Researchers from Sweden's University of Gothenburg recently added another piece of research in favor of the hygiene hypothesis, concerning a device that's found in about 75 percent of US homes:1 the dishwasher.
If you have a dishwasher in your home, you probably consider yourself lucky. But there may be reason to wash your dishes by hand instead. Because they use very hot water (water typically too hot for human touch), dishwashers kill far more germs, and leave your dishes cleaner, than ordinary hand washing.2
But this purported benefit might also be their downfall. In a study of more than 1,000 Swedish children, those with increased microbial exposure were less likely to develop allergies… and this included potential exposure through hand-washed dishes.3
In households where dishes were always washed by hand, rates of allergies in the children were half those from households that used dishwashers. The children using hand-washed dishes were less likely to develop eczema, asthma, and hay fever.
According to the researchers:
"We speculate that a less-efficient dishwashing method may induce tolerance via increased microbial exposure."