Supplements

Prebiotics, Probiotics, Postbiotics: What's the Difference & How Do They Work Together?

Written by Robert Iafelice, MS, RDN, LDN
Medically Reviewed by Dr. Elaine Gavalas, ND, PhD

April 30, 2025

Research on the fascinating link between the gut microbiota and overall health and well-being continues to surge. Not only do the trillions of microbes residing in the gut impact digestive health and nutritional absorption, but they can also influence immune, metabolic (e.g., diabetes, obesity), and mental health as well (1). 

An imbalance in the composition of the gut microbiota (dysbiosis) is linked to numerous conditions, including inflammatory bowel disease (IBD), metabolic syndrome, liver diseases, and bacterial infections of the gut such as C. diff (Clostridium difficile) and H. pylori (Helicobacter pylori). Maintaining a healthy and balanced microbiota is vital for optimal functioning of the immune system and prevention of disease (2). 

For decades, probiotics from foods and supplements have been consumed as a strategy to favorably alter the composition and diversity of the gut microbiota. More recently, prebiotic foods and supplements have also become popular among the health conscious. Newest on the ‘biotics’ scene are postbiotics, which work synergistically with probiotics and prebiotics to potentially maximize health (2). 

Prebiotics … probiotics … postbiotics … there's a lot to unpack here! 

What exactly is the difference between pre, pro, and postbiotics?  How do they all work in tandem to help enhance the composition of the gut microbiota to potentially promote robust health?

Table Of Contents

Probiotics

Probiotics are live, non-infectious microorganisms (bacteria and yeasts) that provide a wide variety of health benefits. Indeed, the term “probiotic” is derived from a pair of Latin and Greek words - “pro” and “bio” - that together mean “for life.” (3). 

Naturally found in yogurt, sauerkraut, and other fermented foods, probiotics are also added to foods such as juices, nutrition bars, and cereals. Probiotic supplements may contain a single bacterium or several different microorganisms. Common strains of probiotics include Bifidobacterium and Lactobacillus while Saccharomyces boulardii is a common yeast strain (4). 

Probiotic supplements must be able to circumvent the harsh acidic environment of the digestive tract in order to reach and colonize the colon, the primary residence of the gut microbiota. This is achieved through effective delivery systems and strategies such as freeze-drying the microbes and the use of enteric-coated capsules that resist stomach acid degradation (1).

How Do Probiotics Work?

In the body, probiotics function in a variety of ways (1). These beneficial microbes: 

  • May help improve the composition and diversity of the gut flora
  • Potentially boost the immune system, possibly resulting in a balance between pro- and anti-inflammatory effects as well as immune tolerance (i.e., the ability to distinguish between harmful and harmless chemicals or antigens)
  • Likely reduce the permeability of the intestinal barrier walls to toxic chemicals and infectious microbes (i.e., a “leaky gut”) by potentially strengthening the integrity of the cells lining the gut
  • Produce compounds including antibacterial proteins and short-chain fatty acids (SCFAs) which may potentially help suppress inflammation 
  • Help block the growth and activity of harmful bacteria and viruses in the gut
  • Help stimulate production of protective mucus
  • Possibly regulate the transit of food through the digestive tract

Health Benefits of Probiotics

Probiotics may be used to help with a myriad of conditions. Some examples supported by strong research evidence include the following disorders:

Intestinal Diseases

Disorders involving the gastrointestinal tract (GI) are often linked to a disruption in the balance of the gut bacteria. These conditions include antibiotic-associated diarrhea, ulcers, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), lactose intolerance, and even GI cancers (3).

By increasing the richness and diversity of the gut flora, probiotics can be harnessed to potentially help alleviate intestinal disorders. Additionally, probiotics  may  help manage these conditions through their ability to potentially  improve immune function, increase production of digestive enzymes (e.g., lactase to digest lactose), and help heal a “leaky gut” (decrease intestinal permeability) (3). 

Allergies & Allergic Diseases

The gut microbiota interacts with the immune system to promote and maintain tolerance (unresponsiveness) to food allergens while also mounting an immune response to foreign antigens (e.g., pollen, bacteria, chemicals). Dysbiosis—changes in the composition of the gut microbiota—can lead to loss of immune tolerance and increased risk of allergic diseases (5). 

Two systematic reviews of controlled clinical trials have concluded that supplementation with probiotics before and after birth  may potentially  prevent eczema and other allergic diseases (6, 7). Strong evidence from animal studies also supports the use of probiotics in the treatment of allergic diseases (8). 

