Nutrition Diet: What are the three types of probiotics?

October 11, 2025 •

5 min read

According to reports, the global market for probiotic supplements continues to grow, reflecting a rising interest in gut health. For those looking to support their digestive wellness and immune function through diet, a key first step is to understand what are the three types of probiotics?.

Quick Summary

The three primary types of probiotics are Lactobacillus, Bifidobacterium, and the yeast Saccharomyces boulardii. Each provides distinct benefits, from aiding digestion and nutrient absorption to protecting the gut during antibiotic use, and can be found in fermented foods or dietary supplements.

Key Points

Lactobacillus is a versatile bacterial probiotic found in fermented foods like yogurt and kefir, known for producing lactic acid that helps inhibit harmful bacteria.
Bifidobacterium primarily resides in the intestines and specializes in digesting fiber to produce beneficial short-chain fatty acids, supporting digestion and immune function.
Saccharomyces boulardii is a unique probiotic yeast that is resistant to antibiotics, making it particularly effective for preventing and treating antibiotic-associated diarrhea.
Specific health benefits are strain-dependent, meaning the efficacy of a probiotic is tied to the particular strain (e.g., L. rhamnosus GG vs. L. plantarum), not just the genus.
Probiotics can be consumed via fermented foods or supplements, but supplements often contain specified, clinically-tested strains at therapeutic doses, which is not always guaranteed with foods.
When choosing a probiotic, consider your health goals, check the CFU count and strain information on the label, and ensure the product is stable and viable.

The Importance of Probiotics in a Healthy Diet

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. These 'friendly' bacteria and yeasts populate the gut microbiome, a complex community of trillions of microorganisms that play a vital role in overall health. A balanced gut environment can influence everything from digestion and immunity to mood and nutrient absorption. However, the gut's delicate balance can be disrupted by various factors, including illness, poor diet, and antibiotics. Incorporating probiotics into a nutrition-focused diet can help restore this balance.

What are the three types of probiotics?

While many different genera of microbes can be classified as probiotics, three of the most widely studied and used types are Lactobacillus, Bifidobacterium, and Saccharomyces boulardii.

Lactobacillus: The Versatile Multitasker

Found naturally in the gut, mouth, and vagina, Lactobacillus is one of the most well-known types of probiotic bacteria. This genus is a type of lactic acid bacteria, meaning it ferments sugars into lactic acid. This process lowers the pH level of the gut, creating a less hospitable environment for harmful bacteria.

Common Lactobacillus Strains and Their Benefits:

Lactobacillus acidophilus: One of the most studied strains, with benefits including enhanced immunity, improved digestive wellness, and potential cholesterol-lowering effects. It is known for its resistance to acid and bile, which helps it survive the harsh gastrointestinal tract.
Lactobacillus rhamnosus GG (LGG): A highly researched strain, particularly noted for its role in preventing and treating various forms of diarrhea, including traveler's and antibiotic-associated diarrhea. It also supports the intestinal barrier and modulates immune responses.
Lactobacillus plantarum: A versatile strain studied for its ability to reduce bloating and abdominal discomfort, especially in individuals with Irritable Bowel Syndrome (IBS).

Sources: Lactobacillus is commonly found in fermented dairy products like yogurt and kefir, as well as fermented foods such as sauerkraut, kimchi, and some cheeses.

Bifidobacterium: The Gut Resident

Bifidobacteria are a crucial group of bacteria that naturally inhabit the intestines, playing a significant role in maintaining a healthy gut from infancy onward. They specialize in digesting dietary fiber and complex carbohydrates that the body cannot break down on its own. This process produces beneficial compounds known as short-chain fatty acids (SCFAs), which provide energy for gut cells and have wide-ranging health effects.

Common Bifidobacterium Strains and Their Benefits:

Bifidobacterium animalis subsp. lactis (BB-12): This strain is known for its ability to support recovery of gut microbe populations after antibiotic use and has shown benefits for improving bowel regularity and immune function.
Bifidobacterium longum BB536: Researched for its ability to support digestive regularity, improve bowel movements, and help manage allergic symptoms.
Bifidobacterium infantis: Helps establish a healthy microbiome in babies and has been studied for alleviating IBS symptoms in adults.

Sources: Similar to Lactobacillus, Bifidobacterium can be found in fermented dairy foods like yogurt and kefir, as well as supplements.

Saccharomyces boulardii: The Probiotic Yeast

Unlike Lactobacillus and Bifidobacterium, which are bacteria, Saccharomyces boulardii is a non-pathogenic, non-colonizing probiotic yeast. It is known for its unique profile and ability to withstand the effects of antibiotics, making it a valuable tool for supporting gut health during and after antibiotic treatment.

