Kissing and the Science Behind It: A Closer Look at Sharing Saliva and Love
Kissing a romantic partner is often seen as a way to share an intimate moment, but did you know that it also involves swapping saliva and tens of millions of oral microbes? Microbiologist Remco Kort from VU Amsterdam in the Netherlands believes that there is more to kissing than meets the eye.
In a new paper, Kort explores the idea that sharing saliva and its various components may play a role in the complex emotions of falling in love. He poses intriguing questions about the impact of swallowing partners’ microbes, how it affects our gut, hormones, and even our feelings of love.
According to Kort, deep kissing involves the mixing of saliva and direct tongue-to-tongue contact, essentially inoculating partners with each other’s oral microbes. This exchange of germs, similar to an oral vaccine, may actually have surprising health benefits.
Recent studies have shown that the oral cavity is home to the body’s second most diverse bacterial community, with implications for inflammation and distant organs like the brain and heart. Kissing between romantic partners leads to the transfer of millions of oral microbes, resulting in oral bacterial communities that become more alike over time.
Saliva also contains hormones like cortisol and adrenaline, as well as bacteria that can respond to neural messengers like oxytocin and dopamine. These physiological changes during kissing may indirectly promote a favorable oral environment.
Some evolutionary biologists suggest that passionate kissing could be advantageous as it shares immune information via oral microbes, helping partners build immunity to each other’s germs. However, this exchange could also spread disease, which is why open-mouthed kissing is typically reserved for trusted romantic partners.
While these ideas are still theoretical, Kort has proposed a study design to explore them further. Couples who volunteer to participate may discover more about their saliva and their partners than they ever imagined.
The study was published in Evolution and Human Behavior.
