Saliva is an important physiological fluid that contains a complex mixture of analytes that may produce a characteristic individual signature. In recent years, it has been demonstrated that urine possesses a clear signature of the individual metabolic phenotype. Here NMR-based metabolomics was employed to analyze saliva from 23 healthy volunteers. About six saliva samples were collected daily from each individual for 10 consecutive days: 7 days in a real-life situation (days 1-7, Phase I) and 3 days (days 8-10, Phase II) under a standardized diet plus a physical exercise program at day 10. The result is the first demonstration of the existence of an individual metabolic phenotype in saliva. A systematic comparative analysis with urine samples from the same collection scheme demonstrates that the individual phenotype in saliva is slightly weaker than that in urine but less influenced by diet.
Keywords: NMR; diet; fingerprinting; individual phenotype; metabolomics; saliva; standardized lifestyle; urine.