What Are Prebiotics? The Ultimate Guide

If you’ve heard of probiotics and how they can benefit your immune system, digestive tract and overall health, then it’s highly likely you’ve also heard of prebiotics. But what are they exactly and how can they benefit you?

We’re taking a look into what they are, where to find them and which aspects of your health they can improve. Keep reading to find out how prebiotics can support your health and wellbeing.

What are prebiotics?

Put simply, prebiotics are food for the friendly bacteria that live in your gut, called probiotics. They help them thrive, multiply and become more resistant to the harsh conditions inside your body so that the probiotics can provide the most health benefits possible. 

Prebiotics are tiny, indigestible fibres that are found in many everyday foods. When you consume prebiotics they travel through your body untouched until your probiotics begin to ferment them in your large intestine.

This fermentation then allows the probiotics to feed on them, giving them the energy they require to function and grow optimally. The two main probiotic species that prebiotics most benefit are Lactobacilli and Bifidobacteria, which are actually two of the most powerful and beneficial kinds of probiotics for human health!

The great thing about prebiotics is that they’re in so many foods that you’re probably already consuming them without even knowing! Here’s a few of the main foods you’ll find them in:

  • Bananas
  • Onions
  • Garlic
  • Oats
  • Asparagus
  • Leeks
  • Apples
  • Cocoa
  • Flaxseeds
  • Seaweed

As you can see, most of these foods are what you would consume in an everyday diet! With prebiotic food, it’s always best to eat them raw if you can as the cooking process may destroy some of the prebiotic fibres, decreasing their potency.

What can prebiotics do for me?

Now that we know what prebiotics are, let’s get into the good stuff! Here are a few benefits of prebiotics that have been medically explored so far:

  • Reducing diarrhea – Research studies on travellers who ingested 10 grams of prebiotic inulin a day for 2 weeks prior to and during their travel, experienced a reduction in the prevalence of infectious diarrhea. Additionally, diarrhea attacks were seen to be less severe than they normally would be.
  • Weight management/satiety – The addition of fibre in the diet has long been known to keep you fuller for longer and encourage your digestion to be as regular as possible. To support this further, in research studies on weight management, it was found that supplementing with prebiotics daily can assist with weight loss by increasing satiety and promoting optimal digestion.
  • Immune support – When it comes to the immune system, as described in this research paper, the best way that prebiotics can support immune response is by boosting the function of probiotic bacteria species Lactobacilli and Bifidobacteria, which are able to decrease the population of harmful bacteria in your gut. However, some prebiotics are actually able to create an environment where pathogens aren’t able to attach themselves to the gut lining and wreak havoc. In addition, it’s also known that prebiotics themselves can induce the activity of immune molecules, boosting their function to keep you healthy. So, this goes to show that prebiotics have super powers of their own that they exhibit whilst supporting your probiotics at the same time.
  • Inflammation – From the above effects on the immune system, prebiotics are also able to fight excess inflammation in a similar way. They can promote the reduction of pro-inflammatory immune molecules to modulate inflammation that is unnecessary and would otherwise cause negative short and long term effects in the areas of the body where the inflammation was present.
  • Colon cancer – In research studies, the symbiotic use of probiotics and prebiotic inulin showed a reduction in the production of cancer cells and an increase in their cell death, leading to an improvement in the strength and function of the colon lining that helped to prevent cancer developing.
  • Digestive system – When consuming a healthy diet, you hope that your body is making the most of your efforts. Prebiotics are able to lower the pH of the intestines to a point where beneficial bacteria can thrive and grow. In addition to this, prebiotics can also increase the absorption of some minerals like calcium and magnesium. They can also help to support those with lactose intolerance.

Types of prebiotics used in supplements

If you’re not too sure if you’re getting the recommended 5 grams of prebiotic fibre in your diet everyday, you might want to look into purchasing a supplement with prebiotics in it. So you know what to look for, here are the most effective and common kinds of prebiotics used in supplements:

Fructooligosaccharides (FOS)

This is the most common and effective type of prebiotic used on the supplement market right now. Fructooligosaccharides (FOS) occur naturally in fruits and vegetables like bananas, garlic, onion and asparagus. This kind of inulin-type prebiotic fibre is the most diverse when it comes to which probiotic strains are able to ferment and consume it successfully. 

According to this research paper, when 55 different Bifidobacterium strains were experimented upon, the FOS were fermented by most strains whereas inulin prebiotics (discussed below) were only fermented by 8 strains.

This is because FOS are made up of shorter-chain fatty acids than other prebiotics, allowing probiotics to ferment and consume them much easier. This is also the case with Lactobacillus type strains, FOS are utilised best by most probiotics when compared with other prebiotics which is why they’re used more often in supplements.

As an added bonus, FOS improve mineral absorption, reduce constipation, decrease cholesterol and are increasingly used in infant food and formulas due to their effectiveness at stimulating the growth of a healthy intestinal flora.


This is the other form of prebiotic that falls under the inulin-type category that you’re most likely to come across when perusing supplements, however, it’s made up of longer-chain fatty acids and so isn’t as effective as FOS, as we’ve explained above. Nonetheless, some manufacturers opt for inulin over FOS as it’s still an effective prebiotic, especially on Bifidobacterium strain types (as all prebiotics generally are). 

This may be due to the fact that inulin is actually made up of a mix of long and short-chain fatty acids, whereas FOS is only short-chain. This mixture means that the prebiotics are fermented and digested slower which may allow the body to get used to it easier than FOS. Digestive discomfort has been noticed more commonly with FOS, possibly due to the quick nature of fermentation by bacteria in the gut.

