How Do Probiotic Supplements Work?
Written By Ana Aleksic, MSc Pharm

How Do Probiotic Supplements Work?

We know that probiotics are live active cultures that when administered in adequate amounts confer a health benefit to the host. But what essentially makes a probiotic a probiotic? To be labeled as a probiotic, the product should be capable of surviving the irritant effects of both the stomach acid and bile to arrive at their destination in the colon where they exert their effects.

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How do probiotics work?

The probiotics work through a number of mechanisms to strengthen our immune defenses and prevent us from sickness.

It is recognized for decades that the restoration of the balance in the microbial gut population is crucial for our health, and its disruption precipitates several GI and non-GI disease states. Depending upon the duration of their effects, probiotics can be classified as transient versus colonizing. Transient probiotics travel to the gut but are incapable of making a permanent home in the microbiome. They work as long as they are taken. In contrast, the colonizing probiotics (as the name implies) tend to colonize in the gut permanently; their effects last even after discontinuing them. Both kinds of probiotics stick to the gut wall to fend off the harmful invaders from adhering and exerting their deleterious effects. They block the growth of the bad pathogens and therefore, serve to boost the immune defenses both locally within and outside the gut.

Probiotics Induce the Production of Protective Mucin

The probiotic supplements stimulate the cells of the intestine to produce mucus that coats the intestine forming a protective barrier. This powerful gut barrier prevents the foreign attackers from invading. The favorable flora, primarily lactobacilli can compete for the binding sites of viruses (such as rotavirus) causing diarrhea in children.

The Probiotic Communicate with the Elements of the Immune System

Moreover, underneath the gut lining are elements of the immune system. The genetic material of colonizing probiotics has the ability to interact with these elements of the immune system. How is this accomplished? It is through the Toll-like receptors (TLRs), which are the key molecules of the immune system involved in identifying and guarding against the intruding bad guys – the so-called “bacterial-epithelial crosstalk.” Moving ahead, this cellular level crosstalk results in a series of reactions that leads to the formation of inflammatory signaling molecules called cytokines. These cytokines have several immunological functions including the movement of white blood cells towards the harmful pathogen that is then engulfed by these blood cells. Our gut immune defenses have a capacity to turn off this inflammatory response. In the absence of this turn-off mechanism, our gut becomes vulnerable to chronic GI ailments like inflammatory bowel disease. [2]

Colonizing Probiotics avert unnecessary Immunologic Reactions

The colonizing bacteria can induce oral tolerance through TLRs. Oral tolerance is the process by which the immune system does not respond to an innocuous agent that enters via the mouth. This, in turn, prevents excessive immunologic responses, including food allergies. [3]

Probiotics Release a variety of Anti-Infective Agents

Current experts suggest that probiotics themselves release bacteria-killing substances like hydrogen peroxide (H202) and bacteriocins. Bacteriocins are proteins that are toxic to other unfriendly bacterial strains but do not harm the friendly bacteria themselves. Hydrogen peroxide is a potent oxidizing agent that is particularly toxic to unfriendly microbes that lack catalase. Catalase is an enzyme that scavenges H2O2. Deficiency of this enzyme makes the bad bacteria susceptible to destruction. [4]

You’ve likely heard of probiotics by now. As the years pass, interest in the microbes we each share our bodies with continues to grow. This leads to common and obvious questions: What’s the attraction? What are probiotics? How do they work? Why should we consider taking them? These are important to ask.

In this guide, we’ll answer these questions and more.

What are probiotics?

Let’s begin at the beginning… What are probiotics?

Originally, this term was coined by combining two parts; Pro referring to
for, or in favor of and biotics referring to bios, or life. Over time, the definition morphed to “live microorganisms which, when consumed in adequate amounts, confer a health effect on the host.”

And there’s the rub. Just because a product contains bacteria does not mean its impacts are beneficial, or that it acts as a cure all. As the
World Health Organization noted, probiotic outcomes are strain specific; the right microorganism is required for beneficial results. To fall under this important umbrella term, microbes, by definition, need to enhance wellbeing; to be pro-life.

