Today we already talked about research explaining that learning as an adolescent helps to keep your brain cels, the BBC adds to this story with research that shows that learning a second language slows down the aging of the brain:

“The findings indicate that those who spoke two or more languages had significantly better cognitive abilities compared to what would have been expected from their baseline test.

The strongest effects were seen in general intelligence and reading.

The effects were present in those who learned their second language early, as well as later in life.

Dr Bak said the pattern they found was “meaningful” and the improvements in attention, focus and fluency could not be explained by original intelligence.

“These findings are of considerable practical relevance. Millions of people around the world acquire their second language later in life. Our study shows that bilingualism, even when acquired in adulthood, may benefit the aging brain.”

But he admitted that the study also raised many questions, such as whether learning more than one language could also have the same positive effect on cognitive ageing and whether actively speaking a second language is better than just knowing how to speak it.”
(source BBC)

The full research can be found here, this is the abstract:

Recent evidence suggests a positive impact of bilingualism on cognition, including later onset of dementia. However, monolinguals and bilinguals might have different baseline cognitive ability. We present the first study examining the effect of bilingualism on later-life cognition controlling for childhood intelligence. We studied 853 participants, first tested in 1947 (age = 11 years), and retested in 2008–2010. Bilinguals performed significantly better than predicted from their baseline cognitive abilities, with strongest effects on general intelligence and reading. Our results suggest a positive effect of bilingualism on later-life cognition, including in those who acquired their second language in adulthood.