Table 1.

Fourteen metabolites for aging overlap with those for fasting and frailty.

Metabolites	Abundance	Levels in Elderly	Levels in Fasting	Levels in Frailty	Fraction	Role in Blood
1,5-anhydroglucitol (1,5-AG)	H-M	↓		↓	RBC	Antioxidant
acetyl-carnosine	L	↓		↓	Plasma	Antioxidant
carnosine	L	↓	↑		Plasma	Antioxidant
ophthalmic acid (OA)	H-M	↓	↑	↓	RBC	Antioxidant
leucine	H-M	↓	↑	↓	Plasma	Muscle maintenance
isoleucine	H-M	↓	↑	↓	Plasma	Muscle maintenance
NAD+	H-M	↓			RBC	Redox homeostasis
NADP+	H-M	↓			RBC	Redox homeostasis
UDP-acetyl-glucosamine	L	↓			RBC	Sugar nucleotide
citrulline	H-M	↑			Plasma	Urea cycle
pantothenate	H-M	↑	↑		RBC	Precursor of CoA
dimethyl-guanosine	L	↑			Plasma	Urine compound
N-acetyl-arginine	L	↑			Plasma	Urea cycle
N6-acetyl-lysine	L	↑			Plasma	Acetylated amino acid

Whole blood metabolomics reported 14 metabolites as aging markers. Of these, six metabolites were enriched in RBCs (red). The upper panel (blue box) shows nine metabolites that decrease in the elderly, while the lower panel (grey boxes) list metabolites that increase in the elderly. Notice that several compounds overlap with markers for fasting or frailty. Properties of metabolites are added. Metabolites with peak area > 10⁷ AU are shown as H-M (High to Medium) in red, and metabolites with peak area <10⁷ AU are shown as L (Low) in blue.