The science of skin and how to nurture yours
9 cool facts about the skin microbiome:
Our skin is our most environmentally exposed organ and, typically, we have about 1,000 species of bacteria on it. These bacteria help train the immune system from the time of birth when the skin microbiome is seeded.
Different bacteria are found in different microenvironments on the skin, with some really enjoying the lipid-rich skin surfaces on the face, and others enjoying a more humid climate in the armpit or toe web.
Dysbiosis, or an imbalance of the microorganism community on or within the body, is connected to skin conditions like acne, vitiligo, and atopic dermatitis.
The skin faces an onslaught of variables—chemical, biological, and physical—that impact its microbial stability and composition. Think aseptic topical products, UV radiation, fabrics and cosmetics. The duration and intensity of exposure influences the effects on the microbiome.
In one study, subjects with highly hydrated skin had significantly increased bacterial diversity. Other studies show that contact with soil and plant leaves transiently alters the skin microbiome.
Systemic antibiotics for acne reduce skin bacteria diversity and may negatively impact skin health by reducing protective bacteria. New microbiome-based interventions are being investigated, such as a skin bacterial transplants for the treatment of acne and other conditions.
Vitamin D3 may help regulate the bacterial flora on the skin and reduce inflammatory processes.
An active area of research is the role of diet, specifically plant fibers, in the role of anticancer/anti-inflammatory properties of the skin (via metabolites produced by the skin microbiota), but it is presumed by many researchers that diet impacts the skin microbiome and influences skin diseases.
There is emerging evidence that the gut and skin microbiome are interconnected, which is called the gut-skin microbiome axis. A number of skin diseases are accompanies by an altered gut microbiome. One study showed that a high-sugar and moderate-fat diet in mice induced both skin and joint inflammation.
3 Ways to Nurture Your Skin’s Microbiome
Support and improve barrier function: Use topical products that have biomimetic ingredients like ceramides, fatty acids, amino acids, and cholesterol. Use facial sunscreen daily.
Hydrate and protect: avoid products that dry out and disturb the naturally acidic pH of the skin, avoid harsh cleansers and over exfoliation, and stay hydrated.
Feed the bugs: eat plenty of fermented foods and a generally nutrient-dense and diverse diet. Consuming fermented foods like yogurt, kefir, kimchi, and other fermented foods increases overall microbial diversity in the gut and lowers inflammation. The more fermented foods consumed, the stronger the effect.
SKIN: Protecting the Life it Encloses
After I came off the birth control pill around age 22, my acne, which the pill had treated quite well, came back with a vengeance like it was making up for lost time after all those years of repression. It turns out, when you stop taking the pill, your body experiences dynamic hormonal shifts and the production of androgen hormones, like testosterone, may suddenly go into overdrive. Androgens are part of the hormonal waterfall that initiates puberty and they play an important role in skin health. However, when there’s too much a good thing, during puberty or after you stop taking androgen-suppressing medications like birth control, excess androgens cause excess sebum production. Sebum is a skin lubricating, waxy substance produced by sebaceous glands. Skin cells, from normal cell turnover, can combine with sebum and plug hair follicles. These plugged up follicles get infected and inflamed and we call those obnoxious blemishes pimples.
In one of the most eloquent sentences I’ve ever read in a research paper about skin barrier function, the skin was described as “an interface between the organism and the external environment” that “plays a major role in protecting and supporting the life it encloses.” Our skin acts as such a naked and visible representation of our internal state. When acne shows up on our skin, we’re getting a message from our bodies that there has been a disruption in our internal balance. That disruption may be related to hormone fluctuations, the food we eat (dairy and wheat are common culprits) or products we use that disrupt our gut and skin microbiota, or other inflammatory processes.
We can’t see our liver or thyroid if they are in distress, but our skin gives us a signal we can’t ignore and it acted as my entry point to deeply reconsidering what I put on and in my body and how I thought about the role and importance of my bacterial populations.
