Probiotics and Prebiotics

Female making hands in shape of love heart over stomach

Did you know that we have 100 trillion bacteria living in our gut?!

While that may leave you feeling a little squeamish, don’t fear! These little guys are on our side, they play important roles in many metabolic, nutritional, physiological and immunological processes which keep us healthy. This includes acting as a barrier to prevent “bad” bacteria from invading and causing illness and producing nutrients that we can’t make ourselves (vitamin K, B12, folic acid, short-chain fatty acids).

There is continual evidence which suggests incorporating prebiotics and probiotics into our diet is beneficial for keeping a healthy balance of “good” gut bacteria. So what are probiotics and prebiotics?


Probiotics are live microorganisms (bacteria or yeast) found in certain foods, which when consumed in adequate amounts are beneficial to our bodies.

Common probiotics include the genera Lactobacillus and Bifidobacterium.

In addition to encouraging the growth of our own “good bacteria”, probiotics have shown to increase our resistance to the common cold, decrease the risk of antibiotic-associated diarrhoea and may potentially prevent the development of allergies.

Evidence connecting conditions such as inflammatory bowel disease, irritable bowel syndrome (IBS) and obesity with an unbalanced “good” to “bad” bacteria ratio in the gut (dysbiosis), and how the use of probiotics may be of value, is still under exploration.

Not all foods which rely on the fermentation process of bacteria/yeast (such as bread) are considered probiotics. The “good” bacteria in these foods don’t always survive during food processing and exposure to oxygen, pH and heat. They also have to combat our digestive enzymes and acidic stomach juices before reaching our intestines where they can grow and replenish the healthy bacteria already there.

  • Foods which may contain probiotics include:
  • Fermented milk products (kefir, buttermilk, Yakult)
  • Fermented vegetables (sauerkraut, pickles, kimchi)
  • Tempeh
  • Miso seasoning

Foods which contain added probiotics should state so on the product packaging – including the name of the strain of bacteria, the viable quantity and whether the product has been clinically tested.


Prebiotic Foods

A prebiotic is a type of fibre found in certain foods, which promotes the growth and activity of good bacteria in the gut.

When consumed, prebiotics pass undigested through the stomach and small intestines until they reach the large intestine where they become “food” for the “good” bacteria living there.

Additional benefits of this fibre are only just emerging. Prebiotics may be associated with increased mineral absorption and improved blood glucose levels.

A wide range of foods are naturally high in prebiotics:

  • Vegetables – green peas, snow peas, corn, garlic, onion, leeks, spring onion, asparagus, beetroot
  • Fruits – banana, watermelon, nectarines, white peaches, pomegranate, dried fruit
  • Legumes – chickpeas, baked beans, red kidney beans, lentils
  • Cereals – couscous, gnocchi, pasta, rye bread/crackers, barley, oats, wheat, soybeans
  • Nuts – cashews, pistachio nuts

Keeping your digestive system happy is a foundation for good health. Try to include a variety of probiotic and prebiotic foods during the week as part of a balanced diet. Your gut will thank you!

**Please note that if you have been diagnosed with IBS and are currently following a low FODMAP diet, prebiotic foods include fructooligosaccharides (fructans, FOS) and galactooligosaccharides (GOS) which are not recommended until the re-introduction phase.

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