Ten seconds of locking lips is all it takes to swap as many as 80 million bacteria.
A study by Dutch researchers involving 21 couples investigating the status of oral microbiota of people who kiss on a relatively frequent basis found that those who kiss at least nine times a day share very similar bacterial communities.
But it's not necessarily something to be disgusted about. The average human body plays host to more than 100 trillion microorganisms, according to a news release about the research. Many of these organisms are important for digestion and even harmful disease prevention.
"Intimate kissing involving full tongue contact and saliva exchange appears to be a courtship behavior unique to humans and is common in over 90 percent of known cultures," Remco Kort, lead author of the study with Micropia and TNO in the Netherlands said in a statement. "Interestingly, the current explanations for the function of intimate kissing in humans include an important role for the microbiota present in the oral cavity, although to our knowledge, the exact effects of intimate kissing on the oral microbiota have never been studied. We wanted to find out the extent to which partners share their oral microbiota, and it turns out, the more a couple kiss, the more similar they are."
In addition to this finding, couples answered a questionnaire about their kissing habits, that revealed men report kissing more frequently than women. Seventy-four percent of men reported more intimate kisses than their female counterpart — men said they got an average of 10 kisses per day, while women reported an average of five.
These findings were published in the journal Microbiome.
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