Turns out, skin health is more than skin deep! In fact, it might even start from your gut.

Current research into the body’s microbiome finds that overall physical and mental health is impacted by the microorganisms throughout the body – especially those found in the gut and skin. Gut microbiome, for example, can influence immune responses, resulting in the development of skin conditions such as psoriasis, acne, dandruff, and atopic dermatitis.^1,2

So, what does this discovery mean for you and your skin? It means that along with using high-quality topical skin care products , maintaining a healthy gut might be a crucial element to keeping your skin looking youthful for as long as possible.

As children, we're taught to wash our hands, brush our teeth, and wipe down tables to keep “germs” away from our bodies. Yes, some (pathogenic) microorganisms do cause illness, but many others are beneficial – and even critical – to maintaining good overall health. In fact, there are three key ways in which microbes impact our health:

• They aid in nutrient absorption and metabolism
• They help regulate the immune system
• They impact systemic inflammation

Nutrients are biological requirements for growth, energy, and cellular function, but they do your body no use without proper absorption - something you rely on the help of gut microbiota for. Humans aren’t able to synthesize all the vitamins and nutrients needed for survival on their own, therefore most of these nutrients come from the diet. Gut microbiota transform dietary compounds into bio-available nutrients that the body can use effectively.⁴

The relationship between the gut microbiome and nutrients is called the micronutrient–microbiome axis, which is a symbiotic relationship the body can’t live without. Gut microbiomes not only help metabolize food into vitamins and minerals for your absorption, but they also need these nutrients for their own growth and functioning. The ingestion of vitamin A and vitamin C, for example, helps to grow beneficial microorganisms like Lactobacillus and Roseburia genera. In turn, these forms of healthy bacteria help to break down lactose, reduce cholesterol, produce brain-friendly short-chain fatty acids (SCFAs), and other critical nutrients. Another example is the creation of vitamin K and vitamin B, both of which are essential for wound healing, skin health, cardiovascular function, and muscle development. These vitamins are processed mainly through the gut microbiome and are vital for maintaining overall health.⁴

A recent review of six articles from the scientific journal Immunology concluded that the gut microbiome and the immune system are closely entwined. In fact, a person’s immune system is developed in large part by their gut’s microbial community, starting from birth and following them throughout the rest of their life.^5,6

A study of 600 healthy babies and 175 mothers found that babies’ microbial communities are shaped from birth, which goes on to influence their immunity and microbiome homeostasis for the rest of their lives. For instance, babies born vaginally are exposed to a mother’s gut bacteria during birth, while the microbiomes of babies born through cesarean section display a stronger correlation to the microbiome found on skin, with fewer of their mother’s gut microbiome. It's the mother’s gut microbiome, however, that jumpstarts a newborn’s immune system, therefore vaginal births provide an immune advantage over cesarean births.^5,6)

Scientists continue to research these implications and how the data may impact future immune system treatments. For example, emerging research such as this points to the theory that colonizing a person’s digestive tract with beneficial microorganisms could serve as effective therapies for chronic inflammatory diseases and immune disorders.^5,6

Perhaps the most exciting area of research in regards to gut microbiota is its relationship to inflammation. In recent years, the study of inflammation has been at the forefront of health science. A building body of research is finding that systemic inflammation can lead to chronic and debilitating diseases, such as cardiovascular disease, chronic kidney problems, autoimmune disorders, and neurodegenerative disorders.⁷

Chronic inflammation may, in many cases, stem from the overabundance of specific bacteria within the gut microbiome. These bacteria trigger the start of inflammatory pathways that lead to sustained chronic inflammation. Gut microbiota also affect the permeability of the intestinal walls, in some cases creating what’s known as a “leaky gut.” In the case of a leaky gut, metabolites from gut microbes may seep or leak into the bloodstream, triggering inflammation. On the other hand, beneficial microorganisms in the gut initiate short-chain-fatty-acids, which reduce inflammation and balance the immune response.⁷

In general, research into gut microbiomes shows that maintaining a healthy gut means creating an environment favorable to the good microbes and unfavorable to the bad microorganisms within the digestive tract, then populating that environment with good bacteria.

