According to this study performed by US researchers, women’s brains are 4 years younger than men’s in how they burn fuel.
Some scientists have found that women’s metabolic brain age is younger than men’s brains in the same age. This difference starts to show up from early adulthood and it stays until the last stages of life.
The results have shown that women’s brains proceed more changes in energy use during a person’s lifetime. Researchers aren’t sure of what are the medical consequences of these changes, but it explains why women stay mentally sharp for longer.
“Brain metabolism changes with age but what we noticed is that a good deal of the variation we see is down to sex differences,” said Marcus Raichle, a neurobiologist at Washington University school of medicine in St Louis. “If you look at how brain metabolism predicts a person’s age, women come out looking about four years younger than they are.”
Positron Emission Tomography is a brain-scanning technique used by scientists to measure the flow of oxygen and glucose in the brains of 84 men and 121 women aged 20 to 82. The results have shown how sugar turned into energy in many parts of the volunteers’ brains.
Another process called Aerobic Glycolysis is increased in babies and children’s brains to increase developing it. As they hit adolescence and young adulthood, it gets scaled down and drops steadily as we grow older until we reach our 60s, then it reaches a very low level and stays there.
Researchers used a computer algorithm to guess people’s ages based on their brain metabolism to see how it differs between the sexes and ages. Scientists started by training it to predict men’s ages from the data gathered from their brain scans.
When the scientists fed metabolism data from the female volunteers, the same result came out. The program predicted the men’s ages accurately, and it predicted women’s age to be 3.8 years younger than their actual ages.
Then, the scientists decided to turn the analysis around and train the algorithm to predict women’s ages from their brain scan’s information. Then, they fed men’s metabolism data into the computer and it predicted them to be 2.4 years older than their actual age. They seemed older because of the way they burned sugar.
“The great mystery is why,” said Raichle. Researchers think that it’s more than hormonal differences, the difference in metabolism stays the same when they enter the menopause.
“I refer to things like this as the curveballs of Mother Nature,” said Raichle. “Maybe women start off with this difference and it’s perpetuated throughout life.”
The difference doesn’t have a clear meaning yet. The researchers were eager to search whether people with low glucose metabolism are more likely to lose their memory, learning problems, and neurodegenerative illnesses as they grow older.
“Is lower metabolism in such and such an area predictive of a particular event down the road? We don’t know,” said Raichle. “But if aerobic glycolysis is protective in some way, and the brain loses some element of it, that could be a problem.” For more details check out this report by Proceedings of the National Academy of Sciences.
Mani Goyal at the university’s Mallinckrodt Institute of Radiology and first author on the paper said men’s brains were not aging faster than women’s. “They start adulthood about three years older than women and that persists throughout life,” he said. “What we don’t know is what it means. I think this could mean that the reason women don’t experience as much cognitive decline in later years is that their brains are effectively younger.”