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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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August 12 2014

How to Safely Expose Your Kids to Dirt

By Mark Sisson
51 Comments

Mud GirlIf you’ve been reading this blog for any reasonable stretch of time, you know that I’m a big proponent of getting dirty. By overvaluing sterility and fearing dirt – in our homes, our guts, even our hospitals – we’ve impaired our immune systems, our gut and digestive health, and even our mental health. The world is a dirty place, and we need to accept that. We need to embrace it, within reason, especially if we’re wards of tiny still-developing humans for whom exposure to dirt has important and resounding benefits. You’ve got the benefits to current and future immune function that I’ve gone over in the past. Then you’ve got soil-based microbes like Mycobacterium vaccae, which increase serotonin levels and may be responsible for the positive disposition that seems to be universal among hobby gardeners. It’s probably why kids have a natural inclination to engage with the ground, get handsy with the soil and make out with mother nature. I say we let them.

But we have to do it right. There’s good dirt and there’s bad dirt. And sometimes the good dirt can be contaminated with bad stuff. We must then promote reasonably safe exposure to dirt. How so?

Let them play in the dirt. Don’t lose your mind if they eat a teaspoon or two (you don’t have to provide actual teaspoons). Encourage mud puddles, or “muddles,” to facilitate greater surface coverage. Actually, encouragement is unnecessary, as kids naturally gravitate toward mud and dirt.

Avoid triclosan handsoaps. Triclosan is an anti-bacterial agent, an antibiotic. It kills some bacteria but promotes antibiotic resistance in those who survive. And don’t forget that we have commensal/beneficial bacteria on our skin that help keep out the pathogens. If triclosan clears a path through those guys, the pathogens can gain a foothold. Plain soap and water are all you need.

Avoid excessive handwashing. If you live in a place like Karachi, Pakistan, where open sewers run through slumsfastidious handwashing can improve child well-being and overall health. I’m not so sure the obsession with handwashing in the relatively pristine environments of more industrialized nations is warranted, and I suspect it’s counterproductive. A little dirt under the fingernails rarely hurt anyone.

Test your soil for contaminants. Soil can harbor heavy metals like lead, arsenic, and Viking death metal (sorry, terrible subgenre joke that my employees insisted I include). I wish I could make broad pronouncements about soil in general, but I cannot; heavy metal content varies widely from country to country, state to state, town to town, and even backyard to backyard. Older houses may be more likely to have lead due to deteriorating lead paint. Do a search for “soil heavy metals [your town]” to find information about your specific area. Another option is to actually test your soil for heavy metal contamination; this is a good guide for taking soil samples.

Pick up dog, cat, and wild animal poop regularly. “Poop is everywhere” is one of those factoids that people love telling to other people. But microscopic amounts of fecal matter are one thing. Full-on turds are another. Also, wild animals like raccoons (who whether you see them or not are probably near you) almost uniformly carry a deadly parasite that can trigger dangerous inflammation in children. In case you haven’t gotten on board yet, feeding a raw prey-model Primal pet diet to your cats and/or dogs has the benefit of making the poop easier to clean up.

Weed using non-toxic approaches, like your hands, boiling water, or vinegar. In previous posts, I’ve discussed the downsides of weed control using Roundup, the glyphosate-based herbicide that inhibits the shikimate pathway in both plants and bacteria (but not mammals). Since we mammals rely on bacteria in our guts to maintain and promote good health, however, Roundup hits us indirectly. The whole idea of dirt exposure in kids is to “seed” them with beneficial bacteria, so spiking their dirt with a bunch of bacteria-killing Roundup with a half-life in soil of nearly 100 days (PDF) is counterproductive. A little elbow grease, a big pot of boiling water (maybe two big pots; watch for errant kids), and/or some white vinegar directly applied to the weeds will take care of them without putting your kids in harm’s way.

Favor “pesticide-free” parks. Public parks are a great place for kids to play, run around, get dirty, meet each other, and generally act like kids. But if they’re going to be playing with, in, and around the dirt – and they will be – focus on parks whose grounds aren’t doused daily in pesticides. Eugene, Oregon has a “pesticide-free parks” program, and I imagine other places do, too. Look around for similar lists in your area. Barring that, contact your city officials and make a list yourself.

