Soil Based Probiotics: Are They Safe?

I admit it. We are a real food diet family but we do not eat fermented foods on a daily basis. I love my raw sauerkraut, kefir and yogurt, but I CANNOT convince my husband to eat them. My kids will drink kefir on occasion, but it’s just that—on occasion. Get them to eat grassfed butter smothered on everything? You bet. Pasture raised bacon every week? Yes please. Fermented ANYTHING? No chance.

Fermented foods are powerhouses of minerals, enzymes and most especially, those healthy gut bugs: probiotics. While I prefer that we get our essential vitamins and minerals from real food versus supplements, sometimes supplements are needed and probiotics are one of those for us.

The benefits of maintaining healthy gut flora are just too great to ignore, so I’m always on the hunt for the best of the best when it comes to our probiotic supplement.

I recently discovered a new brand of probiotics which contains soil based organisms (SBOs). What in the world are these? was honestly my first thought. But then I wondered, Why haven’t I heard of them before? Am I missing something? So started my search into soil based probiotics to discover what they truly are and most importantly, are they safe?

What are soil based probiotics?

Soil based probiotics contain one or more strains of SBOs--bacteria resident to soil. They play a vital role in nature working to maintain healthy soil for plant life to survive.

Though home is soil, SBOs are no strangers to our bodies. From the moment man first picked a plant from the ground and ate it, he ingested dirt and SBOs along with it. Only since the emergence of modern farming practices has our exposure to SBOs via food decreased.

When was the last time you picked a plant directly from the ground and ate it? Chances are your last salad was made from greens that were not once, not twice, but triple washed before being packaged in that nice, neat plastic pack you bought at the grocery store.

Use of herbicides, pesticides and other chemicals have removed harmful bacteria from our food along with these potentially beneficial SBOs. Harsh chemicals have also changed soil quality and composition impacting SBOs. Not to mention our over-reliance on antibacterial soap and hand sanitizer, it’s no wonder our exposure to SBOs is so limited today. Soil based probiotics are trying to change that.

Most soil based probiotic brands contain strains from the Bascillus genus with B. subtilis the most common strain.

What makes soil based probiotics different?

Most probiotic supplements on the market today contain strains of lactic-acid producing bacteria of the Lactobacillus and Bifidobacterium genera. Unlike these lactic-acid producers, SBOs are spore forming bacteria. This spore forming characteristic enables these bacteria to essentially “hibernate” in extreme environmental conditions when nutrients are scarce then germinate once again when food becomes available.

Their hardy nature gives spore-forming SBOs two major advantages over lactic-acid bacteria:

1. SBOs are heat-stable so do not require refrigeration and therefore have a long shelf life.

When I spend money on a probiotic, I want to get what I pay for. Yet one independent test conducted in 2013 showed that 5 of 19 probiotic brands contained only 16% to 56% of the listed amounts of organisms. (source) SBOs are durable so they are not destroyed in the manufacturing process or after packaging.

2. SBOs can survive the acidic environment of the stomach.

The full dose of SBOs ingested will reach your intestines. Score! I also want a probiotic to do its job—populate my gut with healthy bacteria. That doesn’t work if the probiotics are destroyed in my stomach before even making it to my intestines.

These advantages and their ability to stimulate the immune system and kill harmful bacteria make them advantageous to include in probiotic supplements. (source)

What does the research say? Are they safe?

Although one strain of SBOs (B. clausii) has been used as a probiotic supplement in Italy for over 50 years (Enterogermina®), research on their use and effectiveness for humans is limited.

They have been found however to positively impact the following health conditions:

  • Infantile diarrhea

  • Recurrent respiratory infections in allergic children

  • Urinary track infections

  • Side effects from H. pylori treatment (source)

  • Irritable bowel syndrome (source)

  Studies on their safety in humans are even more scarce as most studies looking at their safety have been conducted on animals. (source)

6 Safety concerns of SBOs in probiotics

#1 - Can SBOs cross the gastrointestinal tract lining?

One study with mice showed that it may be possible for SBOs to cross our gut lining into other tissue and organs and proliferate there. (source) We don’t want SOBs going rouge in the body but the fact that they can interact with the gastrointestinal lining demonstrates that they can stimulate the immune system.

#2 - Can SBOs cause infection?

Not all SBOs are safe. Some strains can produce diarrhea, gastroenteritis and food-borne illnesses with vomiting.

#3 - Can SBOs transfer antibiotic resistance?

Some species of SBOs are considered “antibiotic-resistant” so there is concern that they could transfer their drug resistant genes. Yet, this is a quality that defenders like about SBOs because they can effectively kill the bad guys.

#4 - Are SBOs toxic?

Each SBO strain behaves differently so there is concern that certain species have the ability to invade, adhere to the body and produce toxic effects. Some opponents also fear that because SBO species are so hardy, it would be very difficult to kill them off, especially if they were to become pathogenic.

Research has shown however that although SBOs can temporarily make our guts home, they do not permanently colonize it.

#5 - Should SBOs be ingested at such high concentrations in supplements?

Humans have inadvertently ingested SBOs via the food supply, but the question still remains whether it is safe to ingest them in concentrated doses.

#6 - Are soil based probiotics labeled correctly?

Because of the lack of regulations, many soil based probiotics have been found to be mislabeled. Given that strain specificity is so important in how SBOs act in the body, correct labeling is vital. (source)

Clearly these concerns suggest that more research is needed in the probiotic field in general and on soil based probiotics specifically.

Should I make the switch?

Am I ready to make the switch to soil based probiotics? Not yet.

Research into these amazing microbes has just scratched the surface, and though SBOs may look promising, I’m going to take the wait and see approach. The concerns raised give me pause, but these appear to be strain specific with several SBO strains showing promise with gastrointestinal disorders. Since no one in my family is suffering from IBS or the like, we’ll stick to what’s working for us.

In the meantime I think I will step up my plans to finally start that vegetable garden I keep talking about. Here’s to getting my hands, and possibly my gut, dirty!

Have you made the switch to a soil based probiotic? Share your experience in the comments below.