Probiotic Species and Strains: What Are Their Differences?

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Nowadays, it’s practically impossible not to have at least heard about probiotics one way or another. But, despite their increasing worldwide popularity, many people seem to struggle when it comes to distinguishing or even defining these beneficial microorganisms.

Thus, a number of questions arise regarding probiotic species and strains: what are their differences? Do some probiotics ‘matter’ more than others? How do I find the ideal probiotic for me? etc.

The good news here is that probiotics are fairly easy to understand once you get your hands on the right information, as you will see later on.

This means that anybody can become a probiotic ‘expert’ – well, at least to the point where they can improve their overall health on a long-term basis. And that counts for something, right?

But, before that, let us first take a closer look at these bacteria and their contribution to the human body.

What are probiotics?

Probiotics are microscopic organisms which normally reside within the gastrointestinal system beginning with the early stages of infancy.

The etymology of the word roughly translates to ‘pro-life’ bacteria, which makes sense when we consider their vital role in nutrient processing, immune protection, and even mood regulation.

As a part of the upper GI tract – namely within the mouth, nose, and throat – probiotics have the function of improving food decomposition (through their active role in saliva), reducing the occurrence of mouth ulcers or cavities, and eliminating halitosis.

In addition, they can combat virus and microbe infections, whether they are air-borne pathogens or introduced in the organism via contaminated foods, unhygienic hands, etc.

Nevertheless, probiotics are undoubtedly famous for their presence within the lower GI system, that is inside the stomach, small intestine, and colon.

It is here where such ‘friendly’ bacteria enhance food decomposition, facilitate nutrient assimilation, and regularize bowel motility.

The results are overall wellness owed to correct substance absorption at the level of the gut, regularized weight and less instances of visceral fat gaining, as well as highly improved digestive patterns.

The contribution of probiotics to immunity is also very important, more so in light of the fact that 60%-70% of a person’s pathogen screening relies on the antimicrobial effects of gut probiotics.

Their antimicrobial and antiseptic properties ensure that pathogens do not develop within the gastrointestinal or urogenital systems.

Nevertheless, in the case of an infection or bacteria overgrowth, probiotics act as your body’s natural antibiotics in order to meliorate and remove health threats as quickly as possible from the inside.

That being said, you should also know that the normal range of live probiotic cultures for a healthy individual can vary from 1 billion to 100 billion CFUs (colony-forming units) on a daily basis, with factors like a poor dietary routine, food poisoning, infections, and prolonged antibiotic administration being among the top causes for disturbances in these numbers.

Luckily, probiotics can be externally supplemented via fermented vegetables, dairy products, and commercial dietary enhancers, so that you can enjoy a ‘good’ bacteria boost whenever you are lacking one. This then begs another important question: how do you choose probiotics in the first place?

The world of probiotics

Maintaining your probiotic numbers at optimal readings is, of course, something to be desired on a constant basis.

However, the amount of products containing ‘friendly’ microorganisms of this type is so extensive that you might sometimes feel overwhelmed by the choices you have in front of you.

As a result, knowing a few simple notions regarding probiotics – like grouping, characteristics, and health benefits – could help you decide what is best for your wellbeing in the long run.

At its core, the classification of probiotics is most often described in terms of family, genus, and species, with strains being a subcomponent of the latter category.

For instance, the Lactobacillus acidophilus species of probiotics is a part of the Lactobacillus genus and Lactobacillaceae family.

Various strains of the species are generally being cultured with specific roles such as the fermentation of dairy products or to be used as active components in the making of supplements, let’s say.

Although paramount in the structure of any healthy gastrointestinal system, some probiotics can be considered more significant than others when it comes to digestion and immunity, the most widespread and well-known subdivisions being Bifidobacterium and Lactobacillus.

Bifidobacterium probiotics

The Bifidobacterium genus pertains to the Bifidobacteriaceae family and is defined as one of the major colonizers of the human intestinal tract immediately after birth and during early infancy.

In addition, these probiotics have been shown to efficiently decompose carbohydrates and aid in the fermentation of milk sugars (hence generating improved lactose responses).

