Gut microbiota is increasingly an important regulator of host immunity and brain health. Aging processes lead to important alterations in the microbiota that are in turn linked to poorer health and frailty in elderly populations.

However, what are the mechanisms linking such gut microbiota to brain health and immunity in aging?

To this end, a leading research group at Cork University led by John Cryan employed fecal microbiota transplantation from either young (3–4 months) or old (19–20 months) donor mice into aged recipient mice (19–20 months).

Implantation of microbiota from young donors reversed aging-associated differences in peripheral and brain immunity, as well as the hippocampal metabolome and transcriptome of aging recipient mice.

Finally, “the young microbiota” reduced selective age-associated impairments in cognitive behavior when transplanted into an aged host. These results demonstrated that modulation in the gut microbiota could be a key player in the aging processes.