Feeding Our Gut Microbiome: The Best Prebiotics to Eat

Our gut is home to trillions of microbes – altogether, they can weigh up to 2 kilograms. They not only help to digest food via fermentation, but in the process produce molecules called metabolites that influence health and disease – for instance, to support immune function and fighting off diseases.  Now it appears our microbes also have the ability to influence our gene expression through the epigenome, the chemical information that regulates which genes in cells are active.

Each of us has a unique complex ecosystem of bacteria located within our bodies that we call the microbiome. The vast majority of the bacterial species that make up our microbiome live in our digestive systems. It’s not necessarily just about the numbers of gut flora that’s important but microbial diversity. The greater number of different types of bacteria in our guts, the greater our diversity which is linked to improve health.  This is where diet matters.

Foods rich in fat and sugar, especially processed foods, are not necessarily a good source of food for the flora inhabiting the gut. The result is a less diverse microbiome which may even be linked to weight changes. As we get older our microbial diversity can decline. New research suggests that early frailty is correlated to lack of microbial diversity.

The good news is that simply tweaking your diet can have a profound effect on microbial diversity. One of the easiest ways to improve diversity is to include prebiotic foods as well as probiotic daily.

Prebiotics are types of dietary fibre that feed the friendly bacteria in your gut. This helps support a range of gut bacteria which in turn produce nutrients for your colon cells and leads to a healthier digestive system. Some of these nutrients include short-chain fatty acids like butyrate, acetate and propionate which are known to improve metabolic health and lower inflammation.

A prebiotic may be more potent than a probiotic in terms of shifting the microbial composition of the gut. Prebiotics include fructooligosaccharides (FOS), galactooligosaccharides (GOS), isomalto-oligosaccharides (IMO), and the newly emerging, highly potent xylooligosaccharides (XOS).  XOS are found in bamboo shoots, fruits, vegetables, milk, and honey. Prebiotics stimulate numerous bacteria including bifidobacteria and lactobacilli. Others that respond well to these fibres include Akkermansia muciniphila, which constitutes 3-5% of a healthy individual’s microbiota and helps maintain the mucus lining of our large intestine and support gut barrier health.

Here are some great examples of prebiotics to include daily in your diet

Chicory Root

Chicory root is readily available as a coffee-like substitute. You can also use chicory root in cooking. I like adding it to homemade sauerkraut and kimchi.  It’s rich in the prebiotic fibre known as inulin. This is a fabulous fibre for feeding our gut bacteria particularly bifidobacteria spp.  and alleviating constipation. It is also known to aid fat digestion by supporting bile production.

Jerusalem Artichoke & Globe Artichoke

A wonderful starchy root vegetable that’s delicious boiled and mashed instead of potato.The Jerusalem artichoke is better known as sunroot and related to the sunflower family.  It is also great shredded raw added to salads. Rich in iron and potassium it is another brilliant prebiotic. As inulin content is reduced slightly by cooking to get the best benefits try and include more of it raw.

Globe Artichoke is equally great for our gut bacteria. The globe artichoke (Cynara scolymus) is a popular Mediterranean food. It is also rich in inulin fibre and traditional known as a liver supporting food helping in the production of bile.

Dandelion Greens

The humble dandelion greens is delicious used in salads and has a wonderful peppery flavour. It is also rich in fibre with about 4g per 100g. Dandelion greens are also known for their diuretic effects and traditionally known as wet the bed for this reason. You can also add the greens to smoothies or use them in soups.

Coconut Flour

A popular flour in paleo baking, coconut flour is also rich in fibre – in fact it contains more fibre than oat bran with around 11g per 30g serving.

Raw Garlic

Raw garlic is rich in a number of nutrients such as manganese, Vitamin B6, Vitamin C and selenium as well as being high in fibre. It has the added benefits of promoting good bacteria while preventing harmful bacteria from growing.

Raw Onion

Onions are rich in both inulin fibre and FOS prebiotics. Onions are also rich in polyphenols which have also been shown to help stimulate the growth of beneficial bacteria.


Leeks are in the same family as onions and garlic, and offer similar health benefits. Rich in inulin fibre as well as flavonoids, potent protective antioxidants.


Asparagus is a popular vegetable and another great source of prebiotics. With around 2-3g fibre per serving (100g) it is also rich in antioxidants, vitamin C, K and B vitamins.

Bananas and Plantains

The best bananas for gut health are actually unripe (green) bananas which are both rich in inulin and resistant starch to support gut flora. Plantains are a close relative of the banana but higher in starch. A cup of cooked plantain contains around 4.6g fibre as well as plenty of vitamin C and A. Not only can they support our gut flora but improve digestive health and relieve constipation


Oats like mushrooms are rich in a type of fibre known as beta-glucan, as well as some resistant starch. Known for their ability to balance blood sugar, reduce cholesterol they are also linked to promoting gut bacteria.


Stewed apple is one of the best prebiotic rich foods to consume. Packed with pectin which accounts for approximately 50% of an apple’s total fibre content. Pectin helps feed the beneficial bacteria and increase levels of short chain fatty acids including butyrate. They are also high in polyphenols antioxidants which combined with pectin help improve gut diversity.

Larch Arabinogalactan

Larch arabinogalactan is a polysaccharide powder derived from the wood of the larch tree and comprised of approximately 98 percent arabinogalactan. It is available as a supplement in powder form.  It is an excellent source of dietary fibre that is able to increase short-chain fatty acid production (primarily butyrate) via its vigorous fermentation by intestinal microflora. Studies have shown it promotes a number of beneficial bacteria including Bifidobacteria and Lactobacillus.

Yacon Syrup

Yacon root is a popular low glycemic sweetener. It is particularly rich in prebiotic fructooligosaccharides (FOS) and inulin. The inulin in yacon has been shown to improve gut bacteria, reduce constipation and enhance the immune system.

Konjac Root

Konjac root is a tuber which contains 40% glucomannan fibre, a highly viscous fibre which is known to reduce appetite, relieve constipation and promote the growth of friendly bacteria.

These are just a few examples to include.While probiotic rich foods are essential for gut health a prebiotics help “feed” probiotics. By pairing them them together, you can achieve an even better result.