Marriage, emotional support may protect against obesity through brain-gut connection, study finds

Strong social relationships, particularly high-quality marriages, may help protect against obesity by influencing a complex communication system between the brain and gut, according to new research by UCLA Health. 

The study, published in the journal Gut Microbes, is the first to demonstrate how social bonds influence weight and eating behaviors through an integrated pathway involving brain function, metabolism and the hormone oxytocin, sometimes referred to as “the love hormone.”  

The findings suggest that the quality of relationships may be just as important to physical health as traditional risk factors like exercise and diet 

“We've known for years that social relationships impact health, with supportive connections increasing survival rates by up to 50%,” said lead author Dr. Arpana Church, a neuroscientist at UCLA Health. “The biological mechanisms explaining this connection have remained elusive. Our study reveals a novel pathway showing how marriage and emotional support literally get 'under the skin' to influence obesity risk.” 

Nearly 100 participants from the Los Angeles area participated in the study. The participants provided data including marital status, current Body Mass Index (BMI), race, age, sex, diet style and quality and socioeconomic status. Researchers also conducted various tests on the participants including brain imaging while food images were displayed; fecal samples to test for metabolites; blood plasma tests to measure oxytocin levels; and clinical and behavioral evaluations including assessment of their perceived emotional support system.  

The Church lab found that married individuals with higher perceived emotional support had a lower body mass index and exhibited fewer food addiction behaviors compared to married participants with low emotional support. Brain imaging showed these individuals had enhanced activity in the dorsolateral prefrontal cortex, which manages cravings and appetite, when viewing food images. Conversely, unmarried people with and without strong emotional support did not show the same brain patterns, potentially due to more diverse and less consistent social support networks. 

Social support also had significant changes in gut metabolism. Those with stronger support showed beneficial changes in tryptophan metabolites, which are compounds produced by gut bacteria that regulate inflammation, immune function, energy balance and brain health. These metabolites are also involved in producing serotonin and other compounds that can influence mood, social behavior and metabolism. 

Central to these findings is the hormone oxytocin. Married participants with strong emotional support showed higher levels of oxytocin levels compared to unmarried individuals. Church said their findings suggest oxytocin may act as a biological messenger that simultaneously enhances brain regions involved in self-control while promoting healthier gut metabolic profiles.  

“Think of oxytocin as a conductor orchestrating a symphony between the brain and gut,” said Church. “It strengthens the brain's ability to resist food cravings while promoting beneficial metabolic processes in the gut, both of which help maintain healthy weight.” 

The research also challenges oversimplified views about marriage and weight. The benefits relating to self-control, metabolism and oxytocin levels were more pronounced among married participants who endorsed greater emotional support. 

“Marriage may serve as a training ground for self-control,” said Church. “Maintaining a long-term partnership requires consistently overriding destructive impulses and aligning with long-term goals, which may strengthen the same brain circuits involved in managing eating behavior.” 

Church said the study opens potential avenues for obesity prevention and treatment by incorporating the need to build strong social relationships alongside a healthy diet and exercise.  

“These results underscore the critical importance of building long-lasting, positive, and stable relationships to promote overall health,” Church said. “Social connections aren't just emotionally fulfilling; they're biologically embedded in our health.” 

The authors noted several limitations. The study captured data at a single point in time and cannot definitively establish cause-and-effect relationships, Church said. Additionally, most participants were overweight or obese, and married participants tended to be older. Future research with larger, more diverse samples and longitudinal designs is needed to confirm these findings and better understand the mechanisms involved.