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Prebiotics & Probiotics - Can They Help Me?

Updated: Jul 21, 2023

Although it looks like it; Prebiotics and Probiotics aren’t just a misspelling of one another!

With data from the Health and food Supplements Information Service (HSIS) suggesting that only around 1 in 10 people in Britain take them; many people don’t yet know about probiotics and prebiotics.

The market for them both is gathering attention, mostly due to exposure on social media, and ever- emerging information about the gut microbiome.

A paper cut-out bowel with three spoons containing prebiotics and probiotics

With evidence suggesting positive influences of these supplements and benefits regarding brain, cardiovascular, cardiometabolic health and immune function (4); we find it hard not to get excited about them!

So, what is the difference between the two and should you be taking them?

First, we have to understand the basics of the gut microbiome...


The Basics

Your gut microbiome is the term used to describe all of the organisms in your gut. It's a massive ecosystem made up of trillions of bacteria, yeast, fungi, and viruses. These, together, weigh approximately 2kgs!

There are many factors which influence the blueprint of the microbiome, and not only our genetics.

Our microbiome at birth is unknowingly given as a gift from our mothers (influenced by mode delivery and type of feeding), which develops following exposures in childhood (toddlers put everything in their mouths!).

It doesn't end there as diet, stress, lifestyle, medication use and more also continue to influence our microbiome as we age (4).

However, some medical conditions, a poor diet, lifestyle factors and more can disrupt the gut bacteria and lead to gastrointestinal symptoms. These can include pain, bloating, constipation, diarrhoea, and more.

In this case, your dietitian or health care professional may recommend pre and/or probiotics to help.


Let's Cover Prebiotics....

Prebiotics could be interpreted as food for the gut microbiota; they “feed” on prebiotics by fermenting them. This process encourages the growth and balance of beneficial bacteria, positively affecting the overall health of our microbiome (1, 5)

Prebiotics are found in our food, such as fibre we obtain from fruits and vegetables.

Generally, certain foods containing soluble fibres are the only ones that are actually prebiotic.

Examples of foods containing prebiotics: (List not exhaustive...)

Remember to build prebiotics gradually in the diet; too much at once (or one type of isolated fiber in high doses) may cause bloating, gas, diarrhoea and/or constipation. (3)


Now onto Probiotics!

Probiotics are the live bacteria in foods and supplements that are eaten and soon to be (hopefully!) living in our gut.

Fermented foods or those containing live and active cultures, such as yoghurt are natural food sources.

The seven core groups of microbial organisms most often used in probiotic products are Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, Escherichia, and Bacillus s. (1).

These branch into species, subspecies and strains; there are thousands of different types altogether!

It's no surprise that scientists are still studying and classifying as you read this...

Examples of food containing probiotics: (List not exhaustive)


The Evidence

Evidence for the use of probiotics and prebiotics is growing and supports a range of health conditions. We are focusing on gut health here.

Probiotics have a well-established evidence base in the prevention and management of gastrointestinal diseases such as traveller’s diarrhoea, antibiotic associated diarrhoea and Clostridium difficile diarrhoea.

One meta-analysis summed up the results of 63 studies done on a total of 8014 participants.

The overall result was that probiotics may offer a safe intervention in acute infectious

diarrhoea to reduce the duration and severity of the illness (6).

Other bowel conditions where they have a demonstrable clinical impact include ulcerative colitis (specifically in remission rather than maintenance), with less evidence of benefit in crohn’s disease. (8)

Probiotics have also been shown to help with symptoms associated with irritable bowel syndrome (IBS), lactose intolerance, pouchitis (7) and constipation.

Although the longer term health effects of prebiotics are emerging and require further evidence; they have been shown to be beneficial for the health of the gastrointestinal tract by inhibiting pathogens and supporting immune function. (8)


So More Must be Better, Right?

Not necessarily! With both pre and probiotics, the key is variety. Diverse prebiotics can feed diverse populations of bacteria in the gut microbiome.

When looking for prebiotics, it is suggested to look for one with a blend instead of one that has only one

specific kind (3).

When looking for probiotics, a greater CFU number (colony forming units) doesn’t always mean it is more

beneficial. The type of bacteria and the variety is more important than having thousands of

CFU’s in one dose.

To summarise, pro and prebiotics are very different things, although both are very important to gut

health. Pre and probiotics require support from each other for optimal gut health.

Whether you should take supplements or not depends on your condition and health experts recommendations.


Oxford Gastro Dietitians would love to help you with selecting pre and probiotics.

Contact us for a list of probiotics we would recommend!

If you want to ask us any questions before booking your consultation, please book in for our

FREE discovery call which you can book via our website!

Gut love to you all

Cat & Rosie, Registered Dietitians


The information and advice offered by Oxford Gastro Dietitians is solely educational and provides general advice only for the adult population. Information offered on Oxford Gastro Dietitians website, blog and social media accounts is not a substitute for seeing a registered dietitian or another health care professional. All opinions are own views.

See more at the ‘Disclaimer’ section of our website.



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