I’m always on the lookout for insight into how the gut impacts overall health. I recently ran across a statement by Dr. Alessio Fasano, M.D., of Massachusetts General Hospital, whose research has delved into various areas of gut health and function. He said: “Your gut is not Las Vegas. What happens in the gut does not stay in the gut.” And, I’ll tell you, it stuck with me!
The more I thought about it, the more the deep truth of that clever statement sank in. Here’s why: Your gut is connected to your brain via the gut-brain axis, and it’s also connected to your skin through what’s called the gut-skin axis. (I’ll expand on both in a bit.) Therefore, your gut impacts your feelings and thoughts, immune system function, and even skin health.
The takeaway? Your gut doesn’t function in isolation. It is truly the epicenter of your mental and physical health (skin included!). With this understanding, we realize that skin issues (among others, surely) can definitely start in the gut.
Let’s explore the deeper layers of connection between your gut and your skin, plus how to navigate skin issues with a focus on gut health.
The Gut-Brain Axis
You may have heard of the gut-brain axis, the communication network in the body that allows for crosstalk from the gut to the brain and from the brain to the gut. In short, it’s the highway between the gut and the brain that both the gut and the brain travel on, “talking” to and “listening” to each other while influencing each other. This highway is made up of the autonomic nervous system, the hypothalamic-pituitary-adrenal (HPA) axis, and the gastrointestinal (GI) tract nerves.
Why is this significant? These connections give the brain the ability to influence the gut and intestinal activities (such as how immune cells affect the body) and give the gut the ability to act on and influence one’s mood, cognitive function, and overall mental outlook.
Read More: 15 Signs That Something Is Off With Your Gut
It’s clear that the gut-brain axis is a central force in the body, but it’s not the only evidence of the concept that “what happens in the gut doesn’t stay there.” This is also evidenced by the gut-skin axis.
The Gut-Skin Axis
The gut-skin axis is perhaps less well-established than the gut-brain axis. Among some health experts, awareness of the gut’s impact on the skin (and vice-versa) is not as widely known or accepted, even though the concept has been around for over 80 years. (It was first introduced by dermatologists John Stokes and Donald Pillsbury, who “proposed a gastrointestinal mechanism for the overlap between depression, anxiety, and skin conditions such as acne.”)
That said, the concept does seem to be becoming more mainstream. In fact, Dr. Brooke Jeffy, M.D., a fellow of the American Academy of Dermatology, was recently quoted as suggesting we are entering a new era in which dermatologic issues are understood and treated with gut health front and center.
Similar to how the gut-brain axis works, the gut-skin axis refers to all the connections between the skin and the gut, through which they continually communicate with each other. The gut-skin axis can influence areas such as skin structure, inflammation, and sebum production. (Sebum is the oily or waxy secretion of the skin’s sebaceous glands that coats, moisturizes, and protects the skin.)
Truth be told, when the gut microbiome is imbalanced, pro-inflammatory molecules can “jump” into the bloodstream where they can influence inflammation that then impacts the skin’s health and lead to issues like atopic dermatitis, acne vulgaris, alopecia, dandruff, rosacea, and psoriasis.
The Gut Microbiome
Given the microbiome’s role in the connection between the gut and skin, it’s important to break down how it works. The human body is teeming with trillions of microorganisms, including bacteria, viruses, and fungi, which are collectively known as the microbiome—and trillions of them live in the intestines (and elsewhere).
Of these microbes, bacteria have been studied the most. We are, in fact, made up of more bacterial cells than human cells—approximately 40 trillion bacterial cells compared to 30 trillion human cells. (That’s right, we are all slightly more bacteria than human!) There are between 500 and 1,000 bacteria species in the human body at one time and approximately 1,000 bacterial species in the gut, with each functioning differently. Most are beneficial for health, while others can lead to unhealthy effects. Weighing in at approximately your brain’s weight, these microorganisms make up about one to three percent of the body’s mass. This means that a 200-pound adult carries between two and six pounds of microorganisms!
The microbiome is also unique to each person. Part of this uniqueness is driven by the food we eat, the air we breathe, and other environmental or lifestyle factors.
One thing to know about the gut microbiome, specifically, is that having a diverse range of good bacteria in the gut makes for greater well-being since a lack of or overpopulation of specific bacteria can directly affect your health, including your skin.
For example, research points out a definite link between the microbiome and skin disorders, including atopic dermatitis, which is a specific form of eczema. It states that a person’s gut flora (in the gut microbiome) can impact the skin (in this case manifesting as atopic dermatitis) via the gut-skin axis. When there is an imbalance in the skin and/or the gut microbiome, it affects the immune response, promoting the development of skin disorders. Of course, it’s not the only microbiome at play here.
The Skin Microbiome
As the largest organ of the body, your skin weighs approximately six pounds (for an average person) and is in a continual process of change throughout your life. In fact, it regenerates itself approximately every 27 days.