How do you ingest probiotics?

Probiotics are taken orally, so can be consumed in supplemental form or as food or drink. Reputable supplements ensure you receive a specific strain, at a targeted dose, with a research-backed delivery system.

Foods are helpful, too, but you won’t know exactly what you’re getting or how much. In effect, what you eat paints broader brush strokes as opposed to the laser-focused effects of supplementation. Probiotic-rich foods include kefir, kimchi, kombucha, sauerkraut, tempeh, and yogurt.

How do probiotics work?

The benefits of probiotics are both straightforward and complex…

It’s easy to understand the simple aspect so let’s start here. If there is an imbalance, with too few good bugs and too many bad bugs, adding billions of healthy microbes can steady the scales.

The complex aspect is often misunderstood. Because it matters, let’s take a look…

The gut is an incredible organ that stretches from your mouth to your anus. In a way, you can think of it like a donut, where the hole is the gut lumen and the dough is you; your body proper. A single cell layer lines the gut (or, in the donut analogy, the inside of the hole). This allows nutrients to pass through, but keep toxins from crossing over. In health, your gut acts like a sieve for vitamins, minerals and water and a funnel for harmful compounds like allergens and infections.

Along the gut’s lining live trillions of live microorganisms; bacteria, fungi, protozoa, and viruses. Together, they form the gut microbiome. These bugs are not merely passengers along for the ride; they are integral for digestive and health processes. This is where the complexity begins…

As authors Gail Cresci PhD and Kristin Izzo note, “The
gut microbiota plays an important role in nutrient and mineral absorption, synthesis of enzymes, vitamins and amino acids, and production of short-chain fatty acids.”

These short-chain fatty acids, otherwise known as SCFA’s, help feed the
cells lining the gut. In doing so, they protect the lining; the protective barrier between you and the world. There are several species of good gut bugs that lead to the production of butyrate, a SCFA. This appears to increase mucus production, which is important for protecting the gut lining. Think of it like a sticky layer that can plug holes and trap harmful invaders.

Already, you can see that a healthy microbiome produces nutrients that are useful to the rest of the body, and nutrients that sustain and protect the gut lining (its barrier) from injury.

Then there are bad bugs that trigger low-grade inflammation, which is known to impair barrier function. Imagine placing a deflated balloon in a gap between two bricks and then pumping it up. It pushes the bricks apart, creating a larger gap. While not quite anatomically correct, inflammation within the gut has a similar effect.

The damage, then, continues to mount.

The inflammation and damage to the lining causes an increase in free radical damage, which is like biological rust. Intestinal antioxidants are the rust remover, but barrier injury reduces antioxidant levels. This may combine to further impair the intestinal lining. It is a vicious cycle!


The gut should act like a sieve to nutrients and a funnel to toxins. When the lining becomes compromised, so do we. With increased permeability, harmful compounds can “leak” across into your body and your bloodstream. They can create localized inflammation in the gut, which worsens the situation.

Researchers call this increased intestinal permeability. Natural health experts give this a more direct name: leaky gut syndrome.

This brings us back around…

How can probiotics help with digestive health?

As an article published in the journal Current Nutrition & Food Science noted, “Probiotics not only help maintain normal function of the gut mucosa, but also protect mucosa from injurious factors such as toxins, allergens and pathogens.”

So probiotics help the gut in many ways…

These good gut bugs produce and share nutrition. They aid maturation of the immune system, which is key in both gut and general health. They protect the mucus layer of the gut barrier. And they help prevent injury to the lining. 

How do probiotics work with our microbiome?

Most available probiotics are cultured from healthy humans, so they include native species like Bifidobacterium, Lactobacillus, and Saccharomyces.

When we consume probiotics, the new addition adds to the ranks of good bugs already in the gut. They are akin to adding well trained soldiers to the files of a growing army. They already know what to do and get straight to work.

For the bad bugs, though, the new arrivals spell trouble in a number of ways…

As the appropriately named journal article
Bugs that debugs: Probiotics says:

1. Probiotics directly suppress or diminish disease-causing microbes. This makes it more difficult for illness to be triggered.

