The topic of this article is one I’ve been keen to write for quite a while, but wanted to wait until I really felt that I have done sufficient background reading into the area to distill the science down a bit for you guys. Before Christmas, I joined an excellent webinar organised by Nutriwebinar all about the gut microbiome and gut health, which gave me the push and knowledge to share what I learnt with you all. I’ve been reading into this area for the last 18 months and still feel as though I’ve only scratched the surface, which is largely because it’s still such a hot area of research, one which is evolving constantly. So, in this article we’ll discuss the basics about our gut bugs, how we can give them the love they deserve, and why that’s really important for many aspects of our health.
First, a quick note – I want to give Maeve Hanan, registered dietitian and friend of mine, who runs the absolutely fantastic blog Dietetically Speaking a big shout out here. Maeve very kindly proof-read this article for me, and in doing so cast her well-researched and always evidence-based eye on what I’ve written to share with you. If you don’t already, please go follow Maeve on Instagram here and I highly recommend signing up to her blog newsletter too – link to her blog right here. Having her stamp of approval on the blog means a great deal to me, especially on such a new area of science and one which I’m keen to share with you all.
What IS the ‘gut microbiome?’ Who are these ‘gut bugs’ that everyone is talking about? How does this area of science apply to you? Well, it applies to everyone really, to varying degrees of importance, because we all have a gut microbiome. The term ‘gut microbiome’ refers to the population of gut (i.e. gastrointestinal) bacteria we each have, which includes more than 1000 different species! Here’s some fast facts about your gut bugs to get us started:
- Our gut is home to literally trillions of micro-organisms, including bacteria
- The gut microbiota is considered the most metabolically active organ in our body
- Approximately 70% of our immune system resides in our gut
- Our bodies have TEN TIMES more gut microbes than human cells
The microbiome has been linked in research to a very wide range of medical symptoms, systems and conditions (some to a greater extent than others, based on research to date), including immunity, obesity and metabolic syndrome, digestive symptoms such as constipation, bloating and diarrhoea and gastrointestinal (GI) conditions such as irritable bowel syndrome, inflammatory bowel disease and digestive cancers.
There are different species (with overlap in some cases) of gut bacteria at each stage of our GI tract, from the mouth to the stomach, to the small and then large bowel. For example, in the colon (i.e. large bowel), well-known species that predominate include Lactobacillus, Bifidobacterium, Clostridium and Bacteroides.
The gut microbiome is of research and health interest for a variety of different reasons. As well as playing a key role in our digestive health, it is though to have major potential for health optimisation, disease prevention and development of therapeutic interventions using the knowledge we are building about it. It affects our bodies from birth, and throughout life, with effects on the body via it’s role in our digestive health as I’ve said, as well as proposed roles in our immune system, central nervous system, and aspects of health such as metabolic health.
With this area of health getting a LOT of attention over the past few years, a trend has emerged in mainstream and social media towards people advising or discussing their experiences of use of what are called ‘pre- and probiotics‘. Hang on Ciara, I hear you say. Pre- and Pro-what? Good question. Let’s discuss.
Probiotics are live beneficial bacteria and yeast, while prebiotics are substances (non-digestible food substances) that are used BY your gut bacteria. Both are found in food and supplement form. Examples of probiotic sources include fermented foods you’ve probably seen or heard of by now, such as yoghurt, kefir, sauerkraut, miso, kombucha, and tempeh. It’s important to note that in the case of yoghurt, companies can make a claim of this nature if ‘live active cultures’ were used in the processing stage of production, even if the probiotic strain is NOT present in the end product. The yoghurt therefore should say ‘live active cultures’ on the label if this is the case, or if these are actually present in the end product. Prebiotics meanwhile, are food for your ‘good’ or beneficial, gut bacteria. A symbiotic, in case you’ve come across that phrase, is a substance that has effects that are a combination of both (i.e. synergistic effects).