  • Bifidobacterium animalisis alternatively known as Bifidobacterium infantis. As these complementary names suggest, the present probiotic represents a common occurrence within the gastrointestinal tract of the vast majority of mammals during the early years of life. Bifidobacterium animalis therefore plays a big part in intestinal functionality by enhancing nutrient decomposition and absorption alike, which is why major dairy manufacturers from around the world (for example, Dannon) have made this probiotic a key culture in many of their natural yogurts as an organic culture booster. Moreover, Bifidobacterium animalis has been shown to improve upon the symptoms of ulcerative colitis and ameliorate episodes of IBS (Irritable Bowel Syndrome).
  • Bifidobacterium bifidum – represents an early colonizer of the gastrointestinal system, as well as a common presence inside the vaginal and urinary tracts later on in life. Many researchers have often described Bifidobacterium bifidum in terms of a ‘powerhouse’ probiotic as a result of its many positive influences on the human body. Among these we can highlight its ability to restore intestinal flora within optimal readings, boost digestion, and meliorate nutrient assimilation. Furthermore, this ‘good’ bacterium can increase immunity screening by protecting you against Escherichia coli infections and reducing the duration of acute diarrhea episodes.
  • Bifidobacterium breve – as a probiotic, Bifidobacterium breve has been linked with the correct fermentation process of numerous foods, but especially those which are heavy on fillers, additives, preservatives, etc. This constitutes a highly important feature nowadays, because it shows that probiotics can adapt to the new digestive requirements of modern times (no matter how challenging they might turn out to be). Another impressive aspect regarding Bifidobacterium breve is its elevated antimicrobial capacity, which actively inhibits the formation of pathogens such as Escherichia coli and Candida albicans (the main ‘culprit’ in the case of yeast overgrowths for women).
  • Bifidobacterium longum – constitutes one of the earliest and most extensive probiotic colonizers of an infant’s gastrointestinal tract (up to 90% in some instances), but one which dramatically decreases as we get older (approximately 3% of the digestive tract’s total microflora). One reason for Bifidobacterium longum’s high incidence within childhood can be attributed to its digestive enhancing capacities, namely through its intensive production of lactic acid (derived from the fermentation of milk sugars). Additionally, this beneficial microorganism can alleviate the symptoms of ulcerative colitis, antibiotic-induced diarrhea, and even the common cold, as well as provide your organism with increased anti-carcinogenic and antimutagenic protection.

Lactobacillus probiotics

The most prominent aspect regarding the Lactobacillus genus is its capacity to transform the sugars in milk-based foods into the more easily digestible lactic acid.

This crucial fermentative potential explains the predominance of these probiotics within the gastrointestinal system, alongside their employment in numerous commercially distributed products.

In terms of immunity, Lactobacillus probiotics display significant antibiotic action over pathogens that otherwise affect the gastric, urinary, and vaginal systems alike.