Among the mechanisms that underlie the anti-allergic effects of probiotics are production of anti-inflammatory proteins, potentially healing a leaky gut, and possibly balancing immune responses (3). 

High Cholesterol Levels

Probiotics may help lower serum cholesterol levels directly by potentially inhibiting the body’s production of cholesterol and also by possibly reducing the absorption of cholesterol from foods. Indirectly, probiotics may help lower cholesterol by potentially causing increased elimination of bile from the body. This may result in more cholesterol being drawn from the blood to make more bile, thus potentially lowering blood levels (3). 

Both human and animal studies suggest that specific probiotic strains (e.g., Lactobacillus, Bifidobacteria, and L. plantarum) may significantly decrease total cholesterol levels (3).

Cancer

The benefits of probiotics may even include the possible prevention and treatment of various types of cancer, including breast, lung, and colorectal cancers (9). For example, the probiotic strain Lactobacillus casei may  degrade powerful carcinogens known as HCAs (heterocyclic amines) which are formed when meat or fish is charred and overcooked. These chemicals can cause genetic mutations and are linked to cancers of the stomach and colon (10). 

Beyond cancer prevention, probiotics may  be used as a potential  adjuvant (supplemental) therapy in cancer treatment. Experimental studies suggest  that probiotics may possibly  reduce the formation, growth, and metastasis (spreading) of tumors while also potentially  causing programmed cancer cell death (a form of “cellular suicide”) (9).

Probiotics may  also potentially enhance the cancer-killing effects of chemotherapy drugs such as cisplatin. By potentially improving the gut microbiota, these beneficial bacteria may  possibly  decrease the severity of side effects (e.g., diarrhea) as well. Many of the potential anti-cancer effects of probiotics are due in part to their possible anti-inflammatory and immune-enhancing activity (9). 

Obesity

It’s established that the gut microbiota of thin people differs from that of overweight or obese people. Thus, the use of probiotics to favorably alter the composition of the gut microbiota may be a potential therapy for treating excess weight and obesity (11). 

In a recent review of clinical trials in overweight/obese individuals, significant weight loss was achieved in close to 70% of the studies through the use of probiotics. A trend in preventing weight gain was also observed. Combinations of a variety of strains (rather than single strains) of Bifidobacterium and Lactobacillus were found to potentially produce superior results (11). 

Nevertheless, there is a lack of consensus in the medical literature, as other studies showed no effect from probiotics for weight loss (4). 

Other Conditions

Besides obesity, probiotics may potentially help prevent and treat other metabolic disorders such as type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) (12). They may also possibly aid in the prevention of dental caries and urinary tract infections (UTIs) (13).

Prebiotics

Prebiotics are dietary substances that selectively promote the growth and activity of beneficial bacteria in the digestive tract. In other words, prebiotics function as “food” that is gobbled up by the good microbes in the gut, helping them to flourish and multiply (14). 

Soluble fibers such as inulin, fructooligosaccharides (FOS), and galactooligosaccharides (GOS) are among the more common types of prebiotics. Good food sources of prebiotic fibers include bananas, garlic, onions, asparagus, and chicory root (14). Green bananas and legumes contain resistant starch, another type of prebiotic (15). Plant pigments known as polyphenols can also act as prebiotics. These antioxidant pigments are primarily found in fruits, vegetables, tea, and coffee (16). 

Since prebiotics are typically non-digestible, they escape digestion in the small intestine and reach the colon intact. In the colon, bacteria ferment the prebiotics into short-chain fatty acids (SCFAs) such as butyrate, acetate, and propionate. These SCFAs play an important role in gut health by serving as a major fuel source for colon cells and by suppressing intestinal inflammation and the growth of harmful microbes in the gut (14). 

Health Benefits of Prebiotics

The use of prebiotics may promote a greater abundance of good bacteria (e.g., Lactobacilli and Bifidobacteria) and help reduce numbers of harmful bacteria, potentially resulting in a more balanced and healthier gut microbiota (14). Thus, like probiotics, prebiotics may potentially  improve the composition and diversity of the gut microbiota. 

That being the case, it follows that prebiotics may  be used to potentially help prevent and treat the same disorders that benefit from the use of probiotics. These conditions include gastrointestinal diseases (e.g., IBS, IBD) and various metabolic disorders such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD) (12, 14).

Native Note: Dietary supplements that contain both probiotics and prebiotics are known as synbiotics.

Postbiotics

While probiotics and prebiotics are familiar terms to many health-conscious people, there’s a new kid on the block: postbiotics.

So, what are postbiotics?

