Children living in homes where dishes are washed by hand are only half as likely to suffer from allergies than children in homes where dish-washing machines are used.
Swedish researchers studied nearly 1,000 seven and eight-year-olds living in the cities of Gothenburg in western Sweden and Kiruna in the north. They found that where families used dish-brushes children were less likely to suffer from asthma, eczema and hay fever, Xinhua news agency reported Thursday citing the Dagens Nyheter newspaper.
Previous studies have shown that more bacteria tend to stick to the surfaces of hand-washed items than to items washed by machine -- and those bacteria are believed to help strengthen children's immune systems.
"Our findings match the hygiene hypothesis that says you have to be subjected to bacteria early on in life -- preferably bacteria that cannot cause fatal illness -- so that the immune system is kept busy and can develop," said Bill Hesselmar, one of the researchers behind the epidemiological study.
The researchers, though, said other factors could also be at play.
"We have considered other important factors like the number of siblings, the family's education and whether the family owns any pets," Hesselmar explained.