Love & Germs: Couples Share 44% of Oral Microbiome

Cohabitation leads to a significant sharing of the human microbiome, with romantic partners exchanging about 44% of their oral microbes and 19% of their gut microbes. This finding comes from a study analyzing microbiome DNA from individuals in Italy and Fiji.

The transmission of these microbes is thought to occur through close contact, such as kissing, sharing eating utensils, or proximity of toothbrushes. Researchers noted a higher rate of oral microbiome sharing among romantic partners, directly correlating with activities involving saliva exchange.

While most bacteria shared are harmless, the study identified a concerning link between some transmissible microbes and an increased risk of Type 2 diabetes. This raises questions about whether a partner's microbiome health could influence an individual's disease risk, though more research is needed to establish causality.

Experts emphasize that the relationship between microbiome health and disease is complex and bi-directional. Despite potential health correlations, the intimate exchange of microbes is considered a natural part of human and primate social living.