Summary
Live beneficial microbes that, in adequate amounts, support gut health.
In depth
Typical strains are Lactobacillus and Bifidobacterium. They may help with antibiotic-associated diarrhoea, but evidence for many claimed benefits is limited. Prebiotics are fibres that feed beneficial bacteria.
Probiotics must be alive, in adequate numbers and give a documented benefit. Strain specificity matters. Effects often transient.
Common mistake: all fermented foods contain probiotics; some are heat-treated.
The definition from the WHO and FAO is live microorganisms that confer a health benefit when given in adequate amounts. Effects are strain-specific: Lactobacillus rhamnosus GG and Saccharomyces boulardii help against some diarrhoeas, and some strains may reduce risk of necrotising enterocolitis in preterm infants. Prebiotics are fibres that feed beneficial microbes, and synbiotics combine both.
Mechanisms include competition with pathogens, producing acids and bacteriocins, strengthening the gut barrier and modulating immunity. Many commercial claims are not well supported, and products may lack the stated organisms. Safety concerns exist for immunocompromised patients. Faecal microbiota transplants have cured most recurrent Clostridioides difficile infections.
Remember: probiotics usually do not permanently colonise the gut; effects last while taken.
Frequently asked questions
What is Probiotics?
Live beneficial microbes that, in adequate amounts, support gut health.
Which area of biology covers Probiotics, and how advanced is it?
Probiotics is one of the 54 topics in Microbiology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Microbiome, Gut-Brain Axis, Fermentation.
Can you give an example of Probiotics?
Fermented foods such as kefir and kimchi.
What should I learn before Probiotics?
Probiotics is a Beginner topic, so no earlier topic is required. Other Beginner topics in Microbiology that pair well with it include Microorganisms, Bacteria, Archaea.
What topics are related to Probiotics?
The closest topics to Probiotics are Microbiome, Gut-Brain Axis, Fermentation, Microorganisms. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Probiotics?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Probiotics. To practise the whole of Microbiology, use the Microbiology quiz.
How is Probiotics different from Microbiome?
Probiotics: Live beneficial microbes that, in adequate amounts, support gut health. Microbiome: The community of microorganisms living in and on a host, such as the human gut. Read both side by side and note what each one explains.
What is a common mistake about Probiotics?
All fermented foods contain probiotics; some are heat-treated.
How should I study Probiotics step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Microbiome and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.