Prebiotics vs Probiotics:  What’s the difference?  

Gut health plays a central role in maintaining digestive health and general well-being. There are many products on the market claiming to promote good gut health, many of which contain probiotics and prebiotics 

The fact that these 2 terms are very similar can lead to some confusion between their uses and benefits. However, they influence gut health in different ways. 

This article will explore the difference between these as well as their unique benefits. 

Understanding Prebiotics 

Prebiotics are contained in certain supplements as well as a range of plant foods. 

These can be thought of as beneficial fibres that help to support and maintain digestive health and gut function. 

What are prebiotics and what are they used for? 

Prebiotics are used to promote the growth of specific beneficial gut bacteria in the gut microbiome.  

These are types of dietary fibres that are not digested in the small intestine. These fibres travel to the large intestine, where they are fermented by the bacteria. This fermentation process encourages the growth of certain gut bacteria and also increases the levels of gut friend compounds such as butyric acid. 

The fact that different prebiotics feed different bacteria means that when ingesting a certain prebiotic it can selectively feed a specific bacteria, or group of bacteria, in the large intestine. These bacteria can support the gut in a variety of ways. 

Health benefits of prebiotics 

The are many health benefits of prebiotics. They can be in 2 main categories. 

1. To improve digestive health 

1. To support overall wellbeing 

This refers to the fact that prebiotics can help with a wide range of digestive symptoms but also they can support other areas of human health, even in patients who do not have digestive symptoms. 

Prebiotics can help with: 

• Bloating 

• Constipation 

• Diarrhoea 

• Reflux 

From a non-digestive perspective, prebiotics have been found to help with: 

• Reducing anxiety 

• Helping improve mood 

• Supporting skin health 

• Reducing the risk of developing diabetes 

• Supporting cardiovascular health [1] 

Due to the role of prebiotics supporting the residential bacteria in the gut microbiome, it’s been suggested that prebiotics are more beneficial than probiotics. This is due to their ability to modify the gut microbiome, which may be longer lasting than with probiotics. 

Sources of prebiotics 

There are both dietary sources of prebiotics as well as supplemental sources. 

Prebiotics in supplement form include: 

• FOS 

• GOS 

• PHGG 

• Lactulose [2] 

While FOS and GOS in supplements are a more concentrated form, they are also found in foods. For some, 2 main benefits of taking these in supplement form include: 

1. Knowing the exact dose being taken 

1. The ability to increase the dose very gradually. 

These are 2 reasons why using probiotics in powder form can provide more predictable results than from food. 

Dietary sources of prebiotics include: 

Understanding Probiotics  

Probiotics are described as living microorganisms that can improve the health of the person taking them. This might give the impression that after these living bacteria are ingested, they live in the gut, helping to repopulate the microbiome.  

The point that probiotics populate the gut is not strictly correct, however, they can help to support gut health to improve digestion and overall well-being. They can lead and contribute to a more balanced and well regulated gut microbiome.  

These organisms are officially described as transient organisms, which means they travel through the gut but do not reside there. However, along the way, they support the balance of the gut microbiome, the health gut lining as well as the gut immune response. 

What are probiotics and what are they used for?  

Studies have found that these bacteria can both support the gut microbiome as well as the health and functions of the digestive tract.  

For the most part, probiotics are used to address digestive health issues such as: 

• IBS 

• Bloating 

• Constipation 

• Diarrhoea 

• SIBO 

• Inflammatory bowel diseases (Crohn’s disease and Ulcerative colitis) 

They have also been found to: 

• Improve how well antibiotics work when taken alongside each other 

• Reduce the risk of antibiotic-associated diarrhoea 

While these are digestive conditions, there are also health issues and symptoms elsewhere in the body that can respond positively to probiotics. 

These include: 

• Migraines 

• Asthma 

• Eczema 

• Psoriasis [4] 

Health benefits of probiotics 

Rather than adding more bacteria to the gut microbiome, probiotics are considered transient organisms. This means that they do not live in the gut, but travel through. 

However, as they travel through they interact with the gut lining and trigger a beneficial response from the person taking them. This response can vary depending on the specific strain of bacteria being taken. 

