How the people you love influence your microbiome


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How the people you love influence your microbiome


If you’re an Activated Probiotics enthusiast, chances are you love your microbiome and feel an intimate connection to the microbiota that reside in your gut. But have you ever wondered how the people you love influence your microbiome? Does co-habitating with a partner result in a co-mingling of microorganisms? And could someone’s microbiome influence your attraction to them? Join us for an exploration of four key areas of research around the role of the microbiome in interpersonal relationships – as it turns out, your microbiome may be the ultimate matchmaker.

1. Smooching - do we exchange bacteria when we kiss?

We exchange a lot of bacteria when we kiss. In fact, research estimates that we exchange an average total of 80 million bacteria per 10-second kiss. Through a “controlled kissing experiment”, scientists determined that partners have greater similarity in their oral microbiomes compared to strangers. But interestingly, this similarity was observed regardless of kissing frequency. In other words, it’s not only kissing that causes the similarity between oral microbiomes – so do partners already have a similar profile of microbiota before they’ve even made it to first base? (1)

2. Attraction - do you love them or their microbiome?

Attraction is often attributed to the abstract notion of “chemistry”. While it’s true that bioactive chemicals such as hormones and pheromones are at play when it comes to the phenomenon of catching feelings – scientists have dug deeper to determine if bacteria influence the production of these cupids of the endocrine system. According to research, humans may be unconsciously attracted to other humans that possess an immunological profile that complements theirs most effectively.

For example, in one study, participants who had “higher burdens of infectious microorganisms” (indicating potentially low or dysfunctioning immunity) were found to look for more physically attractive partners, a biological indicator of a strong immune system.Those participants that had signs of a stronger immune system were found to be less concerned with looks because they did not require their partner to bring as much immune system strength to the relationship and thus their offspring. This is also reflected in nature, with the most extravagant physical displays (such as peacock feathers) typically indicating immunological strength, which in turn influences their likelihood to be chosen for mating (2).

3. Going all the way - how does intercourse impact our microbiomes?

Of course we share germs during sex. This one’s a no-brainer! Or is it? According to research, the genital microbiome can indeed be exchanged between partners. In the case of intercourse between a man and a woman, however, the implications of the exchange are vastly different (sound a bit like wider society?). The exchanges between male and female genital microbiomes have a significant influence on the vaginal microbiome while the changes to the seminal microbiome are comparatively minimal. However, in spite of these apparently dramatic changes that occur in the vaginal microbiome after intercourse, the relatively long term effects may be limited. The microbiota in a healthy vaginal microbiome are highly resilient species – how’s that for an empowering thought, ladies? (3)

4. Relationship dynamics - what’s an alpha microbiome?

Every relationship has its own unique dynamic – and amazingly, there may be some unseen relationship dynamics going on when it comes to our microbiomes as well. Have you heard of the concept of an “alpha microbiome”? Naturopathic clinician Dr. Leah Hechtman explains it beautifully: when people live together, one person’s microbiome may become dominant, shaping the surrounding microbiomes into communities more similar to the alpha microbiome over time.

They say you can’t buy love and we all know there’s no such thing as Love Potion #9. But perhaps that’s because probiotics scientists never got involved in the research and development.


1. Kort, R., Caspers, M., van de Graaf, A. et al. Shaping the oral microbiota through intimate kissing. Microbiome 2, 41 (2014).
2. Little AC, DeBruine LM, Jones BC. Exposure to visual cues of pathogen contagion changes preferences for masculinity and symmetry in opposite-sex faces. Proc Biol Sci. 2011 Jul 7;278(1714):2032-9.
3. Ma ZS. Microbiome Transmission During Sexual Intercourse Appears Stochastic and Supports the Red Queen Hypothesis. Front Microbiol. 2022 Mar 8;12:789983.




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