According to the International Scientific Association of Probiotic and Prebiotics (ISAPP), prebiotics are defined as “a substrate that is selectively utilised by host microorganisms conferring a health benefit”.

Prebiotics are some types of indigestible (to humans), fibre or polysaccharides (complex chain of sugars) found in fibre rich plants and fruits. They travel through our digestive system intact until they reach our large intestine where they become a food source for the gut microbiome. Prebiotics are essential to support the health of our gut microbiome and just like us, their host, our gut microbiome thrive on diversity of fibre-rich plants and fruits.

There are a number of different types of prebiotics:

Fructo-oligosaccharides (FOS)

Foods high in FOS include onions, spring onions, garlic, leeks, chickpeas, watermelon, tomatoes, asparagus, Jerusalem artichoke, globe artichoke, wheat, barley, yacon syrup, honey and banana, dandelion leaves, dandelion root, burdock root.


Inulin is a similar prebiotic to FOS and is found in high concentrations in dandelion root, chicory root and Jerusalem artichokes. It is also found in globe artichokes, asparagus, leeks, onions, bananas, wheat, maize, rice and garlic.

Galacto-oligosaccharides (GOS)

This prebiotic fibre can be found in human breast milk and is thought to be a food source for baby’s gut bacteria. Other foods that are also rich in GOS include Jerusalem artichokes, lima beans, kidney beans, chickpeas, lentils and green peas. The prebiotic supplement Bimuno is another good way to add additional GOS to your diet.

Xylo-oligosaccharides (XOS)

Although there is less evidence supporting the prebiotic effects of XOS, supplementation with XOS has been shown to increase SCFAs and bifidobacteria. It is found naturally in vegetables, fruits, milk, honey and bamboo shoots.


Arabinogalactan is a complex fibre found in various plants including carrots, radishes, pears, corn, wheat, sorghum, black gram beans, fresh turmeric root, tomatoes, coconut meat, coconut flour and red wine. One of the primary sources of arabinogalactan is from the larch tree and is taken in supplemental form.

Beta Glucans

Beta glucans are polysaccharides present in grains such as oats and barley, and in mushrooms, seaweeds and Saccharomyces cerevisiae (brewers’ yeast). Beta glucans are often taken in supplemental form and are also known to support the health of the immune system.


Lactulose is commonly used as a laxative but is also known for its prebiotic properties. It is a two-sugar molecule consisting of galactose and fructose and has been shown to encourage the growth of probiotic bacteria.  Lactulose is manufactured by heating lactose (milk sugar) and is available to buy from pharmacies.

Resistant starch

Resistant starch is a type of starch that ‘resists’ being digested and absorbed in the human small intestine. Like prebiotic fibre, it travels to the large intestine where gut bacteria use it as a food source; fermenting it and producing SCFAs (Short Chain Fatty Acids).

Resistant starch occurs naturally in foods such as beans, lentils, nuts, peas, chickpeas, green bananas, seeds, oats and other whole grains.  Resistant starch can also be created by heating and cooling starchy foods before eating them. This changes the structure of the starch and makes it more resistant to digestion e.g. cooked and cooled tubers (potatoes), squashes, turnips, parsnips, legumes, beans, pasta and rice.

Acacia gum

Acacia gum, or gum arabic, is a complex polysaccharide which comes from stems and branches of the Acacia senegal and Acacia seyal tree. Acacia gum is fermented at a slower rate than FOS making it better tolerated.  In a study that compared it to FOS, it did not cause any of the cramping or loose stools that were associated with the FOS supplement at the same dosage.

Partially Hydrolysed Guar Gum (PHGG)

Partially Hydrolysed Guar Gum is derived from guar beans but is different to the guar gum that is used to thicken or stabilise food and drink products. PHGG doesn’t swell in the same way that guar gum does and is therefore better tolerated.  The main prebiotic fibre in partially hydrolysed guar gum is glucomannan.


Pectin is a soluble fibre found in fruits and vegetables. Apples, kiwi fruits and carrots are rich in prebiotic pectin, along with peaches, pears, oranges, grapefruit, apricots, tomatoes, potatoes, peas and okra.


Polyphenols are naturally occurring compounds found in plant foods such as fruits, vegetables, tea, coffee, chocolate and wine. Polyphenols act like prebiotics in the gut so are another good food source for the gut bacteria. Like prebiotic fibres, gut bacteria will ferment polyphenols and produce SCFAs.

Rich sources of polyphenols include : spices and herbs, berries, tea, cocoa, dark chocolate, ground flaxseeds, chestnuts, pecans, almonds (skin on), and many other plant foods.

Scientific research shows great health benefits in supplementing with prebiotics.

If you are new to these fibres, you need to introduce them very slowly and increase the amount gradually following your unique digestive challenges.  It might also help to try different types as some may suit your gut better than others, depending on your microbiome profile.

At Taymount, we stock a range of high-quality prebiotics supplements:





Acacia Fiber

Flourish (FOS)

PHGG from Invivo

PHGG is one of our favourite Prebiotic supplements, as it has shown to be well tolerated by our patients suffering from SIBO and IBS.

Annie McCue

FMT Therapist

Nutrition Advisor

Please contact our reception for booking details.  0330 222 1622 or email us at

Share this page

Taymount news

To receive the latest information and news from the Taymount team, subscribe below.

© Copyright 2023 Taymount Clinic | Website powered by The Media Snug