The Gut-Skin Axis According to a Dermatologist

Most people think of skincare as something that happens on the surface. A cleanser. A serum. A moisturizer. But at Bergen Dermatology, we treat skin the way it actually works: as a whole-body system.

One of the most important and most underappreciated parts of that system is the gut-skin axis: the direct communication pathway between your digestive tract and your skin. Understanding it changes everything about how you approach your skin health.

What Is the Gut Microbiome?

The gut microbiome is the ecosystem of bacteria, fungi, viruses, and their metabolites living inside your digestive tract. These microbes are not passive passengers. They actively regulate your immune function, inflammatory pathways, hormone balance, insulin signaling, and nutrient absorption.

When this ecosystem becomes imbalanced, we see a state called dysbiosis; an increased systemic inflammation. And in dermatology, that inflammation has a face.

It shows up as:

• Acne vulgaris
• Rosacea
• Eczema
• Post-inflammatory hyperpigmentation
• Barrier dysfunction.

Healthy skin requires microbial balance both internally and on the skin surface. The gut and the skin are in constant communication  and what disrupts one, disrupts the other.

Probiotics, Prebiotics, and Postbiotics: What Is the Difference?

These three terms get used interchangeably, but they are not the same. Understanding the difference is the first step to using them intentionally.

PROBIOTICS — THE LIVE BACTERIA

Probiotics are live microorganisms that provide health benefits when consumed in adequate amounts. The most studied strains in dermatology include Lactobacillus and Bifidobacterium. Research shows that probiotics can reduce inflammatory acne lesions, improve skin barrier hydration, modulate immune responses, and even enhance tolerance to treatments like retinoids and antibiotics.

Clinical tip: If your yogurt label does not say 'live and active cultures,' it likely does not contain meaningful probiotic activity.

Food sources: Yogurt and kefir

PREBIOTICS — THE FUEL

Prebiotics are nondigestible fibers that feed your beneficial bacteria. Think of them as fertilizer for your microbiome. They increase bacterial diversity, promote anti-inflammatory compound production, and support immune balance.

Food sources: Garlic, onions, leeks, asparagus, green bananas, oats, barley, flaxseed, chia seeds, chicory root, Jerusalem artichokes.

POSTBIOTICS — THE COMPOUNDS

Postbiotics, kimchi and sauerkraut are the beneficial compounds produced when probiotics ferment prebiotic fiber. You do not eat them directly; your body produces them. In skincare, postbiotics strengthen the skin barrier, reduce transepidermal water loss, calm inflammatory pathways, and disrupt acne-related biofilms.

You support postbiotic production by pairing probiotics with prebiotics: yogurt with berries and chia seeds, kefir with oats, kimchi with brown rice.

When you combine prebiotics with probiotics, you amplify the benefit. The sum is greater than its parts.

Why Lactobacillus Deserves Its Own Conversation

Lactobacillus is one of the most studied probiotic genera in both gut health and dermatology — and for good reason! In the gut, it improves intestinal barrier integrity, reduces systemic inflammation, and modulates immune responses. On the skin, Lactobacillus ferments and lysates reduce redness, improve hydration, enhance barrier proteins, and support balanced microbial communities. This is in the Cocoa Barrier Cream to help with your skin barrier. 

Topical products containing Lactobacillus-derived ingredients can help calm acne-prone and rosacea-prone skin while improving overall skin resilience.

Skin Conditions That Benefit from Microbiome Support

At Bergen Dermatology, microbiome-focused strategies are part of how we approach inflammatory skin conditions that respond particularly well to gut and microbiome support. I truly love to empower and educate patients on how their nutrition impacts their skin. When we improve gut diversity and reduce systemic inflammation, we consistently see improved lesion counts, reduced redness, and better tolerance to topical treatments.

Anti-Inflammatory Foods That Support Skin Health

Beyond probiotic and prebiotic foods, the following have strong evidence for reducing the oxidative stress and inflammatory pathways that drive acne and premature aging:

• Fatty fish such as salmon and sardines
• Extra virgin olive oil
• Leafy greens
• Blueberries
• Green tea
• Turmeric
• Ginger

These are not trendy superfoods. They are foods with decades of evidence behind them and they belong on your plate as much as a good serum belongs on your skin.

What Disrupts the Gut-Skin Axis

Just as important as what supports the gut-skin axis is what breaks it down. The biggest disruptors we see clinically:

• Highly processed foods
• Excess refined sugar
• Ultra-processed seed oils
• Frequent unnecessary antibiotic use
• Chronic stress
• Sleep deprivation

All of these contribute to dysbiosis and dysbiosis contributes to the inflammatory skin conditions that bring patients into our clinic.

The Bottom Line

Your skin does not exist in isolation. It is connected to everything: your gut, your immune system, your stress levels, your sleep, your diet. When we treat skin conditions at Bergen Dermatology, we look at the whole system. Not just the surface.