NBl Blog


Prebiotics in food; The good stuff

gut health prebiotics Jan 16, 2021
How prebiotics in food can help us to boost our immune system


I've had a number of people contact me after talking briefly on prebiotics yesterday. So I thought I would expand on that a bit more and dive deeper into the topic.

Firstly, its important to distinguish the difference between a PRObiotic and a PREbiotic.

Most of us are familiar with the term probiotic. These are the bacteria and yeasts which make up our gut flora. They have a positive affect on our physiology, and do a wide variety of things to help support our existence. (Boost our immune system and make important nutrients, for a start)

A PREbiotic is basically the food that feeds the probiotic bugs. They stimulate the growth of the beneficial microbes and the production of beneficial metabolites and nutrients that can support and benefit the host in which they reside. Examples of these nutrients are things like short chain fatty acids, and polyunsaturated fatty acids. (Both essential for life).

Beneficial gut flora and ‘pathogenic’ flora usually have different requirements from their host, so the introduction of a wide variety of prebiotic foods also helps provide protection from these pathogens, and overall maintaining a more balance gut biome. (The knock on to this is a myriad of health benefits, including reduced inflammation).

There are several benefits of using prebiotic foods over simply supplementing probiotics from a bottle, but the main ones which come to mind are:

  • Contain other important vitamins, nutrients, minerals, and enzymes not found in supplements
  • Less expensive than probiotics
  • Lower carbon footprint- if you source your foods as locally as you can
  • Easily done using simple, everyday foods

So where do we get prebiotics from?

First I'll start by saying you really don’t have to overthink this one if you eat a variety of fresh, wholefoods. It is the best thing you can do for your gut health. If you can, try and get some organic stuff in as well.. as much as you can.

Without diving into this hole, pesticides and chemical sprays can directly impact the levels of microbes you are eating, as well as your own gut flora.


Typically speaking, the Western diet is somewhat low in prebiotics compared to diets of those living in the less developed countries of the world. It is well documented that the Hunter Gatherer societies have one of the most diverse and sturdy microbiomes in the world. This translates to far less inflammatory diseases (next to none), and an immune system that is strong.

Prebiotics can be grouped into two main categories: Prebiotic fibre, and prebiotic style compounds.

Inulin a polymer of fructose, is used as a stored food, particularly in roots and tubers of family-Compositae. Pectin is a mucopolysaccharide which is found in cell wall of plants. During the time of fruit ripening, the pectin hydrolyses and gives rise to the constituents of sugar.

Prebiotic fibre

Generally speaking, the prebiotics are the fibres which pass through the GI tract undigested. Whilst they cannot be broken down by us, they can be broken down by, and used by the flora in our large intestine to manufacture beneficial metabolites.

You will tend to see these written on products as fructans, resistant starch, inulin, pectin, or oligofructose and/or fructo-oligosaccharides. These also tend to be the ones which people on FODMAPS diets need to avoid like the plague… This is not the way to go about healing long term. There is far more to the picture than just taking out large food groups.. but more on this another time.

Inulin and FOS: (Fructo-oligosaccahrarides, oligofructose).

These are compounds which are used as food storage for a plant, and are found in abundance in roots and tubers. They are converted by gut microbes and manufactured into metabolites which are beneficial to our health.

These include things like butyric acid, acetate and proprionate. (All short chain fatty acids which are important for our health). These prebiotics also help facilitate the growth of beneficial microbes- think, increase the numbers of the good guys.

Examples of foods which contain prebiotic fibres are:

Onion, garlic, leek, honey, bananas (the less ripe the better), Jerusalem artichokes, Dandelion greens, Sugar beet and Beetroot, Dandelion Greens, asparagus, flaxseeds and wholegrains. They are also found in potato, nuts, oats, and legumes.

Honestly if you think ‘root vegetables’, you probably wont go wrong. Don’t forget to include ginger, turmeric, ginseng, and the other delicious root ‘herbs in this mix. All that resistant fibre is the bees knees to your gut flora!

Prebiotic style compounds:

The prebiotic compounds are nutrients which help to promote the production of ‘good bugs and their metabolites’. They also play another critical role of inhibiting the colonization of some of the enteric pathogens- or let’s just call them ‘bad bugs’. Overall, these compounds keep things in check, and keep the balance of our biomes in better balance.  

There is a wide variety of constituents which fall into the prebiotic category, but some of the more commonly known ones are pectin and polyphenols.

  • Pectin is a mucopolysaccharide which is found in cell wall of plants. During the time of fruit ripening, the pectin hydrolyses and gives rise to the constituents of sugar. It is abundant in fruits like berries, apples, pears, guava and stonefruit. 
  • Polyphenols are diverse in their origin, but the more commonly consumed sources are blueberries, strawberries, peaches, plums, grapes, cacao and tea.

Whilst these foods are probably the more researched ones, the take home message from today needs to be ‘eat whole, plant-based foods to boost your microbiome’.

This prebiotic produce provides food for the gut flora that is 100% necessary for you to survive and thrive.

A final note on insoluble fibre… whilst it doesn’t directly fall under the ‘prebiotic umbrella’, insoluble fibre is important to maintain the motility of the gut, as well as provide other nutrients which help support your gut health. 

Think of it as the stuff that provides the ‘sweeping’ broom action to clear away toxic and old residues. Green vegetables are it when it comes to insoluble fibre, especially leafy greens.

Whilst they don’t directly ‘nourish’ our system, (because we cannot break down the cellulose, we just don’t produce the right enzymes), they are absolutely required to keep everything in check. If you need help making healthier meals for you and your family, schedule a free call with me.

Food for thought.