When you look at your skin, what do you see? Perhaps a source of confidence, or a reflection of age? Look again. You’re actually inspecting your personal armor against the pathogen-filled world (1). Skin ensures nasty stuff in the environment stays out of your body, and it’s linked to an organ system with a similar protective role – the gut.
First, a quick rundown on the virtues of skin. Skin not only keeps the outside out, it also keeps the inside in by preventing passive loss of water and nutrients. In addition, skin contains glands that purposefully release sweat to cool our bodies, and blood vessels that constrict to prevent heat loss. It holds tons of tiny nerve endings that allow us to feel things like pain, temperature, touch and vibration. And the skin needs to be able to regenerate itself, as we are constantly creating cracks in our armor through tiny cuts, burns and scrapes. So, this massive organ is mighty important and needs to be kept healthy.
Keeping your gut happy seems to be part of this process. Scientists have long suspected that gut and skin affect each other (2) – after all, those with gut problems often have skin problems too (3,4). A 2013 study showed that mice fed “good” gut bacteria had thicker skin (5), suggesting that gut bacteria can improve skin health. Human studies have also shown positive skin effects from taking probiotics (6), such as reduced acne (7) and skin dehydration (8,9,10). Probiotics may even reduce the severity of skin disorders such as atopic dermatitis (11).
So, how can does the gut talk to the skin? Research suggests that the gut and the skin communicate most commonly through the immune system (6,12). The gut microbiome can “over-excite” immune system cells and increase inflammation (13) when dysregulated, which has been shown to affect not just the gut but also distant organs (14). In line with this connection, inflammation-associated disorders such as psoriatic arthritis or IBD often feature concurrent gut and skin issues (12).
The gut may directly talk to skin as well. A dysregulated gut can not only cause inflammation, but also allow for local gut signals (15) or maybe even gut microbes (16) to slip into the circulation and go global. Certain gut microbe by-products have been found in the skin (15) which non-human research suggests may affect its function. It has been proposed that the gut microbiome can affect the skin microbiome (6) (yes, you have friendly microbes on your skin too! (17)).
Also important is what you put into your gut. Studies hint that diet may influence the health of your skin if you are on a fat and carb-heavy “Western diet” (18,19,20). High glycemic index (blood sugar levels) can activate specific signaling pathways that increases skin oil secretion beyond normal levels (21), potentially leading to more acne-causing bacteria and skin irritation. Diet can also influence your gut microbiome composition (22), which (as stated above) can affect the skin through immune-mediated inflammation. So, eat well, balance and diversify your diet, and keep your gut content. It may help make your skin stronger and healthier, and make you more confident and ready to face the world.