When we get acne as teenagers and adults, the common approach practiced by dermatologists is to suppress or kill the “problem” instead of wondering how our behaviors, habits and diet are impacting our varied ecosystems and the amazingly diverse creatures that live there. I hadn’t visited the dermatologist since I was a teenager, when I figured a few years ago, that I should probably get a skin check-up. I went in and told the dermatologist that I experienced acne along my jawline around my menstrual cycle. She suggested a prescription of spironolactone, a medication that can be effective for the treatment of acne and that is used to treat high blood pressure, that also acts as an androgen blocker and carries common sides effects like headaches, diarrhea, muscle pain, skin rash, gas, and stomach pain. She also told me I could use topical antibiotics or benzoyl peroxide.
In certain situations, medications are clinically indicated and appropriate. In my case, with non-severe acne along my jawline occasionally, I figured I wasn’t missing a pill, I was lacking education. I wanted to know how my skin worked and figure out how to support it without harsh products or medications. This dermatologist’s suggestions encouraged me to dive into the world of skin and try to learn what no one had ever taught me and what I deeply wish I had known as a teenager and through my twenties.
Those common medications prescribed by the dermatologist either suppress sebum or kill P. acnes, a type of bacteria that is primarily a skin commensal, meaning it has a mutualistic non-harming relationship with other bacteria on the skin and only occasionally acts as an opportunistic pathogen. P. acnes is mysterious and the strain type and our immune and inflammatory response determine whether or not it causes acne. Topical antibiotics also kill all of the other bacteria on the skin and benzoyl peroxide, while effective for many people with acne, had caused my skin serious pain and irritation even in tiny applications.
The skin is a large barrier organ made up of ecosystems of microbial communities whose population, diversity and abundance are impacted by how we were born, what we eat, our genetics, hormones and what we put on our face and body. Birth is an important moment of skin colonization by bacteria and differs depending on whether we’re born vaginally or by c-section. These communities continue their establishment during feeding and skin-to-skin contact.
The bacterial communities on the epithelial surface of our skin are abundant and diverse and there are also yeasts, viruses and a parasitic arthropod called Demodex living its best life on the skin it calls home. Every day an onslaught of endogenous and exogenous chemicals and compounds threaten the balance and functioning of the skin and can cause various inflammatory skin conditions and alter the composition of our bacteria.
Frequent, aggressive face washing and scrubbing, artificial fragrances and essential oils, cosmetics, antibiotics, lifestyle, injury, and anxiety can cause metabolic and endocrine changes in the microenvironments of the microbiome. These changes impact and alter which microorganisms are pathogenic and bound to give you some damned pimples. It is important to avoid over-cleansing, hyper-exfoliation, synthetic preservatives and other hazardous, cancer-promoting, endocrine-disrupting, allergenic, and immunotoxic products. It’s a great idea to avoid these products when you’re growing a baby and it’s a nice bonus that they improve your skin health. EWG’s Skin Deep Cosmetics Database is an invaluable resource to research products and figure out if they’re safe.
I am in awe of my son’s skin. It is perfectly plump, smooth, and even-toned. I don’t want to disturb his skin microbiota, so I don’t use soap on him very often (except his hands of course) and he is a toddler, so his sebum hasn’t ramped up yet like it will during puberty. The top layer of the skin, or the beautiful, visible part I see when I look at my kid, is called the stratum corneum and right beneath it is the epidermis. These layers, known as our barrier layers, are composed of lipids and cells that mediate moisture levels, protect us from UV damage and act as a permeable layer that defend us from the threats of terrestrial life.
The next layer is the dermis, also known as the true skin, as it produces structural proteins like elastin and collagen and contains glands that secrete oil, blood vessels, nerve endings, sweat glands and hair follicles. It’s composition and function create the plump, youthful, hydrated skin we yearn for and it enjoys antioxidant-rich foods like green tea, vitamin-C loaded foods like broccoli, papaya, parsley and citrus fruits and foods rich in collagen like bone broth and slow cooked meats, eggs, fish, and collagen-building foods like leafy greens, pumpkin seeds and strawberries.
