Not to be confused with probiotics, prebiotics are a special kind of fibre that create the ‘good bacteria’ in our gut. Eating plenty of wholefoods and looking out for new products formulated with inulin or resistant starch are great ways to support a healthy gut.

Fibre plays a role in a diverse microbiome

Most of us know that fibre is important for good digestion, but it also supports a resilient and healthy microbiome, or our gut flora.

While all fibre is good for us, prebiotics are a special type of fibre that occur naturally – and cheaply – in plant-based foods like fruits, vegetables, legumes and whole grains. They are worth weaving into your daily diet if you want to improve your gut health.

It’s recommended that we eat 25 to 30 grams of fibre a day, but most of us don’t come close, as this study shows. According to the CSIRO’s latest Gut Health and Weight Loss report, fibre has a multitude of benefits such as:

  • Reduces energy uptake
  • Promotes satiety, or helps you feel full
  • Enhances the microbiome, which may help prevent obesity
  • Moderates blood cholesterol and blood sugar levels

Prebiotics are a special type of fibre that feed the growth of the ‘good’ gut bacteria (or more technically, the probiotic microorganisms). Put simply, probiotics are the live bacteria and prebiotics are the fibre that acts as the nutrient-rich fertiliser to help those probiotics flourish. Prebiotics stimulate healthy fermentation in the gut as our live bacteria digest the fibre to create a thriving microbiome (which researchers now believe has a direct connection to our brain and role in preventing disease).

Resistant starch is also important

Resistant starch is prebiotic, which has been shown to have positive effects on gut health. These starches travel undigested to the bowel, where they act as food for the microbiome, producing anti-inflammatory compounds in the process. The CSIRO recommends eating resistant starch every day because of gut health benefits.

We can eat resistant starch in the form of legumes like beans and lentils, whole grains like oats or brown rice, and sometimes from cooked and cooled starches in dishes such as potato or pasta salad. It’s actually more beneficial for our microbiome to eat pasta or potatoes that are cooked and cooled, rather than freshly cooked.

New prebiotic ingredients are entering the Australian market engineered to be high in resistant starch like hi-maize and Barley Max. There are also naturally-occuring prebiotics like green banana flour, which is now available in some supermarkets and specialty outlets.

As gut health becomes more of a priority for consumers, it’s likely more products will reformulate to be high in resistant starches and prebiotics. You can now find resistant starch added to breakfast cereals, muesli bars, granolas, soy milk and as powder supplements to add to your own home-cooked recipes.

Another prebiotic is inulin. Inulin has been creeping its way into our food supply for years, mostly in the form of an extract from chicory. Many bars and savoury snack foods have been formulated with inulin to boost their fibre. With thickening properties, inulin can also be added to products like yoghurt to combine the probiotic and prebiotic benefits in a single product.

Food manufacturers are also beginning to enrich food with prebiotic fibres. Look for ingredients such as chicory root fibre and inulin if you want to eat more.

Whole foods rich in prebiotics

While prebiotic research is relatively young, there is no clear recommendation for how much prebiotic fibre we need to eat to reap the many benefits. As prebiotics are found naturally in plant foods, it would be wise to include a wide variety of whole foods in your diet to meet the 25-30 gram fibre target and include some of the rich prebiotic sources mentioned below:


  • Jerusalem artichokes
  • Garlic
  • Onion
  • Leek
  • Shallots
  • Spring onion
  • Asparagus
  • Beetroot
  • Fennel
  • Green peas
  • Snow peas
  • Sweet potatoes

Tip: Garlic, onion, leeks, shallots and spring onion act as great flavour enhancers for many traditional cuisines – think garlic and onion in your pasta sauce, spring onion in a stir fry and leeks in a soup.


  • Chickpeas
  • Lentils
  • Red kidney beans
  • Baked beans
  • Soy beans

Tip: Look for convenient pouches or tins to add to salads and soups, or try hummus as a snack with crackers or vege sticks.


  • Cashews
  • Pistachios

Tip: Enjoy a small handful of nuts each day as a snack, or sprinkled on top of breakfast cereal or porridge. Most nuts are fibre-rich and filled with healthy fats to support heart and brain health.


  • Barley
  • Rye bread
  • Rye crackers
  • Pasta
  • Gnocchi
  • Couscous
  • Wheat bran
  • Oats
  • Wheat bread

Tip: Cooking oats reduces the resistant starch – try soaking your oats overnight in your choice of milk and eating them uncooked to maximise the prebiotic content.


  • Green bananas
  • Nectarines
  • White peaches
  • Persimmon
  • Grapefruit
  • Pomegranate
  • Dried dates and figs

Tip: Green bananas may not be so appealing as a snack, so look for green banana flour in the supermarket – this can be used as a substitute for regular flour in baking and will boost the prebiotic content of your baked treats.

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