Prebiotics, probiotics & postbiotics: A guide

Our stomachs are incredibly important, and we’re not just talking about how toned your abs may be.

There’s a whole new area of research dedicated to how the health of your gut can affect the rest of your body. One of the most interesting areas is prebiotics and probiotics, or ‘friendly’ bacteria.

We have 100 trillion bacteria living in our stomach and intestines, but poor diet, too much alcohol, antibiotics, hormones and stress can all upset the natural balance of bacteria in our gut.

Bacterial cultures can provide our digestive system with extra sources of the types of bacteria naturally found in our gut.

It’s thought that four in ten of us are experiencing a digestive problem at any one time.¹

From stomach aches to indigestion, gut troubles can be incredibly uncomfortable and unpleasant.

With this in mind, it’s unsurprising that we often see new diets, products, or lifestyles that promise a healthier gut.

As well as pre and probiotics, there are also postbiotics. But what is the difference between prebiotics and probiotics? And where do postbiotics come into the mix? Find out all you need to know about all three, below.

In this article, you’ll discover

• What prebiotics are, what different types and what they do
• 5 prebiotic foods
• What probiotics are, what different types and what they do
• 8 probiotic foods
• What postbiotics do, how to get them from your diet
• 11 postbiotic foods
• 12 benefits of pre, pro and postbiotics
• FAQs
• Potential side effects

What are prebiotics?

Let’s get started with the basics of prebiotics. These are defined as a group of nutrients that feed the gut microbiota, but they are also degraded by it.

The product that is made as a result of the degradation are beneficial to our health and are released into the bloodstream.²

Different types of prebiotics

There are various different types of prebiotics, but the majority of them are a subset of carbohydrates.

The most common prebiotics include:

• Fructans - like inulin and fructo-oligosaccharide, which may be able to stimulate lactic acid selectively
• Galacto-Oligosaccharides – stimulate two key types of friendly bacteria, Bifidobacteria and Lactobacilli
• Starch and Glucose-Derived Oligosaccharides – a kind of resistant starch that produces a high rate of butyrate, which benefits our health³

What do prebiotics do?

Prebiotics are able to change the composition of the gut microbiome for the better. For example, consuming prebiotics has been shown to support the immune system by increasing the number of protective microorganisms.

As well as this, studies have shown that they can even decrease the number of harmful microorganisms too.^4,5

5 prebiotic foods

Fortunately, you can up your prebiotic intake through your food choices. Some of the best sources of prebiotics include:

1. Chicory root – 68% of its fibre comes from inulin⁶
2. Garlic – promotes the growth of bifidobacteria⁷
3. Onions – a good source of inulin and FOS^8,9
4. Artichoke – also rich in inulin¹⁰
5. Dandelion – another source of inulin fibre¹¹

What do probiotics do?

Probiotics help to maintain a healthy balance in your body. Certain types of probiotics can help to aid digestion and improve some gastrointestinal health concerns.¹⁶

Natural ‘good’ bacteria works to keep you healthy all the time, but supplementing might help address other concerns, especially after you’ve been ill.¹⁷

8 probiotic foods

There are plenty of ways to include more probiotic foods into your diet. These might have ‘probiotic’ on the label or include ‘live-cultured’ or ‘active cultures’ too.

Some probiotic food includes:

1. Live yoghurt
2. Cheese
3. Kefir
4. Uncultured buttermilk
5. Kimchi
6. Kombucha
7. Sauerkraut
8. Fermented olives¹⁸

There are also probiotic supplements available, which can be taken as a capsule, tablet or powder.

If you’re thinking about taking a probiotic supplement, it’s worth talking to your doctor or a specialist. There are a lot of different probiotics on the market, and not all of them will be right for you.¹⁹

Like when taking any new supplement, be aware of the potential side-effects and stop if you notice anything untoward.

Generally, probiotics are thought to be safe to consume for people with healthy immune systems.

The safety of probiotics is also under-researched, so we don’t know exactly how many possible side effects there could be.

