Skin microbiome: feed it right for a healthier look!

Dry skin and atopic dermatitis have been associated with changes in the variety of the skin microbiome. 

Our skin, as the largest organ in our body, has a huge array of commensal microbes that support a healthy skin barrier. One of those is Staphylococcus epidermidis, one of the most abundant bacterial species of the skin microbiome1.

This chubby mutualistic, Gram-positive, facultative anaerobe constitutes up to 90% of the aerobic resident flora of our skin, and has been associated with a healthy-looking skin2. It does not like to be lonely, and usually appears in pairs or tetrads on the surface of our skin, like a protecting biofilm.

Dry skin, for example, is associated with an increase in microbial diversity along with a decrease in microbial load in comparison to more sebaceous areas of the skin, that are usually populated by lipophilic bacteria such as Cutibacterium acnes – that tend to cause those unwanted teenager-look-a-like pimples that nobody likes…

Lactic Acid is one of the Natural Moisturizing Factors (NMF) of the skin barrier, that is essential to maintain the hydration and a slightly acidic pH of the skin surface (i.e., “acid mantle”)3. Higher lactic acid concentrations and lower skin surface pH are known to increase our epidermal renewal and promote a healthier skin. 

New in vitro data suggests that Staphylococcus epidermidis, may be one of the major sources of lactic acid in the skin1

But only if fed the right way. 

It seems that 1% colloidal oat increases Lactic Acid production by this particular bacteria species, making it rely less on simple sugars such as glucose for its metabolism; and, instead use more complex carbohydrates derived from oat.

Oatmeal-containing skin moisturisers significantly changed the metabolism of the Staphylococcus epidermidis, breaking down starch and promoting good gene expression, with an increased DNA and aminoacid synthesis, and an improved ATP metabolism.

How about that?

Bacteria on a diet makes your skin look healthier!

Next time you think about which moisturiser to buy in the drug store:  don’t forget to feed your skin microbiome it’s oatmeal!

Happy Staphys!


1          Liu-Walsh, F. et al. Prebiotic Colloidal Oat Supports the Growth of Cutaneous Commensal Bacteria Including S. epidermidis and Enhances the Production of Lactic Acid. Clin Cosmet Investig Dermatol 14, 73-82, doi:10.2147/CCID.S253386 (2021).

2          Baviera, G. et al. Microbiota in healthy skin and in atopic eczema. Biomed Res Int 2014, 436921, doi:10.1155/2014/436921 (2014).

3          Thueson, D. O., Chan, E. K., Oechsli, L. M. & Hahn, G. S. The roles of pH and concentration in lactic acid-induced stimulation of epidermal turnover. Dermatol Surg 24, 641-645, doi:10.1111/j.1524-4725.1998.tb04221.x (1998).

Yogurt as precision medicine, or how your gut might be undermining your health

The gut microbiome is a community of microorganisms that lives in our gastrointestinal tract. It is so far, the most studied microbial community in healthy humans, because of its known role in a range of functions and diseases, like Inflammatory Bowel Disease (IBD)1,2.

To gain perspective on the magnitude of the bacterial presence inside of us, and potential effects on our bodies, the human body expresses 20,000 eukaryotic genes while the gut microbiome expresses 3.3 million prokaryotic genes. This suggests that the genetic contribution of the microbiome to humans may be many hundreds of times greater than the genetic contribution from the human genome.

Most of the microbes in the microbiome do not cause disease. In fact, we need them to perform many important functions that we cannot do ourselves. Microbes digest food to generate nutrients for host cells, synthesize vitamins, help to absorb nutrients and minerals, produce short-chain fatty acids, metabolize drugs, detoxify carcinogens, stimulate renewal of cells in the gut lining, and activate and support the immune system1

The fermentation by-products acetate, propionate, and butyrate are important for gut health; and, provide energy for epithelial cells, enhance the integrity of the epithelial barrier, and provide immunomodulation and protection against pathogens1

Current investigations explore resident bacterial gene function, and the potential role it might have in human health and metabolism. Each individual has its own microbiome, and no one common microbe is present in all body sites or all individuals. 

Researchers identified the composition of different individual microbiomes, but they also identified the metabolic pathways of the microbial communities found in different body sites (e.g., skin, colon, liver…).  What is interesting is that microbial membership diverges greatly between healthy individuals; but, the metabolic pathways of our own microbiomes is very similar, with common ‘housekeeping’ properties that maintain cell function and a functional body site ecosystem3,4.

The interactions between the gut microbiota and our bodies immune system begins at birth4. The microbiota shapes the development of the immune system; and, in turn, the immune system shapes the composition of the microbiota. This cross-talk between the microbes and our bodies is transmitted through a vast array of signaling pathways that involve many different classes of molecules, and extend upon multiple organs such as the gut, liver, muscle, and the brain. This creates axes of metabolic pathways, or highways of chemical communication, between the gut and the different organs in our bodies.

Because the gut microbiome is highly malleable, it can be altered throughout our lifespan by environmental factors, such as diet, stress and medication. What we have seen during the last 60 years, is an increaseincidence of gut dysbiosis, which is an imbalance in the intestinal bacteria that leads to disease.

As such, there is much interest in developing new therapeutic tools for manipulating the composition of the gut microbiota to benefit our health. A better understanding of how variations in this symbiotic relation within us, supraorganisms, will contribute to disease risk and health sustainability; and, will point the way to new therapeutic interventions and disease prevention strategies.

Danone, a leading yogurt multinational food corporation, is developing “precision probiotics”, for example. Researchers at Danone aim to tailor probiotics to an individual’s diet, phenotype, lifestyle, age, gender, genetics and microbiome. The intention it’s to bring to the gut activities or functions that are not provided by our own gut microbiome, or our own genes.

It’s funny that around 1920’s, Isaac Carasso, the creator of Danone, first started selling yogurt in pharmacies, using ferments isolated from the Institute Pasteur, and label it as health-food. It’s like going full circle.


1          Bordigoni, A., Halary, S. & Desnues, C. in Encyclopedia of Virology (Fourth Edition) Vol.  (eds Dennis H. Bamford & Mark Zuckerman)  552-558 (Academic Press, 2021).

2          Lloyd-Price, J. et al. Multi-omics of the gut microbial ecosystem in inflammatory bowel diseases. Nature 569, 655-662, doi:10.1038/s41586-019-1237-9 (2019).

3          Visconti, A. et al. Interplay between the human gut microbiome and host metabolism. Nature Communications10, 4505, doi:10.1038/s41467-019-12476-z (2019).

4          Nicholson, J. K. et al. Host-Gut Microbiota Metabolic Interactions. Science 336, 1262-1267, doi:10.1126/science.1223813 (2012).