Women may have the advantage over men when it comes to brainpower. But just how it metabolizes glucose can reveal a lot about the brain's metabolic age.
The findings still need to be confirmed in follow-up studies.
Using this as a baseline, the researchers asked the algorithm to estimate the ages of the women based exclusively on their brain metabolism data.
Subjects ranged from their 20s to 80s, and across those age spans, women's brains appeared metabolically younger than men's, said the findings in the Proceedings of the National Academy of Sciences, a peer-reviewed USA journal.
Still, much more research is needed.More news: Sonam Kapoor’s film on an unconventional love story fails at box office
"It's not that men's brains age faster", said senior author Manu Goyal, assistant professor of radiology at Washington University School of Medicine, St. Louis. I think this could mean that the reason women don't experience as much cognitive decline in later years is because their brains are effectively younger, and we're now working on a study to confirm that'.
The brain's major fuel source is sugar, or glucose, but exactly how the brain uses glucose changes with age.
As we get older, our brains burn less glucose to power brain development and more to complete everyday tasks and mental challenges. But as people age, their brain undergoes a reduction in aerobic glycolysis, which reaches very low levels by the time they are in their 60s.
Pointing to existing research, the team surmised that women's brains could be free from neurocongitive decline for longer for a number of reasons.
Obviously the exact age can vary from person to person, but to figure out if there are sex differences in that point, the research team conducted positron emission tomography (PET) scans on 205 people - 121 women and 84 men, from 20 to 82 years old.More news: 'Y: The Last Man' getting full FX series as 'Y'
They researchers created algorithms to calculate the metabolic ages of the participants, which they compared to their chronological ages. They used the women's data as a baseline, and estimated the men's ages based exclusively on their metabolism data.
Then, they trained the machine-learning algorithm using only men's ages and brain- metabolism data.
Men's brains are almost four years "older" than those of females the same age, explaining why women stay sharper for longer in old age, according to new research.
Goyal said that while the differences between the brain age of men and women was "significant", it was "nowhere near as big a difference as some sex differences, such as height".
A study basing age on metabolism rather than birth date found an average 3.8 year difference between the two.More news: CDC: Flu upgraded to 'widespread' in Tennessee
Interestingly, the gap between men and women's brain ages was detectable even in young adults in their 20s.