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Breaking Down Probiotics: Which One is Right For You?

Probiotics have become increasingly popular in recent years. With the increased interest in gut health, a lot of attention is being given to probiotic supplements.

While I am thrilled the gut microbiome is getting the recognition it deserves, the decision to take a probiotic is not something to take lightly.

Probiotics are powerful, and probiotic supplements create powerful shifts in your microbiome. These living organisms don’t just impact gut function, they also impact whole body health. It’s important to make sure you take the right probiotic supplement to get the results you’re after, but with so many probiotic supplements on the shelves, choosing one can be confusing.

In this blog, I’ll explain the different types of probiotics, their effects and benefits, as well as how they can be used to address specific health issues and symptoms.

Additionally I’ll explain how to read a probiotic label, and what you should consider when shopping for a probiotic.


  1. Lactobacillus

  2. Bifidobacterium

  3. Soil based probiotics

  4. Spore forming bacteria

HONORABLE MENTION: Saccharomyces boulardii

Both lactobacillus and bifidobacterium produce lactic acid by eating lactose, sugar and carbs. This feature ha earned them the nickname of LAB bacteria for short (lactic acid bacteria). Some foods like yogurt, milk and cod liver oil can naturally be fermented with these strains.

LAB also nourish the gut lining, stimulate the immune system, and can be helpful in inhibiting Candida. They also help promote regular bowel movements, produce antimicrobials which can ward off pathogenic bacteria, aid in the body’s ability to absorb minerals and nutrients, support healthy levels of stomach acid, and encourage enzyme production.

These bacteria are known as “transient” bacteria which means that they move through the digestive system when consumed and do not colonize (make a home) in the gut. Most of them just can’t survive the harsh conditions of the gut. However they still have a positive impact as they pass through.

Soil based probiotics, also known as SBOS are bacteria that are found in the soil. Ideally, these bacteria should be naturally present on our food, helping us to digest what we eat, however, because of the decline in soil quality, and the abundance of pesticides and chemicals, many of these microorganisms are absent or missing.

Some SBOs colonize in the gut while others (like LAB) are transient, or just passing through. Both types enhance the immune system.

One important distinction to mention is that some soil based bacteria are spore forming, but not all spore forming bacteria are soil based.

Spore forming bacteria are incredibly resistant. They can survive and flourish in literally any environment. They can even survive antibiotics.

Bacillus subtilis is an example of a soil based and spore forming bacteria that is often found in probiotic formulas.

Spore forming bacteria are bacteria that form spores, and as spores these bacteria can remain dormant for years, protected from stresses such as chemicals, heat, radiation and dehydration. They’re insanely robust.

Lastly, it is worth mentioning Saccharomyces boulardii (S. boulardii for short). This isn’t actually a bacteria- which is why I gave it an “honorable mention”- but an extensively researched yeast (microscopic fungi).

Even though the majority of probiotics are bacterial, some yeasts like Saccharomyces boulardii, are good for your health because they are able to combat infections and reduce symptoms. That’s why they’re considered “probiotic” and included in many probiotic supplements, because probiotics are defined as “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host.”

So what are the benefits of these various types of probiotics?


Before I dive into how these types of probiotics differ, and how they can be used, it’s important to ask yourself why you even want to take a probiotic to begin with.

What’s your goal?

Do you have existing gastrointestinal issues?

Is there a specific dysbiosis present that you are trying to correct?

Are you trying to alleviate a specific symptom (brain fog, constipation, anxiety, gas or bloating, etc)?

These are scenarios in which a higher dose of probiotic and/or a more specific set of strains may be warranted so this should be overseen by a qualified professional.

Or, are you relatively healthy and just looking to support your gut health?

Identifying why you want to take a probiotic and what you hope to achieve by doing so will help you determine which type of probiotic might be best for you.


LAB (Lactic acid producing bacteria)

This category of probiotics includes both Lactobacili and Bifidobacterium, and is the most well-researched with over 500 clinical trials.

There are over 100 species of Lactobacilli. They’re arguably the most “well known” probiotic, which is why you’ve probably seen them listed on yogurt containers or kefir bottles.

Bifidobacterium are also fairly well known, with over 30 species. Traditionally these are the first bacteria to colonize your gut, beginning at birth (if born vaginally).

Both these types of bacteria help protect from disease, and they also have ways of stopping pathogens from colonizing the gut, but their functions and benefits do differ slightly, which I am about to get into.

