According to a study, the human brain begins showing signs of accelerated aging around age 44, reaching its fastest decline by age 67. Researchers from Stony Brook University analyzed brain scans from more than 19,000 people, aged 18 to 90.
The team identified key changes in how different brain regions communicate, that weaken with age. The findings suggest that age-related brain decline may start earlier than previously thought.
“What we did not anticipate was that the effects might be occurring as early as the 40s,” said lead author Lilianne Mujica-Parodi, a neuroscientist at Stony Brook University.
The study also supports earlier research that tracked aging through blood samples and found similar patterns of accelerated decline around ages 44 and 60.
Tracking changes in brain activity
Researchers used two types of scans to measure the brain’s internal communication: functional MRI, which monitors blood flow, and EEG, which records electrical signals.
They looked for disruptions in these signals—signs that different brain areas were no longer working together efficiently. This breakdown, known as network disintegration, is a key marker of brain aging and has been observed in age-related diseases.
Insulin resistance linked to faster aging
The team noted that these disruptions were especially pronounced in people with high blood sugar levels and insulin resistance; a condition when cells struggle to absorb sugar from the blood. Similar patterns had previously been reported in individuals with type 2 diabetes.
Brain aging is non-linear, and its main driver is insulin resistance, i.e. declining metabolic health.
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Further analysis revealed that faster-aging brain regions rely heavily on a protein called GLUT4, which requires insulin to move sugar into cells. In contrast, slower-aging areas showed more activity from a protein that allows ketones, an alternative energy source, to enter cells.
This raised a question: Could ketones help slow brain aging?
Testing ketone supplements for brain health
To explore this, researchers conducted a small trial involving 101 adults, ages 20 to 79. Participants fasted overnight before undergoing brain scans.
Then, they were given either a ketone drink or a sugary beverage with the same number of calories. A second scan followed 30 minutes later.
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The results showed that the ketone drink improved brain network activity quickly, especially in adults between 40 and 59. The effect was 80% stronger in this group compared to younger participants. Those aged 60 to 79 saw a smaller benefit.
More research is still needed
Still, researchers cautioned that this experiment had limits. The effects were tested at a single point, and no long-term brain or memory changes were tracked.
Mujica-Parodi said future studies should observe people over time to assess whether ketone supplements offer lasting benefits. She also emphasized that preventing insulin resistance through dietary choices may be a more reliable approach.
Dr. Luis Adrian Soto-Mota, a metabolism expert not involved in the study, noted that the body can produce ketones naturally when sugar levels drop. However, he warned that long-term use of restrictive diets like keto may carry risks.
Ketone supplements may still prove helpful for individuals with severe insulin resistance who struggle to produce ketones on their own, Mujica-Parodi added.