The gut microbiome Vs the skin microbiome

In this blog, I will look at the skin and its microbiome. Yes, we have a jungle in our gut called our gut microbiome, which has trillions of microorganisms working away to keep us healthy. We also have another ecosystem full of microorganisms on our skin.  The biggest difference between the two is the environment.  The environment of the gut microbiome is like a rainforest; it’s moist and nutrient-rich, whereas the skim microbiome is more like a desert; it’s not as moist and not as nutrient-rich.  Also, the skin microbiome environment changes depending on the anatomical location.  For example, the environment for the face, chest, and back is oily, whereas the environment for the arms and legs is dryer. 

Despite this difference, the gut microbiome and the skin microbiome are closely linked, and the gut microbiome’s health directly impacts the skin microbiome’s health. 

The skin is the largest organ in the human body, accounting for around 15% of your body weight.  It has numerous important functions, including the obvious one, basically holding all our insides inside.  Other functions include protection from pathogens, chemical, mechanical and physical injuries, UV light and other hazardous substances.  It also facilitates synthesising vitamin D from sunlight, sensory stimuli, and immune surveillance.  So we want to keep it healthy to allow it to carry out all these functions, but we also want to look good!  All those cosmetic companies use clear, radiant skin as a draw-in to get you to buy their product. 

The concept of the skin microbiome is relatively new, and there isn’t as much research into it as on the gut microbiome. Still, some cosmetic and skin care companies have started adding a strain of probiotic bacteria and advertising that product as “good for your skin microbiome’.  However, as I mentioned above, despite being closely linked, the environment of the skin microbiome and the gut microbiome is like chalk and cheese, so what’s good for the gut microbiome might not work for the skin microbiome. 

The Gut-Brain-Axis (GBA) and the Gut-Skin-Axis (GSA)

There is a Gut-Brain Axis (GBA) and a Gut Skin Axis (GSA). Because of its immunological and metabolic properties, gut health can directly influence skin health. Much more research is required in this area, but multiple studies have supported the connection between gut and skin microbiome health and several dermatological conditions. For example, 10% to 25% of people with Crohn’s disease or Celiac disease also have dermatological conditions. 

The skin microbes

Now, let’s look at the main stars in the skin microbiome. Bacteria come in different phyla; the Actinobacteria phylum accounts for about half the skin microbiome. The two main bacteria species in this phylum are Cutibacterium and Corynebacterium. Cutibacterium is an anaerobic gram-positive, rod-shaped bacteria located in the oil and sweat glands on the face and back. It’s usually harmless but can become pathogenic and cause acne in certain favourable conditions.  Corynebacterium is an aerobic, gram-positive, rod-shaped bacteria.  It’s found in moist areas like the feet and the antecubital fossa (the inside of your elbow).  Like Cutibacterium, it is typically harmless to healthy individuals.  However, some studies show an increased population of Corynebacterium, including pathogenic strains, in psoriatic lesions and ulcers. 

The next most common Phylum found on our skin are Firmicutes, and the most common species are Staphylococcus and Streptococcus.  You’ve probably heard of these before and attribute them to causing infections, and they can, but most of the time, as long as everything is in balance, they are just a harmless part of your skin microbiome. 

Staphylococcus is an aerobic gram-positive coccus, and unfortunately, it has been increasingly associated with hospital-acquired infection in surgical sites and catheters.  You’ve probably heard of Methicillin Resistant Staphylococcus aureus (MRSA), a hospital-acquired infection you want to avoid by constantly washing your hands and using hand sanitiser.  Most Staphylococcus aureus strains are pathogenic and can cause infections such as impetigo, subcutaneous abscesses, furuncles, cellulitis and Staphylococcus scalded skin syndrome.  The Streptococcus species is an aerobic, gram-positive coccus found in dry skin parts like the legs or the arms.  Most strains of Streptococcus are harmless.  However, Streptococcus pyogenes (A Streptococcus) is one of the most significant species for skin infections such as impetigo, cellulitis and erysipelas. 

There are also fungal species, Mallassezia being the most common.

Keeping your skin healthy

Similar to the gut microbiome, if the skin microbiome is out of whack, maybe there are too many or not enough of certain bacteria, and you will see skin issues in varying degrees.  Returning to the Gut-Skin-Axis, both the gut microbiome and the skin microbiome play a massive role in immunity.  If the immune system is triggered, then inflammation occurs, and this could be in the gut or on the skin, and this trigger would have been caused by an imbalance (i.e. dysbiosis).

So, what can you do to make your skin healthy?

1. First of all, look at your diet.  If your diet is not great, for example, you don’t drink much water, you eat a lot of processed foods with refined sugar, high salt content, high saturated and trans fats and lots of additives, then it’s not a gut-healthy diet, thus, not a skin-healthy diet.  You must drink at least eight glasses (1200mls) of water daily.  Eat loads of colourful fruits, vegetables, nuts and legumes.  These are full of vitamins, minerals, antioxidants, polyphenols and fibre, all important for a healthy gut and body.  Also, adding probiotics and prebiotics to your diet is a great boost. 

• Next, try to reduce stress in your life. It’s definitely easier said than done, but stress is really bad for your microbiome. Getting enough sleep is important for reducing stress. Some tips include avoiding blue light for at least an hour before going to bed. You can switch to night mode on your device, use special glasses, or simply put all devices away. Also, try to avoid eating heavy meals before bed, as they can affect the quality of your sleep.

• Lastly, stop overcleaning and over-exfoliating your skin.  Focus on moisturising, and get a moisturiser that has only a few ingredients and is as natural as possible.  If you constantly put chemicals on your skin, it can’t be good for the microbiome.  Also, and this is just from me, why not have no make-up days?  Makeup might be something you enjoy doing, and maybe you feel you need to put some makeup on before leaving the house, but if you’re just relaxing at home, why not let your skin breathe?

Hopefully now you can nourish not just your gut microbiome, but also your skin microbiome.  You know the saying that “Beauty is more than skin deep”?  Well, it is!  If you nourish and feed your gut microbiome, they, in turn, will ensure your skin microbiome thrives.  You can also do things that directly affect your skin microbiome, like make-up-free days, good quality moisturiser and UV protection, but if you come at it from both sides, you’ll have radiant, glowing skin without the big price tag. 

If you’d like to learn more about your own personal gut microbiome, why not check out my personalised Nutrition packages? I offer an easy-to-use at-home microbiome testing kit. 

References

      1.           Sinha S, Lin G, Ferenczi K. The skin microbiome and the gut-skin axis. Clinics in Dermatology. 2021;39(5):829-39.

2.           Bowe DW. Dermatologist on Your Gut Microbiome vs. your Skin Microbiome. YouTube2021. p. https://www.youtube.com/watch?v=LeHxE6DUOqM.