Probiotics, prebiotics and postbiotics are often mentioned together, but they are not the same thing. Understanding how each supports your gut microbiota can help you make smarter choices about food and supplements. This guide explains the differences, benefits, and whether you really need all three for balanced gut health.
Why the Distinction Matters
The gut is home to trillions of microorganisms, collectively known as the gut microbiota. Bacteria within the microbiome play an important role in digestion, nutrient absorption, immune communication and even how the body responds to stress. A range of compounds and nutrients can help support this internal ecosystem, including probiotics, prebiotics and postbiotics. As interest in gut health grows, these terms are used more frequently, but they are often misunderstood or used interchangeably.
Although they are closely linked, probiotics, prebiotics and postbiotics play very different roles. Understanding these distinctions can help you decide whether dietary changes, fermented foods, or gut supplements are appropriate for you.
Probiotics: Live Beneficial Bacteria
Probiotics are live microorganisms, including certain bacteria and yeasts, which when consumed in sufficient amounts help support the natural balance and normal functioning of the gut[1]. They contribute to maintaining healthy gut flora, support normal immune function, help limit the growth of less beneficial bacteria or pathogens, and assist with effective digestion and nutrient absorption[2].
Natural probiotics are found in fermented foods like yoghurt, kefir, sauerkraut and kimchi[3,4]. Supplements are another option, particularly for those seeking targeted support or who do not regularly consume fermented foods.
Not all probiotics are the same, and their effects can vary considerably due to:
1. Strain Specificity
Benefits depend on the specificity of the bacterial strain, as different strains are associated with different functions within the gut. Some strains protect the gut barrier while others may produce antimicrobial substances to deter pathogens. Due to strain specificity, a certain probiotic may be beneficial for one condition/person but not work for another. For this reason, it is important to look beyond general labels and consider which strains are included and why.
2. CFU Count
CFU stands for colony forming units and refers to the number of live, viable bacteria present in a probiotic product[5]. Typically measured in billions, this figure represents the bacteria that are capable of surviving and multiplying, rather than the total amount originally added during production. In this sense, the CFU count gives an indication of a probiotic’s strength or potency.
However, a higher CFU count does not automatically mean a product is more effective. Different probiotic strains have been studied at different dose levels, so suitability depends on the specific strains used and how they have been formulated.
It is also important that CFU counts reflect the number of live bacteria available at the end of the product’s shelf life, not just at the point of manufacture. This helps ensure the bacteria remain viable by the time they are consumed. For this reason, it is worth choosing products that clearly state their CFU count as guaranteed until the expiry date, rather than only at the time of production.
Quality and Stability
Quality and stability are equally important. Probiotics must be manufactured and stored correctly to help ensure the bacteria remain viable throughout their shelf life and are able to survive the journey through the digestive system. Well-formulated products prioritise protective delivery, appropriate storage guidance and transparent labelling to help maintain bacterial effectiveness.
Prebiotics: Food for Your Gut Bacteria
Prebiotics are types of fibre and carbohydrate that human digestive enzymes cannot break down. Instead, they act as nourishment for beneficial gut bacteria. This allows the gut microbiota to become stronger and healthier, which, in turn, can impact overall health.
Common prebiotic compounds include[6]:
- Inulin
- Fructo-oligosaccharides (FOS)
- Galacto-oligosaccharides (GOS)
- Trans-galacto-oligosaccharides (TOS)
Prebiotic foods include onions, garlic, leeks, bananas, chicory root and oats[7]. By feeding beneficial bacteria, prebiotics indirectly support digestion and microbial diversity. Research also indicates prebiotics can help improve metabolic diseases through encouraging the growth of beneficial bacteria.
By nourishing beneficial gut bacteria, prebiotics help support digestion and promote microbial diversity. Research also suggests that prebiotics may play a role in metabolic health by encouraging the growth and activity of beneficial bacteria within the gut[8].
Postbiotics: beneficial by-products
Postbiotics are the bioactive compounds produced when gut bacteria metabolise both prebiotics and probiotics.
These substances include[9].
- Amino acids
- Antimicrobial peptides
- Vitamins, such as B and K Vitamins
- Short-chain fatty acids (SCFAs)
Although postbiotics are not live bacteria, they are increasingly recognised for their role in supporting the gut barrier, helping limit the growth of less beneficial bacteria, contributing to balanced immune signalling, and supporting overall gut comfort and equilibrium.
Levels of beneficial postbiotics can be supported by regularly consuming fermented foods alongside a diet rich in fibres that encourage microbial diversity. Focusing on a diet that promote a varied and balanced gut microbiota may contribute to overall digestive and metabolic wellbeing.
So, Do You Need All Three?
In practice, probiotics, prebiotics and postbiotics work together. This is why products combining probiotics with prebiotic fibres are often referred to as synbiotics.
You may not need supplements for all three if your diet already includes a wide variety of fibre-rich plants and fermented foods. However, some people choose supplements for convenience or targeted support.
What to Look For
When considering gut supplements, quality matters. Look for:
- Clearly labelled strains (not just “probiotic blend”)
- Transparent CFU counts at end of shelf life
- Third-party testing where available
- Appropriate storage guidance (some require refrigeration)
Products that also include fibres, or support digestion through ingredients such as herbs or digestive enzymes, may offer broader digestive support.
Lifestyle Habits to Support Digestive Health
While probiotics, prebiotics and postbiotics play an important role in gut health, everyday lifestyle habits also influence how well the digestive system functions. Supporting digestion is about creating the right conditions for the gut to work efficiently.
Stay hydrated: Adequate water intake supports normal digestion and bowel regularity by helping fibre move efficiently through the digestive tract. Drinking around 6–8 glasses of water spread evenly throughout the day, rather than large amounts at once, may be particularly beneficial.
