The probiotics that live on your skin in your gut and your mouth could reveal your age according to new research1.

The skin's microbiome provides the best prediction of age
In the largest study to date, researchers analysed data on the microbiota from 8,959 samples in 10 different studies. Over 4000 stool samples, over 200 saliva samples and nearly 2,000 skin samples were studied.
Shi Huang, a bioinformatician from the University of California, San Diego, said: "Intriguingly, the skin microbiome provides the best prediction of age."
"The big question here could be if you know your microbiome, what is the difference between yours and what's normal?" adds Shi Huang.
The study revealed that:
· Skin samples could predict age to within 3.8 years
· Saliva samples could predict age to within 4.5 years
· Gut bacteria could predict age to within 11.5 years.
Beneficial at the molecular level
Other research suggests that probiotics may benefit skin at the molecular level. Animal studies and human clinical trials are building a case for their role in intrinsic and extrinsic ageing by restoring skin pH, alleviating oxidative stress, attenuating photo ageing, improving skin barrier function, and enhancing hair quality.2
References
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6702293/
2 https://www.ncbi.nlm.nih.gov/pubmed/26741377