Probiotics For Gut Health: How They Actually Work

You may have read about how probiotics can benefit your digestive tract health. Or your doctor might have prescribed you probiotics to help you relieve bloating or an upset stomach. But how do probiotics for gut health actually work? 

Long story short, probiotics work to balance out the bacteria in your system. A good example is taking probiotics after antibiotic treatment to help re-establish your gut bacterial balance. 

The effect of good, balanced bacteria spans beyond digestive health alone. Good bacteria also supports your intestinal lining, affecting your entire immune system function. As a result, your body is more equipped to fight off infections and protect against inflammation.

Yet, it gets more complicated than that. Learning about your gut microbiome is critical to understanding the whole story around probiotics, so let’s start from there.

A Healthy Microbiome And the Role of Probiotics 

The human microbiome is a healthy mix of gut microorganisms responsible for the proper function of the digestive system. The keyword here is balance. Our bodies need a balance of good and bad living microorganisms to maintain homeostasis

That said, a healthy microbiome is home to diverse colonies of bacteria. These bacteria support the body’s immune function in three different ways. They help the body: 

  • Fight against pathogenic bacteria colonization
  • Absorb beneficial nutrients such as amino acids, vitamins, and short-chain fatty acids 
  • Produce bacteriocins (proteins with bactericidal properties) [1]

The greater diversity of your gut microbiota, the more resilient you are to infections. When the balance of gut bacteria is off, dysbiosis occurs. Dysbiosis is an imbalance in your natural gut microflora. And this is where different health conditions kick in. 

Fact: The main offenders for disrupting the microbiome are poor diet, stress, and the use of antibiotics.

Now, let’s break this down by learning how good and bad bacteria work. We’ll parse the live bacteria that live in the human gut into two categories: pathogenic and non-pathogenic bacteria.

Pathogenic vs. Non-Pathogenic Bacteria
Types of bacteriaDisease-causing or pathogenic bacteriaBeneficial or non-pathogenic bacteria
Bacterial strains Clostridium difficile, Escherichia coli, and ShigellaLactobacillus, Bifidobacterium, and Streptococcus thermophilus
How They WorkPathogenic bacteria cause inflammation by releasing proteins and toxic by-products. This, in turn, can result in symptoms such as diarrhea, bloating, and gas pain. Beneficial bacteria keep pathogens in check and offer many health benefits. 

Now, a healthy microbiome needs both helpful and potentially harmful microbes to thrive. Try to think of it as a seesaw; you should sustain both microbiotas in your body, just as you should have people on each end of the seesaw for it to work. 

When both work to sustain the function of the human organism, we call them beneficial or symbiotic. When they promote disease, we call them pathogenic. [2]

So, both pathogenic and symbiotic microbiota should be able to coexist without creating problems. 

That said, dysbiosis is treated with antibiotics in the case of a bacterial infection. When the long-term disruption of your natural gut microflora is causing you issues, it’s treated with probiotics. 

Below we look at how to use probiotics to help restore balance to your microbiome.  

How Different Bacterial Strains Affect Your Gut Differently 

some probiotic strains will help promote healthy digestion and support your immune health, while others will be better for preventing urinary tract infections and upper respiratory issues
(Image source: Wikimedia)

Taking probiotics for gut health makes sense—especially if you take ones that address your specific digestive symptoms.

Did you know there are more than 120 species of Lactobacillus probiotic strains, of which a dozen are used in probiotic products? It’s hard to tell which ones will help with your specific condition. 

Different strains of bacteria will exert different health effects. Learning more about them lets you know what health benefits you can expect from a given probiotic.

Today, we’ll examine the three most common probiotic species. 


The Lactobacillus species can exert wide-ranging effects on human health. These range from supporting the immune function to treating vaginal infections and helping with weight management. 

More specifically, strains like Lactobacillus rhamnosus GG can promote healthy digestion and help with antibiotic-associated diarrhea. [3] On the other hand, strains like Lactobacillus gasseri have been found to help with vaginal and urinary issues. [4

Other than that, research studies show specific Lactobacilli strains such as Lactobacillus gasseri, L. rhamnosus, and L. plantarum can help decrease gut permeability, reduce inflammation, and increase bacterial diversity. All those metabolic functions play a role in promoting weight loss. [5]  

There’s also some scientific evidence that Lactobacillus can benefit people with respiratory diseases like asthma, infections, and cystic fibrosis. [6


Bacterial strains of the Bifidobacterium species can help treat gut-related conditions such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). They can also help treat gastrointestinal infections. 

