How to keep your brain young: Scientists uncover key link between dementia and your social interactions

A new study shows an association between brain shrinkage and social isolation.

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Published: July 12, 2023 at 8:00 pm

Want to be more socially fit? Well, more frequent interactions with your loved ones could help to protect your brain from dementia, according to a new study.

Scientists at Kyushu University, Japan, have discovered that lonelier old people are likely to lose more of their brain volume as they age – including the part of their brain affected by dementia. Dementia is a disease that affects memory and the ability to perform day-to-day activities.

Meanwhile, people with more frequent social contact are less likely to suffer from brain shrinkage.

“Social isolation is a growing problem for older adults,” said Dr Toshiharu Ninomiya, author of the study published in the journal Neuroscience.

“These results suggest that providing support for people to help them start and maintain their connections to others may be beneficial for preventing brain atrophy [shrinkage] and the development of dementia.”

The 8,896 participants – with an average age of 73 – had MRI brain scans and health exams. None of the participants had been diagnosed with dementia.

The participants were asked about the frequency of their social interactions in person or on the phone with friends and relatives not living with them.

People with the least social contact had the smallest brain volume at 67.3 per cent – whereas the most social group had the highest brain volume at 67.8 per cent. This percentage indicates the total proportion of white and grey matter – some of the most important bits of the brain – within the total volume of the brain.

The scientists also discovered that the more socially isolated participants also had minor damage known as white matter lesions to parts of their brains.

Social connections of various kinds are vital not just to our emotional wellbeing, but to our physical health too. Having good 'social fitness' is key to being in good shape – both physically and mentally.

“While this study is a snapshot in time and does not determine that social isolation causes brain atrophy, some studies have shown that exposing older people to socially stimulating groups stopped or even reversed declines in brain volume and improved thinking and memory skills,” Ninomiya said.

“So it’s possible that interventions to improve people’s social isolation could prevent brain volume loss and the dementia that often follows.”

The study’s sample size consisted entirely of older Japanese participants. Further research will be needed to establish whether the results also apply to people of other ethnicities and younger people.

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