The bond between individuals who share the same environment goes far beyond the simple sharing of habits and behaviors. Spending a lot of time together, in fact, could make you more similar than you think, influencing the very composition of the intestinal microbiome. Recent research from the University of East Anglia suggests that the bacteria that populate our digestive system are transmitted and stabilized through prolonged social interactions, with direct implications for the health of all housemates or household.
The study, which appeared in the journal Molecular Ecologyfocused on analyzing how microbiomes evolve within closed social groups, starting from the assumption that physical contact and sharing spaces are not only vehicles for pathogens, but also for symbiotic bacteria essential for metabolism. Some research carried out in the past was already going in this direction, but the new study adds an interesting piece: in fact, it is not only the shared environment that uniforms the composition of the microbiome, but the social contacts themselves, which could be a direct route of exchange not only of pathogens, but also of beneficial bacteria.
To reach these conclusions, the authors of the research left humans aside, focusing their attention on the Seychelles reed warblers, small insectivorous birds that live in the forest areas of the tropical archipelago of the same name. By analyzing fecal samples collected over years in the Cousin Island nature reserve, English scientists observed how anaerobic bacteria spread between individuals, identifying a precise pattern: the more time they spent together, the more similar the birds’ microbiome was. Physical proximity and social cooperation therefore act as transmission channels for beneficial microbes, potentially capable of strengthening the immune system and digestive health of the entire group of which these birds are part.
The researchers believe these findings reflect what might be happening inside the human home. “Whether it’s living with a partner, a roommate or with your family, daily interactions — from hugs to kisses, to sharing spaces where food is prepared — can promote the exchange of intestinal microbes,” explained Chuen Zhang Lee, a researcher at the University of East Anglia who participated in the study. “Anaerobic bacteria are among the most important for digestion, immunity and overall health. Once inside the gut, they thrive in the absence of oxygen and often form long-term stable colonies. This means the people you live with could subtly shape the microscopic ecosystem inside you,” Lee added. “Translated into human terms, this means that evenings spent together, sharing household chores, or even just sitting together on the couch can bring your microbiomes closer together and silently promote your health.”