The rate at which the brain ages may be linked to the composition of the gut microbiome and the substances it produces, according to a new study by UCLA researchers. The findings point to possible biological processes associated with brain aging that may emerge long before noticeable symptoms appear.
The study results were published in the journal eBioMedicine.
Researchers analyzed brain scans from nearly 1,500 adults across three independent groups. Using a method that assesses interactions between different brain regions at rest, they developed a computer model to estimate each participant’s brain age. This measure was then compared with the person’s actual age. The researchers called the difference the brain aging index (BAI).
Across all three groups, people whose brains appeared older than expected for their age performed worse on tests of working memory and executive functions related to attention, planning, and organization. They also more frequently reported symptoms of depression. The strongest associations were observed in brain regions involved in memory processes and in forming a person’s sense of self.
In one of the groups, the researchers additionally analyzed participants’ stool samples to investigate a possible link between brain health and the gut microbiome. A higher brain aging index was associated with certain types of gut bacteria and their metabolic products. These included several lipid molecules, a cholesterol-related compound, and lower levels of the hormone estriol.
The analysis identified several potential biological mechanisms linking these factors to brain aging. They involve immune system and blood vessel function, communication between nerve cells, and energy production within cells.
“Brain aging does not suddenly begin when a person reaches old age, but its biological signs may be detectable decades earlier,” said senior study author Arpana Church, co-director of the Goodman-Luskin Microbiome Center at UCLA Health.
s.
Follow NEWS.am Medicine on Facebook and Twitter