The gut-skin axis simplified
Our skin is covered with trillions of bacteria.
Almost all of our body is covered in bacteria - actually, our bodies host more bacteria cells than human cells, a lot more! Bacteria are present in our gut, mouth, urinary tract, and our skin.
Skin microbiome is the term that scientists use to identify an ecosystem of thousands of microorganisms - bacteria, viruses, and fungi - living on our skin.
Among them, there are several strains of microbes (they are probiotics, indeed!) playing a crucial role in maintaining healthy skin and protecting it from infections against harmful microorganisms.
In other words, you can imagine your skin as a giant battlefield where huge arms of micro-monsters eat, reproduce themselves, and sometimes decide to fight against each other to colonise different territories.
Our skin has different layers: the corneum stratus is the one most populated by living bacteria. The probiotic strains living on our skin produce antimicrobial agents that help keep us healthy, and direct correct immune responses to fight infections.
Our skin is a marvellous world and scientists have just started to unveil it: however, they are unanimous in saying that our skin microbiome plays a crucial role in many skin disorders such as atopic dermatitis (also called eczema), acne, rosacea, and psoriasis.
The gut-skin axis explained.
Surprisingly, researchers have also discovered that our skin microbiome is directly connected to our gut microbiome [2]. For instance, did you know that changes in diet have been shown to not only impact the flora in our gut but also the bacteria on our skin? Also, skin disorders are not just associated with an altered skin microbiome, but quite often they correlate with an altered gut flora. The connection between our skin and gut microbiota - also known as the “skin-gut-axis” - describes the intimate relationship between the skin and the gut.
These two organs (we can consider our skin as a quite special organ) communicate mainly in two ways: directly or indirectly through our immune system.
The first case happens when the intestinal barrier is impaired and intestinal bacteria enter the bloodstream, accumulate in the skin, and disrupt the skin microbiome.
In the second case, an altered gut microbiota might negatively affect our immune system, which in turn creates a skin dysbiosis - namely an imbalance of our skin microbiota due to an increase of harmful bacteria. This uncontrolled immune response promotes the development of skin diseases, such as atopic dermatitis, psoriasis, acne vulgaris, dandruff and sometimes even more serious pathologies.
What are the typical skin conditions related to gut dysbiosis?
In short, an imbalance in our gut and in our skin microbiome can contribute to common skin disorders such as acne, psoriasis, atopic dermatitis (eczema) and rosacea.
There is a direct link between skin disorder and specific harmful bacteria, for example in numerous studies rosacea has been associated with an increased level of helicobacter pylori both in our gut and skin microbiome.
Atopic dermatitis is a common inflammatory skin disease characterised by xerosis, pruritus and eczema. It has been demonstrated that people with atopic dermatitis show an increased level of the pathogen Staphylococcus aureus in the affected skin (70% compared to 5% for healthy skin). Also, acne is caused by the proliferation of the pathogen P. acnes that obstructed the skin follicles. [3]
So, if you have one of these conditions and your skin creams are not working, start looking at your gut! Explore our Skin probiotics to learn more.
Nerdy readings:
- Lee YB, Byun EJ, Kim HS. Potential Role of the Microbiome in Acne: A Comprehensive Review. J Clin Med. 2019 Jul 7;8(7).
- De Pessemier B, Grine L, Debaere M, Maes A, Paetzold B, Callewaert C. Gut-Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions. Microorganisms. 2021;9(2):353. Published 2021 Feb 11. doi:10.3390/microorganisms9020353
- Catinean A, Neag MA, Mitre AO, Bocsan CI, Buzoianu AD. Microbiota and Immune-Mediated Skin Diseases-An Overview. Microorganisms. 2019;7(9):279. Published 2019 Aug 21. doi:10.3390/microorganisms7090279