2. Probiotics compete against the bad bugs for nutrition. They also fight for space on the gut lining, potentially knocking harmful microbes from their residence so they can’t “stick” around any more. This makes it easier to for them to be expelled in the stool.

3. Probiotics strengthen the immune system and, in this way, reduce harm and disease.

Why are probiotics important to overall health?

The gut is the main hub for the immune system. It is also the site we digest and absorb nutrients and water, and the place through which we expel waste. Without a healthy and functional digestive tract, the rest of our body becomes vulnerable.

Imagine driving your car along a busy mosquito-invested freeway, one you are unable to exit. The oil and gas run out. The radiator overheats. Rust eats through the doors, creating holes through which the bloodsucking insects can enter…

Cars whizz past, some unable to avoid hitting you. Your stopped vehicle is a threat to the freeway and the other users on the road. This has implications for traffic flow and changes the thoroughfare ahead.

The mosquitos then start to feast…

You become subject to numerous insults, have a reduced capacity to repair, and are now vulnerable to disease. You’re stuck and unable to get the aid needed to reverse the challenges you face.

Using a car and your gut as an analogy, can you see how damage within your digestive tract has consequences for the local area and the whole system; for all of you?

Probiotics act as both the repair and the maintenance person. They close the holes, fill the gas and oil tank, pour coolant into the radiator, and get you moving again. Importantly, they help to maintain the gut in good working order to prevent future negative events.

Energy: How can probiotics magnify your mojo?

As we’ve already discussed, your gut microbiome helps to produce and absorb the nutrients required to function energetically; they magnify your mojo.

One nutrient group the gut flora has a key role in producing is those involved in energy production: the
Bvitamins, including folate, riboflavin and vitamin B12.

Riboflavin, or vitamin B2, is involved in cellular metabolism and energy production. It’s unsurprising then that a higher intake has been linked to a raised level of alertness; it helps provide energy for the brain to function well. A vitamin B2 deficiency, on the other hand, may cause anaemia, a throughly tiresome condition.

Folate, or vitamin B9, is one of the more common vitamins we, humans, become deficient in. Symptoms include poor cognitive performance, muscle weakness, tiredness, lethargy and fatigue.

Vitamin B12. In nature, only bacteria and archaea make this vitamin. That means, particularly if you are vegetarian, without the right gut bugs you can struggle to maintain a healthy level. The result of B12 deficiency is exhausting: irritability, extreme tiredness, feeling faint, lack of energy, and cognitive decline including memory loss and poor judgement.

Probiotics help to ensure healthy gut flora and that adequate nutrients can be produced and absorbed. Our products focus on the strain, L. reuteri NCIMB 30242, which has been proven to improve
gastrointestinal health and function.

Focus: How do probiotics enhance your brain function?

B vitamins are key to a healthy, alert and energised brain. In this way, probiotics can increase cognition. But good microbes enhance your ability to think and judge in a number of ways.

Inflammation has been shown to reduce brain function. As an article published in the
Journal of Neuroscience Nursing said, “Higher levels of inflammation have been shown to negatively affect cognitive processes, including memory, speed of processing, and global cognitive function.”

But, how is this linked to the gut microbiome?

Gut dysbiosis is the scientific term for gut bacteria that have become off kilter; less of the good, more of the bad. This imbalance triggers
increased inflammatory reactions in the brain. With it, Alzheimer’s disease, Parkinson’s disease and stroke become more likely. The risk of depression and fatigue rise.

The jury is in: cognitive function can be negatively affected by an unhealthy microbiome.

The good news is the research has shown that
probiotic supplementation can reduce inflammation, improve brain function and aid mood.

Immunity: How do probiotics improve immune function?

As the article, Role of the Microbiota in Immunity and Inflammation, said, “The microbiome plays a fundamental role on the induction, training and function of the host immune system.”

Having the right microbial mix matters.