Sampling is normal, but gorging is suspicious. If a kid is chowing down on dirt, really savoring the soil, and displacing actual food, something’s up. You might need to take a closer look at his diet and look for egregious nutrient deficiencies. Some candidates:

  • Calcium: Calcium deficiency may be linked to pica/geophagy, so unless your kid is willing to eat loads of spinach, consider adding in some high quality pastured dairy (yogurt, cheese, whole milk; try alternate animals, too, like goat or sheep) for some really easy calcium.
  • Iron: Iron deficiency or depletion has also been linked to pica. Rather than resort to a supplement (which can be constipating and poorly absorbed), introduce liver to your kid. This is the perfect time, in fact, because little kids’ palates haven’t been corrupted by gentile society. I mean, the kid’s eating dirt. I’m quite certain he’ll give pastured chicken (the type highest in iron) liver a chance. Daily egg yolks are also a good, palatable, easy to disguise option for iron, not to mention all the other important nutrients they provide.
  • Zinc: Zinc deficiency is also linked to pica. Oysters are probably the densest source of zinc, but red meat, cashews, and pumpkin seeds are also good sources. If you trust the oyster purveyor, there’s nothing like a toddler slurping down a raw one.

Get a furry pet. Cats and dogs have different effects. While I like cats (even though they’d kill us all if they weighed as much as a yellow lab), dogs seem to be more beneficial to overall immune development in children. In one study, cat exposure in early childhood had no effect on atopic dermatitis, but dog exposure was protective. In another, early dog exposure led to big improvements in general resistance to colds; cat exposure was also protective, but less so. However, a 2008 study found that cat exposure was protective against asthma while dog exposure was not. What do we make of it? If I had to guess, I’d say having both a cat and a dog would be most protective against the broadest range of immune disorders.

Be careful about cat litter, especially if you allow your cats outdoors. Outdoor cats who hunt rats may carry the Toxoplasma gondii parasite, which your kid (or you) can pick up when handling cat litter. T gondii has been linked to depression and suicide. (And if your kid happens to be a rat, the parasite will abolish all fear of cats, make cat pee irresistible, and probably lead to his or her gory death.) Even if your cat doesn’t have the parasite, cat litter isn’t going to impart many beneficial microbes and as such should be summarily avoided. You’re not missing out on anything by not sprinkling crumbled cat poop in your smoothie.

Go on lots of hikes, go camping, and play in creeks, streams, and rivers. The backyard is great (and is a great way to introduce tent camping, in fact). It’s handy, it’s right back there, and it’s safe. But it’s not enough. There’s an entire world of dirt that’s just begging to be traversed on all fours. For optimal dirt exposure, take your kid out to the great outdoors. Go on hikes. Pause to look for anthills and interesting fungi. Tramp through creeks. Pause to look for crawdads and tadpoles. Visit deserts, redwood forests, swamps, rainforests. Wherever you are, you don’t even have to make sure your kids “get sufficient dirt.” They’ll find each other.

As you can see, most of the advice is common sense. It’s mostly “let your kid do what kids will” and “but be reasonable about it.” Soil smoothies and cat poop snacks, bad. Mud mustache and a little dirt under the fingernails, probably okay.

That’s all I’ve got today, folks. I hope it was helpful to all you parents out there. Even if you’re not a parent or kid, this stuff works on adults, too. So get to it!

TAGS:  immune health

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51 thoughts on “How to Safely Expose Your Kids to Dirt”

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  1. At 60 I still enjoy a good mud puddle, best when sharing with my grandkids!

  2. Oh this is something I completely agree with- lots of people nowadays seem to forget that you have to build up an immune system for it to be any good. Even though I’ve always been a bit of a “girlie-girl” I spent nearly every day in the dirt/mud/grass growing up playing sports- it’s just natural especially for kids.

    1. Yeah. “Safely exposing” kids to dirt seems like a sneaky bit of dry humor to me. I was never able to keep my kids OUT of the dirt, mud, and dog sh*t. I guess it runs in the family. I use to eat dirt all the time as a child, sometimes even with a spoon. It always smelled so good to me right after a rain. It still does, but my palate is a little more refined these days.

  3. Such a great post today Mark! Excellent work. I’ve always fully believed that my regular contact with mud and running around in the woodland getting green and brown had a lot to do with my exceptional immune system these days!

  4. Awesome! I love the variety of ancestral health posts you can get here. No kids so far here, but I think this is great info for adults too. We could all benefit from getting out in the dirt a bit more.

  5. I’m struggling to fit “play in certified soil” into my child’s schedule. Either voice training, hockey practice, violin, chess club, debate club, or mentoring skills for kids has to go.

      1. That article was excellent!! How refreshing in our “keeping up with the Jones’s world.” Thanks for sharing!

  6. I’d be curious about the positive effects of having pets vs. the risk of developing pet allergies. Quite a few of us who grew up with dogs and cats developed allergies to those very animals, for me this includes allergy-induced asthma whenever I’m in the same room as a dog. Which is a bummer, because I love dogs. Does anyone know of any data or studies in this regard? Does childhood pet exposure have any effect on pet allergies, on average?

  7. Worth noting – Dr. Ruscio made a great point at AHS last weekend that research shows anything before the age of three can help colonization of bacteria in the gut and anything after can be detrimental.