Interestingly, inulin has actually been shown in a research study to aid in the weight and fat loss of people suffering from prediabetes over an 18 week period. Typically, inulin and FOS will both be extracted from chicory root, so, if you see that ingredient on your supplement you’ll know that you’re getting both.

Galactooligosaccharides (GOS)

This is the other kind of inulin-type prebiotic fibre and is probably going to be the one you notice least when shopping around for your next probiotic supplement. They are produced from lactose, naturally occur in human breast milk and are best utilised by the body when combined with FOS. 

GOS has been seen in research studies to have a positive effect on constipated patients, being effective on the elderly, adults and infants as long as they didn’t consume more than the daily limit for their ages respectively (generally 12 grams or less). 

Excess consumption has been known to cause too much intestinal fermentation which can lead to symptoms comparable to lactose intolerance. GOS prebiotics are effective on both Lactobacillus and Bifidobacterium strains, the associated benefits of which are decreasing the risk of developing certain cancers, controlling blood pressure and reducing cholesterol.

Synbiotic supplements

If you’re considering purchasing a probiotic or prebiotic supplement to support the beneficial bacteria in your gut, you should try to find a supplement that includes both – a synbiotic supplement.

The benefit of this is obvious; you’re getting a 2 for 1 deal! And, if it’s a reputable brand, you know that the manufacturers have done the research behind which prebiotic fibres work best with which probiotic strains, and combined them accordingly to give you the best results possible.

According to this research paper, the most popular and effective combination at this time seems to be FOS with a combination of Bifidobacterium or Lactobacillus strains.

The prevalence of synbiotics on the market isn’t very high, this may be due to the fact that manufacturers don’t see the point in including prebiotics in probiotic supplements because it’s so easy to consume enough prebiotics in your everyday diet. However, a little more can’t hurt and we’d recommend finding a probiotic product that contains prebiotics if you can – just so you know you’re getting the most out of your probiotics!

Top 3 Prebiotic Products in 2020

#1 – Editor’s Choice – GoBiotix Prebiotic Fiber Boost Powder

This gets our top choice because of all the boxes it ticks! This is a prebiotic powder made up of NutraFlora FOS where each scoop or daily serving will give you the recommended 5 grams of prebiotic fibre you need each day for optimal gut health. NutraFlora is usually derived from beet or cane sugar and is said to be one of the most effective prebiotics available to us right now. 

Because it’s a flavourless powder, you can blend, mix, shake or stir this into any food or beverage you’d like to (avoiding hot beverages to maintain prebiotic integrity), which is super convenient and will help you incorporate it seamlessly into your everyday routine. This product is organic and plant-based, making it suitable for vegans, vegetarians and those with intolerances to common allergens.


  • 2,700+ reviews on Amazon with an overall 4.5/5 star rating
  • NutraFlora FOS
  • Flavourless to be easily added to your favourite food and drinks
  • Non-GMO and gluten-free 
  • Suitable for vegans and vegetarians
  • 5g prebiotics per daily serving of 1 scoop (1 month’s supply)
  • No added ingredients


  • Less affordable than other options
  • 10 calories per scoop

#2 Dr. Tobias Prebiotic

This product gets our 2nd place choice because of its convenience to use! Instead of a powder, it comes in capsule form and contains PreforPro, which is a clinically studied and manufactured combination of prebiotics and an ingredient called bacteriophage (phage).

Phages are naturally found in the human body and attach themselves to harmful bacteria in both the small and large intestines (prebiotics only work in the large intestine), infecting and destroying them.

The addition of PreforPro means this product works in both the small and large intestine, requires less traditional starch and fibre probiotics (gentler on the digestive system) and kills off bad bacteria to allow the good bacteria to populate. It’s an innovative product and contained in 1 daily capsule for convenience. It’s the most expensive of the 3 products we’re reviewing today but may be worth the extra money considering the science and convenience behind it.


  • 3,800+ reviews on Amazon with an overall 4.4/5 star rating
  • Contains 15mg of PreforPro per serving (1 month’s supply)
  • Less risk of digestive upset due to less starch and fibre-based prebiotics
  • Works in both the small and large intestine
  • Actively kills bad bacteria
  • Convenient once daily capsule
  • Non-GMO and vegan


  • More expensive than other options
  • Contains added ingredients

#3 Micro Ingredients Organic Inulin FOS Powder

This final prebiotic product is another super powder, however, these prebiotics are derived from organic jerusalem artichoke – an excellent natural source of FOS prebiotics. Using the scoop included, you are recommended to consume this powder 3 times daily with your favourite beverages or foods.

One scoop will give you around 2.6 grams of prebiotics meaning that you’ll be consuming almost 8 grams of prebiotic fibre daily. It’s recommended that you need around 5 grams of prebiotic fibre a day so it could be a good idea to consume only 2 scoops daily if your body isn’t agreeing with the high dose.

If you are taking the recommended 3 scoops daily then you’ll be able to get around 4 months worth of use out of this product, and it’s only a couple dollars more than the first product we reviewed which only had a month’s supply. For that reason, we’d recommend this product to anyone looking to get some more prebiotic fibre into their diet on a budget!


  • 900+ reviews on Amazon with an overall 4.6/5 star rating
  • Organic jerusalem artichoke FOS
  • Powder that can be added to your baking, food or drinks
  • 1 bag lasts around 4 months
  • Very affordable
  • Non-GMO, vegan, soy free and gluten free
  • No added ingredients


  • Contains 10 calories per scoop
  • 3 servings daily can be inconvenient
  • Daily recommended intake is 3 grams over what’s needed in average diet


If you’re wanting to get the most out of your probiotic supplement, nourish your gut health and immune system or boost your digestion, then prebiotics are the way to go. Whether you consume them in powder or capsule form or opt to include them in your diet, there’s plenty of research to support all the amazing benefits you should feel!

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