Prebiotics. What are they and do we need them?

By Dr Sue Read, HealthMap, Gut Health Coach and Dietitian

I often see clients who have been on the low FODMAP diet for years.  As a dietitian and a microbiologist, this scares me. Why? The low FODMAP diet is a great diagnostic tool to find the cause of their Irritable Bowel Syndrome (IBS), but it is not a way of life. Eliminating high FODMAP foods results in considerably less prebiotics in our diet which our gut community needs to remain healthy. When prebiotics are taken out of the diet, the diversity of the gut microbial community can become compromised and this may lead to other health issues. What are prebiotics?

Prebiotics are fibre, but not all fibre is prebiotic. To be classed as a prebiotic, the fibre must be:

  • able to resist the acidity of the  gastrointestinal tract,
  • resistant  to digestion by enzymes being absorbed in the upper gastrointestinal tract,
  • fermented by the  gastrointestinal gut bugs; and,
  • able to selectively stimulate the growth and/or activity of intestinal bacteria with the potential of providing positive health benefits.

Major sources of prebiotics include soybeans, inulins, unrefined wheat and barley, raw oats, and non-digestible oligosaccharides such as fructans, inulin, polydextrose, fructooligosaccharides (FOS), galactooligosaccharides (GOS), xyliooligosaccharides (XOS) and arabinooligosaccharides (AOS). The table below gives some examples of prebiotic foods.

Food Group Prebiotic foods
Nuts and seeds Cashews, pistachios, almonds
Fruit Dried fruit such as dates and figs, nectarines, bananas, white peaches, persimmons, watermelon, grapefruit, pomegranate and custard apples
Vegetables Savoy cabbage, chicory, asparagus, artichoke, spring onions, onions, beetroot, fennel bulb, green peas, snow peas, sweetcorn, leek, dandelion greens, chicory root
Legumes Chickpeas, red kidney beans, lentils, baked beans, soybeans
Bread/cereals Barley, gnocchi, couscous, wheat bran, oats, pasta, rye bread


We now know that different members of our microbial gut community prefer different types of prebiotics to thrive. The reason they are so important to our health is that they produce a variety of products such as vitamins, short-chain fatty acids (SCFA), natural antibiotics, vitamins, amino acids, neurotransmitters, organic acids, enzymes, antioxidants, anti-inflammatory compounds and many more still being defined.

Research has shown that by increasing foods high in prebiotics into your diet, your gut bug community will have an increased diversity (different types of gut bugs) and increased richness (number of gut bugs) and therefore have an increased capacity to aid in your health more effectively.

I often tell my clients a story about a gut bug called Akkermansia muciniphila (A. muciniphila) and how a diet rich in prebiotics (e.g. inulin-type fructans with polyphenols) can increase the amount of this very important member of their gut community. These bacteria have been found to improve the parameters in metabolic disorders such as obesity (lowering of body weight), improving insulin sensitivity and reinforcing the gut barrier. They have a positive impact on hypertension, hypercholesteremia and liver disease.


More importantly, A. muciniphila is a prominent player that looks after the integrity of the intestinal lining of your gut by getting rid of old mucous cells and helping new ones generate. Integrating prebiotics back into a clients diet is very individualised, but can be done through increasing our knowledge of the gut and the residents who aid in keeping it healthy.

Using gut health and my knowledge of these beautiful creatures that live in and on us, I have developed new ways to motivate people to eat more whole foods and to be more adventurous with their food so they get the variety their gut community needs.


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Hiippala, K., Jouhten, H., Ronkainen, A., Hartikainen, A., Kainulainen, V., Jalanka, J., & Satokari, R. (2018). he Potential of Gut Commensals in Reinforcing Intestinal Barrier Function and Alleviating Inflammation. Nutrients, 10.

Read, S & Myers, S (2019). When Good Bugs go Bad.

Slavin, J. (2013). Fiber and prebiotics: mechanisms and health benefits. Nutrients, 5(4), 1417-1435. doi:10.3390/nu5041417

Varney, J., Muir, J. G., & Gibson, P. R. (2019). Prebiotics Versus Low FODMAP Diet: An Interpretative Nightmare. Gastroenterology, 156(4), 1222. doi:10.1053/j.gastro.2018.10.060


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