  8. Helicoptor parents…a bane to society. Go outside and play in the dirt for cryin’ out loud.

    1. Dirt can never be safe, in my local park dog poo is spread around the grass, don’t want my kids with e.coli

    2. Can we talk Lyme disease? It and other tick-borne infections are no joke and can devastate the health of active families–and their dogs.

      If anyone in your family is living a great, outdoorsy Primal life but can’t quite get their energy up, has trouble focusing in school, or feels achy and tired–consider Lyme. And treat your dogs with anti-tick medication. Ticks as small as a poppyseed can transmit all sorts of diseases.

      I used to love camping and running in the woods with my dogs. I got Lyme and it sucks.

      1. There have been several articles recently about the Lone Star Tick causing a meat allergy in some people. People become allergic to non-primate mammalian meat. Researchers are unsure if the effect wears off or not, but the problem is on the rise, and showing up in places where the Lone Star Tick should not be. I’ve become much more vigilant about applying bug repellant when I am out in areas where ticks may be. So, far, it seems that you need not coat yourself in the stuff; I usually just apply it to my hair and clothing, shoes/feet, and maybe lower arms. That keep the mosquitoes away, and I assume it works as well for ticks.

  9. I love dirt, not under my nails but for kids yes!
    I was the one who taught my son to stomp the puddles in his boots, play in the fine dry dirt with is trucks, sand at the beach, etc. He’s hardly ever sick. I just wish we could add a dog to his life, not yet we keep telling him. Cats are somewhat more user friendly to busy people, they like their alone time so we can go off to work without driving them crazy like may happen with a dog. He’s also required to be barefoot as much as possible.
    We spent the weekend at the lake, he has pitch spots on his feet now. For anyone who doesn’t know how to rid yourself of pitch…. rub some butter into the spot and then wipe it off. That’s the only way I could get that off the shower floor when we lived there.

  10. I always take it as a cue that we’ve been indoors too long if I find my toddler covered head to toe in green marker instead of dirt.

  11. We are just getting underway creating our back garden area and this is just giving me more desire to do it. I fully plan on letting my girls help me with the gardening (as I think they will gain a better understanding of what fruit and vegetables really are and be more excited about eating them), but this is even more of a reason. Hikes and things are great, but there’s just something about growing food. Good times. Liked this one.

  12. Thanks for all the information, Mark. Might start letting the dogs in to play with the kiddos more often. Can’t wait for them to get a little older so they can help in the veggie garden!

  13. Good to see this! I would like to add that, while antibiotic meds do get out into the environment, they are made to break down in a water-based system (like, in your body). Antibacterial soaps, however, are manufactured to RETAIN THEIR BACTERIA-KILLING PROPERTIES IN WATER. This means that they get into the ground water and kill soils, and/or help to further create antibiotic-resistant bacteria like MRSA. So, don’t buy or use antibacterial soaps! Ordinary soap works just fine, without trashing your environment, and endangering your children’s futures.
    Mark, I would love to hand off some links to journal literature on this theme, but you can find them easily enough.

  14. I eat a tablespoon of dirt every morning. Ok ok, I don’t, but I WAS brought up to play in dirt and I’m just fine. As a whole, our society has definitely become more of a germaphobe society.

  15. I live in sunny Texas and recently found out about raccoon roundworm while researching whether or not squirrels can get rabies when I saw one acting very weird in my back yard. They can’t, but they scavenge raccoon poop for seeds, and get the roundworm, with deadly effects. I certainly have raccoons in my back yard, but I am much more careful with any scat I happen to see than I was before.

  16. I for one can say when I was a kid, I played dirty..and hard!

    I can’t imagine what the future holds for us if we continue the ways of today’s thinking of cleanliness. We can’t be perfect, and the same goes with getting dirty. Just like the flu shots, we need to get a taste of the outdoors if we’re going to keep our bodies fully prepared and strong for whatever!

    Great article Mark, a must read for those who live in a bubble 🙂

  17. My daughters were born in China; the oldest came to the US when she was 8.5 months old and the youngest when she was 2.5 y.o. I credit their early exposure to dirt for their wonderful immune systems. Of course, playing at Grammy’s farm and with their dog doesn’t hurt either. There are so many food and environmental allergies in the US and almost none in China and one has to wonder about the connection between ultra-clean environments and allergies. And no anti-bacterial soaps either! I like to say that my kids lived in squalor as infants–why should I worry about a little dirt!

  18. My daughter had an obsession at age one with eating the poop of our free range chickens. Me: “Noooooooo!!!!”, running to pick her up away from the enticing little piles. She ate a few before figuring out they were off limits as a food source, and seems to have survived just fine.

