For the vast majority of human history (and prehistory), men, women, and children had near-constant contact with the natural world around them. They were walking on the ground. They were playing in the dirt. They were digging for roots and grubs. They were eating with their hands. They were field dressing animals and wiping their hands on the grass. Nothing was sterilized; the tools to sterilize the environment didn’t exist. You could boil water, but that was about it. Bacteria were everywhere, and humans were constantly ingesting it. Even as babies, preindustrial infants nursed for almost four years, so they were getting a steady source of breastmilk-based probiotic bacteria for a good portion of their early lives.
The Agricultural Age: Farms and Fermented Foods
After agriculture and animal husbandry hit the scene, human diets changed, but their environmental exposures didn’t so much. Every day they interacted closely with the soil and/or animals (and their respective bacteria). And they also continued ingesting probiotic bacteria on a regular basis through the use of fermented food—for at least the last 10,000 years. Honey into mead, grains into beer, fruit into wine, alcohol into vinegar.
We know that fermented dairy has been an integral part of any traditional dairy-eating culture because fermentation is the natural result of having milk around without refrigeration. You take raw milk and leave it out for a couple days at room temperature, and it will begin to separate and ferment. Introduce an animal stomach and you can make cheese. Introduce specific strains of bacteria, and you can make yogurt or kefir. But the point is that dairy fermentation—and, thus, the consumption of dairy-based probiotics—was unavoidable in pre-industrial dairy-eating societies.
In areas without (and some with) dairy consumption, they fermented plants. Kimchi , sauerkraut , pickles , chutneys, soy sauce, miso, and natto  are just several examples among hundreds .
Modern Diets, Modern Environments
Here’s my point to all this: probiotics in one form or another have been a constant input in the human experience… until today.
Today? We live sterilized lives.
- We wipe everything down with anti-microbial agents.
- We wash all our plates and eating utensils with ultra-hot water and powerful soaps.
- We wear shoes.
- We don’t touch (or see) dirt for days, weeks at a time.
- We stay indoors most of the day.
- We pasteurize our dairy. We render shelf-stable (and thus inert) our sauerkraut and pickles.
- We sterilize our water.
- We take antibiotics .
- We eat processed, refined food that’s been treated with preservatives and anti-microbial additives designed to remove all traces of bacteria.
- We employ tens of thousands of scientists, bureaucrats, and agents whose primary role is to ensure our food supply is as sterile as possible.
I get all that. There are good reasons for doing all these things, and on the balance I’d of course rather have clean water, clean food, and antibiotics than not, but there are also drawbacks and unintended consequences. We live in a sterile world, and our guts weren’t built for a sterile world. They’re meant to house a diverse array of bacteria.
What Are the Consequences Of Living a Sterile Life?
Hippocrates, the father of medicine, said that “all diseases originate in the gut.” The most obvious example, digestive issues, are some of the most common in the post-industrial world. Constipation, diarrhea, bloating, and general digestive distress affect tens of millions. Food intolerances and allergies, which also have a link to gut health, are rising.
At least since Biblical times (and probably earlier), humans have identified a connection between the gut and our emotions. “I’ve got a gut feeling…” or “I feel it in my gut.” Though it’s usually portrayed as “merely metaphor,” this connection isn’t spurious and can feel quite real. Remember when you held hands with that pretty girl or handsome guy for the first time? You felt those butterflies in your gut. Or how you had to rush to the bathroom before giving that big talk in front of your college class? You felt the nervousness and anxiety in your gut.
Evidence is accumulating  that our gut bacteria can manufacture and synthesize neurotransmitters like serotonin and GABA, and even sex hormones like testosterone . We’ve even identified a legitimate physiological pathway running from the gut to the brain and back again. Couple that with the fact that gut health seems to play a role  in depression, anxiety, and other related conditions, and it starts looking like our lack of exposure to probiotic bacteria could be triggering (or at least exacerbating) the rise in mental health issues.