Spend time outdoors: Exposure to natural light, gentle movement and time in green spaces can support overall wellbeing and help regulate daily rhythms, which are closely linked to digestive function. Activities such as walking outdoors may also encourage healthy gut motility.
Include bitter foods and herbs: Bitter foods have traditionally been used to support digestion by stimulating digestive processes. Foods such as rocket, chicory and artichoke naturally contain bitter compounds. Herbal bitters are another traditional approach, with ingredients like yellow gentian and dandelion root long used to support digestive comfort, appetite and post-meal ease.
Eat mindfully: Taking time to eat without distraction and chewing food thoroughly can support the digestive process by allowing digestive enzymes to function more effectively.
Combining supportive foods, balanced nutrition and mindful daily habits helps support a stronger environment for digestive health alongside targeted gut support.
Supporting Gut Health with Herbal Remedies
Herbal remedies have traditionally played a role in supporting gut health and overall wellbeing.
Note: Before considering any herbal remedies, we recommend speaking to a registered herbalist first. Book a consultation at Napiers to receive personalised guidance based on your individual health profile.
The Napiers Gut Health Protocol is a thoughtfully curated four-week supplement regime designed to support the digestive system. Combining probiotics, traditional herbal support and essential nutrients such as vitamin D, this bundle supports the gut microbiome, digestive function and gut-immune interaction from multiple angles.
This 4-week protocol combines:
- Napiers Happy Gut
- Napiers Jarropick Herb Blend
- Napiers Vitamin D3 and K2 Spray
Rather than focusing on bacteria alone, the protocol takes a whole-system view of gut health. Probiotics and prebiotics in Napiers Happy Gut help nurture microbiome diversity, while Napiers Jarropick Herb Blend supports digestion, liver function and comfort after meals. The addition of Napiers Vitamin D3 and K2 Spray contributes to immune function and nutrient absorption – both important factors in maintaining gut barrier health and overall wellbeing.
This protocol is ideal for anyone seeking longer-term digestive comfort, improved microbiome diversity and gentle, ongoing digestive support as part of a balanced lifestyle.
By combining herbs, probiotics and minerals, the protocol avoids a one-size-fits-all approach often seen in standalone gut and digestive supplements. A four-week structure allows for gradual, consistent support as part of a wider gut health routine.
Save 20% when you shop this 4-week reset protocol with code PROTOCOL20.*
Shop our personalised 4-Week Reset Protocols here.
*Code PROTOCOL20: Code valid once per customer between 00.01 on 26/12/25 and 23.59 on 31/01/26 (GMT). Offer valid on Brain & Stress Support Protocol, Gut Health Protocol, Hormone Balance Protocol, Strength & Joint Health Protocol, Sleep & Recovery Protocol, Complete 4‑Week Reset, and Detox Protocol. This code cannot be used in conjunction with any other discount. Napiers terms of the site apply.
To explore gut health further, read our blog on why the gut microbiome matters and discover practical, everyday ways to support gut health naturally.
FAQs
What are prebiotics?
Prebiotics are non-digestible fibres that feed beneficial gut bacteria, helping them grow and function effectively.
What are the signs I need to take a probiotic?
You may consider a probiotic if you experience ongoing digestive discomfort, irregular bowel habits, bloating, or after a course of antibiotics, although individual needs can vary. To explore additional herbal support for digestive discomfort, read our blog here.
Is it good to take probiotics daily?
For many people, probiotics can be taken daily as part of a routine, but suitability and duration depend on the specific strains used and individual digestive needs.
What is the difference between probiotics and prebiotics?
Probiotics are live bacteria, while prebiotics are the fibres that nourish those bacteria.
Do I need probiotics, prebiotics and postbiotics?
Many people obtain all three naturally through a varied diet, but some choose synbiotics or targeted supplements.
Are gut supplements necessary?
Gut supplements are optional and best used to complement, not replace, a balanced diet rich in fibre and fermented foods.
References
- NHS (2022) Probiotics. Available at: NHS.
- Harvard Health Publishing (n.d.) The benefits of probiotic bacteria. Available at: Harvard Medical School.
- Randell, T. (2023) Top 15 probiotic foods to support gut health. BBC Good Food, 26 May. Available at: BBC Good Food.
- Palsdottir, H. (2024) 11 Probiotic foods that are super healthy, Healthline, 23 August. Medically reviewed by Adrienne Seitz, MS, RD, LDN. Available at: Healthline.
- National Institutes of Health (NIH) Office of Dietary Supplements (2025) Probiotics: Fact sheet for health professionals. Available at: NIH.
- Davani-Davari, D., Negahdaripour, M., Karimzadeh, I., Seifan, M., Mohkam, M., Masoumi, S.J., Berenjian, A. and Ghasemi, Y. (2019) ‘Prebiotics: definition, types, sources, mechanisms, and clinical applications’, Foods, 8(3), p. 92. Available at: MDPI.
- Semeco, A. and Kelly, E. (2024) The 20 best prebiotic foods you should eat, Healthline, 13 May. Medically reviewed by Katherine Marengo, LDN, R.D. Available at: Healthline.
- Gao, X., Hu, S., Liu, Y., De Alwis, S.A.S.S., Yu, Y., Li, Z., Wang, Z. and Liu, J. (2025) ‘Dietary fiber as prebiotics: A mitigation strategy for metabolic diseases’, Foods, 14(15), p. 2670. Available at: MDPI.
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Golen, T. and Ricciotti, H. (2021) What are postbiotics?, Harvard Health Publishing, 1 November. Available at: Harvard Medical School.
