The more languages people know, the slower their brains age, a new study reveals. Photo: RNZ
An international study of more than 80,000 adults shows the more languages people know, the slower their brains age.
The analysis of 51 to 90-year-olds from 27 European countries - published in Nature Aging - found the brains of those who only spoke one language were twice as likely to age faster.
Those who were multilingual were on average about half as likely to experience accelerated ageing, the authors said.
The researchers also found that speaking multiple languages delayed ageing and the more languages spoken, the greater the effect.
They said the results suggest that promoting multilingualism could support healthy ageing strategies.
Dementia researcher and lecturer in psychological medicine at University of Auckland, Dr Etu Ma'u, said the study confirmed what had long been suspected - that being bi- or multi-lingual keeps the brain active and stimulated, which is beneficial for brain health.
Dementia researcher and lecturer in psychological medicine at University of Auckland, Dr Etu Ma'u. Photo: Supplied/Pasifika Medical Association
He said the brain shrunk about 5 percent every year from the age of 40.
Ma'u e said the brain's ageing was a natural process and a balance between incremental damage sustained over a lifetime and things that protect "cognitive reserve" (the brain's ability to keep functioning despite such changes).
"We've known for a while that anything that stimulates our brain is going to be good for cognitive reserve.
"[This] study by Amoruso and colleagues demonstrates that the ability to speak more than one language improves cognitive reserve by slowing brain ageing, and the benefits increase with the number of languages spoken."
Ma'u said the "massive study" with some "really cool modelling" showed the more languages spoken, the younger the brain.
"If you speak more than one language your brain age, or the health of your brain, is coming in at a couple of years younger than what your chronological age is - a younger brain means a healthier brain, effectively.
"If you just spoke your mother-tongue, you had a higher brain age compared to people who spoke two languages, but they've shown that people who spoke three languages, probably had even more of an impact."
He said dementia was the result of cumulative and incremental damage over the course of someone's life, as was building cognitive reserve and resilience.
Therefore, guarding against such age-related diseases was something to think about earlier rather than later, he said, and not just on an individual basis, but at an environmental level.
"We need to think about brain health from infancy all the way through. So clearly learning a second language as a child at school or in your community is good, because it keeps your brain active and stimulated.
"It's never too early and it's never too late to learn a new language to challenge your brain."
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