Introduction: Obesity in younger populations increases the early manifestations of type 2 diabetes (T2DM), although the clinical and social relevance of this disease becomes more pronounced with age. Metabolomic studies have identified plasma biomarkers associated with T2DM, mainly in the context of obesity, but data in older adults remain limited. Understanding metabolic and dietary profiles in this group is crucial for guiding interventions.
Methods: Dietary characteristics of individuals over 65 years were collected using standardized questionnaires. Plasma extracts were analyzed using Ultra-Performance Liquid Chromatography–Mass Spectrometry (UPLC-MS). Partial Least Squares Discriminant Analysis (PLS-DA) was applied to explore metabolic differences. Dietary variables included ratios of sugar-rich foods to vegetables, sugar-rich foods to fruits, starch to vegetables, and meat to fish. Statistical correlations were assessed using SPSS (IBM, v26.0.0.1).
Results: Among diabetic participants, 11.1% had a sugar-to-vegetable ratio >1 and 18.5% had a starch-to-vegetable ratio >1, compared to 9.9% in non-diabetics. Whole cereal consumption was low (22.2%), while processed meat intake was high (54.3%). PLS-DA rendered 12 metabolites as potential biomarkers, including Lyso-PCs, gangliosides, and the dipeptide Gly-His. Nonetheless, only LPC(14:0), one ganglioside, Gly-His, and LPC(20:4) showed significant differences between T2DM and controls. Gly-His showed a significant correlation with dairy consumption in non-diabetics (r = 0.417), with no correlations observed in diabetics, possibly due to altered amino acid oxidation. In T2DM, the starch-to-vegetable ratio correlated positively with LPC18:0 and LPC16:0, which was not observed in non-diabetics, indicating altered carbohydrate metabolism. Correlations between diet and metabolites differed between T2DM and non-T2DM individuals, reflecting disruptions in key amino acid, lipid, and carbohydrate pathways.
Conclusions: T2DM alters the associations between diet and plasma metabolites in older adults, evidencing specific metabolic disturbances. Gly-His and certain LPCs could serve as indicators of metabolic dysregulation. These findings highlight the potential of metabolomics to guide nutritional strategies and personalize dietary recommendations in this population.
