Hot tea for colds, pills handkerchiefs and thermometer. (iStock)

“Don’t go outside with wet hair, you’ll catch a cold!” “Take vitamin C to ward off the sniffles.” “Stay inside during cold season.”

Chances are, you’ve heard these words of advice before, probably from your parents when you were little. Indeed, a survey published last week, shows that many parents have tried these strategies to keep their kids from getting sick — even though little evidence exists that they work.

The survey of more than 1,100 parents with children ages 5 to 12 found that about 70 percent of parents tried to prevent their little ones from catching a cold by employing folklore strategies. For example, about 52 percent told their children not to go outside with wet hair, and 48 percent thought it was beneficial to encourage their child to stay indoors during cold season.

But these strategies have not been shown to make a difference with catching a cold, said researchers from the University of Michigan’s C.S. Mott Children’s Hospital.

What’s more, 51 percent of surveyed parents reported giving their child a vitamin or supplement, such as vitamin C or zinc, to prevent colds. But these products have not been definitively shown to prevent colds.

The good news is that the vast majority of parents — 99 percent — also reported that they encouraged good personal hygiene in their kids to prevent colds. And this is a strategy that is backed by science.

For example, 99 percent of parents said they encouraged their children to wash their hands frequently, 94 percent said they told their children not to put their hands in their mouth or nose, and 94 percent said they encouraged their children not to share food or drink with other people.

“It’s important for parents to understand which cold prevention strategies are evidence-based,” Gary Freed, co-director of the poll and a pediatrician at Mott hospital, said in a statement. “While some methods are very effective in preventing children from catching the cold, others have not been shown to actually make any difference.”

The researchers noted that vitamins and supplements are not regulated the way that drugs are, and that they do not need to be shown to work to be sold.

“These are products that may be heavily advertised and commonly used but none have been independently shown to have any definitive effect on cold prevention,” Freed said.

Other folklore strategies, such as the idea of not going outside with wet hair, have probably been passed down from generation to generation without being confirmed by scientific studies.

The best strategy for cold prevention is for parents to focus on decreasing the spread of cold viruses through good hygiene, such as hand washing, and avoiding direct contact with sick people.

— Live Science