The skin has a multitude of essential functions. As the immune system’s first line of defense, your skin protects the body from external threats. It also prevents dehydration, can cool your body when it’s hot, and hosts a vast network of nerve endings that enable you to feel the world around you. But it has another, equally important job: providing a home to trillions of microbes and their genetic material, collectively known as the skin microbiome.1

These microbes are bacteria, fungi, and viruses that are crucial to your well-being. They communicate with skin cells and the immune system to establish and maintain the skin barrier to ensure optimal skin health. When something disrupts the delicate balance of microbes – such as disease-causing pathogens or a breach in the skin barrier – skin function is impaired, which can lead to infection and a number of adverse skin conditions.1,2 But there are things you can do to keep your skin – and the microbes that call it home – healthy.

Microbiome’s role in maintaining good health

The skin microbiome isn’t just one environment. It comprises three microenvironments: oily (sebaceous), moist, and dry. Each has its own unique population of microbes. For example, oil-secreting sebaceous glands, such as those in the forehead, are dominated by the bacterial genera Cutibacterium and Staphylococcus. Areas of the skin that are moist – the bend of the elbow and the bottoms of the feet – have high levels of bacteria that thrive in humid environments, such as Staphylococcus and Corynebacterium. Dry skin typically contains all three bacterial genera.2,3

Microbes protect the human body in several ways.6

  • They regulate the formation of the outermost layer of the skin (stratum corneum), facilitating normal skin barrier structure and function.
  • They ward off invasion, colonization, and infection from disease-causing pathogens. 
  • Some species of bacteria on the skin produce their own antibiotics that inhibit the activity of harmful bacteria.
  • Microbes play critical roles in the recruitment and stimulation of immune cells in the skin and enhance wound healing. 

The microbes that inhabit the skin are especially hardy because the skin is one of the least nutrient-rich microbiomes in the human body. The skin provides only basic proteins and fats, making it a more difficult environment to survive. 

To overcome this, skin microbes have adapted to use resources they find in sweat, oil, and dead cells located in the outermost layer of the skin. Environmental factors challenge these microbes daily, including climate, pollution, ultraviolet light, cosmetics, soaps, and antibiotics.2 Despite all this, the skin microbiome remains relatively stable throughout life, usually returning to its previous state even after using cosmetics or washing with antimicrobial soaps.2,4,5 

The connection between an unbalanced microbiome and skin conditions 

There are times in an individual’s life when the skin microbiome isn’t stable. For example, oil production in the skin decreases as a person ages. This creates a loss of nutrients for resident microbiota and provides a chance for opportunistic microbiota to spread. The skin’s natural immunity also wanes in later years, increasing the risk of infection and skin cancer.2,4,5

Much research is underway to determine if an imbalance in the skin’s microbiome causes skin conditions ­– or if the skin condition leads to an imbalance in the microbiome.3 

  • A loss of diversity of skin microbiota might contribute to acne. Bacteria called Cutibacterium acnes trigger an inflammatory response that forms a biofilm or barrier, making it difficult for antimicrobial acne treatments to penetrate the skin.3 
  • Dandruff is linked to fungi that are thought to cause an overproduction of oleic acid. This disturbs cells in the outer layer of skin and causes an inflammatory response on the scalp.4 
  • Atopic dermatitis, also known as atopic eczema, might occur when the bacteria Staphylococcus aureus overwhelms the resident microbiota.5
  • Although the exact cause of alopecia areata (non-scarring hair loss) is unknown, some research links it with an imbalance in the microbiota found in the hair follicles.4 
  • Skin cancer and actinic keratosis are associated with imbalances in the skin microbiome. It’s thought that a decrease in bacteria that offer protection against UV damage are partly to blame.3 

The future of research: Enhance the skin microbiome to improve health

Research continues to explore the relationship between the microbiome and skin health – and there are some promising results. Oral and topical probiotics, particularly Lactobacillus and Bifidobacterium, have been linked to improvements in oxidative stress, photodamage, and skin barrier dysfunction. Some research has found that probiotics might aid skin hydration.7

Another area of study is skin microbiota transplantation – based on the same premise as fecal transplantation, which repopulates an ailing gut microbiome with healthy microbiota to treat digestive disorders. Researchers are investigating methods that can “knock out” a compromised skin microbiome by using antibiotics and replacing it with a healthy microbiome. The idea is to one day use a healthy and balanced skin microbiome to treat skin conditions, such as atopic dermatitis.5

Defining the role of the skin microbiome in health and disease is a fast-moving and evolving topic, with much to be discovered. While research works out how to harness the power of the microbiome to treat skin conditions, there are things you can do to improve the overall health of your skin.8 

  • Protect skin from the sun. Use sunscreen, wear protective clothing, and seek shade when the sun is intense.
  • Don’t smoke. Smoking depletes the skin’s nutrients and increases the risk of squamous cell skin cancer. 
  • Be gentle. Limit bath time, avoid strong soaps, and moisturize skin regularly.
  • Eat a healthy diet, including plenty of fruits, vegetables, whole grains, and lean proteins.
  • Drink plenty of water to keep skin hydrated. 
  • Manage stress. Get enough sleep, scale back your to-do list, and make time for enjoyable activities. 

A word from Thorne

Thorne offers supplements containing several strains of Lactobacillus and Bifidobacterium to support a healthy skin microbiome from the inside out.* In addition to drinking plenty of water, Thorne’s Collagen Plus contains HydroPeach, which is derived from Japanese peaches and supplies ceramides – lipid molecules that help maintain the water balance of the skin.* Ceramides occur naturally in the skin but decrease as one ages.

References

  1. Swaney MH, Kalan LR. Living in your skin: microbes, molecules, and mechanisms. Infect Immun 2021;89(4):e00695-20.
  2. Byrd AL, Belkaid Y, Segre JA. The human skin microbiome. Nat Rev Microbiol 2018;16(3):143-155.
  3. Callewaert C, Knödlseder N, Karoglan A, et al. Skin microbiome transplantation and manipulation: current state of the art. Comput Struct Biotechnol J 2021;19:624-631.
  4. Carmona-Cruz S, Orozco-Covarrubias L, Sáez-de-Ocariz M. The human skin microbiome in selected cutaneous diseases. Front Cell Infect Microbiol 2022;12:834135.
  5. Boxberger M, Cenizo V, Cassir N, La Scola B. Challenges in exploring and manipulating the human skin microbiome. Microbiome 2021;9(1):125.
  6. Harris-Tryon TA, Grice EA. Microbiota and maintenance of skin barrier function. Science 2022;376(6596):940-945. 
  7. Ratanapokasatit Y, Laisuan W, Rattananukrom T. How microbiomes affect skin aging: the updated evidence and current perspectives. Life (Basel) 2022;12(7):936.
  8. Skin care: 5 tips for healthy skin. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/skin-care/art-20048237. [Accessed Nov. 9, 2022.]