However, if you’re in good health, they could be a safe addition to your diet.²⁰

What are postbiotics?

First things first, let’s define what postbiotics actually are.

While probiotics are gut-friendly bacteria, postbiotics are bioactive compounds created by probiotic bacteria when they have consumed fibre or prebiotics.²¹

What do postbiotics do?

Our expert nutritionist Alex Glover adds that:

“Postbiotics are compounds produced as the end product of our good bacteria fermenting prebiotic fibres. Compounds such as lactic acid, butyrate and other short chain fatty acids help to maintain intestinal pH, mucosa and are being researched for a variety of other beneficial physiological functions.”

How to get postbiotics from your diet

Unfortunately, postbiotics are harder to get your hands on when comparing them to the accessibility of pre and probiotics.

Specific health food shops or online retailers may sell postbiotic supplements, but you can also get postbiotics from your diet by consuming foods and drinks that are key sources of prebiotics and probiotics.

Want to know what kinds of foods these include? Find out the top eleven foods and drinks for postbiotics below.

11 postbiotic foods

Our top postbiotic foods are...

1. Miso

Ideal for using in soups, salad dressings, miso is a great way to promote postbiotics in your diet.

The main probiotic strain found in miso is called oryzae, which may help to contribute to a healthy gut.^22,23,24

2. Yoghurt

When most people look to include more probiotics in their diet, they opt for yoghurts so this one may not come as a surprise to you.

Made through culturing milk with bacteria cultures that contain bacteria that produces lactic acid (Lactobacillus bulgaricus and Streptococcus thermophilus) yoghurts are a great way to encourage postbiotics through your diet.²⁵

3. Tempeh

Another source of probiotics is tempeh. This is a fermented soy product similar to tofu, which is often used as a source of protein in vegan and vegetarian recipes.

What’s great about tempeh is that it is a source of both beneficial prebiotics and postbiotics – double whammy!²⁶

Handpicked content: Miso tempeh, sweet potato & shiitake mushroom bowl recipe

4. Buttermilk

Traditional buttermilk, as consumed in India, Pakistan and Nepal, is another great source of probiotics.

Though it’s not to be confused with the American, shop-bought variety which doesn’t share the same probiotic properties.

If you use buttermilk to get postbiotics in your diet, you’ll also be receiving a healthy dose of protein, calcium and riboflavin.²⁷

5. Sauerkraut

While fermented cabbage doesn’t sound like the most appetising food in the world, sauerkraut is a great source of probiotics and therefore postbiotics.

Originating from China over 2,000 years ago and traditionally used to prevent the cabbage from going off, the fermentation process offers a range of health benefits for your gut, immune system and brain health.^28,29,30,31 

6. Sourdough bread

As well as containing a lower amount of gluten, sourdough bread also offers prebiotic and probiotic properties.³²

This is also believed to make the process of digesting sourdough bread easier on our system.

Handpicked content: Mozzarella, mushroom & pesto sourdough toasties recipe

7. Kefir

Kefir is another great probiotic, but it also converts into kefiran (a postbiotic) when consumed, which promotes beneficial effects on food allergies from the intestinal microbiome to the immune system.³³

8. Pickles

We’re not really talking about vegetables that have been pickled quickly in vinegar here.

The kind of pickles we’re referring to are the type that are fermented over a longer period of time, prepared with brine and come with bacteria naturally found in and on them.³⁴

9. Soft cheeses

In a similar way to yoghurt, soft cheeses such as cheddar, parmesan and best of all gouda, are a great source of probiotics.

Studies on the probiotic effects of gouda cheese on elderly people found that they exhibited a clear enhancement of natural and acquired immunity.³⁵

10. Kimchi

Another type of fermented food that is rich in probiotics is kimchi.

It contains the same strains of healthy lactobacilli bacteria found in yoghurt and cheese, which means it’s another food that supports gut health as well as many other bodily functions.³⁶

Handpicked content: Kimchi poke bowl recipe

11. Kombucha

And finally the last postbiotic promoting product on our list is kombucha.

