For years, "probiotic" has been a familiar word in health food stores across the country – ever since adverts for energetic, healthy-looking people knocking back shots of what looks like runny yoghurt first appeared. We've known for a while that probiotics have something to do with gut health.
More recently, the word "prebiotic" has entered the conversation too, and it's easy to get the two confused. So what's the difference, why do we need them, and how do we get both into our diet?
What Are Probiotics?
Billions of beneficial bacteria, viruses, yeasts and fungi live in our gut, collectively known as the microbiome. Probiotics are live bacteria and yeasts that can be consumed through food or supplements to support that microbiome.
Without these beneficial bacteria, many aspects of our health would suffer, including gut function. Microbiome health is also linked to immune function, mental wellbeing, and risk factors for chronic inflammatory conditions, obesity and certain cancers.
A healthy, thriving microbiome is diverse – made up of thousands of different bacteria types picked up from the food we eat, the places we go, and the people we spend time with. The more variety across all three, the more diverse your gut bacteria is likely to be. Conversely, a narrow routine of the same foods, places and people tends to produce a less diverse microbiome.
Those familiar probiotic yoghurt drinks typically contain billions of bacteria, often strains of Lactobacillus or Bifidobacterium, and drinking them regularly is thought to help maintain healthy gut bacteria levels. Probiotics are also available in tablet form, and occur naturally in fermented foods.
It's worth considering a probiotic supplement course after a round of antibiotics, since antibiotics don't distinguish between harmful and beneficial bacteria – a probiotic can help restore what was lost alongside the infection being treated.
Many foods also naturally contain probiotic bacteria, including good-quality plain yoghurt, goat's cheese, fermented foods such as olives, pickles, sauerkraut and kimchi, and fermented drinks like kombucha, kefir and miso soup.
What Are Prebiotics?
Unlike probiotics, prebiotics aren't live microorganisms at all. They're a type of fibre that the human gut can't digest, but that probiotic bacteria can – effectively acting as food for your beneficial gut bacteria and helping the microbiome thrive.
Prebiotic foods contain indigestible fibres called inulin and oligosaccharides, and include onions, leeks, garlic, oats, lentils, asparagus, Jerusalem artichokes, chicory root (sometimes used as a caffeine-free coffee substitute), konjac root, yacon root, and even dandelion greens.
A Healthy Gut, a Healthier You
Eating a diet rich in both pro- and prebiotic foods, alongside plenty of fresh fruit and vegetables, lean protein and whole grains, helps your microbiome thrive. A diet high in processed, fatty, salty or sugary foods tends to have the opposite effect, with knock-on impacts on other areas of health too.
If you're eating well but still experiencing ongoing bloating, discomfort or irregular digestion despite a gut-friendly diet, it may be worth investigating whether a specific food is the trigger rather than gut bacteria alone – a food intolerance test can help rule that in or out. And if IBS specifically is part of the picture, our guide to the best probiotics for IBS goes into more targeted detail.
