There has been a lot of talk recently about the importance of your gut microbiome, and certainly since I have been including dietary advice or referral to a nutritionist when dealing with inflammatory skin conditions, there has been a real spike in achieving positive results for my clients. There will be multiple reasons for this of course, but gut health definitely influences skin health.

What exactly is the gut microbiome?

Our gut microbiome is a collection of bacteria, viruses, fungi and protozoa that colonise the gastro-intestinal tract. The common understanding in years gone by is that it was only the harmful bacteria we needed to be concerned about, and the commensals (which make up the huge bulk of the bacteria present) were of no particular importance and just happened to be there. We now know that they provide metabolic and immune benefits to the host, including helping in the production of certain nutrients like Vitamin K.

They can also directly protect us from invasion from external pathogens by preferentially binding to epithelial cells, and indirectly by triggering immunoprotective responses. The gut microbiome produces short-chain fatty acids (SCFA’s) as a by-product of dietary fibre fermentation, and these play an important role in maintaining gut barrier function, glucose homeostasis, immunomodulation, appetite regulation and prevention of obesity.

What is interesting is that if the gut lining becomes permeable, which can happen due to multiple reasons including responding to stressors, it appears that the intestinal bacteria as well as intestinal microbiota metabolites can travel to the bloodstream and end up in the skin, causing a disruption to the skin’s homeostasis.

There are about 100 trillion bacteria, good and bad, living in your gut, making the colon the most densely populated habitat for microbes on earth. There are between 300 - 1000 different species, although most people only have between 30-40 present at any one time, and the greater the diversity in each of our microbiome, the greater the benefit to the health of the host. Fortunately, this is something we can directly influence.

How to increase the diversity of your gut microbiome

Professor Tim Spector, genetic epidemiologist and one of the founders of Zoe (a company which creates personalised nutritional programs) recommends 4 basic guidelines to help improve the health of your gut microbiome, no matter what diet you are choosing to follow:

1. Eat at least 30 different kinds of plant based foods a week, including nuts, seeds and herbs.

2. Eat foods rich in polyphenols (defense chemicals present in foods which give them their bright colour). These include nuts, seeds, berries, dark chocolate, coffee and red wine - I had no idea my diet was so healthy… There is some evidence now to show that polyphenols alone aren’t enough though - they aren’t active until they come into contact with gut microbes, so don’t pick and choose which guidelines to follow, you really need to follow them all to get the full effect.

3. Eat a small quantity of fermented food daily, such as kimchi, sauerkraut, kefir or kombucha. This might be a little more challenging for some to include, I would personally recommend making your own at home if at all possible. Certainly so far as kimchi is concerned, I’ve had it on good authority (my partner spent two years in Korea) that the homemade version not only tastes more authentic than the shop bought, but is more active and will therefore be more beneficial to your gut.

4. Avoid ultra-processed foods.

There are also several things that you can do to boost your gut microbes which aren’t food related.

1. Get a good night’s sleep.

2. Align yourself with your circadian rhythms - eat your dinner earlier and go to bed earlier.

3. Incorporate periods of fasting daily. This doesn’t need to be hard, if you eat your dinner earlier then the period between finishing dinner and when you eat breakfast is considered a fasting period. Extending this time for as long as you can has shown to have a beneficial effect for your gut, as early studies indicate that gut microbes may need time to rest and recuperate just like we do.

4. Get regular exercise.

5. Good relationships with others have a positive effect on your gut - this also includes your pets!

6. Keep an eye on your stress levels and have a strategy for managing stress.

7. Finally, while we have largely all been hyper-aware of hand hygiene particularly in the past 18 months, it’s something to consider that we shouldn’t be too clean. If you are out and about in the countryside (and not close to lots of other people of course), then don’t be too free with hygiene gel and soap. Allow the diverse range of microbes in nature some access into your system, it’s good for your health!

“But what about probiotics?” I hear you ask.

Everyone likes a quick fix, particularly if it means that they don’t need to change their habits. This is something I come across every day in the clinic when I’m advising someone on their skincare, which will pretty much always come with diet and lifestyle changes recommended. I’ve been aware of the link between diet and skin health for well over a decade now, and the role of different nutrients in maintaining that health. What became apparent to me after a few years of following industry guidelines regarding mega dosing supplements was that firstly, this subject is huge. Secondly, it’s a relatively new area and we are constantly finding out new information about how the body uses nutrients. We’d be told that we should take high doses of nutrient X one day, and then a few months later find out that it interferes with the absorption of nutrient Y in high doses and we should take less. After a few of these incidences, I take the approach that supplements should be just that - supplementary. We are only just discovering how the micronutrients present in food interact and play a role in our general health, and trying to isolate THE ONE thing that does the job we want is daft. It’s much better to eat a wholefood diet with a large range of different foods daily, and then if you want to, take a supplement on top of that.

In the case of probiotics, there have been some studies which show that they can help in some disorders, but should really be taken alongside a varied diet with a lot of plant based ingredients. The highly specific nature of each person’s gut microbiome means that it’s a bit of a hit and miss affair to just take a probiotic and hope it works - you won’t know what your personal gut microbial profile is or which microbe you are needing to supplement it with. That said, there’s nothing wrong with trying (it might work very well) but if you are currently fit and healthy then it is better to just eat well.

The short lifespan of microbes means that no matter where you get them from (food or supplementation), you need to constantly feed them. It’s not enough to just eat well two or three times a week and eat processed and/or fast food the rest of the time. I’m not a nutritionist but I’d suggest the 80/20 rule applies here - do what you should 80% of the time and the rest of it you can indulge should you want to.

Finally, I would like to add that all of the above is very generalised information - if you have a specific health concern then please consult with a qualified nutrition expert who will guide you towards your best diet and optimum health.

https://pubmed.ncbi.nlm.nih.gov/30125885/

https://www.frontiersin.org/articles/10.3389/fmicb.2018.01459/full#B86

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6244749/

https://www.youtube.com/watch?v=ve88R0jeJ64

https://blogs.bmj.com/bmj/2019/01/30/tim-spector-breakfast-the-most-important-meal-of-the-day/