Scott Napper has a hypothesis: What if his daughters' tendency to pick their noses and eat the dried nasal mucus - their boogers - actually had some health benefits?
Napper, who teaches biochemistry at the University of Saskatchewan in Canada, told the CBC that he'd wondered whether the "sugary" taste of the dried mucus was meant to signal to the body that consuming pathogens caught in the mucus was a good thing.
"I've got two beautiful daughters, and they spend an amazing amount of time with their fingers up their nose," Napper told CBC. " And without fail, it goes right into their mouth afterwards. Could they just be fulfilling what we're truly meant to do?"
The hygiene hypothesis has long blamed allergies, asthma and autoimmune disorders on a lack of exposure to certain pathogens early in life. Napper contends that eating boogers exposes people - and their immune systems - to the pathogens inside.
Napper said he uses his hypothesis to engage his first-year biochemistry students. He told the CBC that he's already been approached by people looking to participate in a study.
But Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University, said it's not likely that eating boogers would offer much additional immune system support, because people already unconsciously swallow nasal mucus.
"It happens naturally all the time, and the cells in your own mucous membranes are exposed to whatever is in the mucus constantly," he said. "Because it's part of your own body fluids, you swallow nasal secretions all the time during the day and while you're asleep."