As part of the first line of defense of the immune system, your skin fends off germs and infections and also shields you against heat, light, and injury. It also functions as a sensory organ, body temperature regulator, a storage place for water and fat, and a manufacturer of vitamin D (when you’re exposed to the sun).
Similar to the gut microbiome, your skin microbiome also is teeming with trillions of living microorganisms, including bacteria, fungi, and viruses—and serves as a significant part of influencing your overall health.
The skin microbiome works with other parts of your skin to help ward off infections. In fact, some of its microorganisms function as natural antibiotics. Likewise, the microbes serve to keep your skin more on the acidic side, which is inhospitable to germs.
Your skin microbes also communicate with your immune system, letting it know when harmful bacteria or viruses invade, as well as influencing the activation or deactivation of the immune system. Additionally, they play a primary role in promoting a healthy response to inflammation.
Your skin microbiome can be affected by a variety of things, including genes, diet, lifestyle choices such as smoking, your environment, air quality, and exposure to UV light.
Tips For Narrowing Down Gut-Related Skin Issues
Many factors can ultimately affect skin health. If you’re trying to get to the bottom of how your gut might be impacting skin issues, these tips can help you investigate and support greater balance.
1. Try an Elimination Diet
This short-term diet—oftentimes a month or two—helps you identify foods that may be leading to gut-related issues that then impact the skin. You should always work with your healthcare professional when going on an elimination diet.
For context, an estimated 20 percent of people have a food intolerance or sensitivity. However, those food intolerances and sensitivities can be difficult to uncover. Interestingly, eight food types account for most allergies—as well as intolerances and sensitivities. They are eggs, fish, milk, peanuts, shellfish, soy, tree nuts (such as pecans, almonds, and walnuts), and wheat.
Additional food or ingredient intolerances or sensitivities can include alcohol, corn, gluten (a protein found in wheat, rye, and barley), histamines (which naturally occur in foods such as cheese, pineapple, bananas, avocados, and chocolate), nightshades (foods or spices containing alkaloids, such as peppers and eggplant), and food additives such as monosodium glutamate (MSG) and sulfites (found in red wine and beer).
So, how do you sift through these potential culprits and find which may trigger gut-related skin issues? Enter the elimination diet. In fact, nutrition experts praise elimination diets as the “gold standard” for uncovering food intolerances.
During an elimination diet, you discontinue eating possible problem foods for several weeks while keeping a food journal as documentation of what you eat and how it affects you. From there, you gradually begin to reintroduce those foods into your diet again, keeping track of how you feel as you do so. Slow and steady reintroduction is key here so that trigger foods can be identified.
After the elimination diet, your healthcare professional can help you identify cause-and-effect patterns and determine which key foods you may need to remove.
2. Consult with Your Healthcare Team About Gut Testing
Since gut health is related to so many areas of bodily health, including the skin, you may want to talk to your provider about tests available for assessing a person’s overall gut health if you’re having problems. There are a few different types of tests integrative health professionals might consider, if you’re experiencing issues:
- a gut microbiome test (which measures levels of certain microorganisms, including amounts of certain bacteria, in a person’s gastrointestinal tract)
- an intestinal permeability test (which measures overall gut barrier function by recording permeability markers through and between epithelial cells)
- a Calprotectin test (which measures gut inflammation).
While at-home versions of these tests can provide some general information and serve as a starting point, a provider who specializes in gut health will be best able to guide testing and interpret results (while also considering your personal health history and symptoms) to give you a personalized evaluation and potential action plan.
Diet and Lifestyle Tips to Help Promote Gut And Skin Health
If you want to support a healthy gut and gut microbiome (and, hence, a healthy skin microbiome and complexion), consider prioritizing these lifestyle changes.
1. Examine Your Diet
Diet is foundational to overall health, so it makes sense to examine your diet in the face of gut and skin troubles. In addition to considering an elimination diet, make a few changes to ensure your eats are doing your gut microbiome and function (and skin!) good.
The microbiome can be highly responsive to diet. For example, the standard American diet is typically high in inflammatory foods (think ultra-processed and fast foods), which can lead to dysbiosis, which occurs when the normal gut bacteria changes in its activity or becomes imbalanced. Typically, dysbiosis is due to the loss of the beneficial bacteria, an increase in the non-beneficial bacteria, and/or diminished gut bacteria diversity.
Read More: 7 Situations When You Should See A Dietitian
Fortunately, some foods can generally impact the microbiome positively. They include fermented foods (including fermented dairy foods), vegetables, fruits, nuts, fish, beans, and peas. Fermented foods help supply the beneficial bacteria (probiotics) that your gut microbiome requires to flourish. Meanwhile, plant foods are beneficial because your gut microbiome requires a variety of plant fibers (prebiotics) to remain robust.
