There are a lot of beneficial organisms in soil that are probably uniquely suited to colonizing the gut biome of dogs. Here is a good article that has a survey of the studies and a downloadable spreadsheet of links to the studies and a summary of each...this gal did a really nice job laying this out!

In my experience, puppies will almost always eat dirt, and adults will occasionally eat dirt. I have no study regarding this, but I assume the reason puppies feel more compelled to eat dirt is that they are still colonizing their gut biome.

Eating soil is not as weird as it might seem...in lots of places around the world, clay is a normal part of human diets.

The jury is out on the advisability of soil-based probiotics (SBOs), at least for humans. The proponents of SBOs praise their ability to resist gut acid and re-colonize the gut. Opponents claim that SBOs represent a danger of overrunning the natural gut biome and becoming pathogenic.

I do find the claim that SBO resists stomach acid and therefor more effectively can colonize the gut very interesting, because the PH of a dog’s stomach can dip as low as battery acid during the digestion cycle. It’s possible (although not proven) that SBOs might resist this acidic environment and confer more probiotic benefits on dogs.

In my observation and experience, dirt-eating is an extremely common behavior in dogs, particularly young dogs, who are raised in enriching environments, have ample opportunity for social interaction, and do not display any other behavioral abnormalities. This suggests that dirt-eating is a beneficial adaptation and not a behavioral problem.

So SBOs might be a natural fit for dogs.

If I do see a dog or puppy eating dirt, they get dosed with a half-teaspoon of bentonite clay each day for a week. I have found that this stops the dirt eating almost immediately.

For a point of reference, our dogs weigh 55-75 pounds. For a smaller dog I would use much less and a larger dog might need more. Occasional use of small doses of nutritional clay has no reported side effects so you can play around with dosing until you feel comfortable with the results.

Again, this is not a “more is better” situation. Occasional small doses of nutritional clay can have great probiotic properties and provide important trace nutrients. But large doses of clay over time can bind up other necessary nutrients and cause health disorders. So, moderation is key.

Do your dogs eat dirt? If you try adding nutritional clay to their diet, let us know how it worked for you - did it stop the dirt eating?