It is a question of metabolism: the female brain ages slower than the male brain of the same age by approximately three years, and the difference can be observed throughout all stages of life, not only in the elderly.
This was demonstrated by radio-neurologists from the Washington University School of Medicine in St. Louis, who published on the scientific review PNAS the results of a study conducted on 121 women and 84 men aged between 20 and 82.
All of the participants in the study were given a PET (positron emission tomography) scan, which measures the consumption of sugars in vivo by the various “districts” of the body (the US researchers, of course, focused their attention on the brain).
This choice – to measure the consumption of sugars to assess biological age – was based on the fact that the brain uses sugars in different ways, depending on the stage in life.
In particular, a series of chemical reactions (collectively called aerobic glycolysis) that enables the sugars to split and be transformed into energy, is very pronounced in children and new-borns and remains high in adolescents and young adults. However, afterwards these chemical reactions start to decrease, even if they never completely disappear. Since the PET scan is able to detect the differences in the consumption of sugars, the researchers thought of “measuring” the aerobic glycolysis in people of different genders and ages, and developed an algorithm that allowed them to guess biological age on the basis of the observed metabolism.
The difference of around three years emerged when the men’s results were compared with those of women: in other words, regardless of age, women’s brains appeared three years’ younger (metabolically speaking) than men’s.
Why does this happen?
The explanations are complex and – according to the researchers – it has to do with the different ways that the numerous DNA traits linked to aging, which behave differently in the male and female body, “express themselves” (activate themselves).
In addition to better defining better the difference between men and women, the study published in PNAS may also be useful in the planning of interventions aimed at preventing cognitive deficits, starting with the metabolic activity data and biological age of each brain.