Foods to avoid include alcohol, sodas, processed foods, high-fat processed meats, sugary foods, and foods high in saturated fats. These feed the non-beneficial bacteria (amongst causing other trouble). For example, processed foods are not only nearly devoid of fiber, vitamins, and minerals, but they also often contain additives or preservatives that can negatively impact the microbiome.
2. Make Sure You’re Not Short on Vitamin D
As we know, the skin makes vitamin D when exposed to sunlight’s UVB rays, and having adequate vitamin D levels is associated with more microbial diversity in the gut. Due to most people’s general lack of sun exposure and the fact that not too many foods offer significant amounts of vitamin D, a good way to ensure a measured intake is through supplementation. The recommended daily allowance, or RDA, for vitamin D for children over a year of age through adults age 70 is 600 IU. For most adult age groups, the safe upper limit of daily vitamin D intake ranges from 2,000 to 4,000 IU.
3. Take Steps to De-Stress
Some animal studies indicate that stress can negatively impact the microbiome, including the gut and its health. However, there are stress management tactics that can help. Ways of de-stressing can include taking a walk, meditation, taking a soothing bath, engaging in your favorite hobby, spending time with those who uplift you, minimizing phone and screen time, reading a good book, getting a massage, practicing yoga, and journaling.
4. Evaluate Medication Use
You’ll need to work with your healthcare professional on this, but remain mindful that certain drugs can contribute to gut—and subsequent skin—issues.
Antibiotics, for example, attack all bacterial species they encounter and can’t differentiate between good and bad bacteria. Overuse of antibiotics is connected to dysbiosis, so it’s wise to use antibiotics prudently and as sparingly as possible.
Antibiotics aren’t the only medications that can negatively impact the microbiome, though. Other medications, such as laxatives, metformin, and proton pump inhibitors (PPIs) can take a toll, too.
5. Quit Smoking
Then there’s smoking/nicotine. Research points out that people who smoke have higher amounts of the “bad guy” bacteria and lower amounts of the “good guy” bacteria. The silver lining in this is that research also shows that quitting that nicotine habit can lead to increased microbial diversity. Again, you’ll need to consult your healthcare professional for this.
6. Monitor Your Toilet Trends
Your bowel transit time, or how long it takes for food to move through your digestive system (from start to finish), as well as your motility (or regularity) can also impact your gut microbiome.
Here’s how: Regular bowel movements support a healthy gut microbiome since digesting food and moving waste through your GI tract distributes different microbes in various places. If your motility is too fast, the microorganisms don’t have enough time to settle and do their jobs before they’re moved out of the body. However, if motility is too slow, those microorganisms can graze too much and overgrow, taking over territory they shouldn’t, which results in negative effects.
7. Get Moving (And Often)
A review of relevant literature suggests that regular exercise contributes to beneficial microbial changes that promote normal immune pathways, support a healthy response to inflammation, and promote metabolic health. It concludes that exercise-induced changes in microbial diversity can help glean benefits for healthy tissue metabolism, cardiorespiratory health, and more. Of course, the gut-skin axis means that all of these perks carry over to your skin.
The current research suggests that a broad spectrum of exercise modalities, frequencies, and intensities offer various gut health benefits. If you’re not sure what to aim for, the general recommendation of at least 150 minutes of moderate exercise (think brisk walking or biking) or at least 75 minutes of vigorous exercise (think running or swimming laps) a week is a good place to start. Pair this with strength training for all major muscle groups (using your body weight, free weights, or other resistance) at least twice a week.
8. Consider Probiotic and Prebiotic Supplements
Both probiotics and prebiotics can promote gut health and a healthy gut microbiome. In addition to foods like kefir, kimchi, tempeh, and kvass, a probiotic supplement can also bolster the number of “good guy” bacteria in your gut, supporting overall balance and health. Prebiotics, meanwhile, act as food and fuel for those probiotics—and can also be a beneficial supplement if you’re looking to support digestion and, in doing so, your skin.
A unique option that checks both of these boxes: Ancient Nutrition SBO Probiotics, which include not only clinically studied, resilient soil-based organism (SBO) probiotics but also prebiotics, a powerful combination for digestive health.
Final Takeaway
If you’re wondering whether your skin issues actually originate in your gut, guess no more! Since skin health is directly related to gut health, it’s quite common for dysfunction or imbalance within the digestive system to show up on your skin.
Thankfully, taking good care of your gut can help both your digestion and your complexion. Remember: Your gut isn’t Las Vegas!
Dr. Josh Axe, D.N.M., D.C., C.N.S., is a doctor of natural medicine, clinical nutritionist, author, and co-founder of Ancient Nutrition. Dr. Axe operates one of the world’s largest natural health websites, sharing healthy recipes, herbal remedies, nutrition and fitness advice, and information on essential oils and natural supplements. Dr. Axe founded one of the largest functional medicine clinics in the world and has served as a physician for many professional athletes.