So today we're going to talk about one of my all time favorite topics..... the GUT MICROBIOME and it's connection to health, disease and immunity.

We're going to be focusing on how we can build resilience through nurturing the collection of microorganisms that reside in our guts, delving into:

- THE OVERALL ROLE OF THE GUT MICROBIOME (collective name for the little pals in your gut)

- From WEIGHT GAIN TO AUTOIMMUNITY.... the consequences of DYSBIOSIS.... (imbalance of said little pals)

- FOODS TO AVOID/INCLUDE - to maintain a healthy gut microbiome (which foods your best pals like)

- And finally LIFESTYLE HACKS to support the microbiome (letting your little pals live their best lives)

Before we get into the gut, it's worth pointing out the overall scale of microorganisms (microbes) thriving within us.... 

We actually have multiple microbiomes (e.g. oral, vaginal, nasal etc) and about 100 trillion microbes within the human body. It's actually estimated that these non-human cells make up just over half the cells of the human body. Pretty cool huh?!    

SO WHAT'S THE OVERALL ROLE OF THE GUT MICROBIOME?!

Let me start by saying that research around the gut microbiome is rapidly evolving, and truly I suspect our current knowledge is only really scratching the surface of their integral role in our health. 

What we 'understand' so far is that the gut microbiome helps to support a resilient immune system, as well as playing an integral role in all manner of diseases from diabetes to cardiovascular disease, weight gain to respiratory dysfunction and skin disorders etc. 

The 'optimal' balance of our microbiome is essential for healthy digestion and production of certain vitamins such as B12, folate and vitamin K. Our microbes are also involved in gene expression, production of neurotransmitters such as serotonin and GABA (it's no wonder your mood will tank with poor gut health) and generation of short chain fatty acids (the main fuel for the cells of your colon, but SCFA's also play a role in many other beneficial functions such as boosting enzyme activity in the liver and muscle tissue, leading to improved blood sugar regulation). 

FROM WEIGHT GAIN TO AUTOIMMUNITY.... THE CONSEQUENCES OF DYSBIOSIS....

Dysbiosis sounds very complicated (and it is when you get into the nitty-gritty details) but as a general overarching term it simply means an imbalance of microbes in the gut, with poor diversity of your commensal bacteria (the good guys) and too many of the more opportunistic organisms (the bad guys). 

It's important to note the emphasis on diversity rather than overall numbers, as it's not just a case of using probiotics to boost a couple of strains and hoping for the best. Your commensal bacteria cross-feed and keep each other in check :) Think of them like your neighbourhood watch, lots of representatives from different households creates a safer, stronger community than all the representatives from one household. 

When testing for clients, I will often find that one or more commensal bacteria are close to undetectable levels, whereas others are thriving (and yes this is very much dictated by the diversity and types of food we eat in the typical western diet). This makes the homeostasis of the gut hard to maintain, and we consequently see other more pathogenic bacteria increasing in numbers. 

With depleted diversity we also see the maintenance of the gut wall decline, and this will contribute to leaky gut (along with poor digestion further upstream and consumption of highly refined foods etc). 

For example, a key player in this overall homeostasis and maintenance of the gut wall is one mighty little pal called akkermansia muciniphila (yeah they've got some cracking names!) which feeds off the mucin lining of the gut. You might be thinking that sounds like a bad thing, but it actually encourages regeneration of cells, strengthening the mucin layer. It's also a key producer of butyrate, acetate, propionate (three of the most common short chain fatty acids I mentioned earlier) which help to cross-feed other commensal bacteria. 

The importance of a healthy mucin lining is amplified in the presence of gram negative bacteria (some of the more inflammatory bacteria that we don't want to see in detectable levels). These bacteria release toxins called lipopolysaccharides (LPS) which not only cause chronic inflammation in the gut, but in the presence of a leaky gut they can make their way across the gut wall into the bloodstream. 

This is particularly bad news for our immunity as LPS increase cross-talk with immune cells (called toll-like receptors) triggering release of inflammatory cytokines. Raised levels of LPS are consequently strongly associated with autoimmune disease, as well as many other health conditions such as liver damage, Parkinson's, Alzheimer's and diabetes. 

It's worth noting that the alliance between our microbiome and our immune system goes far beyond the impact of LPS, our microbes play a crucial role the development and maintenance of protective responses to pathogens. 

When we look further at the impact of dysbiosis we also observe the role of certain bacteria in weight management, again akkermansia appears to be beneficial in this regard as production of acetate may help to regulate appetite and body fat stores. Christensenella also seems to be coming up trumps for maintaining a healthy weight, although levels/presence of this bacteria is largely dictated by your genes. 

Furthermore, high levels of gram negative bacteria such as klebsiella have been found to up-regulate glucose transporters in the gut, meaning that you will essentially absorb more of the glucose (sugar) from a given meal, not only impacting your ability to maintain a healthy weight but also your blood sugar regulation. 

Anyway...... I bet you're all wondering what you can do to best support your overall health and resilience..... and even if you're not, I'm about to make some suggestions ;)

FOODS TO AVOID:

Firstly (and I'm not sorry if I sound like a broken record because this is an important message) there's obviously no one size fits all when it comes to the optimal food to support the gut microbiome. 

Sure different diets (eg vegan, keto, carnivore etc) are going to have huge implications on the abundance of certain bacteria, but depending on which microbes are out of whack will largely influence the most beneficial protocol for you (this is where microbiome testing can be hugely beneficial). 

