Prebiotics vs. Probiotics vs. Postbiotics: Which Do You Need?

We have both good and bad bacteria in our bodies. Bacteria might sound unhealthy, but beneficial bacteria are what keep our guts flourishing and support our overall wellness. These good gut bugs help keep us healthy in more ways than one.

Probiotics are living microbes (such as bacteria and yeast) that can offer health benefits when taken in proper doses. But they aren't the only heroes of digestive health: prebiotics and postbiotics also play an important role. Like probiotics, these compounds can support digestive health, immune system function, and overall well-being. While their names and benefits may be similar, each of these gut health heroes serves different roles within the body and can come from varying food sources.

Here's a rundown on how probiotics, prebiotics and postbiotics can impact our wellness.

What are prebiotics, probiotics and postbiotics?

All three of these "P"s play an important role in our overall health. Here's what you need to know about how each works in the body.

Prebiotics.

Prebiotics are components from foods that can feed the microbes in the gut, such as non-digestible fibers that end up being fermented by your gut bacteria—a process that promotes growth of more beneficial microorganisms.

• Source: Prebiotics are found in fruits, vegetables, whole grains and legumes.
• Examples: Specific prebiotics include xylo-oligosaccharides (XOS), fructo-oligosaccharides and galacto-oligosaccharides.
• Benefits: Prebiotics serve as food for the bacteria in your gut microbiome. Fermentation of prebiotic fibers results in the production of beneficial short-chain fatty acids such as acetate, butyrate, and propionate.

Probiotics.

These are living microorganisms—specifically, bacteria and yeasts. When taken in sufficient amounts, probiotics can promote health benefits like supporting gastrointestinal health and digestion.

• Source: Beneficial, living microbes are found in fermented foods, such as yogurt, kimchi, miso, sauerkraut, and kombucha—although if the label does not list which strains are present and CFU, there's no way to know whether you are consuming microbes in meaningful amounts. For this reason, there's no way to know if they actually meet the official definition of a probiotic. A probiotic supplement that lists strains and CFU can help you meet clinically studied intake levels.
• Examples: All probiotic bacteria will be classified by genus, species, and strain, meaning that a probiotic will have three words in its name. (The first word in the name may just be a letter, since it's customary to abbreviate it.)
• Benefits: Their benefits are as diverse as the bacteria themselves. Some probiotics focus on digestive comfort, helping with bloating or irregular bowel movements. Others target immune system support, and many offer benefits we're still discovering through ongoing research.

Postbiotics.

Postbiotics are inactivated bacteria and the compounds released by bacteria. Postbiotics are very shelf-stable.

• Source: Postbiotics are inactive microbes or compounds secreted by bacteria, so you'll find them in fermented foods that contain(ed) living microbes, like sauerkraut and tempeh.
• Examples: Dried yeast and heat-treated bacterial strains (often designated as "HT §" before the strain name) are examples of postbiotics. Other types include peptides and short-chain fatty acids.
• Benefits: Postbiotics offer different benefits depending on the strain or specific components. Some focus on digestive comfort while others support various aspects of overall health.

Why your gut needs prebiotics, probiotics and postbiotics to thrive

Prebiotics, probiotics and postbiotics have a symbiotic relationship. That means it is important to have all three in your diet to support gut microbiome health. Your microbiome needs food to sustain itself (prebiotics), healthy microbes (probiotics), and the various metabolites that support function (postbiotics). All three types have been shown in clinical studies to support health, although some probiotic strains have more clinical support than others. It's important to choose strains studied to support your specific health goals.

Probiotic supplements are often synbiotics, or products that combine probiotics and prebiotics for even more benefits. Synbiotics can be complementary (which occurs when a probiotic and prebiotic are not co-dependent, but are beneficial when taken together). They can also be synergistic, which is where the prebiotic specifically nourishes the probiotic microorganisms, supporting their survival in the digestive tract.

Supplements vs. gut food: which is better?

