Dirt can be good for kids, some say

Three-year-old Jack Kern loves playing in his bare feet. His mother Dana believes exposing him to germs will boost his immune system. "I don't think there is any harm in that and it’s fun to watch," she offered. 

Thomas Whitten also allows his four kids to play in the dirt. "Yeah they still make mud pies and build dirt castles and come in covered head to toe!" 

Jack Gilbert, author of the new book ‘Dirt is Good,’ and a microbial ecologist, believes both parents are right.  

"What we see is when we expose children who are susceptible to developing asthma to a rich and diverse microbial flora, for example the one you'd find on a farm or with pets in the home, it actually reduces their likelihood of developing asthma," he explained.

It is all part of the hygiene hypothesis, which says because our environments are too clean, white blood cells -- that patrol our bloodstream looking for germs -- grow old. This causes them to overreact to things that aren't a threat. 

"If they are in circulation for too long, they get sticky and they become very inflammatory. So when they finally see something like a piece of pollen or a piece of dog dander, they go crazy, which cause hives and itching," continued Gilbert.

He believes toiling in the soil may actually help our mood. Scientists have uncovered bacteria in soil, which can reduce depression and make you less anxious. 

"People who garden, especially their children, if they are digging up plants or planting new ones, it can actually help them to feel more calm," he said.

But before playing in soil, Gilbert warned, you'll want to make sure your child is vaccinated. Soil is where you might find the bacteria that causes tetanus. "As long as your child is vaccinated, as long as you have a healthy immune system response to the world, then exposure to more microbes can be beneficial."

Gilbert says there is evidence that people in China would take boxes of soil from their hometown when they traveled. If they felt homesick or developed diarrhea, they would take some of the dirt and mix it up in a tea and drink it. Of course, that is not something he recommends.

Also, remember dirt can contain contaminates like lead paint or chemicals. You do have to be cautious where your kids play.