The skin microbiome-age-health connection

Most of us are familiar with the visible signs of healthy skin, whether it’s even texture, firmness, elasticity, or a dewy glow.  If you look a little closer…closer again, you’ll find one of the most critical (yet often forgotten about) components of healthy skin - the skin microbiome. 

This microscopic ecosystem that inhabits the skin’s surface, is made up of a diverse array of bacteria, fungi, viruses and even mites (yes, mites!).¹  While it’s easy to envisage having skin ‘bugs’ as being a bad thing, research has shown when skin microbes form part of a balanced and diverse microbial community, they not only live in harmony with our skin but also support skin health.[1]  Conversely, imbalances in the microbial diversity of the skin (AKA dysbiosis) have been associated with various deviations to healthy skin function.

Therefore, the skin’s microbial balance not only affects the way our skin looks and feels, but the way it functions.  Let’s take a closer look at the skin microbiome and what we can do to help support it, and our skin’s health, throughout the different stages of life.

Beyond skin deep

The skin is the largest organ of the body and performs a long list of important functions.  In addition to being our outer face to the world and an expression of our beauty and identity, skin is one of our best defenders.  Healthy skin forms a barrier against the harsh threats of the outside environment, including but not limited to pollution, allergens, cosmetics, pathogens, UV and extremes in temperature.[2]^,[3] Whilst working to keep the ‘bad guys’ out, the skin also functions to keep the ‘good guys’ in, such as moisture, electrolytes, warmth and, well, all our inner bits and pieces!  The skin is also responsible for producing Vitamin D, an important nutrient required for bone and immune health.[4]

Getting to know your skin microbes

In order to function as an effective barrier, the skin relies on certain ‘helpers’ to keep everything in check.  These helpers include the millions of microbes that inhabit each square centimeter of skin, arguably the most important of which being bacteria.¹ Due to limited space, there is constant competition between good (beneficial) bacteria and bad (pathogenic) bacteria, for not only space to grow but nutrients as well.  Good bacteria help to protect against the overgrowth of bad bacteria by:

• Crowding out bad bacteria
• Producing anti-microbial peptides, which can inhibit growth of bad bacteria
• Regulating the local immune system

When good bacteria are outnumbered, bad bacteria can disturb skin barrier function by:

• Producing enzymes which break down the components of the skin barrier
• Dysregulate the local immune system
• Encourage further growth of bad bacteria

It’s all about balance

Maintaining the balance between beneficial and non-beneficial bacteria is a constant work-in-progress. Many factors can affect the skin’s ability to maintain this important balance, including water intake, diet and skin washing routines. Essentially, it is the environment we create for our bacteria that will determine which bacteria will survive and which won’t, and our age can play a big part in determining the environment of our skin microbiome.

There’s no place like home

Just like us, our skin bacteria have preferred places to live. Some like it humid (e.g., armpits, skin folds), some like it oily (e.g., face, scalp, neck and back) and others like it dry (e.g., palms and soles).  The micro-environment provided by these body sites, help certain microbes flourish, typically by increasing their preferred food source.[5]

A life’s journey

The changes that occur in our bodies with age also contribute to changes in these micro-environments.  For instance, the super-cute, roly-poly skin folds common to babies create a lot of heat and moisture, attracting growth of moisture-loving microbes such as Staphylococcus aureas.  On the other hand, hormonally driven, hyperactive sebaceous glands during our teen years, attract the growth of oil-gobbling bacteria such as Cutibacterium acnes.  The same bacteria naturally decline in numbers with the reduction in sebaceous secretions in older adults.⁵

These age-associated microbial changes can give rise to common skin imbalances associated with specific life stages, such as teenage acne.

It all starts at birth

Our skin microbiome is not only shaped by our micro-environments but also from our macro-environments – i.e., what we are exposed to in the big wide world. 