Finally, the adipose layer, which is vascularized and made up of fat, connective tissue and nerves. My son doesn’t have any wrinkles because his fat reserves are plentiful, but as we age, our fat cells shrink, and it shows on our face. Not surprisingly, this fat-rich layer is supported by fat-rich foods like butter from grass-fed cows, fats from sustainably raised animals, oily fish, and full-fat cultured dairy products. These layers create diverse habitats for our microbiota that are fed by what we eat and what we put on our skin for them to eat.
Skin care is changing. Many dermatologists are shifting their research, focus and treatments to the microbiome. They acknowledge that what we eat, how we live, how we feel and what we put on our skin either promotes bacterial symbiosis or dysbiosis. Promoting healthy barrier function and abundant and diverse microbial communities is gentle and it makes sense. It is another realm of health where you can take back the power and make choices that not only improve the appearance of your skin, but also improve the health of your whole body.
So, what should we put on our skin? Thinking about what to put on our skin is a lot like thinking about what to put in our mouths. In her book The Acne Answer, chemist and skin care specialist Marie Veronique provided examples of effective and safe treatments for acne and other skin conditions based on 21st century science that honors the microbiome versus 20th century science that villainizes bacteria. Instead of using oil-free moisturizes that can dry out skin and cause breakouts, she recommended using oils with omega 3-6 balance that support and improve the barrier function of the skin. Instead of scrubbing your skin with aggressive and abrasive products, exfoliate with oils that don’t disrupt the structure and protective duty of the skin. And, importantly, focus on consuming yogurt and other fermented foods that support immune function and reduce inflammation while supporting a healthy gut microbiome.
Finally, what I wish I’d known 15 years ago, instead of suppressing androgens with medications, first try a gradual approach to improving acne through diet and topical treatments rich in vitamins and minerals like B5, B3, zinc, calcium, magnesium and omega-3s. And, if needed, use the treatments recommended by the dermatologist to treat your skin conditions but take the other steps to improve your overall health along with your skin health.
I can’t overstate how much learning about my skin and how it works impacted my life. When we learn how to manage something we’ve always associated with shame and frustration, it is the ultimate moment of empowerment and possibility.
Learn more about your skin and how to nourish it:
I love the skincare brand Marie Veronique and I really enjoy and appreciate the information shared on their blog. This is a great starting point to dive into skin science and care.
If you haven’t already, you’ll soon start seeing skincare products, like probiotic skincare sprays, that promise to promote an optimal skin microbiome. Some brands I trust and some I don’t. I’m wary of these products because if I’ve learned anything about skin, it’s that we don’t know everything, it’s complex, and usually takes a holistic approach versus a one product quick fix. A holistic approach includes actions like increasing the amount of fermented foods in your diet (think kimchi, sauerkraut, yogurt, etc), getting enough sleep, moving your body frequently, eating a diverse, nutrient-dense diet, and caring for your mental and spiritual health. I love these basics so much that they are the basis for How to Grow a Baby and my forthcoming book about menstrual cycles.
Check out this never before seen skin illustration by Michelle Lassaline and take care of your dermis folks!
This information was originally in my book, How to Grow a Baby. Find tons of other fascinating, useful and actionable information in the book!
Sources
“Extrinsic factors shaping the skin microbiome.” (2020). Microorganisms.
“The skin microbiome.” (2020). Nature.
“The skin microbiome and immune system: potential target for chem-prevention?” (2017). Photodermatology, Photoimmunology & Photomedicine.
“Gut-skin axis: current knowledge of the interrelationship between microbial dysbiosis and skin conditions.” (2021). Microorganisms.
“Short-term western diet intake promotes IL-23-mediatd skin and joint inflammation accompanied by changes to the gut microbiota in mice.” (2021). Journal of Investigative Dermatology.
“Gut-microbiota-targeted diets modulate human immune status.” (2021). Cell.