Couples share 30% of their gut bacteria - here's how that may affect health

Research suggests couples living together share around 30% of their gut bacteria, a figure that rises the longer they live under the same roof.

Shared diet, shared households and simple daily contact appear to drive the overlap, effectively creating a partly shared microbiome.

Scientists say this may matter for health, since gut bacteria are linked to digestion, immune function and even mood, meaning benefits and risks can be shared too.

The research is still early, and the effect of any single bacterial transfer on health outcomes remains hard to isolate.