• Natalie Gibson

Prebiotics and Probiotics - what are they?

Everyone is now talking about prebiotics and probiotics, these words are becoming more common – they are on our food labels, being discussed in the media and even GPs/pharmacists are discussing them with us.

So what are they?


Prebiotics are defined as non-digestible food ingredients (otherwise known as oligosaccharides) that reach the colon and are used as substrate for gut bacteria to use to produce energy, metabolites and micronutrients.

Put simply it’s the food for your gut bacteria.

But prebiotics have other benefits for us also:

  • They reduce the prevalence and duration of infectious and antibiotic-associated diarrhoea

  • Reduce the inflammation and symptoms associated with inflammatory bowel disease

  • Administer positive effects on bowel habit by decreasing the time for food passage through the entire gastrointestinal tract and increasing faecal bulk. Their main effect is on stool consistency and frequency of defecation as they increase the softness of faecal matter

  • They have a favourable effect on fermentation in the colon. The prebiotic breaks down to short chain fatty acids which decreases the pH of your colon making it favourable to good bacteria and non favourable to pathogenic bacteria

  • Supporting role in reducing blood (LDL-) cholesterol levels by being absorbed into the blood stream and suppress cholesterol synthesis from the liver. The fermentable fibres may have an effect on bile acid metabolism which can lower blood lipids.

  • Have shown to improve blood glucose and insulin levels

  • Exert protective effects to prevent colon cancer. Epidemiological studies have shown that an increased fibre intake is subsequently linked to a reduction in colon cancer

  • Stimulate the selective growth of certain beneficial species (mainly bifidobacteria and lactobacilli) in the intestinal microbiota

  • Enhance the bioavailability and uptake of minerals, including calcium, magnesium, and iron

  • Can improve brain function

  • Lower some risk factors for cardiovascular disease

  • Promote satiety and weight loss and prevent obesity. The fermentable fibre can contribute to an increased feeling of fullness and therefore reduce energy intake. This may lead to a change of gut hormones that regulate satiety leading to a reduction in food consumed.

Prebiotics sound pretty amazing don’t they! They are definitely beneficial to your digestive function, support the growth of good bacteria and minimise the growth of pathogenic bacteria.

So what foods are prebiotic?

The answer to this is fibre rich foods.

However, all prebiotics are fibre, however not all fibre is prebiotic.

Prebiotic rich foods include:

  • Nectarines

  • Watermelon

  • Banana

  • Berries

  • Grapefruit

  • White peaches

  • Dried fruit

  • Garlic

  • Leek

  • Dandelion greens

  • Onion

  • Spring onion

  • Jerusalem artichokes

  • Fennel

  • Chicory

  • Snow peas

  • Green peas

  • Savoy cabbage

  • Asparagus

  • Shallots

  • Potato

  • Lentils

  • Red kidney beans

  • Soy beans

  • Baked beans

  • Chickpeas

  • Oats

  • Barley

  • Wheat bran

  • Rye

  • Pistachios

  • Cashews

  • Hemp seeds

  • Flax seeds

  • Honey

  • Rice

  • Psyllium

  • Kefir


Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”.

Probiotics are derived from traditional fermented foods, from beneficial commensals or from the environment. They act through diverse mechanisms affecting the composition or function of the commensal microbiota and by altering host epithelial and immunological responses.

Probiotics can be beneficial for changing your microbial environment: encouraging beneficial bacteria to thrive and increase butyrate in the gut which assists the immune system to regulate function.

Probiotics are seen to be like personal trainers for your gut.

They are used to provide discipline, get your microbes working, get rid of the bad bacteria and tone your digestive system to work correctly.

Probiotics are not recommended continually. As naturopaths, we use probiotics to support gut function in particular for conditions such as immune regulation, reducing digestive discomfort from bloating, skin conditions, preventing food-borne illness and also if someone is taking antibiotics.

Different strains of bacteria have different actions. There is not a quick fix when it comes to probiotics and they all don’t act in an identical way. Probiotic strains used for skin conditions are very different strains used to support antibiotic use.

If you were wanting to take a course of probiotics, you should talk to a naturopath, nutritionist or anyone in the natural health field for advice on which one is most suitable.

But there are ways you can use probiotics at home. Probiotic rich foods include:

  • Sauerkraut, pickles, kim chi

  • Kefir, natural yoghurt (with no added sugar) or aged cheeses

  • Miso, tempeh, natto, tamari

  • Traditional sourdough bread

  • Kombucha

It is recommended that you start with one serve of probiotics daily and increase from there over the coming weeks if you do not experience any negative side effects.

For example, 1 teaspoon of sauerkraut daily for a few days and then increase to 2 teaspoons.

So how do you get these foods into your diet?

- Sauté vegetables with garlic, leek and onion

- A bowl of fruit salad

- Stewing apples and pears and adding to your breakfast porridge or cereal (see our post on Stewed apples for gut health)

- Adding a teaspoon of sauerkraut to your salad

- Adding nuts and seeds to your salads, stews, breakfasts

- Adding legumes to stews, soups, salads, curries

- Starting your meal with a homemade miso soup entree

- Increasing your vegetable content - adding veggies to your breakfast smoothie, roasting vegetables and adding to salads, adding another 1-2 serves of veggies to your evening meal

If you are still confused or unsure, please be in touch or speak to a natural health practitioner to find out more information.

In the next week, we will also be discussing symbiotic and modbiotics so don't forget to sign up so you never miss a post!

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