Lactobacilli produce several important substances, including lactate (lactic acid), short-chain fatty acids (SCFA), and antimicrobial substances which work to deter opportunistic bacteria from disrupting the ecosystem, and your health.

The production of lactate and acetate from sources of prebiotic dietary fibers is an important factor in the pH of the gut. They help to keep the acidity of the gut balanced in a way that encourages beneficial and commensal (harmless) species while deterring invaders that could make you sick.

Acetate is the most abundant SCFA in the large intestine and is produced by both Bifidobacteria and Lactobacilli.

Acetate is really important because it feeds butyrate-producing bacteria, a process scientists call call cross-feeding. Cross-feeding is considered to be essential in maintaining a healthy digestive tract.

Butyrate I’d another example of a SCFA, and is essential for the maintenance of the colon lining to prevent inflammation. The butyrate produced by our gut bacteria is essential for a healthy GI tract, especially because it provides 70% of the energy used by our intestinal epithelial cells.

So not only do LAB help to keep us healthy, but they enable other bacterial species in the gut to thrive, too.

In addition to producing short chain fatty acids, Bifidobacteria in particular are able to make vitamins directly in your gut, including several B vitamins and vitamin K.

Like Lactobacteria, the fact that they produce lactate and acetate helps balance the gut pH, making the environment sufficiently stable for a healthful gut microbiome, but acidic enough to deter invaders.

Bifidobacteria are protective, they actually produce antimicrobial chemicals targeting pathogenic bacteria specifically. This helps prevent invaders from settling down and doing things that make you sick. At the same time, just by adhering to your gut lining, Bifidobacteria are also able to deter undesirable bacteria in your gut.

LAB bacteria (both Lacto and Bífido) are great for promoting optimal GI function, a healthy immune system response, and the ability to support a healthy and balanced microbiome.

Additionally they are helpful for alleviating anxiety. they can offer support for Inflammatory Bowel Disease, are beneficial in allergic and inflammatory conditions, can help vaginal infections ( here and here), and can help reduce bacterial overgrowths, gas production, and abdominal pain in the small intestine.

Soil Based and Spore Forming

If you’ve taken other types of probiotics and they haven’t worked well for you, soil-based probiotics might be worth trying.

For most of human history, we were living close to the earth. We got our food from the ground, not the supermarket, and we didn’t use disinfectants to wash it. This brought us into constant contact with these soil based organisms.

But today, unless you grow your own food or eat organic produce straight from the field, you probably won’t ever come across soil-based probiotics.

SBOs are helpful for many of the same things any probiotic is helpful for, like improving microbial diversity, reducing side effects of antibiotics and promoting a healthy microbiome.

Soil-based probiotics are a particularly viable option if you have SIBO (small intestinal bacterial overgrowth)

A 2007 study compared the effects of SBO supplementation to taking an antibiotic on SIBO patients. Half the patients took Bacillus clausii for one month, while the other half got an antibiotic. Afterwards, 56% of the group taking Bacillus clausii had cleared their bacterial overgrowth, while only 40% of the patients on the antibiotic did.

Additionally SBOS can help improve diarrhea, abdominal pain, bloating, and stool consistency in IBS patients ( here, here, here, here, here, here, here, and here).

The science doesn’t clearly demonstrate the impact of SBOs on constipation, only diarrhea.

They help improve leaky gut, decrease inflammation (here and here), decrease respiratory tract infections (helpful in lieu of COVID-19), and can decrease post-exertional muscle soreness.

There are two main differences between probiotics with soil-based organisms and other probiotics.

  1. Soil based probiotics have a longer and more stable shelf-life, so they don’t need to be refrigerated.

  1. They are also hardier. They appear to survive the first part of the journey through the stomach and small intestine. Some studies suggest traditional probiotics are less likely to survive to the same extent.

However if your microbiome or immune system isn’t as robust as it should be, SBOs may not be the best option.

Their hardiness makes them strong, sometimes too strong.

Typically I don’t recommend SBOs for anyone who is immune-compromised as they are most likely to suffer from side-effects or react poorly to them.

Also, if you’re generally healthy, and aren’t looking to target a specific GI issue, SBOs likely aren’t the best option. Saccharomyces boulardii

There are many different probiotics that include Saccharomyces boulardii, but it can also be utilized or supplemented with on its own.

The benefits of Saccharomyces boulardii mainly apply to your gut where it works to protect against inflammation.

It’s an anti toxin which means it can stop toxins produced by infectious bacteria that make people ill, and it’s also anti bacterial. S. boulardii can directly stop infectious bacteria from reproducing.