The benefits can include: 

• Crowding out less beneficial bacteria 

• Supporting the body’s production of antimicrobial compounds (which can lower the levels of less beneficial gut bacteria in the gut) 

• Supporting the health of the gut lining 

• Supporting an appropriate immune response 

• Reducing inflammation 

Due to these factors possibly underlying other health issues and symptoms (e.g. eczema or migraines) supporting the gut in this way (and with the correct probiotic strain) can lead to an improvement in these non-digestive symptoms. [5] 

Sources of probiotics  

The 2 main sources of probiotics can be via supplements as well as fermented foods. 

Probiotics supplements are in forms such as: 

• Capsules 

• Powders 

• Liquids 

However, the benefit is related to the specific strains included in the supplements. 

Fermented foods are good sources of a wide range of beneficial bacteria. These may be less specific than probiotic supplements but can be helpful in addressing digestive issues. 

These include products such as: 

• Sauerkraut 

• Kefir 

• Kimchi 

• Kombucha [6] 

Benefits Comparison of probiotics vs prebiotics

How to Incorporate Prebiotics and Probiotics Into Your Diet  

There are simple ways to include probiotics and prebiotics in the diet.  

Firstly, rather than having a large amount in a single serving or meal on a rare occasion, including both probiotics and prebiotics on a regular basis in small or moderate amounts is going to be more beneficial.  

This ongoing inclusion of probiotics and prebiotics will benefit the gut over a longer period of time. This ‘little and often’ approach will provide more microbiome stability rather than having the occasional meal with prebiotics or probiotics. 

This can be a tablespoon of fermented foods each day or ½ a cup worth of the prebiotic-rich foods mentioned earlier in this article each day. 

Common Myths and Misconceptions  

One of the most common myths about probiotics is that these bacteria live in the gut forever. Similar to how it would be if these bacteria were filling up the gut as if it were a jar. 

In actual fact, these organisms are termed transient organisms. As already described, this means that they travel through the gut but do not colonise/live there forever. However, as they travel through, they lead to gut health benefits.  

The misconception around the fact that probiotics colonise the gut can also lead to the incorrect introduction of probiotic strains. This is commonly the case following gut health tests which may suggest that if a certain type of bacteria is low, then this needs to be taken as a supplement. Unfortunately, this is not the right use for probiotics. 

This is actually where prebiotics may be helpful to nourish this species of bacteria and increase levels. Often, this is where information can be gathered from a microbiome test to select the most appropriate prebiotic.  

A common misconception around prebiotics is that these fibres simply bulk the stool. This is not correct. Prebiotics act as an energy source to feed specific gut bacteria which then contribute to improvement in the gut microbiome and digestive health. [8] 

Conclusion

Both probiotics and prebiotics and helpful tools in addressing gut health issues. However, their use and recommendation are based on various factors that include symptoms, health history and test results. 

Working with a gut specialist can help to navigate product marketing and help you get to the actual root of your gut issues. 

Frequently Asked Questions 

Can I Take Prebiotics and Probiotics Together? 

Prebiotics and probiotics can certainly be taken at the same time. Since these support the gut and the gut microbiome in different ways, taking both at the same time can complement one another. This can lead to a greater improvement in gut health.  

Often probiotics and prebiotics can be available in the same capsule. However, the dose of prebiotics in capsule form is often too low to benefit the gut microbiome. For a therapeutic dose, prebiotics in powder form is often needed. 

Which is More Important: Prebiotics or Probiotics? 

Which is more important often depends on if there are certain symptoms or underlying issues that need addressing. 

However, for long-term gut health prebiotics can be considered a more robust way to support the gut and the gut microbiome. 

Are There Any Side Effects of Taking Prebiotics or Probiotics? 

Unlike medications, there is not a long list of possible side effects from taking either of these supplements. However, personal situations and the health of the gut microbiome may lead to certain symptoms. 

These may be at a low level and resolve over a period of time as the gut adapts to the supplements. In other cases, this may be an increase in symptoms. 

These can be an increase in symptoms such as: 

• Bloating 

• Flatulence 

• Constipation 

• Diarrhoea 

In rare cases, some patients may respond with headaches or nausea when supplements are taken. 

In sensitive patients, a slow and gradual introduction of supplements is often suggested. This can reduce any increase in symptoms as well as allow the gut to adapt to the supplements as the dose is slowly increased. 

How Long Does It Take for Prebiotics and Probiotics to Work? 

Most studies into pre and probiotics are over a 4-8 week timescale. 

Within clinical practice, for the supplements to be shown to be beneficial an improvement in symptoms would be noted within this time frame.