Gut Bacteria are Shared with Family and Friends

Could Gut Health Be Social?

With all the concern about gut health these days, we may have one more factor to consider: who we are sitting next to. Yes, this study suggests that the more time you spend with someone, the more similar your gut bacteria profiles look—at least for birds. We know that those billions of tiny bacteria in our GI tract play a big role in so many other functions of our body, this finding could carry some significant implications for lifestyle changes.

A Quick Bacteria Refresher

For those needing a refresher, bacteria are single cell organisms, generally much smaller than our cells, which fill the world around us. Most could not care less about our presence, but many either help or hurt our health. In our GI tracts, a few hundred billion live mainly in three to five pounds of stool in our colons and a few through the rest of our GI system. Most of them, the good little bacteria, help digest food, strengthen our immune system, and even produce a few vitamins for us. Sometimes, we get nasty bacteria that lead to illness.

Understanding the Gut Microbiome

This collection of bacteria is our ‘gut microbiome,’ and through different mechanisms it plays a significant role in how we can optimize our health. Many of you may be taking probiotics, eating fermented foods, or paying attention to fiber intake in order to keep your gut healthy. Each of these lifestyle patterns affect which bacteria, good or bad, live in your gut.

What the Research Suggests

Now we have this research on gut bacteria and social interaction which suggests that who we spend more time with could also impact our gut microbiome. The researchers looked at a group of birds on isolated islands and compared the microbiome compositions of birds that spent more time together versus those which don’t spend as much time together. They focused more attention on anaerobic bacteria, the bacteria which do not like oxygen, as these are less likely to be floating around for long periods outside the bird’s GI tracts.

What the Study Found

This study showed that the birds that spent more time together shared more common patterns in which types of bacteria their stools contained. While the result is not immediately translatable to humans and has some possible confounders to explain the similarities, it does raise the question whether our time with others could be influencing our gut microbiome.

Why More Research Is Needed

Among the potential problems for this study is that human interactions are a lot more complex and varied than a bunch of birds on a set of islands. We also have to weigh the possibility that birds who spend time together just share more of their diet and that this similarity is the reason for the similar microbiomes.

Could This Apply to Humans?

Regardless, the possibility of finding similar situations in humans is plausible. Other studies have shown that family members share similar microbiome patterns. While I don’t suggest that we choose our friends by their microbiomes or gut health markers, maybe it is worth encouraging those we’re around the most to care for their gut bacteria, since they might be sharing that microbiome with us. It’s just a thought.

Gut Health as a Family Conversation

For now, this is just interesting. But, in striving for a healthier, more abundant life, we may one day be discussing gut health in terms of families rather than just individuals. Getting whole families to change eating patterns might go further than focusing on only one individual’s gut health. Learn more about whole-person care through Sanctuary Functional Medicine.

Original Article:
Chuen Zhang Lee, Sarah F. Worsley, Terry Burke, Jan Komdeur, Falk Hildebrand, Hannah L. Dugdale, David S. Richardson. Social Structure and Interactions Differentially Shape Aerotolerant and Anaerobic Gut Microbiomes in a Cooperative Breeding Species. Molecular Ecology, 2026; 35(7). DOI: 10.1111/mec.70304

Source:
ScienceDaily, University of East Anglia, April 13, 2026.