Supporting Our Guts In the Age of Sterility
The foundation of gut health has to be diet : 1) Eating fermented foods to provide probiotic bacteria and 2) eating plant and animal foods that provide prebiotic substrate to feed and nourish those bacteria. That’s been the way of humans for tens of thousands of years—from ingesting soil-based and animal-based bacteria on the food we ate as foragers to directly producing and consuming fermented food—and it should remain the primary mode of probiotic  procurement.
But there’s also a place for probiotic supplementation. Food alone probably can’t atone for the sterile existence we’ve built for ourselves. Food alone can’t counteract the several years of breastfeeding you didn’t get, the dirt you didn’t play with, the antelope colons you didn’t handle with bare hands , the untreated water you didn’t drink. You may get it now, but what about ten years ago? What about when you were a kid?
Evolutionarily novel circumstances often require evolutionarily novel responses to restore balance.
And probiotics aren’t even that “novel.” We’re clearly designed to consume probiotics in the food we eat, and probiotic supplements  utilize the same ingestion pathway, especially if you consume them with food. The dosages may sound high. Primal Probiotics , the one I make (and take), contains 5 billion colony forming units (cfu, a measure of bacteria that are able to survive digestion and establish colonies in the gut) of good bacteria per dose—but that’s right in line with (or even well under) the dose of probiotics found in common fermented foods.
A single milliliter of kefir can have up to 10 billion cfu .
A cup of yogurt can contain up to 500 billion cfu .
A tablespoon of sauerkraut juice can contain 1.5 trillion cfu. Kimchi is probably quite similar.
A single gram of soil can contain almost 10 trillion cfu . A gram of soil is easy to consume if you’re eating foods (and drink water) directly from the earth.
Now, Primal Probiotics isn’t the only option. It may not even be the best option if you have specific conditions that other strains are particularly adept at addressing. (I’ll cover this in a future post.) But the way I designed Primal Probiotics was to be a good general, all-purpose probiotic with particular applications for Primal, keto, and other ancestrally-minded people living their modern lives.
For instance, one of my favorite strains I’ve included is Bacillus subtilis, the very same bacterial strain that’s found in natto, the traditional Japanese fermented soybean. B. subtilis addresses many of the issues we face in the modern world. It helps break down phytase in the gut and turn it into inositol, an important nutrient for brain and mood and stress . It helps convert vitamin K1 (from plants) into vitamin K2  (the more potent animal form of the vitamin). It can even hydrolyze wheat  and dairy proteins  to make them less allergenic.
There’s also Bacillus clausii, an integral modulator of the innate immune system  (PDF )—the part of the immune system that fights off pathogens, toxins, and other invading offenders. Innate immunity is ancient immunity; it’s the same system employed by lower organisms like animals, plants, fungi, and bacteria. It’s the foundation of what we know as the immune response. What’s funny is that B. clausii has such a powerful effect on our innate immunity that one could argue B. clausii is an innate aspect of our gut community.
I’ve also included a small amount of prebiotic substrates in the latest iteration. I use raw potato starch (for resistant starch) and a blend of fructooligosaccharides and galactooligosaccharides. The prebiotic  doses are low enough that they shouldn’t exacerbate any gut problems or FODMAPs  intolerances and high enough to provide enough food for the probiotics to flourish.
Again, you don’t have to take Primal Probiotics . It’s my opinion that they provide the perfect combination of strains for most people’s needs, especially when combined with regular intakes of fermented veggies like sauerkraut and fermented dairy like yogurt , cheese , and kefir , but the actual strains themselves aren’t proprietary. You can find them elsewhere if you want to get individual probiotics. Hell, you may not even need a probiotic supplement. Depending on your personal health background, the level of sterility in your life history and current life (if you grew up on a farm drinking raw milk , for example), and the amount of fermented foods  you currently consume, you may not need supplemental assistance.
But it’s sure nice to have around.
Anyway, that’s it for today.
How do you get your probiotics? Do you find them necessary for optimum health? What kind of benefits have you experienced from taking probiotics, either via food or supplementation?
Thanks for reading, everyone. Take care.