Everyone knows you can catch germs just by locking lips with someone. It is just that no one likes to think about that for obvious reasons.
Unfortunately, we have to confront this reality now thanks to a new study published in the journal Microbiome. The study didn't just confirm that, yes, bacteria spreads between two people, but it also found exactly how much gets transferred.
And are you ready for the results? The study found that a 10-second "intimate kiss" transfers an average of 80 million bacteria. Well, that's one way to ruin the mood.
In the study, researchers sampled 21 couples visiting the Artis Royal Zoo in Amsterdam in July 2012. They were mostly heterosexual, with the exception of one female and one male homosexual couple. Each participant answered a questionnaire that asked about such topics as kiss frequency and time passed since last kiss. The researchers then collected samples from the tongue and saliva of each of the participants before and after an "intimate kiss" of 10 seconds.
One partner was then asked to drink a probiotic yogurt drink, which contained bacteria. The researchers collected another sample from each of the partners before and after a kiss of 10 seconds.
Interestingly, intimate partners share more bacteria on their tongues and in their saliva than strangers. The more often partners kiss, the more bacteria they share, according to the study. "It didn't matter whether the couples said they French kissed nine times a day or nine times a year," Remco Kort, one of the study's authors, said in a statement. The researchers also found that the bacteria from the probiotic drink did actually transfer between the partners.
However, if all of this makes you want to come up for air, the bacteria transferred during kissing could actually be beneficial to your health and the health of others. "There are a number of studies that show if the diversity in bacteria increases — more different types of species — this is a good thing," Kort told TIME. Kissing can also act as a form of immunization, helping you build up tolerance to various micro-organisms. Although, the benefits of kissing depend on who you're kissing and the type of micro-organisms.
So there you have it. Science proves that kissing is actually gross, but it can be good for you, too. Well, you can't win them all.
