You can't see them, perhaps you have no idea... but there are approximately 100 trillion micro-organisms organisms living in your digestive system! Bacteria, viruses, yeasts, fungi... there is as much diversity as there are numbers. We refer to them as the gut microbiota (in greek "small life"). We also use the word microbiome which means the collective genomes of the micro-organisms in a particular environment.
Why should we be bothered to think about these tiny organisms living inside us? Well, recent links have been shown between reduced bacterial diversity in the gut and inflammatory bowel disease, diabetes, atopic eczema, coeliac disease, obesity and blood vessel stiffness. The gut microbes are key players in our digestion, help produce some vital vitamins and are also important in fighting off infections. This whole crowd is estimated to weigh 2kg in each of us! Curious? Read along and come meet them!
The majority of our tiny inhabitants are found in the large intestine which acts to absorb water and nutrients that were not absorbed by our 20-foot long small intestine. Microbiota helps our large intestine to do its job as these bacteria help to break down touch particles. The products can then finally get absorbed by our large intestine. In return, the intestine offers a place for the bacteria to stay with stable temperature and pH conditions and regular deliveries in food, overall a great collaboration for both.
The role of bacteria doesn’t stop there! Similarly, they can break harmful toxins or medication products that would otherwise pose a problem to our bodies. Some bacteria also synthesise products that we need and would otherwise be lacking such as B vitamins (cobalamin, folic acid, biotin, thiamine, riboflavin, nicotinic acid, pyridoxine and pantothenic acid) as well as vitamin K. The bacteria are providing us directly with our food supplements! It’s almost like going to Boots to get your multivitamins! How do scientists know this? Firstly, none of the cells in our body has any genes to produce these important vitamins, so scientists believed they had to be acquired through the diet: that was the only way. However, while analysing the end product of our digestion (our poo!) they discovered that there were more of these vitamins coming out that there had been coming in! So the vitamins had to be coming from somewhere, and scientists soon found out that some bacteria have these incredible genes in their books!
Finally, the gut microbiota is very important training for our immune systems. Our immune system is a group of cells ad mechanisms that fight off infection, and in the early years of life they need some training to become effective but also tolerant. If they are not effective you get ill more often and cannot get better from an infection. If they are not tolerant you will react badly to normal things of the environment: this is called hypersensitivity, or an allergy. Scientists now think there might be a link between the gut microbiota in the first months of life and the development of allergies, asthma, eczema... This is because a lot of immune cells go for training in your gut, where they can see some micro-organisms for the first time and learn how to react to them if they see them again somewhere else.
The incredible thing is that we all have different microbiota! Different species in different proportions that affect our general health. So what must we do to nurture the little friends that live in our gut? How can we take care of our microbiota? 5 tips below!
1. Don’t play with antibiotics! Of course, antibiotics can be vital for some very specific infections, so if your doctor has prescribed them for you or your child, make sure you take them! However, follow the dose carefully and take the course for the time needed, don’t decide yourself when to start or stop your course! Antibiotics do not help cure viral infections which are often the cause of respiratory tract infections like the common cold.
2. If you need to take antibiotics, you should know these will not only kill the bad bacteria causing your disease but also the friendly bacteria that live in your gut. If the friendly bacteria are wiped out, who knows what may settle in their empty space! This is why it might be helpful to give your gut a hand by taking some probiotics while on a long course of antibiotics. Speak to a pharmacist for further recommendations on key types such as Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium breve, Lactobacillus acidophilus, Lactobacillus rhamnosus and Lactobacillus bulgaricus. There are also natural sources which can be found in apple cider vinegar, kefir, kombucha, organic pickles, miso, sauerkraut and kimchi. All to be taken in moderation of course!!
3. Prebiotics are another thing available that can help you take care of your gut microbiota. Prebiotics combines the best molecules, mostly fibre, to feed the good bacteria of your intestine, while not encouraging the less desirable bacteria. If your bacteria are having a difficult time, they might need some specific boosting and nutritionists are fantastic at helping support people in this department. Some nutritionists and doctors now utilise special tests which help to determine how healthy your gut microbiome is.
4. If (unfortunately) you have caught a little virus that caused you to have diarrhoea, this fast emptying of your bowel can suddenly wash out all the bacteria living peacefully in the folds of your intestine. This also leaves your gut inflamed and the bacteria won’t be able to settle there anymore. After your diarrhoea has calmed down, the bacteria should come back by themselves, but watch out for symptoms, in some cases your gut may benefit need some extra bacteria in the form of probiotics. Go back to point 2!
5. Eat a varied diet! Oh, strange, yet another person telling us to drop the chocolate and sweets? But it’s worth it, I promise! The bacteria that live off chocolate and sweets are not the friendliest bacteria of the whole population! Indeed, these are bacteria that produce a lot of gas (oh oh!) and not many nutrients. The ones that help your immune system and produce your vitamins need some more varied elements, such as a variety of fruit and veg! Also, fermented foods are absolutely loved by your microbiota (yoghurt, cheeses, fermented veggies…), go and try them and treat the little friends inside your gut!
Want to know more?
· Role of the gut microbiota in nutrition and health, BMJ 2018; https://www.bmj.com/content/361/bmj.k2179
· Gut: the inside story of our body's most under-rated organ, Guilia Enders (2015)
Written by: Marianne, Purpose Print Team
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