The Relationship Between Gut Health and Skin Health

How many times have you heard that beauty comes from within us? This saying is true, and not just in a metaphoric sense. Did you know that skin health is directly influenced by the gut microbiome through the gut-skin axis? Keep reading to learn how our intestinal microflora can affect our skin health. 

What is the gut-skin axis?

As the name suggests, the gut-skin axis is a communication path between the intestinal and skin microbiomes. Any disruption or loss in the intestinal microbial protective barrier will allow toxic components and neurotransmitters involved in inflammatory processes to pass from the gut into the bloodstream, reach the skin and increase susceptibility to dermal issues. These gut microbiome alterations can occur due to physical or emotional stress, environmental factors, a poor diet, and genetic background. [Bowe, W. et al., Bowe, Whitney P, and Alan C Logan, Lee, Learn-Han, et al.].

A healthy human gut microbiome is diverse, changes with age, and comprises various microorganisms that reside in perfect balance with each other. Some of the most important beneficial bacteria in the intestinal microbiome are Lactobacillus and Bifidobacterium species. The gut microbiome is involved in vitamin production, metabolic processes, protection from pathogenic microorganisms, maintaining a healthy lipid level, modulation of inflammatory processes, and supporting a healthy immune system [Ellis, Samantha R., et al., Huang, Shi, et al., ].

The skin microbiome is also highly complex and comprises different bacteria for each area of the body, depending on skin moisture and the density of the sebaceous glands. Specific microorganisms, for example, Staphylococcus epidermis, protect the skin from the overgrowth of pathogenic bacteria and infection by supporting the local skin barrier. Skin health is directly influenced by the local microbiome homeostasis, but as you will see further in the article, it is also under the direct influence of gut health. 

What is the exact mechanism behind gut-skin axis disturbances?

• While the precise impact of the gut microbiome on skin health is still being researched, it is well known that intestinal microflora directly influences our body's immune system and inflammatory response. A weakened immune system can also disrupt the local cutaneous immune response, allowing pathogenic microbes to overgrow and trigger or aggravate skin conditions. 

• Intestinal microbiome imbalances can exacerbate both systemic and cutaneous inflammatory responses aggravating pre-existing skin conditions or even contributing directly to the occurrence of skin health problems; 

• Changes in the gut microbiome homeostasis can alter fatty acid levels, which are essential for skin structure and cell renewal [Ellis, Samantha R., et al., Salem, Iman, et al.].

Skin conditions associated with impaired gut microbiome:

• Acne is often encountered in people suffering from an imbalanced gut microbiome. This process happens as almost 80% of our immune system resides in the intestinal tract, influencing our overall immune response to pathogens. An impaired systemic immune response will also interfere with the skin's defense against pathogens. A decreased immune response at skin level allows pathogenic bacteria, fungi and viruses to overgrow and trigger skin breakouts or aggravate acne [Bowe, Whitney P, and Alan C Logan, Vighi, G., et al.];

• Atopic dermatitis (AD) is an allergic reaction to environmental factors which evolve with redness, dry and pruritic skin lesions. AD affects almost 20% of children and 3% of adults worldwide. The leading causes of this skin health problem include genetic predisposition, exposure to toxins, excessive hygiene, but also a reduced diversity of the gut microbiome. 

A less diverse intestinal microbiota can lead to a weaker immune response and a lower capacity to modulate inflammation;

• Rosacea is often associated with intestinal tract microbiome imbalances, in particular in people confirmed with a gut bacteria called Helicobacter pylori. While the primary effect of this bacteria is the occurrence of stomach ulcers, this pathogen can also trigger rosacea lesions. Further, similar to AD, rosacea may occur as a consequence of decreased immune response and altered inflammatory response;

• Psoriasis affects 2 to 3% of the population worldwide. This skin condition can evolve with scaly, red pruritic lesions. The exact link between psoriasis and gut microflora imbalances is not well known. However, it is suspected that intestinal microbiome imbalances may promote the production of some inflammatory factors that may trigger psoriasis [Chen, Lihui, et al.]; 

• Seborrheic dermatitis (SD) affects the areas of the skin rich in sebaceous glands such as the scalp, face and trunk. SD is an inflammatory skin condition that is often associated with gut microbiome imbalances.