  • Lactobacillus acidophilusis undeniably one of the most famous probiotics of its kind, having been used by dairy manufacturers from all over the world in order to promote their digestive-boosting yogurts, for example. With good reason too, since Lactobacillus acidophilus can regulate bowel movement, prevent the formation of yeast overgrowths, and improve lactose intolerance responses – after all, it is an ‘acid-loving’ bacterium.
  • Lactobacillus brevis – aside from the human body, this probiotic can be usually found in the makeup of preserved vegetables like brine pickles and sauerkraut. Its fermentative properties allow for both food conservation and normal metabolic processes. Lactobacillus brevis has also been associated with an increased screening against pathogens of the Helicobacter pylori type through its antimicrobial action.
  • Lactobacillus casei – although a more aggressive category of probiotics, Lactobacillus casei employs its positive effects on digestion and immunity all throughout the gastrointestinal tract. For example, this ‘friendly’ bacterium exhibits powerful antiseptic properties at the level of the mouth, food decomposition boosting within the stomach and intestines, and increased pathogen screening within the colon.
  • Lactobacillus fermentum – as the name suggests, Lactobacillus fermentum can greatly accelerate decomposition processes inside the digestive tract of humans. Its ability to withstand great variations in pH and bile levels enables it to resist for longer in this environment, thus improving nutrient absorption and pathogen inhibition alike.
  • Lactobacillus helveticus – this probiotic can be found as a live culture in the composition of various brands of cheese, with Emmental, Cheddar, and Parmesan being the most representative. The employment of Lactobacillus helveticus in dairy products traces back to its fermentative properties, which successfully transform lactose into lactic acid and hence relieve symptoms otherwise linked to lactose intolerance. This beneficial microorganism can also improve calcium assimilation within the body and elevate bone mineral density over time.
  • Lactobacillus plantarum – aside from soft cheeses and fermented vegetables, Lactobacillus plantarum can be considered a normal presence within the human organism, where it helps with digestion, immunity, and the normal functioning of the urogenital system (for instance, it inhibits the development of renal calcium deposits). One of its main attributes is that of enabling intestinal permeability, which – in turn – allows for proper nutrient absorption and regularized bowel movement.
  • Lactobacillus rhamnosus – is a ‘multipurpose’ probiotic in the sense that it extends its good influence beyond the gastric system. As a consequence, Lactobacillus rhamnosus cultures have been linked to fewer instances of allergies and eczema breakouts, shorter episodes of rotavirus diarrhea, reduced cases of upper respiratory infections, etc.
  • Lactobacillus salivarius – this probiotic benefits the gastrointestinal tract by alleviating IBS symptoms (like bloating and gas) and reducing internal inflammation. Moreover, Lactobacillus salivarius can inhibit the development of major pathogens and drastically reduce the occurrence of infections or various diseases within the body.

Other major probiotics

Aside from the Bifidobacterium and Lactobacillus genera, there are other major categories of probiotics that should be mentioned in connection with human health and wellbeing.

One of these is the Bacillus subfamily of beneficial bacteria that also help ferment milk sugars into lactic acid and therefore alleviate lactose intolerance for sensitive individuals.

By associating with other probiotics, microorganisms such as Bacillus laterosporus, Bacillus sphaericus or Bacillus subtilis can maintain abdominal wellbeing even in instances of IBS and IBD (Inflammatory Bowel Disease). They are indispensable to immunity as well, since they inhibit Helicobacter pylori overgrowths.

Probiotics like Saccharomyces boulardii and Saccharomyces cerevisiae of the Saccharomyces genus have been proven to maintain intestinal microflora active and wholesome, reduce diarrheal episodes (whether acute or antibiotic-induced), stop the recurrence of colitis infections, and meliorate IBS side effects.

Another major representative of beneficial intestinal flora is Streptococcus thermophilus from the Streptococcus genus.

This probiotic can resist great variations in heat and acidity, hence thriving for longer inside the gut and promoting regular bowel motility and good nutrient assimilation for extended periods of time.

In addition, it can improve lactose tolerance, boost anti-inflammatory responses in the organism, and shorten the intensity of diarrhea episodes.


Similar, yet different – that is how you could correctly define probiotics in the context of their contribution to human wellness.

On the one hand, you have their common features: better digestive movements, increased nutrient assimilation within the gut, and overall increased immunity screening.

On the other hand, each probiotic species – and, by extension, their various strains – possesses some unique quality that can help with anything from intestinal disorders to skin problems.

Consequently, knowing more about probiotics and their different roles within the organism can help you become healthier in a wholesome manner in the long run.

So don’t be afraid to become pro-probiotics – your body will thank you for it later!

About the Author

Maya Caplin
Maya Caplin
My name is Maya Caplin and I am the creator of ProBiotics America. I love to write about probiotics. Why is that? Because I firmly believe that you can substantially improve your health by taking probiotics supplements. Your body craves beneficial bacteria so it can continue to function at peak levels. As a probiotics expert, I've created this website so you can easily access all you need to know about how to create your own probiotics lifestyle. It's easier than you think. Changing your thinking to include the importance of what you eat is fundamental to everything about a new lifestyle. That's where I come in. My strong belief is that given the right information about anything, and you will be able to make accurate decisions that will bring you the best benefits. Learning all you can about probiotics is my number one goal for you. It's what I do best, and what I want to give to you. Choose your best life, and stay informed. My research is always thorough and I stay informed so you don't have to do the hard work yourself. Just keep us bookmarked for the best in probiotic information you will ever receive.

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