Gut Microbes, Loneliness, and How We Connect

When we think about loneliness or feeling disconnected, we often focus on friends, family, or social activities. As a therapist who works in a holistic and functional way, I want to invite you to think about something that’s hidden but powerful: the community of tiny living things inside your gut—your microbiome—and how that may connect with how we relate to others, how we feel, and how we heal.

What the Research Shows

Two important human studies suggest that our gut-microbe community may be tied to our sense of connection, support, and loneliness. In one study of 184 adults aged 28 to 97, researchers found that people who reported more loneliness and less social support, wisdom, or compassion had lower gut microbial diversity. In other words: fewer kinds of gut bacteria were associated with more loneliness. Read more.

In a second study, researchers looked at adults who had experienced social exclusion (feeling rejected or left out) versus those who had not. The excluded group had different gut-microbe profiles: for example, they had a higher chance of a “Prevotella-enriched” microbiome, a lower Firmicutes/Bacteroidetes ratio, and less of certain “friendly” bacteria like Faecalibacterium. The excluded group also reported more anxiety and loneliness. Read more.

Together these studies suggest something interesting: our gut bacteria and our social/emotional lives may be connected in ways we are just starting to understand.

Why Might Gut Microbes Link to Loneliness and Social Connection?

Here’s how I see it from a functional mental-health lens:

• The gut-brain axis: The gut and brain are linked via nerves, immune signals, and chemical messengers. When gut microbes shift, they can influence mood, stress, inflammation, and nervous-system regulation.

• Microbial diversity as resilience: In the first study, higher microbial diversity (meaning a rich mix of species) was associated with more social support, wisdom, and engagement. Lower diversity (a more limited mix) was paired with more loneliness. The authors suggested a more diverse gut microbiome might help the body be more resilient to stress, which includes social stress. Read more.

• Social stress impacts microbes: In the second study, social exclusion itself was linked to changes in the gut microbiome. This links physical/social trauma (feeling excluded) to gut changes, which may then impact mood and behavior. Read more.

• Behavior, microbes, and connection loop: From a therapy perspective, imagine a loop: Someone feels lonely → stress responses activate → gut microbiome shifts → mood regulation becomes harder → feeling of disconnection increases, which may further weaken social engagement → loop continues. If we interrupt that loop by supporting gut health, nervous-system regulation, and social connection, we may help restore resilience.

What This Means in Therapy and for Wellness

As a therapist who uses holistic and functional approaches (focusing on mind, body, and environment), here are the practical take-aways I give to clients:

• Ask about social connection AND gut health. In a therapy intake or review, I’ll ask: “How enclosed or connected do you feel socially? How often do you feel lonely? How’s your digestion, gut health, probiotics, fiber, patterns of bowel habits?” These might seem unrelated, but the research shows links.

• Support gut health as part of mental health. While we don’t yet know exactly which bacteria do what, we do know that having more diverse gut microbes tends to be good. So I encourage:

  • Eating lots of fiber-rich foods (vegetables, legumes, whole grains)

  • Including fermented or probiotic foods if appropriate (yogurt, kefir, kimchi)

  • Reducing chronic stress (which can harm gut flora)

  • Supporting good sleep and movement (both impact gut health)

• Support social connection and engagement. Since the first study showed that social support, compassion, social engagement and wisdom were positively linked to gut microbe diversity, I include relational and community work in my practice:

  • Encouraging participation in meaningful groups or volunteer work

  • Building compassion and reflective practices. Read more.

• Nervous-system regulation supports both gut and social systems. When someone is locked in a “lonely” state (which often means hyper-vigilance or withdrawal), their nervous system is dysregulated. I help clients with grounding, body-based regulation (breathwork, orientation, gentle movement) because when the nervous system is calmer, the gut and brain can better sync, and the person can better engage socially.

A Case Example (Hypothetical)

Imagine Jane, mid-40s, who says she has few friends, works mostly from home, and often feels lonely even when she’s “okay” outwardly. She complains of irregular digestion, bloating, and low mood. In our work, we talk about her gut history: diet, antibiotic exposure, stress, sleep. We also talk about social connection: who she sees, how often, what meaningful interaction means to her.

We create a plan:

• Diet: more fiber, fermented foods 2-3 times weekly

• Movement: two short walks each day

• Social: join a small community group (book, gardening, walking) once weekly

• Regulation: daily 5-minute grounding/breathing practice

• Therapy: explore feelings of loneliness, social safety, and relational attunement

Over time — say 3-4 months — we might see improved digestion, slightly better mood, more willingness to engage socially, and her sense of being connected increases. While this isn’t proof of microbiome change (we’re not doing gut sequencing in her therapy), the integrated approach makes sense given what research is showing.

Important Cautions

• These studies show association, not that loneliness causes gut microbial changes or vice-versa in a simple causal way. Many factors interplay (diet, sleep, genetics, environment, infections).

• Microbiome research is still emerging: we don’t yet have specific “loneliness bacteria” or exact “social-connection microbiome profiles” that are ready for clinical use.

• Therapy and wellness work never replace medical care when someone has serious gut disease, mental-health disorders, or other medical issues. This is complementary, not a substitution.

• Social connection is one piece: we still need to address meaning, identity, trauma, nervous-system regulation, environment, and more.

Bringing It All Together

As a functional-mental-health therapist, I believe this research gives us an expanded lens: mental health is not just “what’s in your head.” It’s also “what’s in your gut,” “how you connect with others,” and “how your nervous system manages stress and safety.” When someone feels lonely or disconnected, I don’t just ask: “How many friends do you have?” I also ask: “How safe do you feel in your body? How is your gut, your diet, your sleep? What kind of community interaction do you have?”

If you’re reading this and you feel lonely, disconnected, or you notice your gut is off, know this: you’re not just isolated in your feelings. There’s a whole network of body systems, microbes, and social ties that can be supported and healed. You can cultivate connection — not only outwards to others, but inwards to your gut and nervous system. And as your internal system calms, you might find you’re more able to reach out, engage, belong, and feel seen.

So when we think about healing from loneliness or rebuilding connection, let’s include the gut. Let’s include the microbes. Let’s include the community and the body. Because we are interconnected — not just socially, but biologically — and healing across those layers brings strength, resilience, and wellness.

For those wanting to dive into the research:

Nguyen TT et al., “Association of Loneliness and Wisdom With Gut Microbial Diversity and Composition: An Exploratory Study.” Front Psychiatry. 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8029068/

Kim CS et al., “Experiencing social exclusion changes gut microbiota composition.” Translational Psychiatry. 2022. https://www.nature.com/articles/s41398-022-02023-8