Postbiotics are by-products formed primarily during the fermentation of beneficial probiotic bacteria or yeasts. Among the wide range of molecules that can make up a postbiotic supplement are various proteins, vitamins (e.g, folate, vitamin K), enzymes, polyphenols, and short-chain fatty acids (SCFAs) (17).

Postbiotic supplements often consist of the products from bacterial/yeast digestion together with the non-living organisms that produce them. For example, ‘yeast fermentate’ is a postbiotic that includes both vitamins and other compounds created from yeast fermentation along with the yeast cells themselves, though no longer alive (18). 

The absence of live organisms in postbiotics confers some advantages over probiotics. These include a longer shelf life, greater stability, and easier storage (17).

Health Benefits of Postbiotics

Postbiotics may be responsible for many of the potential health benefits of probiotics via their possible immune enhancing, antioxidant, anti-inflammatory, anticancer, and antimicrobial activity. They may potentially be used to help prevent or treat a number of diseases, including those with unknown causes (e.g., Alzheimer’s disease, inflammatory bowel disease, and multiple sclerosis) (19).

Butyrate is one of the most popular postbiotic supplements, and for good reason. As one of the short-chain fatty acids produced by beneficial gut bacteria, butyrate is well recognized for its potential role as a key energy source for the cells lining the intestinal tract. As such, it may help intestinal cells repair and renew themselves, potentially strengthening the barrier function of the gut wall in keeping foreign chemicals and invaders from entering the body (19). 

Moreover, a review of studies suggests butyrate may help protect against potential atherosclerosis (plaque buildup in the arteries). In one study, butyrate generated from the bacterial digestion of high-fiber foods was shown to potentially reduce the size of arterial plaques in mice (20).

Native Note: Interestingly, you can also get butyrate from eating good old butter (NOT margarine), from which it derives its name (21). 

The Bottom Line

Probiotics, prebiotics, and postbiotics work synergistically to help promote a healthy and balanced gut microbiota and potentially strengthen the immune system: 

  • Probiotics are actual live beneficial bacteria and/or yeasts that compete with the harmful bacteria in the gut.
  • Prebiotics serve as non-digestible food ingredients that provide nourishment for the friendly bacteria in the gut, thus potentially encouraging their growth and proliferation.
  • Postbiotics are the by-products (“waste”) created from the fermentation (digestion) of prebiotics by probiotic bacteria. Postbiotics mediate many of the potential health benefits of pro- and prebiotics. 

A healthy gut microbiota is critical for optimal overall health. By leveraging the complex interaction between the gut microbiota and the immune system, all three biotics may help prevent or treat numerous diseases potentially ranging from intestinal disorders to metabolic disorders (e.g., obesity and diabetes) to mental health conditions. 

As personalized (or precision) medicine becomes the future of healthcare, medical treatments and preventive measures for various health conditions may ultimately be based on the microbiota profile of each individual. Prebiotics, probiotics, and postbiotics could be the next generation of medicines that revolutionize healthcare by targeting an individual’s unique gut microbiota (1, 14). 

Robert Iafelice
Article by

Robert Iafelice

Robert Iafelice, MS, RD, LDN is a functional nutritionist and freelance medical writer. He is the author of Hold On to Your Muscle, Be Free of Disease, a unique perspective on wellness and disease in the context of muscle health.

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    Medical Disclaimer

    This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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    Research on the fascinating link between the gut microbiota and overall health and well-being continues to surge. Not only do the trillions of microbes residing in the gut impact digestive health and nutritional absorption, but they can also influence immune, metabolic (e. g., diabetes, obesity), and mental health as well (1). An imbalance in the composition of the gut microbiota (dysbiosis) is linked to numerous conditions, including inflammatory bowel disease (IBD), metabolic syndrome, liver diseases, and bacterial infections of the gut such as C. diff (Clostridium difficile) and H. pylori (Helicobacter pylori). Maintaining a healthy and balanced microbiota is vital for optimal functioning of the immune system and prevention of disease (2). For decades, probiotics from foods and supplements have been consumed as a strategy to favorably alter the composition and diversity of the gut microbiota. More recently, prebiotic foods and supplements have also become popular among the health conscious. Newest on the ‘biotics’ scene are postbiotics, which work synergistically with probiotics and prebiotics to potentially maximize health (2). Prebiotics … probiotics … postbiotics … there's a lot to unpack here! What exactly is the difference between pre, pro, and postbiotics? How do they all work in tandem to help enhance the composition of the gut microbiota to potentially promote robust health?