Seeing friends and family boosts our immune system, reduces the risk of stroke and slashes the chances of developing type 2 diabetes, according to a study.
Scientists have discovered five proteins specifically linked to loneliness that can contribute to a raft of health issues.
They drew this conclusion after studying proteins from blood samples taken from tens of thousands of adults recruited to the UK Biobank.
And they said their findings drive home the importance of social contact in keeping us healthy.
Previous research has found that both social isolation and loneliness are linked to lower wellbeing and an early death, but the underlying mechanisms through which relationships impact health have remained elusive.
The team, from the University of Cambridge, examined proteins in blood samples donated by 42,000 adults aged 40-69.
This allowed them to see which proteins were present in higher levels among people who were socially isolated or lonely, and how these proteins were connected to poorer health.
Analysis revealed five proteins whose abundance was caused by loneliness - some of which are already linked to cardiovascular disease, high cholesterol, the development of insulin resistance and an early death.
Dr Chun Shen, one of the study’s authors, said: ‘We know that social isolation and loneliness are linked to poorer health, but we’ve never understood why.
‘Our work has highlighted a number of proteins that appear to play a key role in this relationship, with levels of some proteins in particular increasing as a direct consequence of loneliness.’
Professor Barbara Sahakian, from the Department of Psychiatry at the University of Cambridge, added: ‘These findings drive home the importance of social contact in keeping us well. More and more people of all ages are reporting feeling lonely.
‘That’s why the World Health Organization has described social isolation and loneliness as a ‘global public health concern’.
‘We need to find ways to tackle this growing problem and keep people connected to help them stay healthy.’
The findings were published in the journal Nature Human Behaviour.
