A team of researchers from Stony Brook University (USA) has identified an age threshold after which human cognitive function begins to decline.
By analyzing brain scan results and tests from 19,300 volunteers, the scientists determined that the onset of brain degradation occurs at age 44. It is at this age that cognitive abilities start to gradually deteriorate, reaching their peak decline by age 67.
While this may not be comforting news, brain aging does slow down by the time individuals reach 90.
Why is this discovery important?
The university team believes that the findings from this study could be instrumental in developing methods to enhance brain health in later stages of life.
“Understanding when and how brain aging accelerates gives us strategic time points for intervention. We have identified a critical period in midlife when the brain begins to experience reduced access to energy, but before irreversible damage occurs: essentially, it’s a breaking point before a breakdown,” noted neurobiologist Liliana Muhika-Parodi, the lead author of the study.
Together with her colleagues, she identified a potential underlying factor for this decline: neuronal insulin resistance, as reported by Science Alert. The results showed that as our brains age, insulin has a diminishing effect on neurons. This means that less glucose is absorbed as energy, leading to disruptions in brain signaling.
Thus, the researchers suggested that replacing or restoring energy sources for neurons could help slow brain aging and potentially provide another treatment option for neurodegenerative diseases.
“In middle age, neurons experience metabolic stress due to a lack of fuel; they struggle but remain viable. Therefore, providing alternative fuel during this critical period may help restore function. However, in later years, prolonged starvation of neurons can trigger a cascade of other physiological effects that make intervention less effective,” said researcher Muhika-Parodi.
Promising experiment with ketones
The researchers tested their hypothesis on a group of 101 individuals who were given ketone supplements. These organic compounds serve as an alternative energy source when glucose supply or production is limited. Ketones enhance the sensitivity of brain cells to insulin and suppress metabolic disturbances.
After taking the ketone supplements, the brain degradation of participants stabilized. Notably, the greatest benefits were observed in middle-aged individuals (ages 40-59). This suggests that this type of treatment could be effective, but timing will be crucial.
Neurobiologist Botond Antal, a co-author of the study, remarked, “Instead of waiting for cognitive symptoms to appear, which may not manifest until significant damage has occurred, we can potentially identify at-risk individuals using neurometabolic markers and intervene during this critical window.” The study’s findings were published in the journal PNAS.