Age by saliva
Researchers from the Okinawa Institute of Science and Technology (OIST), Japan, analyzed the metabolites that make up human saliva in samples taken from a group of people aged 27 to 33 years and a group of people aged 72 to 80 years. Sample collection was easy and non-invasive. 27 volunteers collected saliva at home and sent it to the laboratory for analysis.
Metabolites are intermediate or final products of chemical reactions occurring in the body. They can be related to energy synthesis, digestion, growth, cell health and many others. As a rule, the concentration of metabolites in saliva is very low compared to the concentration in blood and urine, which makes it difficult to detect them. However, using liquid chromatography-mass spectrometry, the researchers identified 99 metabolites, some of which had not previously been detected in saliva. They also showed that saliva contains information that reflects a person's biological age. Levels of 20 metabolites, including those associated with antioxidant activity, energy synthesis, and skeletal muscle function, were lower in the elderly.
Interestingly, the level of ATP – a metabolite associated with energy production – in the saliva of elderly people was 1.96 times higher. Perhaps this is due to a decrease in ATP consumption with age. Among the metabolites, the number of which decreased, there were two that are associated with taste (perhaps older people lose some ability to taste), and others that are associated with muscle activity, including swallowing. These age-related metabolites of the salivary glands together reflect a decline in oral function during human aging.
Two more metabolites – creatinine and acetylcarnosine – showed a significant difference in concentration in men and women, and their number was lower in women than in men. These metabolites are associated with muscle activity.
The results obtained in the study may be useful in the future for non-invasive metabolic assessment of the aging process or for detecting early signs of age-related diseases.
The researchers plan to continue studying the composition of saliva in different groups of people. They hope that in the future saliva will become a sample that is easy to obtain, but will provide a huge amount of information about human health.
Article by T.Teruya et al. Human age declined saliva metabolic markers determined by LC–MS is published in the journal Scientific Reports.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on OIST materials: How we age, as told by spit.