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Healthy gut 101: Do you need prebiotics, probiotics, synbiotics & postbiotics?

Improving gut health is top of the agenda for many and rightly so. Whether you want better, digestion, more energy, a brighter mood, and even weight loss, diversifying your microbiome should be up there with one of your goals. The problem is there’s a lot of jargon surrounding the area so best to break it down.

What is a probiotic?

Probiotics are usually taken as a supplement and contain friendly bacteria that can populate your large intestine. In order for the supplement to gain probiotic status it must contain enough of a certain bacteria known to provide health benefits.  Some digestive and health issues warrant the need for a tailored probiotic to ease symptoms such as bloating and rebalance the gut microbiome during dysbiosis. The problem is, a lot of these probiotics don’t arrive at the gut alive and often are not personlised enough for the individual’s desired benefit.  A trusted healthcare professional can guide you with probiotic recommendations that are right for you and your symptoms, however if you’re just looking to improve your gut health you will have great benefit from introducing fermented foods into your day to day.

What is a fermented food?

Fermented foods have been around for hundreds of years and it’s only recently their miraculous health benefits are being acknowledged. Live cultures found in kefir, live yogurt, Kimchi, saurkrawrt, miso, pickled veg and kombucha are great examples of everyday foods that can be added to your routine. Just  2-4 servings per day improves microbiome diversity and decreases markers of inflammation (1). If you imagine a diverse microbiome as a rainforest with lots of varieties of plants and an unhealthy gut as a desert with not much diversity. Good bacteria ferment fibrous foods in the large intestine and produce anti-inflammatory short chain fatty acids such as butyrate (2).

What is a prebiotic?

Just like humans, the microbiota (collection of microbes) in our gut needs to eat to survive, stay healthy and work well! If you imagine all the different microbes having different taste preferences, we must ensure a variety of different foods to satisfy them to thrive. The foods you need to feed your gut bacteria are plants that are full of fibre. This fibre is also known as a ‘prebiotic’. Fruits such as berries, vegetables like green beans, and foods such as lentils, beans, and whole grains are fantastic sources of prebiotic. The higher fibre of the plant, the better it will be for your microbiome. As humans, we don’t have the mechanism or enzymes to break down plant fibres so for us to benefit from their energy, our gut bacteria ferment them for us as a form of breaking them down. In the process, we get energy and lots of lovely health compounds, and they get fed to stay strong and healthy. Do you need a prebiotic supplement? Absolutely not, best to get your fibre from real food.

What is a synbiotic?

Synbiotics are supplements  that combine both probiotics and prebiotics believed to have a synergistic effect by inhibiting the growth of pathogenic bacteria and enhancing the growth of beneficial organisms. Further research is needed to evaluate interaction between probiotics and prebiotics, and the effects of synbiotic on individuals. Do you need to take one? Why not just incorporate fermented foods with fibrous foods and make your own synbiotic!

What is a postbiotic?

These supplements contain the bioactive compounds your gut bacteria produce when they consume fibrous foods. These ‘waste products’ are actually incredibly beneficial to the body and shouldn’t be ignored, with potential benefits to the immune system, digestion amongst other things (3, 4). Postbiotics aren’t as readily available as prebiotics and postbiotics however do appear in health food stores. Instead of adding another supplement to your regime, why not create more of your own postbiotics internally, eating a wide range of fermented foods and including fibrous foods at all meals and snacks.

Pro tip: I educate my clients with the 30:30 approach… aim for 30g of fibre per day from 30 varieties of plants per week. You can do this by rotating your fruit and vegetables, carbohydrates, nuts, seeds and herbs, and spices at each meal and including high fibre fruit, veggies, whole grains, nuts, and seeds daily!


(1)     Wastyk, Hannah C. et al. Gut-microbiota-targeted diets modulate human immune status Cell, Volume 184, Issue 16, 4137 – 4153.e14

(2)   Sanders, M.E., Merenstein, D.J., Reid, G. et al. Probiotics and prebiotics in intestinal health and disease: from biology to the clinic. Nat Rev Gastroenterol Hepatol 16, 605–616 (2019).

(3)  Żółkiewicz J, Marzec A, Ruszczyński M, Feleszko W. Postbiotics-A Step Beyond Pre- and Probiotics. Nutrients. 2020 Jul 23;12(8):2189. doi: 10.3390/nu12082189. PMID: 32717965; PMCID: PMC7468815.

(4)  Silva JPB, Navegantes-Lima KC, Oliveira ALB, Rodrigues DVS, Gaspar SLF, Monteiro VVS, Moura DP, Monteiro MC. Protective Mechanisms of Butyrate on Inflammatory Bowel Disease. Curr Pharm Des. 2018;24(35):4154-4166. doi: 10.2174/1381612824666181001153605. PMID: 30277149.

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