  19. Taxoplasmosis is very common. It is rarely diagnosed as the conventional American medical community rarely thinks of parasites as the cause of illness as if these pathogens no longer exist in the developed world. If one knows any horny cat ladies, chances are they are infected with TG. Hookworm infestation is one of the primary causes of intestinal blockage. However your GI specialist is trained to, and gets paid to cut and resect, not to kill off the hookworm with the herbal remedies like wormwood and black walnut hulls. Humans have been infected with parasites used natural cures for centuries. Grok did not have a microscope nor a laboratory. He did have parasites. Grok also had plants, fungi, mineral deposits and plenty of time to figure out what works. If he intentionally ate dirt is because it smelled like the dirt the elders ate for whatever purpose they ate it. We have the modern privilege of knowing good pathogens from bad pathogens. I prefer to culture my “dirt” with known pathogens. Raw milk is great but many people from my grandparents generation died from M. tuberculosis from raw milk extracted with the less than sanitary practices used today.

    Perhaps Mark could do a post or two on herbal remedies that Grok and his pre Pasteur descendants may have benefitted from. It’s also nice to know that modern science is still finding good from bad bugs

    http://www.sciencelearn.org.nz/Contexts/Fighting-Infection/Sci-Media/Video/Hookworm-the-immune-system-and-asthma

  20. my brothers and I were always running the creeks, wallowing in mud, running through dirty puddles, etc. We got dirty. Boy did we get dirty. I never get sick. My man get colds and sinus infections a few times a year. I will subject myself to his colds on purpose just to see what happens. Nothing. My immune system is strong. My auto-immune system is another matter entirely!!

  21. My mother-in-law always warned me that “gentile society” is corrupting…

  22. Oh the millions of mud-pies I made as a child! It led to the baking obsession that was my glutenous undoing. I should have stuck with the mud version! 😀

  23. Interesting points all around although in some cases the contents of the dirt may be more harmful than beneficial so it’s a tough issue for parents. 1st world problems I guess

  24. We have a mid pit in our back garden. My boys absolutely love it. We often find the little one standing in a hole that the older one has dug and filled with water. My brother came round the other day with his two girls and was disgusted, needless to say both my nieces get regular colds and infections where my oldest son has had 1 sick day off school in 4 years.

    Let’s get dirty!!!

  25. I played in the mud quite a bit as a kid…and got ringworm enough times to prove it!

  26. My kids (13 and 2) eat viggies right out of the garden. Completely chemical free of course, and only use compost for nutrients. Just wipe the dirt and grass off that cucumber with your pant leg and chomp away. ( Ok, I wash root veggies under water for the most part)

  27. This is a great reminder and great tips! My husband needs to read this as he’s less than thrilled with the kids getting dirty. Around my area you just don’t see kids playing in the dirt outside much and it’s all about organized activities that are mostly inside. I know we have to be better about getting them out in nature.

  28. “Pick up dog, cat, and wild animal poop regularly.”

    Did anyone else initially read that as “[Your kid should] pick up…poop regularly”? No? Just me?

    I was really wondering where that was heading…but after a confused 30 seconds I figured it out…

    1. Well, your kid SHOULD pick the poo up, it’s their pet right? Just use those little bags instead of bare hands.
      😛

  29. How timely!
    This is the conversation I overheard today…
    9yo son: Dad, when are the sprinklers scheduled to come on?
    Husband: What do you need to know that for?
    Son: I need to know when I can get my mud!

  30. If daily dirt level all over arms, legs, feet, face, clothes is any indication of health level, then my boys are in the 100th percentile. Every.single.day. they look like they’ve been rolling in the dirt. They probably have been.

  31. The bit about the raccoon round worm is a bit scary, especially considering a momma raccoon has been coming into my garage at night and eating my outdoor cats’ food. Fortunately, my youngest child just turned 12, so our overall risk factors are fairly small. Still, I think handwashing after working in the yard is a good idea.

  32. A short piece of info that relates here: Wife has a viral infection in the sole of her foot. Much Dr. intervention (surgery, etc.) with minimal success over the last two years. This summer she shuns socks / hose and walks barefoot in the yard where we keep our home flock of hens. The disease is going away. Markedly so. We don’t know why. It may be related to the environment in which she walks. Just sharin’ some interesting stuff.

  33. I have such a hard time with this idea. It certainly seems like a good one, and I’m trying not to be over protective with my youngest child. The problem is that my oldest had a Mycobacterium infection when she was two years old that damaged her lymph nodes, resulted in multiple surgeries, and left a scars on her face. I know in my head it was an unusual infection but it’s hard for me to not want to keep my kids “clean” as a result!

  34. Thumbs up for the Viking Death Metal! I wish the soil at my place had more of this… 🙂

  35. Very nice read =) I agree on a lot of points. Parents must allow their children to get their hands dirty on healthy soil. This not only boosts their immune system but also enhances their cognitive skills making them smarter.