What Are Prebiotics?

Prebiotics have increased in popularity over recent years for their positive effects on the gut microbiome.

Prebiotics can be described as non-digestible food ingredients that cannot be broken down by human enzymes in the GI tract. Prebiotics are then fermented and essentially ‘fed on’ by bacteria in the intestines to populate the gut with friendly bacteria.1

Our digestive tract needs a positive ratio of good to bad bacteria in order to thrive and maintain good health.2

It has been established that gut health affects our immune system, heart health, brain health, sleep, energy, and even our mood. Emerging evidence continues to support the major role our gut has in sustaining overall health.3

Why Should You Take Prebiotics?

As prebiotics are not broken down by human enzymes, they pass through the acidic environment within the stomach intact and reach the intestines where the majority of gut bacteria live, to be utilised.

The stability of prebiotics means that they can also be added to food or drink without their structure being compromised.4

The two main molecules found in prebiotics that contribute to many gut health benefits are Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS).

These sugar molecules help to produce butyrate, a short-chain fatty acid that helps to support the immune system, colon health and helps to reduce the risk of many diseases of the GI tract.5

Due to their high fiber content, prebiotics have been shown to improve glucose levels, help with insulin resistance and positively impact metabolic and digestive health.6

Gut health can be affected by many factors such as:

- Stress
- Alcohol
- Antibiotic use
- Age
- Sleep
- Diet - Lack of diversity/high sugar intake

Ingesting prebiotics regularly ensures that you keep your gut health supported throughout any stage of life.7

When Should You Take Prebiotics?

As prebiotics are created from food sources, they are perfectly natural and safe to ingest daily.

Whether you have gut health symptoms or simply want to support your gut for optimal health, prebiotics can be taken by anyone.

Prebiotics are found in many food sources, therefore can be ingested up to several times daily to contribute towards populating beneficial bacteria in the gut.

Probiotic sources work synergistically with prebiotics to improve gut health. Probiotics (not to be confused with prebiotics) are live microorganisms; essentially good bacteria itself, which when ingested add beneficial bacteria to the gut.

Probiotics can be found in fermented and cultured food sources or can be taken in supplement form.

As prebiotics feed good bacteria, it is beneficial to take probiotics and prebiotics together to increase effectiveness.

Prebiotic Foods

Prebiotics are fiber-rich carbohydrates and can be found in many whole foods.


A recent study showed that garlic increased the growth of L. acidophilus, a beneficial bacterium in the gut due to its high FOS content.8

Freshly crushed garlic also contains Allicin, an enzyme that has been studied for its potent antibacterial and antifungal properties.9

Jerusalem Artichoke

A member of the cruciferous family, Jerusalem artichoke has liver-boosting and antioxidant health properties.10

Jerusalem artichoke is rich in inulin, a potent prebiotic, and may relieve constipation and manage blood glucose and metabolic disorders. 11


Asparagus, a rich source of prebiotic fructans, have been shown to help grow beneficial bacteria strains Prevotella, Megamonas, and Bifidobacterium, whilst inhibiting the growth of Haemophilus, a pathogenic bacterial strain.12

Chicory root is a popular caffeine-free high-fiber coffee alternative.13
Rich in prebiotic FOS, studies show that chicory root boosts beneficial bacteria whilst reducing the growth of bad bacteria in the gut.14

Prebiotic Supplements

Prebiotic supplements are a great option as the number of ingredients they contain are measured and dosed to enhance therapeutic benefits. A supplement ensures that you know just how much you are ingesting, easily and effectively.

Prebiotics are great to take with probiotic supplements due to the synergistic effects mentioned.

A good probiotic supplement will contain both probiotics and prebiotics to boost the beneficial properties of both.

Prebiotic Side Effects

Although prebiotics are safe and well-tolerated, it is important to note that due to their effects on the ecology of the gut, the change in the microbiome may cause temporary side effects such as:

Stomach gurgling
Excess gas/bloating
Abdominal discomfort
Loose stools

The high content of fiber in prebiotics may also temporarily increase the frequency and urgency to pass stool.15

It is recommended to gradually introduce and increase prebiotic-rich food sources and supplementation over several days to allow the environment within the gut to adjust.

Any side effects experienced are mainly temporary, however, if gastrointestinal upset occurs for longer than seven days, consult your GP.

Related content: What Are Probiotics?


1. Probiotics and prebiotics in intestinal health and disease: from biology to the clinic - PubMed (nih.gov)

2. Gut Microbiome: What We Do and Don't Know - PubMed (nih.gov)

3. The Gut Microbiome: What we do and don’t know (nih.gov)

4. Xylooligosaccharides chemical stability after high-intensity ultrasound processing of prebiotic orange juice - PubMed (nih.gov)

5. Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS) Increase Bifidobacterium but Reduce Butyrate Producing Bacteria with Adverse Glycemic Metabolism in healthy young population - PubMed (nih.gov)

6. Dysbiosis, Probiotics, and Prebiotics: In Diseases and Health (nih.gov)

7. Alterations in intestinal microbial flora and human disease - PubMed (nih.gov)

8. Prebiotic activity of garlic ( Allium sativum) extract on Lactobacillus acidophilus - PubMed (nih.gov)

9. Allicin Bioavailability and Bioequivalence from Garlic Supplements and Garlic Foods - PubMed (nih.gov)

10. Human CYP2A6 is regulated by nuclear factor-erythroid 2 related factor 2 - PubMed (nih.gov)

11. Jerusalem artichoke (Helianthus tuberosus L.) as a medicinal plant and its natural products - PubMed (nih.gov)

12. A novel inulin-type fructan from Asparagus cochinchinensis and its beneficial impact on human intestinal microbiota - PubMed (nih.gov)

13. Chicory Root Health Benefits, Nutrition Facts and Uses - Dr. Axe

14. Inulin-type prebiotics--a review: part 1 - PubMed (nih.gov)

15. Fiber and prebiotics: mechanisms and health benefits - PubMed (nih.gov)

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