veg stir fry noodles in sweet and sour sauce

Everyone is familiar with the phrase ‘you are what you eat’, but actually, you are what you absorb, and this is where good gut health comes into play.

The gut is our gastrointestinal tract, and is integral to our overall health, affecting everything from our metabolism to our immune system function and even our mood.  


Microbiota is the name given to the trillions of microorganisms or bacteria living in our gut, made up from thousands of different species. It’s about 50% of our total bodily cells, and two-thirds of our gut microbiota is completely unique to us, similar to DNA.

When we’re in our mother’s womb our gut is sterile, meaning it’s completely free from these bacteria. During labour we acquire gut microbes from our mum’s body, as well as from the environment we’re born in and the air around us.

Our microbiota is influenced by what we’re fed as a baby – breast milk from a mum who has a healthy balanced diet is really beneficial here – and changes up to the age of about three years old, when it starts to stabilise. So, those early years can be really important to our future gut health.



When we feed our gut microbiota it increases in numbers, helping us to have a happy gut. As well as helping us to maintain a healthy digestive system, it:

  • Helps us to break down foods that we cannot digest, specifically fibre, into energy that we can actually use
  • Helps our immune system to fight infection and helps to prevent harmful bacteria from transferring into our bloodstream
  • Helps with the production of some vitamins, such as:
    • Vitamin B12 – for healthy metabolism, immune and nervous system function, and red blood cell formation, keeping us awake and alert
    • Vitamin K – for strong healthy bones 
    • Folate – preventing tiredness


Probiotics are live bacteria that are commonly known to aid gut health, and are often referred to as ‘friendly bacteria’.

Prebiotics are looking like the holy grail when it comes to changing our gut environment for the better. They’re naturally found in some plant fibres, and to be honest, the best prebiotic going is a healthy, balanced diet.



Probiotics are naturally present in a few foods, namely natural yoghurt, and fermented foods such as kimchee and sauerkraut (the latter are beneficial, but should be enjoyed in small amounts due to their high salt content).

You can also take probiotics in the form of shop-bought yoghurt drinks, some of which contain up to billions per millilitre (just be wary of added sugars), and as tablets, capsules and powder. What’s not clear, when it comes to these products, is whether they contain enough bacteria to have an impact, or whether the bacteria can survive the digestive process long enough to make it down to your lower gut (the colon) and do its thing. Emerging research is suggesting that small microcapsule probiotics seem to stand the best chance of holding up against stomach acid and surviving that journey to the colon, so look out for more on this.

Prebiotics can be found in foods such as bananas, onions, garlic, asparagus, leeks, artichokes, chicory and wholegrains, particularly oats. As you can see, these are fairly common ingredients, so if you can start including them in your diet more regularly, that’s only going to be a good thing.


Probiotics are thought to help restore the natural balance in our gut, especially after a course of antibiotics, which can often disrupt our gut microbiota, and to help ease the symptoms of irritable bowel syndrome (IBS), to aid digestion and to improve our immune response.

Prebiotics are digested by our gut microbiota, and it flourishes on them, causing it to grow and multiply. Our gut microbiota is also able to ferment some other fibres that we can’t digest, turning them into short chain fatty acids. These acids are able to influence our gut environment by lowering the PH level, in turn keeping our gut healthy and increasing the amount of nutrients we can utilise from our food.


Extract adapted from Super Food Family Classics by Jamie Oliver, published by Penguin Random House Jamie Oliver Enterprises Limited (2016 Super Food Family Classics). Cover photography by Paul Stuart.

About the author

Jamie Oliver

Jamie Oliver is a world-renowned chef and food campaigner.

Jamie Oliver