Brain Metabolism Study Reveals Age Differences Between Sexes

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By Mae Pyer

A new study may have found a scientific reason for women’s cognitive sharpness later in life. Researchers discovered that, in terms of brain metabolism, women’s brains appear three years younger than men’s.

Discovering the Difference

Manu Goyal and his colleagues at Washington University School of Medicine recently published their findings in Proceedings of the National Academy of Sciences, comparing the brain metabolism of both sexes with their participants’ actual ages.

“We’re just starting to understand how various sex-related factors might affect the trajectory of brain aging and how that might influence the vulnerability of the brain to neurodegenerative diseases,” said Goyal, assistant professor of radiology, neurology, and neuroscience. He noted that brain metabolism might provide the answers needed to understand these differences.

It’s known that the brain requires sugar to function properly, a good portion of it being used for aerobic glycolysis where glucose is converted to lactate with oxygen present. This process, linked to brain development and growth, is most active in babies, children, and adolescents and slows with age.

Sugar that’s not used in this process is used to fuel everyday tasks. But the brain changes as the body grows, using less and less sugar for aerobic glycolysis and more for day-to-day function.

“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.”

Brain Metabolism and Age

A total of 205 people, including 121 women and 84 men, participated in Goyal’s study. The group ranged in age from 20 to 82, providing an opportunity to learn how brain metabolism changes with time.

Each participant underwent a PET scan to measure oxygen and glucose activity in the brain. Researchers were able to find the amount of sugar each person was using for aerobic glycolysis. Then, using a machine-learning algorithm, they entered metabolism data for both male and female participants, and the actual ages of the former, asking the program to calculate the brain age of the latter.

The algorithm determined that the women’s brain ages were an average of 3.8 years younger than their actual ages. The same analysis was performed on male participants, their brain ages averaging 2.4 years older. These variances were seen in participants of all ages, even those in their 20s.

Goyal commented that while this is both significant and reproducible, “It’s nowhere near as big a difference as some sex differences, such as height."

The algorithm determined that the women’s brain ages were an average of 3.8 years younger than their actual ages.

What It Means

Until this study, not much was known about brain metabolism in both sexes. Scientists believe this research is only the beginning and that there is more to uncover.

Researchers have seen that older women tend to outscore men of the same age on reasoning, memory, and problem-solving tests. As a result, Goyal and colleagues plan to continue their studies by tracking a group of adults over time to see if there’s a correlation between brain age and cognitive problems.

“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 currently working on a study to confirm that,” said Goyal.

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