Prebiotics can come from artificial/manufactured sources, or be found naturally. For example, human breast milk is a source of prebiotics, as are certain foods such as banana, leeks, onions, chicory, asparagus and artichoke. Another example is oats and barley, which contain the prebiotic fibre beta-glucan. There is a lot of ongoing research into examining how prebiotics may potentially be used to feed good gut bacteria to influence optimal health outcomes, particularly in conditions where research has shown an association with the gut microbiome, and some prebiotics have been more extensively studied and are more well-known than others. So basically, by consuming prebiotics, we are providing our good gut bugs with a steady source of food to chow down on, which allows them to survive and increase in population numbers (i.e. in greater numbers than the bad bugs).
Now, time to touch on a relevant point that you guys might be wondering about. Where does FIBRE fit into all of this? We’ve all heard of fibre (also known as roughage, and what keeps your bowels ‘regular’). I’ve written a full blog post on the importance of fibre, with recipes too, which you’ll find here.
Fibre is VERY important, and unfortunately, we know that in Ireland and the U.K., as a population most of us don’t meet our daily fibre intake. If you’re not sure what exactly it is, I encourage you to read the blog post I’ve linked. In this article, I shared the following definition: ‘all carbohydrates that are neither digested nor absorbed in the small intestine and have a degree of polymerisation of three or more monomeric units, plus lignin.’ That’s probably clear as mud to many of you – but basically, fibre is what we call the parts of plants and seeds that we cannot digest. The most up to date guidelines from here in Ireland and the U.K. recommend that adults consume at least 30g of fibre per day, and it’s no secret that as a population, we aren’t hitting that target. Fibre has two major actions in our bodies, which confer it’s wide range of health benefits – the physical properties it has when consumed, and the effect it has on our gut microbiome. Most of our fibre comes from cereals and cereal products, vegetables and the humble spud (potatoe, for those of you not from Ireland or the U.K.). Foods with 6g or more of fibre per 100g are considered ‘high fibre’, with a minimum threshold of 3g fibre per 100g required for a food to be considered a fibre source.
Fibre increases the bacterial and faecal mass in our gut, keeping our bowel habit regular and reducing constipation. It contributes towards the satiety of a meal (i.e. keeping us fuller for longer). In terms of overall health benefits, studies show an adequate fibre intake has been associated with lower risks of bowel cancer, insulin resistance in type 2 diabetes mellitus, reduced cholesterol, blood pressure and coronary heart disease. So yep, pretty important. The webinar I joined on the gut microbiome defined fibre quite nicely, as ‘carbohydrates that are not digested or absorbed in the small intestine, but which can be digested by the microflora.’ Importantly, not ALL fibres are prebiotics, because prebiotics are the fibres digested by our GOOD gut bacteria, while other fibres (not prebiotics) can be digested by the potentially harmful bacteria that live in our gut. So for a fibre to be a prebiotic, it has to only be food for good gut bugs in the colon, and must be resistant to digestion.
Now, there’s 2 related key points to get to here. Firstly, the question I’ve seen asked SO many times both on social media (to me directly, and others), and in general, is ‘Should I be taking a supplement for my gut bacteria?‘ We’ll get to that, but it ties into my second key point, which is this – as I said, the vast majority of us don’t consume enough fibre from our diets, with the estimated average at about 19g per day for the typical person in the U.K. Here’s an example of the fibre in grams in relatively well-known foods:
- 3 Servings of Fruit per day: 7.5-8g
- 2 Slices of Wholemeal Toast topped with 30g Peanut Butter – 7.6g
- 2 Weetabix – 3g
- 1 bowl of porridge – 3g
- 1/2 tin of chickpeas – 10g
- 1/2 tin of baked beans – 7.5g
- 1 serving of brown rice – 2g
- 100g Sweet Potato – 2.5g
- 50g raw carrots – 3g
- 100g boiled broccoli – 4g
The webinar made an excellent point that hitting our recommended 30g of fibre per day actually requires a pretty healthy diet, with meals ideally home-cooked, and based on high fibre starchy foods, plus high fibre snacks (e.g. seeds, nuts, dried fruit) and minimal high sugar foods during our day to day. We would DEFINITELY need to hit our ‘five a day’ servings of fruits and vegetables at a minimum, and ideally more like 8 a day. Unfortunately, the majority of the population don’t meet their recommended five a day, as well having an inadequate fibre intake. So clearly, there’s work to be done at a basic healthy diet level, before we start even discussing supplementation. Below you’ll see an excellent and very helpful image showing you a slide from the webinar which illustrates a day of healthy meals and snacks designed to provide sufficient fibre intake to provide the recommended 30g per day (in green), compared to (in red) what might be considered a day’s food intake for the typical ‘Westernised’ diet.
