Our Brains Are Getting Bigger

They've increased in volume over the decades, which may be good news for dementia risks
By Gina Carey,  Newser Staff
Posted Mar 30, 2024 9:00 AM CDT
Our Brains Are Getting Bigger
A closeup of a human brain affected by Alzheimer's disease, on display at the Museum of Neuroanatomy at the University at Buffalo.   (AP Photo/David Duprey)

Though theories abound that humans are getting dumber, evidence suggests that our brains are actually getting bigger. Researchers from UC Davis Health found that they've grown in both volume and surface area after comparing MRIs from people born in the 1930s with those born in the 1970s, per Newswise. And larger brains may mean reduced risk of dementia.

  • 75 years of research: The study was part of the Framingham Heart Study (FHS), which began 75 years ago and tracks thousands of participants—some second and third generation—through various health markers. This recent paper analyzed the brain size of 3,226 people between 1999 and 2019 and learned that the brains of participants born in the 1970s increased in volume by 6.6%, and brain surface by 15%.
  • Why are brains growing? Better nutrition during key developmental periods in pregnancy and childhood is seen as a big factor, per Earth.com.
  • Dementia: So how does this connect to dementia? "Larger brain structures like those observed in our study may reflect improved brain development and improved brain health," says lead author Dr. Charles DeCarli. "A larger brain structure represents a larger brain reserve and may buffer the late-life effects of age-related brain diseases like Alzheimer's and related dementias."
  • Not a complete picture: Neuroscience News & Research notes that participants in the study were healthy, well-educated, and predominantly non-Hispanic whites. "Current evidence indicates that social-cultural and health disparities, which are more common among non-white individuals in the US, may adversely affect brain health," the study authors noted.
  • Ancient brains: While the FHS study goes back 75 years, CNN reports that an archive of ancient human brains could give researchers insight into which brain diseases have been around longer than others. Scientists have cataloged more than 4,000 such brains, some of them up to 12,000 years old, per Popular Mechanics. As they explain in the Proceedings of the Royal Society B, the scientists also are trying to better understand how the soft tissue manages to survive so long in some circumstances.
(Ancient Greeks didn't seem to get dementia.)

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