It also helps out your immune system by regulating immune responses and functions as an anti inflammatory which improve gut lining health.

S. boulardii has been used successfully in research for IBS, the treatment of diarrhea, C. difficile infection, Crohn’s disease and UC, treatment for parasitic infections with Giardia and Blastocystis hominis (here and here), and increasing the clearance of H. pylori infection (here and here).

Although S. boulardii does not appear to colonize the gut, it has shown some pretty impressive results, including the ability to fight off bad bugs and correct dysbiosis.


Now that I went through the benefits of each type of probiotic, I wanted to share some guidance on selecting a quality probiotic supplement.

First- it’s important to understand what you’re looking at when you read a probiotic label.

Probiotic bacteria are named and categorized by genus, species, and strain. When looking at a label for a probiotic, you’ll find each bacterium in that formula listed.

The genus is the first word in the name of a probiotic bacteria. The species is the second word. The strain is the series of numbers or letters following the species name. This typically reflects the company that manufactured the strain.


• Lactobacillus reuteri 1063: Lactobacillus is the genus, and reuteri is the species. The particular strain of Lactobacillus reuteri is 1063.

• Bifidobacterium infantis 35624: Bifidobacterium is the genus, and infantis is the species. The particular strain of Bifidobacterium infantis is 35624.

You may also find it helpful to consider the following:

1. How many CFUs does the supplement have?

CFU stands for “colony-forming unit.” This is the number of live bacteria contained in each dosage of the supplement. Many brands tout the number of CFUs as a selling point, but more isn’t necessarily better.

Quality is better than quantity, so take time to research the brand rather than get swayed by numbers alone. More isn’t always better.

If you’re considering a probiotic to treat an existing gut issue or are taking antibiotics, discuss the recommended number of CFUs with a qualified professional.

2. Look for a date of manufacture and a “best by” date.

It’s best to choose probiotics that are within the “best by” date listed on the label. This is the manufacturer’s indication that the bacteria are still viable. You also may want to take into account how the probiotic is stored and whether it has been exposed to heat or cooler temperatures which may have affected the bacteria within the probiotic – make sure that you store them correctly and they’re not exposed to extreme heat or humidity for more than 10 days .

3. What packaging and delivery system are used?

Probiotic packaging will vary depending on the route of delivery used, whether liquid, tablet, capsule, or powder.

Most packages from reputable brands are designed to ensure probiotic viability, such as choosing packaging or ingredients to reduce moisture content.

Some probiotics require refrigeration, which should be indicated on the label. If they do not require refrigeration look to see if appropriate packaging methods are used to ensure safety and viability of the product.

Also look at the encapsulation method. The contents of your stomach are naturally so acidic that many standard veggie capsules quickly break down and the probiotic bacteria are destroyed before they have a chance to reach your gut.

Some studies have shown that regular veggie capsules will only get around 4% of their bacteria past stomach acid.

With every probiotic you take you run the risk of stomach acid killing the bacteria before it even makes it to your gut so the more protected your probiotic is, such as specific coasting or a delayed-release capsule, the more likely the bacteria will reach the gut in order to work.

5. Read the other ingredients on the label. Many commercial or consumer probiotic supplements contain undesirable binders and fillers, including lactose or cornstarch that may cause a reaction, like gas and bloating, if you are sensitive to these ingredients. Make sure whatever your purchase is labeled free of common allergens and other substances you may want to avoid (e.g. gluten-free, non-GMO, vegan)

6. Good Manufacturing Practices (GMP) certification

7. Lab-verified for probiotic species and potency by third-party analysis (independent lab testing)

8. Multiple strains. Typically, multi strain probiotics have a better effect then single strain. Different strains of bacteria provide different benefits to the body. And studies have shown that multi-strain probiotics are more effective than single-strain probiotics.

While I am on the topic of strains, you may want to also look for a brand that offers coded strains which shows that the company is able to track the exact origin of the strains that they use.

Some cautions:

1.Probiotics are generally recognized as safe, but they’re typically not recommended if you have a compromised immune system.

2. As with any facet of health or fitness it’s important to remember that bio individuality will come into play. It may take some trial and error to find the right probiotic that works for you. If you notice no benefits from one product after a few weeks, try a different CFU total, or switch to another one with different strains of bacteria.

3. Be prepared for some changes in your GI tract. Probiotics may initially cause bloating and gas, as well as changes in your stool patterns — all indications that the product is working.

However if they persist past a week or two it may be that the probiotic you’re trying is not working optimally for you. That’s why I always recommend working with a professional!

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