Meet Mark

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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February 07, 2009

The Dirt on Dirt

By Worker Bee
36 Comments

The prevailing opinion at MDA is that listening to one’s body is good policy. Natural instinct has been kind to us over the years – just as long as we listen to it. Oh, sure, some instinctual behaviors have little relevance nowadays and should be ignored (like our tendency to tribalize and shun newcomers for protection – made sense when we were living off the land in small inclusive clans competing for resources, but today it just causes war, racism, and nationalism), but most instincts are hard-wired into us for a reason. Consider salivation, which tells us delicious, wholesome food is to be had (I know I’m not the only one with an utterly Primal tendency to drool at the prospect of a rare steak), or our sense of fairness, which makes for a more harmonious environment (good for survival and for everyone involved). We like to stress the importance of listening to your body’s natural inclinations.

By definition, pretty much any instinctual behavior confers evolutionary advantages (otherwise it wouldn’t have been kept around for so long) – this is the basis of the Primal Blueprint, with our focus on living in accordance with our Primal ancestors (whose actions, behaviors, and diets were highly instinct-driven).

A series of recent studies examined a young child’s tendency to eat dirt, lick stuff on the ground, and put whatever he can find in his mouth. Is there some evolutionary benefit to be conferred from eating dirt? We have a rather unhealthy (or is it?) obsession with dirt, so we were interested to read the results.

Dirt vindicated, once again! Mud pies, it seems, aren’t just a tasty way for a fledgling baker to get his start in life. The ingestion of dirt introduces a number of bacteria and viruses that actually spur the development of our immune systems. And certain worms have been shown to redirect messed up immune systems that would normally result in autoimmune disorders, asthma, and allergies.

When he puts random things in his mouth, a child is letting his “immune system… explore his environment,” writes immunologist Mary Ruebush. That kid with a dirty mouth isn’t increasing his chances of getting sick; he’s actually giving his immune system “practice” figuring out what’s benign and what’s dangerous.

As we’ve discussed before, over-sterilization of our environments can actually be counterproductive. Scientists suspect that even as the increasing sanitization of developed countries has eliminated some health concerns – contaminated food and drinking water, for example – it has also introduced a whole host of other issues, including rising levels of multiple sclerosis, Type 1 diabetes, inflammatory bowel disease, asthma, and allergies – all potentially stemming from a reduced, or eliminated, exposure to bacteria early on. We’ve gotten “cleaner,” but in doing so we’ve eliminated both good and bad dirt. We’ve also strengthened the bad stuff. All those antibacterial products – Purell and the ubiquitous variants you see in purses, attached to kids’ wrists, in “fun size” – might actually be creating antibiotic-resistant strains of dangerous bacteria. Remember, evolution works both ways (and much more rapidly in bacteria).

That’s not to say we shouldn’t wash up. We should, especially if we’ve been touching dirty diapers, handling raw meat, or using the toilet. Just don’t go overboard with it. Basic soap and water are good enough.

And of course, it goes without saying that kids should have access to plenty of dirt growing up – if not for their immune systems, then for the fact that playing in the dirt is an awesome part of childhood that no kid should be without. It’s in line with the Primal spirit of play, too.

Oh, and you might want to ease up on the strict “wash your hands before dinner” rules – we might be doing more harm than good.

beccaplusmolly Flickr Photo (CC)

Further Reading:

Should I Get a Flu Shot?

8 Ways to Reduce Your Chemical Load

The Dope on Energy Drinks

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12 Comments on "The Dirt on Dirt"

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new_me
new_me
8 years 2 months ago

I love the caption under the picture! I think I’m going to use that in my scrapbooking, I have the perfect picture for it.

Ryan Denner
8 years 2 months ago

I couldn’t agree more about society going overboard on “cleanliness”, and thus, making our immune systems weaker!

Hell, I survived 3 years in a fraternity house with 35+ dudes. If people can do that, then they can live through just about anything 🙂

Tom Parker - Free Fitness Tips
8 years 2 months ago

Haha good point Ryan. I shared my University house with 11 other guys and I think some new organisms started growing in our kitchen it got that bad.

fasching
fasching
8 years 2 months ago

Problem is that the dirt that is present in most urbanized areas isn’t the kind of dirt we used to ingest. The chemical and bacteriological load is likely to be quite different – and not different in our favor, sadly.

Todd
8 years 2 months ago

Overprescription of anti-biotics, not ethanol-based hand sanitizers, are causing the evolution of superbugs. Just sayin.

aisha
aisha
8 years 13 days ago

what in the hell is dirt lick?

Mert
Mert
7 years 1 month ago
Dear Mark, As a person making his PhD on children’s soil eating and object mouthing behaviour, I must say ingesting little amounts of even natural, uncontaminated soil may be HIGHLY dangerous, because the natural levels of metals in soil can have toxic effects. This is especially valid for children ingesting soil. We are already exposed to heavy metals via food, air and water (called background exposure) and no matter how clean we eat, drink or live, we cannot prevent it. Additional exposure to heavy metals through soil ingestion, environmental pollution or any other reason adds to the present risk levels.… Read more »
Matt Forrester
Matt Forrester
7 years 1 month ago

Leave it to someone getting his PhD to ruin eating dirt. Darn you Smart PEOPLE!!!

Mert
Mert
7 years 1 month ago

What do you mean? Have you read my post with an intention to learn something new, or what? I’m trying to contribute.

I’d rather prefer to hear what do you think about the arguments stated, and I’d better like to know yours, as well as other people’s.

Adam Long
Adam Long
5 years 1 month ago

I think he meant: you make a really good point… damn you for ruining what could have been playful and fun (it’s all. your. fault.)

Can you link a few sources on the nutrient/contaminant/bacterial profile of dirt for us? Where is the Arsenic coming from, apple juice spills on playgrounds (sort of kidding… stupid juicy-juice)?

Kes
Kes
4 years 11 months ago
Absolutely, there are contaminated in dirt. Granite rocks are responsible for leaching uranium for example (if I am remembering correctly, I’m in chemically induced menopause for breast cancer). There are also a lot of contaminates in the air, in our household chemicals, our vinyl shower curtains, in food from California organically grown but dusted from fallout from rocket testing, etc.. Consider the source of your dirt. We have a garden and a greenhouse and have built up our own soil, it’s about as safe as we can make it and I my kids eat a dirty carrot or two, so… Read more »
Lauren
Lauren
3 years 7 months ago

I’m more concerned with washing my hands after handling tons of stuff at a store (because of dirty people) than I am with dirt or raw meat. I don’t even think I wash my hands – just rinse of debris – after handling meat or touching stuff outside.

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