Associations Between Blood Nutritional Biomarkers and Cerebral Amyloid-ß: Insights From the COGFRAIL Cohort Study.

Understanding the relationship between blood nutrients and neurodegeneration could contribute to devising strategies for preventing Alzheimer's disease. We investigated the associations between fatty acids, vitamins D, B6, B12, folate, homocysteine, and the cerebral load of amyloid ß (Aß). This cross-sectional study included 177 older adults (70-96 years, 65% female) with objective cognitive impairment, prefrail, or frail. Cerebral Aß load was determined using positron emission tomography Standardized Uptake Value ratios. Fatty acids were assessed in erythrocytes, vitamins D and homocysteine in serum, and the other vitamins in plasma. Linear regression models corrected for multiple comparisons evaluated the associations between each nutrient and Aß. The principal component factor followed by linear regression grouped the fatty acids strongly correlated (factor) and associated with Aß. Higher concentrations of polyunsaturated fatty acids (PUFAs): clupanodonic acid (22:5n-3; ß: -0.13; p = .001), mead acid (20:3n-9; ß: -0.07; p = .036), and adrenic acid (22:4n-6; ß: -0.05; p = .031) were associated with lower global Aß load, whereas linoleic acid (18:2n-6) was associated with higher global Aß load (ß: 0.18; p = .042). Clupanodonic acid was inversely associated with Aß in all cerebral regions except the thalamus. The factor composed of mead, clupanodonic, and arachidonic (20:4n-6) acids was associated with a lower global Aß load (ß: -0.02; p = .002). Some erythrocyte PUFAs were inversely associated with Aß load in the brain, and most of them were metabolites of the essential fatty acids linoleic and α-linolenic. Given the cross-sectional design, these results must be carefully interpreted, and longitudinal studies are needed.

The role of dietary strategies in the modulation of hallmarks of aging.

The hallmarks of aging constitute an interconnected network of basic mechanisms that modulate aging and can be modulated by lifestyle factors, including dietary strategies. This narrative review aimed to summarize the evidence on promoting dietary restriction or adherence to specific dietary patterns on hallmarks of aging. Studies with preclinical models or humans were considered. Dietary restriction (DR), usually operationalized as a reduction in caloric intake, is the main strategy applied to study the axis diet-hallmarks of aging. DR has been shown to modulate mainly genomic instability, loss of proteostasis, deregulating nutrient sensing, cellular senescence, and altered intercellular communication. Much less evidence exists on the role of dietary patterns, with most of the studies evaluating the Mediterranean Diet and other similar plant-based diets, and the ketogenic diet. Potential benefits are described in genomic instability, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, and altered intercellular communication. Given the predominant place of food in human life, it is imperative to determine the impact of nutritional strategies on the modulation of lifespan and healthspan, considering applicability, long-term adherence, and side effects.