The gut microbiota is a complex community of micro-organisms that live in our digestive tracts, while the gut microbiome refers to the genomes of these micro-organisms. It is composed of hundreds of different species, mainly consisting of bacteria, but also other micro-organisms like fungi, protozoa and viruses. The amount of these is huge and the number of genes in the microbiome vastly outnumbers the number of human genes that we have. There are 23,000 genes in the human genome, but the human microbiome contains over three million genes!
What are the functions?
Over time, humans have developed a symbiotic relationship with our gut microbiota. This means that these micro-organisms benefit from us and we benefit from them too. The good news is that the microbiota carries out a number of important functions for our bodies. It stimulates immune function, improves our resistance to infections and improves our ability to acquire nutrients by helping us to digest certain food components that we cannot digest on our own.
Factors that influence the Gut microbiome
A number of lifestyle and diet factors affect the development of our gut microbiota. Lifestyle factors such as the frequent use of antibiotics may disrupt its balance or reduce its diversity. Events that occur early in our lives can also have a large impact. For example, a caesarean delivery at birth may reduce its diversity. Formula feeding is also less beneficial for the microbiome compared to breastfeeding. Of course, there is nothing that we can do about these early life events at this stage of our lives, but it may have some influence on how our microbiota has developed.
However, diet also plays a huge role and is something that we have control of! Diets that are low in fibre and high in simple sugars and saturated fats don’t provide sufficient support to encourage growth of our microbiome.
What Can We Do to Help Our Gut Microbiota?
- Consume enough fibre – Fibre helps to promote the growth of healthy bacteria in our gut and improve the diversity of our gut microbiome. Fibre can be found in wholegrain products (e.g. brown bread and brown rice), vegetables, fruit, nuts and pulses (e.g. beans, peas and lentils).It is recommended that we consume around 30g of fibre per day, but the average adult consumes less than half of this amount! Try to consume the recommended 5 portions of fruit and vegetables per day to help you to reach this target. Leave the skins on them where possible to increase the fibre content. Try to include a wide variety of different fruit and vegetables in your diet to promote diversity of the microbiota.
2. Consume omega-3 fatty acids – These also promotes a healthy gut microbiota. Try to include some oily fish in your diet 1-2 times per week to meet your requirements of omega-3 fatty acids.
3. Avoid high amounts of free sugars and saturated fats – The by-products created when these are broken down in the body can be harmful to the gut microbiota. The long-term effects of this can promote chronic diseases and inflammation in the body. Moderation is important when it comes to consumption of these foods.
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4. Breastfeeding – It offers so many health benefits to both the mother and baby. One of these benefits is helping to improve the microbiota of the baby. If you are planning on having children, this is one more reason to try to breastfeed if it is possible for you.
5. Prebiotics and Probiotics – A lot of research is still being carried out on these but it is thought that they can play roles in promoting a healthy gut microbiota. Prebiotics are specific types of carbohydrates that are a growth substrate for certain bacteria in the gut. In this way, they increase the amount of these beneficial bacteria. Foods that contain prebiotics include certain vegetables (e.g. asparagus, chicory), fruit (e.g. nectarines), legumes, nuts and seeds. Probiotics are live micro-organisms that can increase the number of micro-organisms in the gut when they are consumed and can improve our gut health. Probiotic foods include certain yogurts, kombucha, miso and sauerkraut.
Thankfully, a lot of these tips are part of the general healthy eating guidelines! So, by incorporating them into your lifestyle, you will be taking steps to improve the health of your microbiota and your overall general health too! As the gut microbiota carries out so many important functions for our bodies, by helping it we are also helping ourselves.