Other skin health issues associated with impaired gut microbiome:

• Dehydration and loss of skin elasticity are often associated with gut microbiome imbalances due to the decreased water absorption from the intestinal tract;

• Premature aging can occur in people suffering from chronic gut microbiome imbalances [Huang, Shi, et al.]. 

Diet and skin – Foods and natural supplements you can include in your daily diet to support the intestinal microbiome and skin health:

• Probiotics are "live beneficial microorganisms" which support digestive processes and contribute to our overall health. If administered in the right amount, probiotic supplements can help reestablish imbalances in the gut microbiome and may support the treatment of associated pathologies, including skin issues. Probiotics were documented to limit the overgrowth of specific bacteria involved in acne, such as Cutibacterium acnes (formerly Propionibacterium acnes);

• Prebiotics serve as "food" for the healthy gut microbiome and support beneficial microorganisms' growth and activity. The healthy gut microorganisms ferment prebiotics and produce short-chained free fatty acids (SCFAs), butyrate, acetate, and propionate. While these names may sound complicated, these byproducts further support intestinal healthy cell lining, decrease the inflammatory response, strengthen the immune system and were also proven to prevent cancer. SCFAs also support the growth of beneficial skin microbiome, increase the local immune defense and decrease inflammation; 

• A balanced diet rich in healthy fatty acids supports the cells of the large intestine or the colon. Fiber-rich foods promote the synthesis of SCFAs, decrease various toxic components in the intestinal tract, improve gut health and microbiome diversity. Polyunsaturated fatty acids such as Omega-3 also support the growth of SCFA-producing bacteria; 

• Avoid processed foods rich in saturated fats and sugar as they negatively impact the gut microbiome and skin health. High-fat diets and processed comfort foods devoid of fiber cause alterations to digestive processes and gut microbiota.

Avoiding stressful situations, either emotional or physical, can help prevent the negative impact on the gastrointestinal microflora structure and function. Although this might be easier said than done, it is not impossible. 

As you can see, there is no doubt that our gut microbiome is essential for healthy skin. Studies are currently researching methods to improve the intestinal microbiome to help with various health issues, including those affecting our skin. Time and again, we learn how it is essential to focus a little more on our diet, work out, even if for ten minutes a day, keep away from stressful situations, and take care of our health. 

References:

Bowe, W., et al. "Acne Vulgaris, Probiotics and the Gut-Brain-Skin Axis: From Anecdote to Translational Medicine." Beneficial Microbes, vol. 5, no. 2, 2014, pp. 185–199., doi:10.3920/bm2012.0060.

Bowe, Whitney P, and Alan C Logan. "Acne Vulgaris, Probiotics and the Gut-Brain-Skin Axis - Back to the Future?" Gut Pathogens, vol. 3, no. 1, 2011, p. 1., doi:10.1186/1757-4749-3-1. 

Chen, Lihui, et al. "Skin and Gut Microbiome in Psoriasis: Gaining Insight into the Pathophysiology of It and Finding Novel Therapeutic Strategies." Frontiers in Microbiology, vol. 11, 2020, doi:10.3389/fmicb.2020.589726. 

Ellis, Samantha R., et al. "The Skin and Gut Microbiome and Its Role in Common Dermatologic Conditions." Microorganisms, vol. 7, no. 11, 2019, p. 550., doi:10.3390/microorganisms7110550.

Huang, Shi, et al. "Human Skin, Oral, and Gut Microbiomes Predict Chronological Age." MSystems, vol. 5, no. 1, 2020, doi:10.1128/msystems.00630-19.

Lee, Learn-Han, et al. "IDDF2020-ABS-0112 Gut-Skin Axis: Decoding the Link between the Gut Microbiome and Hives." Abstracts, 2020, doi:10.1136/gutjnl-2020-iddf.22.

Salem, Iman, et al. "The Gut Microbiome as a Major Regulator of the Gut-Skin Axis." Frontiers in Microbiology, vol. 9, 2018, doi:10.3389/fmicb.2018.01459.

Vighi, G., et al. "Allergy and the Gastrointestinal System." Clinical & Experimental Immunology, vol. 153, 2008, pp. 3–6., doi:10.1111/j.1365-2249.2008.03713.x.