Thirty is a special age. You’re over the high-school awkward phase, you probably make more money than you did at age 20, and you’ve maybe even found a group of friends who like the same things you like. But thirty is perhaps also the time you start to notice physical signs of aging. And while a daily skincare routine, can help you age gracefully on the outside. On the inside, though, there is no cream to smooth the metaphorical “wrinkles” in the inevitable aging of the human brain.
An aging brain can negatively affect your thinking, learning, and memory. You can work on Sudoku puzzles and exercise to delay cognitive decline but unless you’re Dorian Gray, such entropy is unavoidable.
But research published earlier this year may offer the closest solution yet to dousing yourself in a (murky-watered) fountain of youth. In a study published in the journal Nature Aging, scientists suggest that older mice given gut bacteria transplants from younger mice show learning and memory abilities similar to those of the younger rodents. In other words, the gut bacteria transplant appeared to reverse some of their brain’s decline.
The discovery — In the study, the researchers transplanted the poop of 3 to 4-month-old rodents into the intestines of 19- or 20-month-old mice. In humans, this is equivalent to an 18-year-old’s poop being transplanted into the body of a 70-year-old.
In the old mice, the transplanted fecal bacteria seemingly promoted the growth of gut microbiota resembling the younger mice’s microbiome.
The team then studied how the older mice’s spatial memory — remembering information needed to plan a route — changed following the transplant using a water maze test.
Older mice with or without a fecal transplant were placed in a water maze where they needed to plan and follow a path to get to a dry platform.
Older mice that had got the fecal transplant found the platform with greater success than did mice without the transplant. This indicates that certain gut bacteria could influence cognitive functions that tend to decline with age, like memory.
Later, the researchers looked at the brains of the older mice to see if the behavioral improvements were reflected in their neurobiology — they found that the old mice’s hippocampus, a brain region associated with memory, resembled that of younger mice.
Here's the background — To understand the implications of this study, it helps to zoom out to consider the brain as a whole. Multiple brain areas work together to orchestrate complex cognitive processes, such as problem-solving, memory, judgment, and language.
The frontal cortex of your brain works as the control center to manage learning and memory processing. Another brain area is the hippocampus that works to form and store memories. Both of these regions shrink with age.
Aging also comes with decreased production of chemical messengers in the brain known as dopamine and serotonin. These are some of the many reasons why older adults report more trouble remembering names, multitasking, or remembering where they last left their keys.
Everyone has a lapse in memory now and then, but people with frequent memory and thinking problems have a higher risk of developing dementia.
Why it matters — While the world is ways away from recruiting poop donors for anti-aging medicine, the study brings insight into the role of the microbiome in aging.
“By restoring the microbiome, we’re targeting it through this transplantation, we’re able to reverse age-related cognitive deficits,” study co-author Katherine Guzzetta told Inverse at the time. “That’s mind-blowing.”
The results also sync up with previous work showing the gut microbiome influences the aging process. For example, a study found that people who live to be older than 100 have a distinctive gut microbiome that may be protective against age-related diseases and infections.
Breaking down the nuances of how specific bacterial strains help older gut microbiomes will help in the long run to create anti-aging treatments for future generations.