While there aren’t a lot of studies on the probiotic benefits of kombucha itself, there have been studies on the species of lactic-bacteria that it contains and their benefits.³⁷

12 benefits of pre, pro and postbiotics

So how can pre, pro and postbiotics be beneficial for our health?

We’ve listed 12 key advantages that are backed up by science, below.

1. They may help with weight loss

If you’re struggling to lose weight, your stomach could be the reason in more ways than one.

Previous research has found thin people have different gut bacteria to those who are obese.

This may be because a high-fat-low-fibre diet encourages the growth of ‘bad’ bacteria in the digestive system.

A study published in the British Journal of Nutrition found taking probiotics could help women lose weight – and keep it off!

The researchers concluded that rebalancing gut bacteria may strengthen the intestinal wall, making it harder to absorb large fat molecules.

2. They’re mood boosters

We know our emotional state can affect our digestion, now scientists have proven our gut can influence our brain.

Existing evidence shows that creatures under stress have different gut bacteria to those with a more cheerful outlook.

One theory is that bad bacteria disrupt the nerve signals – which transmit feelings of fullness and stress – from the stomach to the brain.

But probiotics have been shown to boost mood. Researchers from UCLA’s School of Medicine discovered taking probiotics could relieve anxiety and stress by reducing activity in the emotional area of the brain.

MRI scans of women involved in the study revealed the brain circuits involved in anxiety were less sensitive after a month of taking probiotic supplements.

3. They may fight colds and flu

Forget eating a ton of oranges every winter; healthy people who take probiotics may experience fewer colds and winter infections.

A recent study found New Zealand athletes who took a probiotic supplement for a month suffered 40 per cent fewer colds and stomach bugs than those who took a placebo.

4. They can help maintain normal blood pressure

High blood pressure is one of the main risks for heart disease. A healthy diet and exercise can help lower blood pressure, but the latest evidence suggests prebiotics can help too.

Prebiotics are complex carbohydrates, found naturally in foods including bananas, asparagus, parsnips and garlic, that help ‘feed’ probiotics and encourage them to multiply.

Malaysian researchers discovered prebiotics not only tackle high blood pressure, they could protect against the condition too.

They found prebiotics help reduce the absorption of cholesterol from food, in turn lowering our cholesterol levels and reducing high blood pressure.

5. They may tackle cystitis

For years, cystitis sufferers have relied on drinking lots of water or cranberries to ward off infection, but emerging evidence suggests probiotics could help here too.

A major review of studies found probiotics can help rebalance ‘bad’ bacteria in the vagina and urinary tract, protecting against infection.

Even better, they could help stop recurring cystitis too. Read more here: How friendly bacteria can help UTIs

6. They may control  your blood sugar

The first benefit of postbiotics, in particular, is their impact on blood sugar.

Specifically, studies have shown that intestines lacking in microbe balance can be a contributing factor to obesity.

However, muramyl dipeptide (a postbiotic bacterial component) is said to relieve glucose intolerance through increasing insulin sensitivity.³⁸

5. They may help to support your immune system

Another way that postbiotics can be beneficial is by supporting the immune system.

They have several properties that can help, such as butyrate, which has the capability to stimulate T cell production in the intestine that are used to control the extent of the immune system response.³⁹

Not only this but postbiotics like cell wall fragments and supernatant help to up the production of cytokines, which are anti-inflammatory chemical messengers that lower levels of inflammation and encourage immune responses.⁴⁰

This effect has been highlighted in a study from 2010 using 80 healthy adult participants, who were supplemented with a form of postbiotics every day.

The results of this study showed a decreased risk of respiratory infection, doubled with a better ability to create antibodies that help to fight harmful toxins and bacteria.⁴¹

6. They support each other’s functions

Since pre, pro and postbiotics are all related, it’s no surprise that they support one another.