Key Benefits of Saccharomyces boulardii:

Antibiotic-Associated Diarrhea (AAD): Numerous clinical studies have demonstrated its effectiveness in reducing the risk of AAD in both children and adults by restoring gut flora and reducing inflammation.
Traveler's Diarrhea: A well-known application for this probiotic is its use in preventing traveler's diarrhea, with studies showing a significant reduction in incidence.
Specific Infections: It helps fight disease-causing organisms in the gut by adhering to harmful bacteria like E. coli and Salmonella and facilitating their removal. It is also used alongside standard treatments for Clostridium difficile infections.

Sources: Saccharomyces boulardii is primarily available in supplement form, such as Florastor, rather than common fermented foods.

Sources of Probiotics: Food vs. Supplements

Probiotics can be incorporated into a diet through both foods and supplements, but there are key differences.

Fermented Foods: Foods like yogurt, kefir, and sauerkraut are excellent natural sources of beneficial bacteria. However, not all fermented foods contain microbes that meet the specific criteria to be called a 'probiotic' and may not deliver a scientifically proven health benefit. The number and type of bacteria can vary widely depending on the product, and some processing methods, like pasteurization, can kill off beneficial organisms.
Probiotic Supplements: These products are designed to deliver a specific, controlled dose of one or more defined strains of live microorganisms. For a supplement to be effective, it should clearly state the genus, species, and strain (e.g., Lactobacillus rhamnosus GG), the number of colony-forming units (CFUs), and an expiry date.

Choosing the Right Probiotic

Selecting a probiotic depends on your specific health goals, as the effects are strain-specific, not just genus-specific. For example, a strain that helps with constipation may not be the most effective for immune support. Consulting a healthcare professional can help you make an informed decision.

Comparison of Common Probiotic Types


Feature	Lactobacillus	Bifidobacterium	Saccharomyces boulardii
Microbe Type	Bacteria	Bacteria	Yeast
Primary Location	Gut, mouth, vagina	Intestines	Not a normal gut resident; passes through
Digestion Support	Produces lactic acid, helps with lactose digestion	Digests fiber, produces SCFAs	Supports gut function during disruption
Immune Function	Strengthens immune system, anti-inflammatory	Supports immunity and manages inflammation	Modulates immune response
Antibiotic Resilience	Can be compromised by antibiotics	Can be compromised by antibiotics	Resists antibiotics; beneficial alongside treatment
Key Applications	Diarrhea, gut barrier, cholesterol	IBS, bowel regularity, infant health	Traveler's diarrhea, AAD, C. difficile infections
Common Sources	Yogurt, kefir, sauerkraut	Yogurt, kefir, kombucha	Supplements (e.g., Florastor)

Conclusion

Understanding what are the three types of probiotics? is essential for anyone seeking to leverage nutrition for improved gut health. Lactobacillus, Bifidobacterium, and the yeast Saccharomyces boulardii each bring unique strengths to the table, addressing different aspects of digestive and immune wellness. Whether sourced from fermented foods or targeted supplements, adding these beneficial microbes to your diet can be a powerful strategy for maintaining a balanced and thriving internal environment. Always consider your specific health needs and consult a professional when choosing the right probiotic regimen for you, as the benefits are highly strain-specific.

How to get more probiotics - Harvard Health

Frequently Asked Questions

A probiotic is a live microorganism that confers a health benefit, while a prebiotic is a non-digestible fiber that acts as food for these beneficial bacteria, helping them to grow and thrive.

No. While all fermented foods contain microorganisms, not all are considered probiotics. For a microbe to be a probiotic, it must be scientifically proven to provide a health benefit when consumed in adequate amounts.

It is generally recommended to take a probiotic supplement throughout your antibiotic treatment and for at least a few weeks after. Separate the antibiotic and probiotic doses by at least 2 hours to maximize effectiveness.

Some strains of probiotics, particularly certain Bifidobacterium and Lactobacillus strains like B. infantis and L. plantarum 299v, have been shown to help reduce symptoms of Irritable Bowel Syndrome (IBS), such as bloating and abdominal pain.

Probiotics are generally safe for most healthy people. However, individuals with compromised immune systems, severe underlying health conditions, or those who are critically ill should consult a healthcare provider before taking probiotics, as there can be a risk of infection.

Choosing the right strain depends on your specific health goals. Since benefits are strain-specific, you should identify your needs (e.g., gut health, immunity, or managing a specific condition) and then look for a product containing a strain with clinical evidence for that purpose.

CFU stands for Colony-Forming Units, which indicates the number of live and active microorganisms in each serving of a probiotic. A higher CFU count generally means more live bacteria per dose, but the specific strain and its viability are more important.