New research suggests that spending more time alone could not only harm our mental health but also our physical health. A study indicates that social interactions with friends and family could enhance our immune system and lower the risk of diseases such as heart disease.
The research, conducted by a team from the University of Cambridge and Fudan University in China, analysed blood samples from over 42,000 adults aged between 40 to 69 years old. They specifically examined groups of proteins in the blood known as proteomes.
This allowed them to identify which proteins were present in higher levels among individuals classified as socially isolated or lonely, and how these proteins were linked to poorer health. Each participant was given a social isolation and loneliness score.
Social isolation was determined based on factors such as living alone, frequency of social contact, and participation in social activities. As reported by Science Daily, the loneliness score was a subjective measure based on an individual’s feelings of loneliness.
After taking into account factors such as age, gender and socioeconomic background, researchers identified 175 proteins linked to social isolation and 26 proteins associated with loneliness. Most of these proteins are produced in response to inflammation, viral infection and immune responses, and have been connected to cardiovascular disease, type 2 diabetes, stroke, and premature death.
The team then investigated the causal relationship between social isolation and loneliness, and protein levels, discovering five proteins that increased due to loneliness. Dr Chun Shen from Fudan University 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 Jianfeng Feng from the University of Warwick continued: “There are more than 100,000 proteins and many of their variants in the human body.
“AI and high throughput proteomics can help us pinpoint some key proteins in prevention, diagnosis, treatment and prognosis in many human diseases and revolutionise the traditional view of human health. The proteins we’ve identified give us clues to the biology underpinning poor health among people who are socially isolated or lonely, highlighting why social relationships play such an important part in keeping us healthy.”
One of the proteins produced in higher levels due to loneliness was ADM. This protein has been previously associated with regulating stress hormones and social hormones like oxytocin. Increased levels of ADM were linked to a greater risk of early death.
Professor Barbara Sahakian, from the Department of Psychiatry at the University of Cambridge, commented: “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 Organisation 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.”
According to the Office for National Statistics (ONS), 27 percent of adults in the UK reported feeling lonely in the period from December 2023 to January 2024. This includes people who felt lonely some of the time, often, or always.
The study was published in the Nature Human Behaviour journal.