Studies have shown that probiotics reduce
pathogen-induced inflammation, make it more difficult for infective agents to attach to the gut lining and sneak through its barrier, and provide good gut bugs that compete against — and so eliminate — foreign invaders.

Cholesterol: How one unique strain of probiotic can lower an unhealthy LDL blood lipid level?

As you probably know, bad cholesterol and heart disease are strongly linked. If you’ve ever had a poor test result, your doctor might have called you in for a chat and a possible prescription. But, as with all medications, these come with potential side effects.

That makes research performed on one particular probiotic very interesting…

Lactobacillus reuteri NCIMB 30242 is a unique probiotic strain. It has been termed a “heart healthy probiotic” because it is the only probiotic clinically proven to significantly
lower LDL cholesterol.

Vitamin D: How can probiotics boost your level of this crucial vitamin?

A low level of vitamin D comes with serious health risks, including osteoporosis, cardiovascular disease, diabetes, and cancer. Yet, this deficiency is common, affecting at least one in four Americans.

A healthy vitamin D level can be difficult to sustain because the main source that powers production is the sun. Particularly in the wintery months, there just aren’t enough hours in the day. We also need to limit our sun exposure to prevent sunburn and skin damage.


Yet, one randomized controlled trial found that Lactobacillus reuteri NCIMB 30242 increased the average circulating vitamin D (25-hydroxyvitamin D) level by a staggering 25.5%. That’s enough to bring many people out of deficiency, without supplemental vitamin D or sun exposure!

Why might you consider taking probiotics?

There are many key reasons why adding a science-backed probiotic to your daily routine is well advised.

The first is to restore gut health, with its local and systemic effects.

The second is because the therapeutic outcomes are holistic and broad. Enhanced energy, focus, immunity, cholesterol balance and a healthy vitamin D level are crucial. And they’re not the only benefits!

Probiotic supplementation is also safe, with minimal risk of side effects.

The only real proviso is this: Many gut products don’t do what they say on the box, so to speak. When choosing a probiotic, it’s important to focus on the right strain, a therapeutic dose and make a science-backed decision.

That’s why we at MicrobiomePlus are so passionate about sharing our deep knowledge; so you can make the best decisions to support your health. It’s why our probiotic won the NEXT Innovation Summit's NutraAward. It’s why our customer keep coming back.

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ready to get started?


  1. Behnsen J, Deriu E, Sassone-Corsi M, Raffatellu M. Probiotics: Properties, Examples, and Specific Applications. Cold Spring Harbor Perspectives in Medicine. 2013;3(3):a010074. doi:10.1101/cshperspect.a010074.
  2. Wells JM, Rossi O, Meijerink M, van Baarlen P. Epithelial crosstalk at the microbiota–mucosal interface. Proceedings of the National Academy of Sciences of the United States of America. 2011;108(Suppl 1):4607-4614. doi:10.1073/pnas.1000092107.
  3. Tanaka K, Ishikawa H. Role of intestinal bacterial flora in oral tolerance induction. Histol Histopathol. 2004;19(3):907-14.
  4. Gillor O, Etzion A, Riley MA. The dual role of bacteriocins as anti- and probiotics. Applied microbiology and biotechnology. 2008;81(4):591-606. doi:10.1007/s00253-008-1726-5.

Statements made on this website have not been evaluated by the U.S. Food and Drug Administration. Information provided by this website or this company is not a substitute for direct, individual medical treatment or advice. It is the responsibility of you and your healthcare providers to make all decisions regarding your health. Microbiome Plus recommends that you consult with your healthcare providers regarding the diagnosis and treatment of any disease or condition. Products sold on this website are not intended to diagnose, treat, cure, or prevent any disease. 

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Statements made on this website have not been evaluated by the U.S. Food and Drug Administration. Information provided by this website or this company is not a substitute for direct, individual medical treatment or advice. It is the responsibility of you and your healthcare providers to make all decisions regarding your health. Microbiome Plus recommends that you consult with your healthcare providers regarding the diagnosis and treatment of any disease or condition. Products sold on this website are not intended to diagnose, treat, cure, or prevent any disease.

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