Malnutrition Risk in Older Adults: Evaluating the Diagnostic Relevance of Serum Biomarkers: SIRT-1, CCK-8, Melatonin, and Total Antioxidant Capacity (TAC)

<b>Background/Objectives:</b> Addressing the risk of malnutrition at an early stage is crucial to preventing its development, which can have a detrimental impact on physical and mental health status. This study investigates the potential role of biochemical biomarkers such as sirtuin 1 (SIRT-1), melatonin, cholecystokinin-8 (CCK-8), and total antioxidant capacity (TAC) in identifying the risk of malnutrition. <b>Methods:</b> This cross-sectional study assessed malnutrition risk in 153 community-dwelling older adults using the Mini Nutritional Assessment (MNA). Serum levels of SIRT-1, melatonin, and CCK-8 were analyzed with enzyme-linked immunosorbent assay (ELISA), and total antioxidant capacity (TAC) was measured using the ferric reducing ability of plasma (FRAP) method. <b>Results:</b> Serum levels of TAC and CCK-8 were significantly positively correlated with grip strength and visceral adipose tissue, with TAC levels also showing associations with appendicular skeletal muscle mass index (ASMI), total body water, total energy expenditure, fat-free mass index, and fat mass index (<i>p</i> < 0.001). CCK-8 emerged as a strong predictor of malnutrition risk (AUC = 0.58 in females, AUC = 0.64 in males), whereas SIRT-1 (AUC = 0.57 for both sexes), melatonin (AUC = 0.46 for females, AUC = 0.51 for males), and TAC (AUC = 0.42 for females, AUC = 0.54 for males) exhibited weaker predictive abilities. A multivariate model incorporating CCK-8 demonstrated excellent predictive accuracy (AUC = 0.84, 95% CI: 0.77-0.90) and indicated a potential association between elevated CCK-8 levels and a higher risk of malnutrition. <b>Conclusions:</b> In conclusion, this study highlights the effectiveness of a multi-parameter model incorporating CCK-8 as a reliable approach for assessing malnutrition risk in older adults, offering a comprehensive evaluation of the condition. However, further research is needed to confirm its applicability and accuracy in diverse elderly populations and clinical settings.