What do your intestines and your skin have in common? A lot. Although invisible to the naked eye, a look under the microscope reveals that both tissues are home to astonishing flora. With around one billion microorganisms per gram of intestinal wall, the large intestine is one of the most densely populated places in the world. The surface of our skin is also full of life: There are about as many microbes per two square meters of skin as there are people on Earth – an incredible piece of data. Upon closer examination, it's no surprise that there's a close connection between these two organs and their extensive microflora. How does it work? Let's dive into their relationship and find out.
We know that good skin reflects a healthy gut – and there's scientific evidence to back it up.
Your skin and gut go hand-in-hand. It may sound romantic, but the facts are rather dry. The skin and intestines are not only the human organs with the largest surface area and the densest microbe population, they also develop from the same embryonic layer. These two organs, with their extensive nerve and blood vessel networks, are also connected through the immune system. So it's no wonder that these structures have a close relationship, as studies on the intestines’ influence on skin health have shown.
Although there is still much to learn about the underlying mechanisms, it seems that the immune system plays a particular role in facilitating the gut-skin axis of connection. The intestinal flora, weighing a total of one to two kilograms, pulls the strings by continuously interacting with immune cells to trigger the production of antibodies. This immunity-building exercise benefits the skin as well as the intestines.
Think of your intestinal flora as a powerful chemical laboratory in your belly, which produces a variety of different substances – including key materials for skin health, like hyaluronic acid or the skin-friendly vitamin biotin, in addition to substances that support the gut's ability to digest and process food. Ultimately, it is this “cocktail” of substances in the intestines that manipulates the nervous system, which in turn influences circulation to the skin, among other things.
Skin problems: Sensitivity.
Our skin has a language of its own. It uses this language to tell us about our habits, emotions, or physical and mental equilibrium. The appearance of redness, irritation, tightness, or blemishes, for example, quickly leave us feeling uncomfortable in our own skin. But what is bothering this sensitive organ?
Apart from the natural, genetically influenced process of skin aging, there are other factors that can pose additional challenges for our skin. These include excessive sun exposure, certain medicines, or improper skin care routines. An unhealthy lifestyle also leaves its mark on the skin – alcohol, nicotine, lack of sleep, stress, dehydration and, last but not least, poor nutrition –all can negatively affect the skin's appearance.
The Gut-Skin Axis: When the intestines are in trouble, the skin suffers along with them.
“You are what you eat,” the saying goes, and it's true: sensitive reactions in your belly are reflected in your skin. This relationship has been the focus of several studies, which show that people with skin problems are often found to have compromised intestinal flora (e.g. not enough lactobacilli and bifidobacteria) or intestinal walls – problems that can worsen with stress (Hello, gut-brain axis)!
In addition to stress, medicines like antibiotics or laxatives, as well as an unhealthy diet lacking proper nutrients (see boxes) can also lower the diversity of gut bacteria. Studies have shown that tribal populations have a larger variety of microbial species in their intestines than industrialized populations, whose diets and lifestyles contribute to a loss of 40% of this diversity. This decrease also impacts the cocktail of substances created by the bacteria, as well as the intestinal flora's ability to extract nutrients from our food and protect us from toxins. Ultimately, this shows up in our skin, thanks to the connection explained above.