Interactions with friends and family may play a crucial role in maintaining our health by boosting the immune system and lowering the risk of several diseases, including heart disease, stroke and type 2 diabetes, according to new research.
A team of researchers led by the University of Cambridge and Fudan University in China examined blood samples from over 42,000 adults participating in the UK Biobank to understand the biological mechanisms behind the impact of social relationships on health. Their groundbreaking findings were published in the journal Nature Human Behaviour.
Social relationships significantly contribute to our overall well-being. Previous studies have shown that both social isolation and loneliness are linked to poorer health and premature death. However, the underlying biological processes have remained elusive until now.
By analyzing proteins circulating in the blood -- crucial molecules produced by genes that support bodily functions and serve as drug targets -- the researchers aimed to shed light on how social connections influence health.
The team categorized participants' social connectedness using objective measures of social isolation (such as living alone, frequency of social contact and engagement in social activities) and subjective measures of loneliness.
Their analysis identified 175 proteins associated with social isolation and 26 proteins linked to loneliness, with 85% of the proteins overlapping between the two conditions.
"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," Chun Shen, a postdoctoral research fellow at Fudan University and a visiting researcher in Cambridge's Department of Clinical Neuroscience, said in a news release.
Further analysis using Mendelian randomization -- a statistical method to explore causal relationships -- identified five proteins whose levels were directly influenced by loneliness.
One key protein, ADM, was found to respond to stress and regulate mood-improving hormones like oxytocin. Elevated ADM levels were associated with changes in brain regions related to emotional processing and an increased risk of early death.
Another protein, ASGR1, was linked to higher cholesterol levels and elevated cardiovascular disease risk. Other identified proteins were found to be involved in insulin resistance, atherosclerosis and even cancer progression.
Jianfeng Feng, a professor of computer science at the University of Warwick, highlighted the potential of this research to revolutionize our understanding of human health.
"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 revolutionize the traditional view of human health," Fend said in the news release.
The significance of these findings underscores the role of social connections in health.
"These findings drive home the importance of social contact in keeping us well. More and more people of all ages are reporting feeling lonely," added Barbara Sahakian, a professor of clinical neuropsychology in Cambridge's Department of Psychiatry. "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."