So how do we foster an optimal environment and ensure the healthy microbes make it into our intestine? Our diet is the primary avenue in which microorganisms are introduced into the body, especially intestinal microbiota. Food is also the best way to introduce healthy fibers and prebiotics to cultivate the growth of beneficial bacteria . So maintaining a healthy diet is key to fostering a healthy gut microbiome.^3,4

The study of gut microbiota is still a new avenue of research and there’s no single composition of a “normal gut microbiome”. However, you can tell when your gut microbiome is out of balance if you experience the following symptoms:^3,4

• Stomach disturbances like excess gas, constipation, diarrhea, or bloating.
• Sudden and unintentional weight changes.
• Skin problems like changes or irritation.
• Excessive or constant fatigue.
• Sleep disturbances like insomnia.
• Food intolerances.

Your skin has its own microbiome, but it’s largely influenced by your gut’s microbiome. Because digestive microorganisms impact the immune system, nutrient metabolism, and can cause inflammation, it is not surprising that gut microbiome also affects the skin's condition. For example, inflammation due to an unhealthy gut may show up in the skin in the form of rosacea. In fact, studies of people with rosacea indicate that certain bacteria are more abundant in their gut microbiome than in the general population.⁸

Your skin may show symptoms of an unhealthy gut if you develop any of the following skin conditions:

• Rosacea
• Psoriasis
• Acne
• Eczema
• Atopic Dermatitis
• Seborrheic Dermatitis

Scientists refer to the interaction between the gut and skin as the gut-skin axis. The concept of the gut’s interconnectedness to distant organs isn’t new. After all, researchers are already familiar with the gut–lung axis and gut–brain axis. The gut’s microbiome is tightly bound with the body’s immune and inflammatory responses, which affects all systems and organs in the body, including the integumentary system — your skin.⁸

The skin, in particular, is sensitive to changes in the immune system and to any inflammation, thus making the skin exceedingly susceptible to changes in the gut microbiome –creating a gut-skin connection. The gut-skin axis also involves the processing of vital nutrients and the release of hormone-like compounds, which as we all learned in our teens, can greatly impact the skin. In fact, intestinal microbes release at least 30 hormone-like compounds, many of which directly affect skin health.^5,8

The intestinal system has many similarities to the integumentary system.

• Both are lined with epithelial cells that are exceptionally sensitive to inflammation.
• Both are also closely tied to the immune system.
• Both hosts trillions of microorganisms.
• Both are constantly subject to exposure from factors in the environment.
• Both have a high cell turnover rate.

Although some microorganisms from the intestine may be able to find their way to the skin and vice versa, more often, the gut-skin axis is indirect, with changes in one impacting already existing microbiota in the other. For example, gut microbiomes may release chemicals or induce inflammation that affects existing microorganisms throughout the body and in the skin. These microorganisms may proliferate and become overpopulated, perhaps causing infections on the skin.⁸

The scientific jury is still out when it comes to the exact link between gut health and the development of acne, but all signs currently point to a strong relationship between the two. Research into acne shows that three primary factors accompany the development of acne symptoms; ductal obstruction, sebum oversecretion, and inflammation caused by a microorganism called Propionibacterium acnes.⁹

Researchers hypothesize that intestinal flora may directly influence the output of endocrine hormones and brain neurotransmitters from the gut, affecting the presence of Propionibacterium acnes, sebum secretions, and inflammation on the skin. Additionally, nutrient malabsorption from an unhealthy gut can result in chromium, folic acid, selenium, and zinc deficiencies – all of which are essential in keeping the skin healthy and acne-free.⁹

Poor digestive health can be indicated by skin issues. Individuals who struggle with digestive issues often see accompanying skin issues. One symptom of inflammatory bowel disease (IBD), for example, are skin rashes or lesions. In IBD, intestinal balance becomes disrupted and disturbs the immune response. The unbalance causes a cascade effect stemming from the digestive system, affecting other organs like the liver and the skin.¹⁰

Although science has yet to fully understand the connection between gut health and the physical signs of aging, they do know that such a connection exists. A 2021 literature review of research published in Nutrition, Metabolites, and Human Health, found that “understanding the relationship between the gut microbiome and healthy aging is fundamental to achieving systemic longevity.”^11,12

