Dutch scientists have discovered why kissing is beneficial 0 8

A kiss with a loved one is not only a romantic gesture but also an exchange of a huge amount of saliva and millions of microorganisms that inhabit the mouth. Although the very idea of "exchanging microbes" sounds unappealing, microbiologist Remko Kort from VU University Amsterdam in the Netherlands sees this not as a reason for disgust but as a scientific interest – a kind of "kissing virus."

The scientist suggests that the transfer of saliva and its contained substances may play a much more significant role in the formation of romantic feelings than is commonly believed. In his new work, he formulates a whole series of questions that currently have no clear answers. For example, what happens when a person swallows their partner's microbes during a kiss? Can they influence the intestinal microbiota, hormonal balance, or even brain function? Can such an exchange somehow enhance feelings of attachment and love?

Kort believes that this is quite likely. In his hypothetical article, he considers saliva as a possible "biological mediator" of intimacy – a factor that not only reflects an intimate connection but may also strengthen it. In his opinion, positive feedback may be at work here: love and emotional closeness contribute to better health, and good health, in turn, supports and enhances feelings. After the intestines, the oral cavity is considered the second most diverse bacterial ecosystem in the human body. Increasing research shows that the composition of the oral microbiota affects not only the condition of the gums and teeth but also the level of inflammation in the body as a whole, and may also reflect on the functioning of distant organs – for example, the brain and heart.

Moreover, data from recent years, including Kort's previous experiments, confirm that during a kiss, partners exchange millions of microorganisms. If such contacts occur regularly, the microbial communities in their oral cavities gradually become more similar. However, saliva is not just bacteria. It contains hormones, including cortisol and adrenaline, which can potentially affect another person. Furthermore, there are bacteria in the mouth that can "react" to neurotransmitters – such as oxytocin, dopamine, and endorphins, the levels of which rise sharply during an intimate kiss.

According to Kort, such physiological changes may indirectly create an environment in the mouth that is favorable for certain microbes. Earlier, evolutionary biologists hypothesized that passionate kisses may have been established during evolution precisely because of the exchange of immunologically significant information through oral microorganisms. Such exchange may contribute to the formation of partial immune adaptation between partners and to new pathogens they have not encountered before.