People who speak more than one language are more likely to stay sharp in old age, according to a study.
Tests carried out in a group of native English speakers suggest that speaking an additional language slows down the decline of thinking skills in later life.
BBSRC-funded researchers examined the results of standardised intelligence tests taken by the group at age 11, and compared them with results of thinking tests taken when group members were 73.
Individuals have been tested on a number of physical and mental functions as they grow older, including changes in reasoning, memory, speed of thinking, many aspects of fitness and health, eyesight and blood composition.
The 853 people tested were part of the Lothian Birth Cohort 1936, a group of individuals who were born in 1936 and took part in the Scottish Mental Survey of 1947.
Researchers at the University of Edinburgh who studied the test results found that those who spoke two or more languages had significantly better thinking skills in later life compared with what would be predicted from their IQ results in childhood. This was the case even if the second language was acquired in adulthood.
Thomas Bak, of the University of Edinburgh's Centre for Cognitive Ageing and Cognitive Epidemiology, said: "These findings are of considerable practical relevance. Millions of people around the world acquire their second language in later life. Our study shows that bilingualism, even when acquired in adulthood, may provide a small benefit to the aging brain."
Caroline Abrahams, Charity Director at Age UK said: "Over one million people in the UK aged 65 and over are estimated to have some degree of cognitive impairment. We urgently need to understand what influences cognitive ageing so that we can give people better advice about protecting their cognitive health. The Disconnected Mind project has already uncovered a range of factors. This latest breakthrough is another stride forward in finding out how thinking skills can be preserved in later life."
The study, published in Annals of Neurology, was funded by Age UK. The work was undertaken by the University of Edinburgh as part of the Lifelong Health and Wellbeing Initiative with funding from BBSRC and Medical Research Council.