Chronic inflammation, even low-grade inflammation, leads to significant cell damage – thus causing tissue injury and fast-tracking the aging process. Some of this tissue injury stems from an unbalanced gut microbiome, which encourages a systemic immune response marked by a constant state of inflammation. When your body focuses more on the immunity in your gut biome due to microorganisms that shouldn’t be there, it isn’t able to focus on the development and growth of healthy cells. Over time, the appearance of aging is accelerated.^6,11,12

Genetic research also provides clues into how gut microbes impact aging. Information gathered from the gene sequences database of the National Center for Biotechnology found that bacterial pathways connected to aging affected the production of ceramides, fatty acids, and pigmentation – all factors that affect the skin barrier and skin’s biological age . Ceramides and fatty acids compose the skin barrier, maintaining skin’s elasticity and preventing sagging. ^11,12,13

Additionally, studies show that skin and gut microbiome samples can both determine chronological age within 4 years of accuracy. This is because the gut and skin microbiome change with age. Due to this relationship, it’s thought that the gut and skin microbiome may play an important role in accelerating and decelerating the aging process. Furthermore, skin and gut microbiota may affect susceptibility for age-related diseases due to their close ties with the immune system and the inflammation process.^12,13

You are what you eat — at least when it comes to your intestinal microbiota. The food you consume can either promote or inhibit microorganisms within your gut and skin. This means that even if you are consistent about cleansing your face and applying an ultra-nourishing peptide moisturizer on the daily, if you aren’t looking out for what you feed your body, this may detract from your ability to experience healthy skin to its full potential . Eating too many processed foods and added sugars, for example, may decrease the number of healthy bacteria in your gut and lead to inflammation. The following are other factors that affect gut health.¹⁴

• Lack of a balanced diet. You need to eat the right amount of fruits, vegetables, and whole grains for the best gut health.
• Not enough prebiotic fiber. This type of fiber passes through the body undigested while promoting the growth of good gut bacteria.
• Drinking too much alcohol. Not only does alcohol contain sugar, but the fermentation can also kill good gut bacteria.
• Taking antibiotics , which can kill the good bacteria in your gut.
• Cigarette smoking, which fills your body with cancer-causing substances and is one of the risk factors for several digestive diseases.
• Lack of sleep. Sleep allows your body to heal and restore itself. A lack of sleep can decrease good bacteria in your gut, in part because you eat more when you sleep less.
• Too much stress . High levels of stress can cause a lack of blood flow to the gut while increasing digestive sensitivity.
• Not enough exercise. Physical activity helps you regulate your blood glucose levels. When these are off, your gut health may suffer.

Gut bacteria can reduce or induce inflammation, which is why so many digestive disorders cause skin changes. This link is highlighted in numerous studies performed in the last decade. One study done with mice found that Lactobacillus reuteri supplementation resulted in experienced improved dermal thickness and thicker, shinier fur.^8,14

This connection between intestinal microbiome supplementation and achieving healthy skin also extends to humans. For example, volunteers who consumed Lactobacillus paracasei supplements for 2 months had decreased skin sensitivity and enhanced skin barrier integrity. So, if you experience skin inflammation or have itchy skin, you may want to check your diet and digestion, as well as look into what the best foods for skin repair are .¹⁵

An unhealthy gut can cause a variety of skin conditions, some of which are:¹³

• An aggravation of the fatty layer under the skin, called panniculitis. Panniculitis occurs as a symptom of Crohn’s disease or ulcerative colitis.
• Reddish-purple inflamed nodules on the neck, face, and arms called neutrophilic dermatoses caused by colonic diseases and bowel-associated dermatosis-arthritis syndrome.
• A thickening of the skin on the palms or feet is called palmoplantar keratoderma - a symptom of gastrointestinal tumors.
• Acceleration of biological aging in the form of sagging skin, hyperpigmentation, and leathery patches.

As science uncovers just how integral your gut is to your well-being – and beauty– it’s important to keep the digestive system as healthy as possible by:

• Getting a sufficient amount of sleep.
• Lowering your stress levels to keep gut inflammation down.
• Staying hydrated to protect the mucosal lining of the gut and keep bowel movements regular.
• Eating slowly to aid in digestion and nutrient absorption.
• Avoid harmful bacteria and be aware of what kind of foods you are consuming.
• Maintaining a high-fiber, low-sugar, low-fat diet with minimal processed foods. Some suggestions for a healthy gut microbiome are: ^8,14
• Fermented foods such as kim chee, yogurt, and miso.
• Longevity foods high in collagen like bone broth and salmon, and lean meats.
• High-fiber foods like bananas, peas, legumes, and oats.
• Taking a prebiotic or probiotic supplement . Prebiotics are nutrients that serve as “food” for existing beneficial bacteria in the gut. Probiotics, on the other hand, are live bacteria that aid in creating and maintaining a healthy digestive system.