From an almost bacteria-free environment within the womb to the microbial zoo of the outside atmosphere, birth is quite the introduction to the world of the microbiome.  Even our mode of entry makes an impact, with significant microbial differences found between babies who had vaginal versus c-section births.[6]

By the first 4-6 weeks after birth, the infant skin microbiome starts to take shape as it expands and diversifies, until it finally stabilizes at around 3 years of age.[7]  Different body sites begin to take on their own unique microbial patterns, and microbial communities start to reflect our individual differences, some of which can be determined by:

• Diet – such as macronutrient (e.g., carbs, protein and fats) and alcohol intake
• Smoking
• Exercise habits
• BMI
• Use of emollients and washes
• Animal contact
• Living location and much more[8]

While it is well recognised that the human microbiome is heavily influenced by the world around us, scientists have discovered that age is one of the strongest determinants of microbial patterns.  In fact, a 2020 study found that samples of the skin microbiome can predict a person’s age to within 4 years of accuracy.[9]

Supporting skin microbial health through the ages

The skin microbiome, being as dynamic and adaptable as it is, can respond to positive diet and lifestyle interventions. Measures that you can take to support the health and balance of your skin microbiome can include:

Nurture your gut – Research has shown dysbiosis of the gut to be more common in those who suffer from acne compared to healthy individuals.[10]  This is believed to be influenced by Western-style diets, rich in refined carbohydrates, saturated fats, dairy, chocolate and low omega-3 fatty acid consumption.⁵  Eating a diet rich in plant foods, antioxidants, fibres and essential fatty acids can not only directly support skin health but also the health of your gut and skin microbiome.

Stay hydrated – Drinking sufficient water daily is an important part of general health maintenance.  For those who are on the lower side of water intake or have a higher risk of dehydration from exercise or older age, a mix of studies have shown an increase of at least 100ml-2L of water per day may help support skin health by improving deep skin hydration and elasticity, while reducing dryness and roughness.[11]

Strengthen your skin barrier – a healthy skin barrier function is as important to the skin microbiome as it is to the skin.  Supplementing with collagen has shown to support skin integrity and elasticity.[12]

For more specific health advice on how to care for your skin microbiome, see your health practitioner.

[1] Baldwin HE, Bhatia NC, Friedman A, Prunty T, Martin R, Seite S. The role of cutaneous microbiota harmony in maintaining a functional skin barrier. SKIN The Journal of cutaneous medicine. 2017 Oct 27;1:s139-.

[2] Krutmann J, Bouloc A, Sore G, Bernard BA, Passeron T. The skin aging exposome. Journal of dermatological science. 2017 Mar 1;85(3):152-61.

[3] Stefanovic N, Flohr C, Irvine AD. The exposome in atopic dermatitis. Allergy. 2020 Jan;75(1):63-74.

[4] Bikle DD. Vitamin D and the skin: Physiology and pathophysiology. Reviews in Endocrine and Metabolic Disorders. 2012 Mar;13(1):3-19.

[5] Grice EA. The skin microbiome: potential for novel diagnostic and therapeutic approaches to cutaneous disease. InSeminars in cutaneous medicine and surgery 2014 Jun (Vol. 33, No. 2, p. 98). NIH Public Access.

[6] Luna PC. Skin microbiome as years go by. American Journal of Clinical Dermatology. 2020 Sep 10:1-6.

[7] Byrd AL, Belkaid Y, Segre JA. The human skin microbiome. Nature Reviews Microbiology. 2018 Mar;16(3):143-55.

[8] Moitinho‐Silva L, Boraczynski N, Emmert H, Baurecht H, Szymczak S, Schulz H, Haller D, Linseisen J, Gieger C, Peters A, Tittmann L. Host traits, lifestyle and environment are associated with the human skin bacteria. British Journal of Dermatology. 2021 Mar 18.

[9] Huang S, Haiminen N, Carrieri AP, Hu R, Jiang L, Parida L, Russell B, Allaband C, Zarrinpar A, Vázquez-Baeza Y, Belda-Ferre P. Human skin, oral, and gut microbiomes predict chronological age. Msystems. 2020 Feb 11;5(1):e00630-19.

[10] Dréno B, Dagnelie MA, Khammari A, Corvec S. The skin microbiome: a new actor in inflammatory acne. American Journal of Clinical Dermatology. 2020 Sep 10:1-7.

[11] Akdeniz M, Tomova‐Simitchieva T, Dobos G, Blume‐Peytavi U, Kottner J. Does dietary fluid intake affect skin hydration in healthy humans? A systematic literature review. Skin Research and Technology. 2018 Aug;24(3):459-65.

[12] Choi FD, Sung CT, Juhasz ML, Mesinkovsk NA. Oral collagen supplementation: a systematic review of dermatological applications. Journal of drugs in dermatology: JDD. 2019 Jan 1;18(1):9-16.