Prebiotic vs Probiotic: What’s the difference and do we need both?

Key Points

• Variety in prebiotic-rich foods is crucial for feeding different gut bacteria.
• When it comes to probiotics, fermented foods are your go-to source.
• Prebiotic and probiotic supplements may offer health benefits.

In the ever-evolving world of gut health, navigating terms like prebiotics, probiotics, and postbiotics can be a tad confusing. 

Your gut is home to a community of tiny organisms and bacteria, which make up the gut microbiome. These microbes play a crucial role in digesting and converting food into nutrients for your body. Your gut microbiome may influence your physical and mental wellbeing and various factors, including your diet, can affect the amount of good and not-so-good bacteria in your gut. 

So what is the difference between prebiotics and probiotics? Do we really need them, and how may they contribute to our gut health and overall wellbeing? 

To shed some light on this topic, we spoke with dietitian Kate Agnew.

“Research around gut health is still evolving,” shares Kate, “but what we do know is that the diversity of bugs living in our gut is a good marker for gut health. The good news is that what we eat is one of the biggest factors that improves diversity, specifically through probiotics and prebiotics, with the postbiotics that are then created.”

Let’s take a closer look.

What’s the difference between prebiotics and probiotics? 

Let’s start with the basics. People may regularly use the terminology in the same  sentence, but prebiotics and probiotics play different roles. 

Probiotics are living microorganisms, typically beneficial bacteria or yeast that may provide health benefits when consumed in adequate amounts. These tiny organisms reside in our gut and help maintain a balanced microbial community. They work their magic by introducing these friendly microbes into our gut in a bid to aid digestion and support our immune system. Some well-known strains of probiotics include lactobacillus and bifidobacterium.

Prebiotics, on the other hand, are non-digestible fibres or compounds found in certain foods. They provide the nourishment that helps probiotics thrive. While they don’t contain live organisms, prebiotics are essential for maintaining a healthy gut microbiome. 

“Variety in prebiotics is important because different bacteria like feeding on different plant foods,” Kate says. “For example, you may choose to fill your plate with broccoli and carrots, which means you will feed the bacteria that like these foods. If you don’t include other plant foods like chickpeas or mushrooms, it may mean starving the other bacteria that like these particular foods.”

How do postbiotics fit into the picture?

Postbiotics are compounds produced by the fermentation process by probiotics. They include substances like short-chain fatty acids, which have been gaining attention for their potential health benefits. While still an emerging area of study, postbiotics are believed to promote gut health. 

Miso soup is a good source of probiotics, along with other fermented foods

What are some good dietary sources of prebiotics vs probiotics? 

Dietary choices are key to ensuring a healthy balance of prebiotics and probiotics in your gut. When it comes to probiotics, fermented foods are your go-to source. 

Examples of foods containing probiotics include: 

• yoghurt
• kimchi
• kombucha
• miso
• sauerkraut

As Kate shares, “Fermented foods like yoghurt and kefir that contain live probiotics may support gut health by introducing probiotics, which are good bacteria strains, to your gut microbiome.” 

Examples of foods containing prebiotics include: 

• onion
• garlic
• asparagus
• artichoke
• leek
• bananas
• legumes
• fruits
• nuts and seeds
• whole grains

“When it comes to prebiotics, the important thing is diversity in what you feed them,” Kate says. “One strategy to achieve this is to aim for 30 different plant foods per week as research suggests this supports gut bacteria diversity and therefore overall gut health.”

What is the most well-known postbiotic?

“The most well-known postbiotic is short-chain fatty acids (SCFA)”, explains Kate. “This is produced when the microbes or bacteria feed on dietary fibre.” These SCFAs offer numerous possible health benefits, including protecting the lining of the gut (gut barrier function) and offering potential anti-inflammatory benefits; they may support the immune system and improve blood sugar.

Probiotic and prebiotic supplements may be beneficial

Are prebiotic or probiotic supplements recommended? 

While dietary sources should be your first choice for prebiotics and probiotics, supplements, available in capsules, powders, liquids and other forms, may be a practical option to consider. 

“It’s important to get the foundations right first, as no amount of supplementation can counteract a diet that is low in vegetables, legumes, fruits, nuts, seeds and whole grains,” Kate says. “However, there is evidence to show that supplementing with a probiotic and/or prebiotic for certain health concerns may provide benefits.”

She says there is promising research for probiotic supplementation in supporting medically diagnosed IBS and constipation and the reduction of antibiotic-associated diarrhoea. Not all probiotic strains are equal, so it’s best to talk to your healthcare professional to understand which one is right for you.

Kate adds that prebiotic supplementation may be particularly helpful for individuals with gut disorders or when following a short-term low-FODMAP diet, although further research is required.

Prebiotics are found in fruit, vegetables, nuts, whole grains and legumes and are just as important for gut health as probiotics

Nurturing your gut means consuming both probiotics and prebiotics 

So, do we need both prebiotics and probiotics? In short, yes. While they are fundamentally different, the bottom line is that they all work together to support your gut health.

If you have concerns about your gut health or are considering supplements, always seek guidance from a healthcare professional before making any major changes.

Related:

• What are the worst foods for gut health?
• What is the best fruit for gut health?
• Can your gut health affect your skin?

Kate Agnew is an Accredited Practising Dietitian who is passionate about innovation and problem-solving in health & nutrition. Her goal is to ultimately create a healthier environment for all Australians.

Reviewed by Healthylife health experts September 2023.