Probiotics and Prebiotics... What exactly are they?

Gut health is quite a buzz word at the moment. It's almost fashionable to be taking probiotics these days. Prebiotics have also become quite popular with more and more packaged foods being marketed as having so popular that plant based milks are now advertised as containing them. But what exactly are pro- and pre-biotics? And why are they so popular? Read on...


Our microbiome is made up of a variety of microbes including bacteria, viruses, fungi and yeasts. As well as in our gut, we have different microbiome communities living all over our body including our skin, nose, mouth and reproductive organs. The microbiome within our gut has been studied the most. New research is released often showing different ways in which our gut microbiome affects the digestive system, immune system, mental health and more. The gut microbiome has also been shown to be associated with health conditions such as asthma, eczema, obesity, type 2 diabetes and Alzheimer’s disease. There are more microbial cells in the human body than there are human cells. In fact, there are more microbial cells in the human body than there are stars in the Milky Way! That's why there is so much research being done... There is so much to research!

Numerous factors affect the make-up of microbes within our microbiome including diet, lifestyle, stress, medications, genetics, where we live and many others. These factors can cause an imbalance in our microbiome (dysbiosis) which may lead to symptoms such as bloating, stomach pain, constipation and diarrhoea. Due to these factors the make-up of microbes within each person's microbiome varies as we all lead different lives. While we don't know exactly what the best microbiome make-up looks like, we know that there are good microbes and bad microbes and that a certain ratio of microbes within our gut is are required for good health. Bad microbes produce inflammatory molecules which can enter the blood stream causing inflammation in areas of the body including the brain. Good bacteria produce anti-inflammatory molecules which also feed the cells in the large intestine, further adding to overall health.


Probiotics are usually bacteria or yeasts which are taken in supplementation form or through fermented foods to enhance the variety of missing or depleted strains of microbes and rebalance the microbiome. There are many studies which show the benefits of taking certain microbial species for certain health conditions. Taking probiotics, however, can exacerbate digestive symptoms if the wrong species are taken. Rather than helping reduce symptoms, this can further add to the imbalance of microbes. Probiotics are measured in CFU (colony forming units) which will tell you the number of cells in each dose. The CFU can vary greatly between products and the correct CFU dose will vary depending on what is being treated.


Prebiotics are fibres found in food which the body is not able to digest (breakdown and absorb). These prebiotic fibres are found in fruit, vegetables and wholegrains. So, not only is fibre required for regular bowel motions, fibre is also required for a healthy gut microbiome. When we swallow our food it breaks down further and further as it passes through the digestive tract. While some nutrients are absorbed in the stomach, most are absorbed in the small intestine (which is why the small intestine is so long - around 7 metres in an adult - the body is better able to absorb more nutrients along the whole length). Prebiotic fibres help to support the travel of food along the digestive tract and is also a fuel source for the microbiome A good supply and range of prebiotics supports a healthy number and diversity of microbes.

In summary.

Probiotic supplementation can absolutely reduce digestive symptoms and treat a number of health conditions when taken correctly. However, if the original cause of the microbiome imbalance is not corrected, it’s likely that after probiotic supplementation is stopped, the microbiome will return to its imbalanced state. To support a healthy microbiome, diet and lifestyle are key. Choose foods that are as close to their natural state as possible as this means they've had the least amount of processing and will retain the most nutrition. Include fermented foods daily, if your digestion allows, as this will help to keep your microbiome diversity strong. Keep hydrated, aim for 7-9 hours sleep, limit alcohol and coffee, move your body daily and avoid packaged foods as they usually contain excess sugar and fat which the bad microbes love and many additives which the good microbes hate. Getting back to the basics are the most important factors for microbiome optimisation and overall health.

Here is a link to my Easy Coconut Yoghurt recipe which is a yummy fermented food you can include in your daily diet.