When it comes to nourishing your body, food should be the top priority. Aim to eat a healthy, balanced diet rich in whole foods (fruits, vegetables, legumes, whole grains, nuts, seeds and healthy fats) to help support a healthy gut with prebiotics. Then add in some fermented foods for their beneficial microbes.

As their name suggests, supplements should supplement your already-healthy diet. They can be used as added support to fill in any gaps in your regular eating plan; they can also offer targeted support, like helping with digestive comfort or promoting regularity.

If you struggle with getting enough high-fiber plant foods, like fruits and veggies, or you don't like the sour taste of many fermented foods, you may benefit from adding a gut supplement to your routine.

How to choose the right microbiome supplement

Doing your research and talking to a healthcare professional can help you get the best recommendation for a gut health supplement for your needs. Here's a breakdown on what to look for before adding a bottle to your cart.

• What to look for: Look for probiotic supplements that are clinically supported and list the specific dose and strains on the label. Always choose a supplement company that uses third-party testing for quality and efficacy.
• Dosage: Dosage varies widely between supplements. Prebiotics typically come in doses of several grams while probiotics are measured in colony-forming units (CFUs), which is the number of living cells, usually in the hundreds of millions or billions. Postbiotics are often dosed in milligrams, so don't be concerned about the smaller amounts. Look for strains and doses that match clinical research.
• Form: You always want the clinically studied forms of each. Probiotic and postbiotic supplements usually come in capsules, so the serving size might be smaller (and therefore easier to swallow). Prebiotics often require higher doses, so they might be available as chewable tablets or powders, which are easier to take in larger quantities.

Should I take all three: prebiotics, probiotics and postbiotics?

Yes, you can take prebiotics, probiotics, and postbiotics together. Remember to check with your doctor before adding a supplement to your daily routine to make sure it fits with your health concerns and lifestyle.

Is there a best time of day to take them?

Always follow the instructions on the supplement label, unless otherwise advised by your doctor. If a time of day isn't included in the instructions, it probably doesn't matter. Try taking them at different times to find what feels right for you. (Since some prebiotics can encourage healthy bowel movements, timing might matter depending on your schedule.) Overall, the best time to take a supplement is as directed on the label, and if there is no specified time, then whenever you'll remember to take it consistently.

Are postbiotics okay long-term?

Certain postbiotics, such as heat-treated B. longum ES1, have been studied in clinical trials for 12 weeks without any negative effects, and there is no evidence that taking them longer would not be okay. Still, you'll want to check with your doctor about all the supplements you take for your specific health goals.

References

• Davani-Davari D, et al. "Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications." Foods. March 2019. https://pubmed.ncbi.nlm.nih.gov/30857316/
• Kleerebezem M, Führen J. "Synergistic vs. complementary synbiotics: the complexity of discriminating synbiotic concepts using a Lactiplantibacillus plantarum exemplary study." Microbiome Res Rep. September 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11684985/
• Li HY, et al. "Effects and Mechanisms of Probiotics, Prebiotics, Synbiotics, and Postbiotics on Metabolic Diseases Targeting Gut Microbiota: A Narrative Review." Nutrients. September 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8470858/
• Prajapati N, et al. "Postbiotic production: harnessing the power of microbial metabolites for health applications." Front Microbiol. December 2023. https://pubmed.ncbi.nlm.nih.gov/38169918/
• Srivastava S, et al. "A randomized double-blind, placebo-controlled trial to evaluate the safety and efficacy of live Bifidobacterium longum CECT 7347 (ES1) and heat-treated Bifidobacterium longum CECT 7347 (HT-ES1) in participants with diarrhea-predominant irritable bowel syndrome." Gut Microbes. January-December 2024. https://pubmed.ncbi.nlm.nih.gov/38630015/
• Yadav MK, et al. "Probiotics, prebiotics and synbiotics: Safe options for next-generation therapeutics." Appl Microbiol Biotechnol. January 2022. https://pubmed.ncbi.nlm.nih.gov/35015145/
• "Probiotics and prebiotics." World Gastroenterology Organisation. February 2017. https://www.worldgastroenterology.org/UserFiles/file/guidelines/probiotics-and-prebiotics-english-2017.pdf