Gut and skin: how your gut flora influences your skin

What is the gut-skin axis?

Billions of bacteria, fungi, and other microorganisms live in your gut. Together, they form your gut microbiome: an internal ecosystem that helps you digest food, produces certain vitamins, and trains your immune system. The latter is no minor detail. An estimated 70% of your immune cells are located in and around your gut wall, making your gut one of the most important control centers of your immune system. The gut-skin axis revolves around the understanding that this ecosystem does not work in isolation, but is connected to your skin — your largest organ, which also has its own microbiome.

Important: it's not a one-way street. A disturbance in your gut can affect your skin. Conversely, many skin conditions are accompanied by changes in gut flora. Researchers, including those from Ghent University, mapped this interaction in a frequently cited review article in 2021, and found that a surprisingly large number of skin conditions are associated with an altered gut microbiome.

How does your gut flora affect your skin?

Image: increased intestinal permeability

But how does your gut flora affect your skin? There are three mechanisms that emerge in research.

Dysbiosis and low-grade inflammation

When the balance between good and bad bacteria shifts—dysbiosis—it can put your immune system into a slight, dormant state of alert. This low-grade inflammatory response does not stay neatly in your gut, but spreads through your bloodstream throughout your body and is associated with inflammatory skin conditions.

Increased permeability of the intestinal wall

Your intestinal wall acts as a selective gatekeeper: nutrients are allowed through, unwanted substances are not. If this barrier is disturbed, substances that normally stay out can pass through, which can again irritate your immune system. The term "leaky gut" is often heard for this, but scientists prefer to refer neutrally to increased intestinal permeability.

Nutrient absorption

A healthy gut extracts building blocks from your diet that your skin needs, such as vitamins A, C, and E, zinc, and omega-3 fatty acids. If your digestion functions less well, the supply of these skin-friendly nutrients can also suffer.

Which skin problems are linked to your gut?

Not every skin problem is equally related to your gut, and the evidence varies greatly per condition. Anyone who claims that the gut is "the number one cause" of skin problems simplifies too much.

Acne

The link between gut flora and acne is the most researched. In comparative studies, people with acne often had fewer beneficial bacteria like Bifidobacterium and Lactobacillus in their gut than people without acne. A recent patient study also found higher levels of a gut-related metabolic marker (TMAO) in people with acne. Promising, but note: this shows a correlation, not a proven cause.

Eczema

Eczema is perhaps the strongest keyword regarding gut and skin, and not without reason. In babies who later develop eczema, the gut flora in the first months of life often appears to be less diverse than in babies who do not get eczema. Whether gut problems and eczema in adults reinforce each other is less clear, although several studies point to a role for gut flora.

Rosacea

Rosacea has a striking connection with SIBO, an overgrowth of bacteria in the small intestine. Italian research found SIBO much more frequently in people with rosacea than in a control group. In those whose overgrowth was specifically treated, the skin clearly improved. This is one of the stronger indications within this topic, although it concerns a specific group of patients.

Psoriasis

Psoriasis is also linked to an altered gut microbiome, but research on this is still in its early stages.

Dry or dull skin

Finally, many people experience dry or dull skin without a clear diagnosis. A logical explanation runs through the absorption of nutrients, but strong evidence that your gut is the decisive factor here is still lacking.

How do you know if your gut flora is out of balance? There is no reliable commercial home test that simply "reads" your gut flora, but there are signs that can indicate an unbalanced digestive system. These include a bloated feeling, irregular bowel movements, a changed color or texture of your stool, persistent fatigue, and skin flare-ups without a clear cause. Important to note: these disturbed gut flora symptoms are not very specific. They can just as easily be caused by stress, diet, or lack of sleep. So, view them as an invitation to look more closely at your lifestyle habits, not as a diagnosis.

What can you do yourself? The good news is that your gut flora is surprisingly sensitive to your lifestyle, and much of what is good for your gut also benefits your skin. Start with fiber and variety. Your gut bacteria thrive on plant-based fibers, and the more varied your diet, the more diverse your microbiome. A commonly cited guideline is to aim for about thirty different plant species per week: vegetables, fruits, legumes, nuts, seeds, and whole grains all count. Fermented foods such as kefir, yogurt, sauerkraut, and kimchi also provide live bacteria. At the same time, it helps to consume less sugar and alcohol, which can disrupt the balance.

Don't forget your mind. Sleep and stress control your gut through the stress hormone cortisol. Those who chronically sleep poorly or are under stress often feel it in both their gut and skin.

Also, stay hydrated: good hydration supports both your digestion and your skin.

Can supplements help?

High-quality supplements can support your digestion and a balanced lifestyle. Symbiotic Digest combines 10 bacterial strains with 11 digestive enzymes. It helps support your digestion and the normal functioning of the stomach and intestinal tract. Gut Night focuses on nocturnal digestive comfort. It contributes to the normal function of the stomach, helps support digestion and promotes body purification.

And for those who want to work directly on the skin, there is the Smart Collagen Shot, with 10 g of collagen and vitamin C. Vitamin C contributes to normal collagen formation for normal skin function and helps protect cells from oxidative stress. If you want to look broader, you will find a wider overview in our digestion supplements. Not miracle cures, but well-thought-out support alongside your diet.