Consult with your healthcare provider if your gut problem doesn’t improve after you’ve implemented the changes above. The longer your digestive condition remains untreated, the more damage it can do to your body.

If you struggle with skin issues and have tried every remedy, maybe it’s time to look into your gut health. As research uncovers more about the gut’s importance on all aspects of your health (including mental health), the more thankful you’ll be about all the care you’ve put into your gut health!¹⁰)

• Your gut health and skin health are highly interconnected due to inflammation in the gut causing a body-wide immune response.
• Poor gut health can affect the entire body, especially the skin.
• Good gut health can lead to radiant, good skin health.
• You can improve your gut health through diet and lifestyle changes.
• Because an unbalanced skin and gut microbiome may accelerate aging, take steps to maintain a healthy digestive microbiota.

Sources:

1. De Pessemier, Britta et al. “Gut-Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions.” Microorganisms vol. 9,2 353. 11 Feb. 2021, doi:10.3390/microorganisms9020353
2. \"The Microbiome.\" HSPH Harvard. https://www.hsph.harvard.edu/nutritionsource/microbiome/
3. \"What is Homeostasis?\" Scientific American. 3 January, 2000. https://www.scientificamerican.com/article/what-is-homeostasis/
4. Frame, Leigh A et al. “Current explorations of nutrition and the gut microbiome: a comprehensive evaluation of the review literature.” Nutrition reviews vol. 78,10 (2020): 798-812. doi:10.1093/nutrit/nuz106
5. La Flamme, Anne Camille, and Simon Milling. “Immunological partners: the gut microbiome in homeostasis and disease.” Immunology vol. 161,1 (2020): 1-3. doi:10.1111/imm.13247
6. \"Babies' gut bacteria affected by delivery method.\" Science Daily. https://www.sciencedaily.com/releases/2019/09/190918131447.htm
7. Al Bander, Zahraa et al. “The Gut Microbiota and Inflammation: An Overview.” International journal of environmental research and public health vol. 17,20 7618. 19 Oct. 2020, doi:10.3390/ijerph17207618
8. Salem, Iman et al. “The Gut Microbiome as a Major Regulator of the Gut-Skin Axis.” Frontiers in microbiology vol. 9 1459. 10 Jul. 2018, doi:10.3389/fmicb.2018.01459
9. Lee, Young Bok et al. “Potential Role of the Microbiome in Acne: A Comprehensive Review.” Journal of clinical medicine vol. 8,7 987. 7 Jul. 2019, doi:10.3390/jcm8070987
10. Fields, Deborah. \"Gastrointestinal Disease and Skin Problems.\" News Medical. https://www.news-medical.net/health/Gastrointestinal-Disease-and-Skin-Problems.aspx
11. Stocum, Linda. \"Gut Bacteria Linked to Inflammatory Skin Disease.\" Dermatology Times. 11 May, 2021. https://www.dermatologytimes.com/view/gut-bacteria-linked-to-inflammatory-skin-disease
12. Uildriks, Lori. \"Harnessing the skin’s microbiome could help combat skin aging.\" Medical News Today. 11 November, 2021. https://www.medicalnewstoday.com/articles/harnessing-the-skins-microbiome-could-help-combat-skin-aging
13. Huang, Shi et al. “Human Skin, Oral, and Gut Microbiomes Predict Chronological Age.” mSystems vol. 5,1 e00630-19. 11 Feb. 2020, doi:10.1128/mSystems.00630-19
14. Begum, Jabeen. \"What Are the Symptoms of an Unhealthy Gut?\" Medicine Net. 12 July, 2021. https://www.medicinenet.com/what_are_the_symptoms_of_an_unhealthy_gut/article.htm
15. Traub, Michael. \"Probiotic Treatment of Sensitive Skin.\" Natural Medicine Journal. https://www.naturalmedicinejournal.com/journal/2014-07/probiotic-treatment-sensitive-skin