Figure 2. A typical urine ¹H NMR spectrum with identified metabolites.

The metabolites are numbered accordingly: 1: valine, 2: 3-hydroxyisobutyrate, 3: 4-deoxyerythronic acid (4-DEA), 4: 3-aminoisobutyrate, 5: 4-deoxythreonic acid (4-DTA), 6: 3-hydroxyisovalerate, 7: threonine/lactate, 8: 2/alfa-hydroxyisobutyrate, 9: alanine, 10: acetate, 11: phenylacetylglutamine, 12: p-cresol sulfate, 13: citrate, 14: dimethylamine, 15: creatine, 16: creatinine, 17: proline betaine, 18: carnitine, 19: trimethylamine-N-oxide (TMAO), 20: taurine, 21: glycine, 22: hippurate, 23: trigonelline, 24: ascorbate, 25: xylose, 26: allantoin, 27: urea*, 28: 4-hydroxyphenylacetate, 29: tyrosine, 30: 3-indoxyl sulfate, 31: histidine, 32: formate, 33: trigonelline, *urea peak was not quantified.