with its limitations. The cross-sectional nature of the research means that it can’t definitively establish cause and effect. Additionally, the sample consisted of older adults who were either prefrail or frail, which may not represent the broader population.
“Our study has a cross-sectional design and was conducted with a very specific population (older adults with a light degree of cognitive impairment and who were at least pre-frail). So, some questions I can list include: has the association between clupanodonic acid and amyloid-beta happened by chance? Is this association true in populations in different conditions? What is the timing? – when does it start and when does it finish?” França explained.
The study, “Associations Between Blood Nutritional Biomarkers and Cerebral Amyloid-β: Insights From the COGFRAIL Cohort Study“, was authored by Natasha A. Grande de França, Gustavo Díaz, Laetitia Lengelé, Gaëlle Soriano, Sylvie Caspar-Bauguil, Laure Saint-Aubert, Pierre Payoux, Laure Rouch, Bruno Vellas, Philipe de Souto Barreto, and Sandrine Sourdet.