The Dirt on Playing With Dirt

Summer is all about long bike rides and lemonade stands, swimming until sunset and catching fireflies at dusk. It’s also a lot about dirt. Babies and kids just want to play in it, right? Take a breath. There’s no need to freak out. We chatted with Jack Gilbert, the director of the Microbiome Institute and co-author of “Dirt Is Good,” who says that a little dirt might actually be good for little ones. Here’s what else he has to say.


“We are told and indoctrinated that all bacteria are bad. I especially worried about washrooms, making sure that I picked the cleanest looking one, especially for my kids. I am definitely less worried about that after publishing a study on the restroom microbiome. There are approximately a trillion microbial species on the planet, and a tiny fraction of 1% are highly infectious. Of course, if you’re immune suppressed or have an open wound then many types of microbes will take advantage. But if you have all your vaccinations and live in a country with proper sanitation then nearly all germs you will find in your backyard or in your pet’s saliva, etc., are likely to cause you no harm. And they may be helpful for strengthening our immune system.”


“The microbiome is the ecosystem of bacteria, fungi, and viruses that live inside all of us. They are a critical part of our health as they shape our immune system, our hormones, even how our brains develop. If you’re predisposed to asthma there is evidence that exposure to animal microbes early in life (under nine months) can actually protect you from developing the disease. If you already have asthma or allergies, then we are working on solutions. Some include giving probiotics, which has been shown to have a positive benefit for cow’s milk allergy.”


“I was outside with the dog once and a family new to our area were walking by with their infant son. I walked up to say ‘hi’ and my dog was by my side and was sniffing at the child. The father immediately grabbed the kid up and said he was afraid that the dog would infect his son. So I carefully explained the science behind the fact that dogs were healthy for his child and that exposure would likely enhance his immune system. After around 20 mins of talking he let his son down and Beau licked his face!”


“If a child is playing in the dirt, let them. The only difference between your yard and the public park is the type of plants. Of course, if you suspect you live in an area with excessive pollution or other toxic problems, then be careful. Otherwise, just let them get on with it, and when you are ready to take them back you can wash their hands with soap and water (and their faces and everything else, if your kids are like mine!). I strongly advise against using sterilizing wipes.”


“Not over sterilizing your kids’ pacifier, food, and environment could help to increase their exposure. Also, get them outside more, let them play in the backyard or take them to a park and spend time in the woods. Even let them play with the dogs and cats. Just let them be kids!”

Whitney Harris

Whitney C. Harris is a freelance writer living in Westchester, NY, with her husband and toddler daughter. Find her online.