In particular, probiotics and postbiotics have been shown to work together to exhibit benefits, as the aftermath of the two often causes immunomodulatory responses.⁴²

Handpicked content: 14 of the best probiotic foods and supplements

7. They may help with diarrhoea

Another digestive issue that postbiotics may be able to prevent and treat is diarrhoea.

A 2020 review on using postbiotics for preventing and treating common infectious diseases in children found that using postbiotic supplements shortened the amount of time they had diarrhoea.

It was more effective than the placebo at preventing it, as well as preventing pharyngitis and laryngitis.⁴³

8. They have antimicrobial properties

Since both probiotics and postbiotics work to fill the gut with an ecosystem that promotes the growth of ‘good’ bacteria, it lessens the production of more harmful, infectious types.

This creates an antimicrobial effect, as the combination of this and how postbiotics directly fight harmful bacteria all works to defend the body against infection.⁴⁴

9. They may help with eczema

Another benefit of postbiotics is their potential to help with allergies like eczema.

One particular study found that taking a postbiotic supplement for between 8 to 12 weeks notably lessened the severity of the symptoms – whereas the placebo group didn’t record any improvements like this.⁴⁵

10. They may help to suppress appetite

As well as helping with obesity by potentially lowering blood sugar, multiple studies have also highlighted the link between postbiotics like short-chain fatty acids.

In particular, they suggest that they may help with people’s weight loss goals by suppressing hunger signals.^46,47,48

Are prebiotics and postbiotics the same thing?

Nope! While they both work together to support gut health, they have different functions. Prebiotics feed the gut microbiome, whereas postbiotics are the compounds that are created by probiotics.

Is it better to take probiotics or prebiotics?

If possible, it’s best to take both, as they both work together to keep your gut happy and healthy.

Do you need both prebiotics and probiotics?

While you don’t necessarily need to take a prebiotic for a probiotic to work, taking one may enhance the effect of the probiotic in the small intestine and the colon.⁴⁹

Are postbiotics good for you?

Much like pre and probiotics, postbiotics may also provide some health benefits – highlighted earlier in the article.

What is the difference between prebiotics and postbiotics?

The key difference between pre and postbiotics is their role in gut health – and the order they come in.

Prebiotics essentially act as ‘food’ for probiotics, whereas postbiotics are basically a sort of waste product of this process – but that doesn’t mean they don’t have their benefits.

What are postbiotics in skincare?

As well as supporting gut health, postbiotics can also be used to benefit our skin.

These postbiotic skincare products contain the ‘byproduct’ of pre and probiotics – but they’re not necessarily a new thing in the skincare industry.

For example, some of the most popular postbiotic skincare products are lactic acid and glycerol.⁵⁰

Are pre, pro and postbiotics suitable for everyone?

We’ve highlighted the potential benefits, but pre and probiotic supplements to increase the production of postbiotics isn’t necessarily safe for everyone.

People who might be advised to avoid these supplements include: 

• Those who are recovering from surgery
• Children
• People who are pregnant
• Those with digestive tract disorders
• Those who have structural heart disorders⁵¹

What are the potential side effects?

While taking pre and probiotics to increase the production of postbiotics can have a range of different benefits, it’s important to be aware of potential side effects.

For example, initially, you may experience some gastrointestinal discomfort like bloating, wind and mild stomach issues – but these usually pass once your body has adjusted to them.⁵²

The Wellness Edit is the H&B Podcast.

In this episode, Eve Kalinik, author of Happy Gut, Happy Mind, and Holland & Barrett nutritionist Isabel Tarrant reveal how to take care of your gut – so it takes care of you.

Listen to the podcast below and discover more episodes here.

The final say

Postbiotics can potentially help to support the immune system, reduce the symptoms of IBD, reduce the symptoms of some types of allergies and prevent or treat diarrhoea.

But if you’re thinking of trying them for yourself, it’s best to speak to your GP first to get personalised advice.

Some of the content in this article has been adapted from longer features appearing in Healthy, the Holland & Barrett magazine.

The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.

Last updated: 1 March 2022