However, there's certainly some foods/medicines we want to avoid where possible (obviously the later is to be advised by your doctor):

- REFINED SUGAR - unless you're keen to increase levels of inflammation/dysbiosis and exacerbate a yeast overgrowth

- ARTIFICIAL SWEETENERS - can be toxic to your microbes and damage the mucin lining

-PROCESSED FOODS - as well as refined sugar and sweeteners, there’s a whole host of ingredients packed into refined food that may alter the gut microbiome such as emulsifiers, hydrogenised vegetable oils, preservatives etc

- ALCOHOL - associated with higher levels of dysbiosis, some alcohols more than others, eg the polyphenols in red wine may actually be beneficial in moderation.

- NSAIDS (non-steroidal anti-inflammatory drugs eg ibuprofen) - these are known to damage the mucin lining, contributing to leaky gut. 

- ANTIBIOTICS - for obvious reasons.... antibiotics are not selective, they're there to wipe out unwanted microbes and that means your good guys get hit in the process. It can take anywhere from 2- 6 months to repopulate your gut after a course of antibiotics. 

- ANTIMICROBIALS - although antimicrobial herbs are not thought to be as damaging as antibiotics they may still have a significant impact on wiping out your good bacteria so should only be used for short periods and under the guidance of a practitioner.

- CONTAMINATED FOOD - this should really go without saying but we want to limit our ingestion of toxins such as pesticides, herbicides and fungicides, all of which will disrupt the microbiome. This is one of the reasons why considering the source of your food is so important, opting for organic or home grown produce is advisable where possible. 

- ANIMAL FAT, DAIRY & COCONUT OIL - now I'm certainly not recommending this for everyone but, if you know you have a high level of gram negative bacteria, reducing intake of these foods may help. Some of these bacteria thrive on animal fat and dairy, furthermore the saturated fat in these foods has the potential to transport LPS (toxins) across the gut membrane. All this said, saturated fat is certainly not the 'bad guy' and these sort of restrictions would not need to be long term. 

FOODS TO INCLUDE:

Again of course, there's no magic combination of foods that's going to result in the perfect microbiome for everyone, but here's some foods to consider:

- RESISTANT STARCH - such as cooked and cooled rice or potatoes, oats, unripe bananas (in moderation). Consider this fuel for your commensal bacteria. 

- POLYPHENOLS - such as berries, pomegranate, cocoa, dark chocolate etc (I don't know about you, but I loooooooove polyphenols) 

- PREBIOTIC FOODS  - other sources of fuel for the commensals.... such as garlic, onion, apples, flax seeds, asparagus etc

- PROBITIC FOODS - these are fermented foods like live bacteria such as sauerkraut, kimchi, kefir, yoghurt, kombucha etc.

- MUCIN SUPPORTING FOODS - such as collagen, bone broth and omega 3 fatty acids will support a healthy gut lining. To boost your omega 3 intake you could include plant sources like flax seed oil, walnuts and chia seeds, as well as your more obvious sources of fatty fish. 

One key point with these additions (and any other types of fibre you increase), is not to throw everything in all at once, gradually increase new foods in small portions so that your microbiome is not overloaded. For example starting with a tablespoon of sauerkraut or kimchi with your evening meal is a great way to boost your bacteria levels, but if you're also drinking all the kombucha and kefir on top of this, you may exacerbate digestive issues. Slow and steady!

LIFESTYLE HACKS TO SUPPORT YOUR MICROBIOME:

Finally our lifestyle is arguably as important as our nutrition when it comes to all aspects of health, and that includes the health of our microbiome. 

So here's some lifestyle factors to consider:

- EXERCISE - studies have found that exercise increases microbial diversity including the abundance of butyrate producing commensal bacteria (the good guys). Higher levels of akkermansia muciniphila were also found in the guts of those who exercise regularly (good news for your gut and good news for healthy weight loss). 

- STRESS - increased levels of stress have been found to disrupt the microbiome, causing inflammation and depleted levels of short chain fatty acids. Furthermore, meditation, breath work and cold water exposure have also been found to decrease the impact of LPS (those pesky toxins we were talking about earlier). 

- SLOWING DOWN - making time to slow down for meals, focusing on bringing yourself to a parasympathetic state (rest and digest) and chewing thoroughly rather than eating on the go will help greatly with the preliminary stages of digestion. This has a knock-on effect for the whole cascade of digestion and will promote efficient breakdown and absorption of nutrients. 

- SLEEP - the often overlooked lifestyle factor (for all aspects of health). Studies have found that just 2 days of sleep deprivation can cause subtle changes to the gut microbiome, increasing the abundance of bacteria associated with weight gain, obesity and diabetes. So it's definitely worth getting a handle on your sleep, aiming for a minimum of 8 hours/night.

- POLLUTION - as well as the toxins associated with food, we are also obviously inhaling many toxins through air pollution, this has also been found to disrupt the microbiome. Another very pressing reason we should be focusing on reducing our carbon emissions and overall impact on the planet. 

- NATURE - Our exposure to nature and the microbes that live within it are associated with huge benefits for shaping the health of our microbimome. The rapid urbanisation of the planet is thought to be contributing to poor microbial diversity and therefore increased risks of inflammatory disease.

So as you can see, as complex as the microbiome may be, there is plenty you can do to support a healthy balance of microbes and consequently support your own health and resilience. 

As always, shoot me any questions, and if you're interested in finding out what's going on in your own gut microbiome, give me a shout :)

Stay well everyone!! :)

Harri 

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The content in this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding your health.