• What are they?
  • What do they do?
  • Are they healthy?
  • Are they over hyped?
  • Which one is the best?
  • Why would you take them in the first place?

These are just some of the many questions that arise when you bring up the topic of probiotics.

Where do we even start?

Well, in my four-part Probiotic Series, I’ll address these questions and try to answer them the best I can from the literature out there and, of course, my own personal experience. Here in part I I’ll be defining probiotics and what they do.

Probiotics Defined

The most widely accepted definition of a probiotic is any “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host” (1). In laymen’s terms, this means that there are “good bacteria” that help various bodily processes that support your body to reach optimal health.

In addition, a probiotic also must be a microbe, defined as a bacteria or yeast, that is alive when administered, has been properly identified (genus, species, and strain), and is safe for intended use (1, 2). You’ll notice, for example, when you take a probiotic supplement, that there are many different species of bacteria, such as Lactobacillus acidophilus and Bifidobacterium longum. Each strain of bacteria serves a specific purpose and is intended to treat and/or aid certain bodily functions and processes.

In Lactobacillus acidophilus case, for instance, this strain is known for it’s work in the small intestine where it helps break down food by producing lactic acid and hydrogen peroxide that create an “unfriendly” environment for “bad” bacteria, among other benefits (5). What’s interesting is that many different popular Yogurt brands, like Dannon, are creating proprietary strains that’s only found in their yogurt or product (2). The effectiveness of their strain, however, is debatable (I’ll touch on the effectiveness of certain probiotic foods and supplements in part III).

With that said, it’s important to note that the probiotic world has many subcategories, as well. They are defined as (1):

  • Probiotic food
  • Probiotic supplement
  • Probiotic drug
  • Designer probiotic
  • Direct fed-microbial

We’re familiar with the first three, I’m sure, but a designer probiotic is one that has been genetically modified and a direct fed-microbial is for animal use. All have their own purpose and role in the probiotic world with goal of keeping our bodies healthy.

What Probiotics Do

Now that we have defined probiotics, let’s explore more into what they do and what they are good for.

As I mentioned, each strain of probiotic usually has a specific purpose or small handful of primary benefits that make it significant for consumption. The two most common strains of probiotic strains, Lactobacilli and Bifidobacteria, inhabit the small and large intestine respectively.

Lactobacilli is known for preventing the overgrowth of disease causing microbes, such as candida species, E. coli, and salmonella, by producing antimicrobial properties (3). In addition, lactobacilli also aids digestion of lactose, improves nutrient absorption, helps prevent vaginal and UTI infections, and helps maintain low pH levels to fight off malignant pathogens and yeast (4).

In contrast, Bifidobacteria is known for helping keep the integrity of the large intestine by preventing pathogenic bacteria and yeasts from colonizing (3). Bifidobacteria also helps the absorption of calcium, iron, magnesium, and zinc, while also aiding the manufacture of B-complex vitamins (3, 4).

(For a more complete list of functions of both types of bacteria, bifido and lactobacilli, click here).

What Next?

There’s no doubt in my mind that probiotics are indeed beneficial, but how effective and beneficial? You’ll just have to stay tuned for part II to see if probiotics do indeed live up to the hype or have become adulterated by the industry.

As always, thanks for reading, and feel free to comment down below.

Until next time, be strong and be you.


  1. How Do We Know When Something Called “Probiotic” Is Really a Probiotic? A Guideline for Consumers and Health Care Professionals
  2. How To Choose A Probiotic
  3. Probiotics and Prebiotics
  4. List of Probiotic Bacteria
  5. Lactobacillus acidophilus

(Photo Credit)


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