It’s a science lesson you probably learned in grade school: You can only catch certain illnesses, like the flu, from another person. But a new paper argues that many diseases seen as noncommunicable, like most cancers and heart disease, might be transmissible sometimes—thanks to the seemingly harmless microbes living in and on our bodies.
In animals, studies have shown that if you wipe out the gut microbiome of healthy mice and transplant a microbiome sourced from obese mice, the former group of mice are more likely to become obese than control mice. Studies of the reverse concept—altering the microbiomes of sick mice to make them resemble healthy mice—have also been shown to treat or slow the progression of not only obesity but other chronic ailments, like Alzheimer’s and heart disease.
There’s even some early evidence of human-to-human transmission of our microbiomes in general, such as from mother to child in the womb or from other people’s fecal bacteria that ends up in our food and water.
“When you add up these [data], it makes a compelling case,” lead author Brett Finlay, a microbiologist at the University of British Columbia in Canada, told Gizmodo via email.