Okay. Let’s recap.
- The gut microbiome is a very important part of our bodies, our physical and our mental health.
- The research into the area is ongoing and evolving constantly, but we do know that much.
- We know that having an adequate fibre intake is associated with a wide range of health benefits.
- We also know that we aren’t eating ENOUGH fibre, and therefore many of us are potentially missing out on some of those benefits.
- We know that probiotics are live, beneficial bacteria and yeast found in fermented foods like yoghurt, kefir, kombucha and sauerkraut.
- We know that prebiotics are a special form of dietary fibre, and are the FOOD source for our good gut bugs.
- The theory is that by feeding our good gut bacteria we encourage their numbers to increase, and ideally dominate the bad guys living in there.
- We know that we can get prebiotics from a wide range of foods, including onions, bananas, oats and leeks.
All in all, to me, and as was concluded by the experts in the webinar, what we need is to first address our prevalent fibre deficiency, and optimise our diets to help us meet our 30g per day. This has the double-whammy effect of increasing the prebiotics we can get from eating certain high-fibre foods (examples above). When doing so, we should seek to maximise our diversity of plant-based foods we consume – up to and above 30 different plant-based foods has been recommended. So lots of different colourful fresh fruits and vegetables, upping your whole-grain intake (a simple tip is to swap your white breads/pastas/rices for brown!), trying oats if you haven’t before (overnight oats and porridge are my favourite breakfasts!), and consuming plant protein sources high in fibre such as chickpeas and lentils. If you are keen to try fermented foods I’ve mentioned above if you haven’t before (I’m a big fan of kefir!) they are very tasty foods in my opinion, but the research on their benefits is still in it’s infancy. There may be a benefit is all we know right now, which is why people are increasingly including them in their diet or trying them out.
I hope this helps guys. A person I really want you guys to check out in this area of health is Dr. Meghan Rossi (also known as @theguthealthdoctor on Instagram!). Meghan is a registered dietitian with a PhD in Gut Health, and actively involved in the research in this area. She shares incredible, evidence-based content and has done a wide range of Podcasts and interviews in print and online. I highly recommend going over to her website and following her on social media!
Finally, if you are curious as to whether you may need to take a probiotic supplement, there is some evidence for certain cases where this might be helpful to help restore the natural gut bug balance of your system if it has been disturbed and disrupted by an illness or a treatment. Examples where there is some evidence includes use of probiotics to reduce the risk of traveller’s diarrhoea, antibiotic-associated diarrhoea, and for management of certain cases of irritable bowel syndrome, particularly for the symptoms of IBS.
Finally, I really want to stress here, as I’ve discussed and checked with Maeve, that probiotic and prebiotic supplements aren’t yet recommended for the general public.
Additionally, only in really specific doses have probiotics been seen to be useful for specific conditions. As I’ve said, this is not my area of expertise, hence why I wanted Maeve to proofread this article based on my own learning research into this fascinating area. The studies into these areas are ongoing and much more research is required on both GI and non-GI conditions and their relationship with the gut microbiome. Therefore that’s beyond the scope of this article, so my advice is, if you do have such queries, to speak with your doctor and a dietitian or nutritionist in your community to get advice, and referral on for specialist advice if required.
I hope this article was helpful guys! I really want it to be informative and easy to understand, to share with you the basics on your gut bacteria and how to keep them as healthy as possible! Let me know your thoughts, as always! I’m @theirishbalance on Instagram/Twitter/Facebook!
Ciara 🙂 x