According to a review published in the Journal of Microbiology and Biotechnology, probiotic products containing Bifidobacterium strains can be effective against multidrug-resistant bacteria. Research shows they do this by stopping the pathogenic bacteria from reproducing and attaching themselves to our intestinal walls. [7

Although research is limited, there is some evidence that Bifidobacterium probiotic bacteria can be combined with Lactobacillus strains to help with IBS-related symptoms. These include diarrhea, constipation, and abdominal pain. [8]

Streptococcus Thermophilus

Streptococcus thermophilus might be your go-to probiotic species if you’re looking to benefit your gastrointestinal health. They’ve been found to have overarching effects on different GI-related issues. 

Used in the production of dairy products, somewhat paradoxically, they can help manage problems related to lactose intolerance. Aside from that, according to the Journal of Functional Foods, Streptococcus thermophilus can help promote the growth of other beneficial bacteria in the gut. [9]

And the best part. Streptococcus thermophilus can survive the human gastrointestinal tract without being destroyed by stomach acid. 

Sources of Probiotics 

eating fermented foods and taking probiotics will help you promote the growth of healthy bacteria in your gut
(Image source: Unsplash)

So, what’s the best way to take your probiotics? Fermented foods and over-the-counter probiotic products are the two options. 

You can satisfy your body’s needs for probiotics by choosing fermented products such as sauerkraut, pickles, yogurt, or miso. These products are made by lacto-fermentation. Beneficial strains of bacteria use this process to survive. More specifically, they do this by feeding on the food’s sugar and starch to create lactic acid.

Below is a short list of fermented foods just to get you started: 

  • Fermented or cultured dairy products
  • Tempeh
  • Miso
  • Soy beverages
  • Sourdough bread
  • Kimchi

Furthermore, there are 10-100 trillion bacteria specific to the human microbiome, but this does not make them probiotics. Products are qualified as probiotics only if the beneficial bacteria come in quantities sufficient to be effective. There also needs to be adequate scientific evidence showing these strains can effectively treat specific conditions. 

Over-the-counter probiotic dietary supplements come in different forms, including capsules, tablets, or powder, and typically contain some of the following most common bacterial strains:

  • Lactobacillus acidophilus
  • Lactobacillus bulgaricus
  • Lactobacillus plantarum
  • Bifidobacterium bifidum
  • Bifidobacterium lactis
  • Enterococcus faecium
  • Saccharomyces boulardii

What Makes a Good Probiotic Dietary Supplement? 

As seen above, the effects you can expect from probiotic supplements are strain specific. So, how do you find the best probiotic product for your needs? 

First things first, let’s look at how formulated probiotics are made. Some will contain various live bacteria, while others contain a few strains or single-strain probiotics. 

The question here is, which one do you go for? 

If you’re looking for a product to help with your IBS symptoms, you may want to try multi-strain formulations. According to the British Dietetic Association, these formulations were twice as likely to help with IBS symptoms in many clinical trials when compared to a single-strain product. [10] Yet, you can try single strains if you’re trying to target a more specific condition.  

The best probiotic supplement will be the one that targets your health condition most accurately. So researching the strains that go into your probiotic supplement is on the agenda. 

No less importantly, research for a reliable vendor—that’s how you’ll ensure the product you choose is of good quality. 

Ortho Spore IG

If you’re looking to diversify your gut microbiome, adding more of one species isn’t going to do it. Instead, look for a multi-strain probiotic that contains not only different strains but also different species and genera. 

Ortho Spore IG contains strains from the three major probiotic species, Bacillus coagulans, Bacillus clausii, and Bacillus subtilis. Taking strains from different species is more likely to create a supportive environment where other strains will thrive.  

Ortho Molecular’s probiotic formula not only maintains your GI barrier, but it also maintains gastrointestinal balance and enhances mucosal immunity. Importantly, Ortho Spore IG is made in a cGMP manufacturing facility — meaning there’s a high level of quality control from start to finish.

Find the Right Probiotic Supplements to Support Your Gut Health

Keeping your gut bacteria balanced is critical for the health of your digestive system. Yet, the health impact of good bacteria is not reserved for intestinal tract-associated ailments only, like IBS and IBD. Some scientific data indicates that it extends to help with issues like weight gain and vaginal health. 

And the rules are pretty cut and dried here—stock up on fermented foods or take a probiotic. 

That said, contact your healthcare provider to match your health condition to the right supplement and maximize your health gain. Or head straight to our online store—we carry only high-quality premium probiotic supplements.  

You may also want to keep learning how to improve your gut health—you’ll help yourself in the long run. If this hits home, a few articles on gut health-related topics are below. 













Follow me

Medically reviewed by Dr. Jamy Antoine, D.C. — by Chris Bowman — On September 7, 2023


Chris Bowman

Chris Bowman is the CEO and Co-Founder of and has over 15 years of experience in nutritional sciences and wellness. Simply Nutrients is a part of Dr. Jamy Antoine's Select Health Practice in Edina, Minnesota. Chris is passionate about helping people live healthier lives by using the best practices of nature, nutrition, and medicine.