Probiotics have become a familiar term in conversations around digestive health, but what exactly are they? In simple terms, probiotics are live microorganisms that are used in food products and dietary supplements. While the word "bacteria" often carries negative connotations, many microorganisms play a helpful role in maintaining microbial balance in the gut environment.

Probiotics in Food

Probiotics are most commonly associated with fermented foods. Traditional recipes from around the world—such as yogurt, kefir, sauerkraut, kimchi, miso, and kombucha—rely on the fermentation process to preserve food and develop flavor. During fermentation, beneficial bacteria or yeasts convert sugars into acids or alcohol, creating environments where these microorganisms can thrive.

These foods naturally contain live cultures, and in some cases, specific probiotic strains are added to enhance consistency. However, not all fermented foods automatically qualify as probiotic sources. To be considered probiotic, the organisms must be alive at the time of consumption and identified by genus, species, and strain—such as Lactobacillus rhamnosus GG or Bifidobacterium lactis HN019.

Probiotics in Supplements

In addition to fermented foods, probiotics are widely available in supplement form. Capsules, powders, gummies, and even beverages are often formulated with specific strains of bacteria or yeasts, carefully chosen for their ability to survive manufacturing, packaging, and storage.

These strains are typically measured in colony-forming units (CFUs), which estimate how many viable microorganisms are present. Depending on the product, this number can range from a few million to several billion CFUs per serving. 

Understanding Probiotic Strains

The classification of probiotics follows a taxonomy similar to other living organisms. The genus (e.g., Lactobacillus), species (e.g., acidophilus), and strain (e.g., LA-5) all give insight into the specific properties and origin of the microorganism. This specificity matters because different strains behave differently, even within the same species.

Probiotics can include both bacteria and yeasts. The bacterial genera Lactobacillus and Bifidobacterium are among the most common in supplements and foods, while Saccharomyces boulardii is a beneficial yeast that’s used in many targeted formulations.

Product Variety and 

Probiotics may originate from dairy cultures, vegetable fermentation, or specialized laboratory cultivation. Regardless of the source, successful probiotic ingredients are generally chosen for their stability and compatibility with their intended use—whether in food preservation, digestion-focused products, or wellness blends.

It's also worth noting that not all probiotic products are the same. Some include a single strain, while others offer multi-strain complexes. Some are shelf-stable; others require refrigeration. 

A Growing Area of Interest

As science continues to explore the many layers of microbial life, probiotics remain a key area of focus. Their presence in food and supplement culture highlights how microorganisms are becoming part of the broader conversation about what we consume and why.

As always, talk to your doctor before taking any supplements. Get professional advice if you think you might need any supplement or are already taking one to ensure you’re not exceeding the amounts you may need.