The Gut-Skin Axis: What the Science Really Says

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Our skin is often thought of as a mirror of our internal health — and when it comes to the gut, this couldn’t be more true. The concept of the gut-skin axis is gaining attention, not just in wellness circles, but in high-quality scientific research.

In this blog, I’ll break down what the latest science says about how your gut affects your skin, what lifestyle changes can help support a healthy microbiome, and whether supplements like probiotics are truly worth your investment. This topic is part of a larger series I’m currently developing on the science and lifestyle strategies that support healthy skin from within.

Skin Conditions Linked to Gut Health

There’s growing evidence that imbalances in the gut microbiome (dysbiosis) can play a role in common skin conditions:

  • Acne: Gut inflammation may increase systemic inflammation, potentially worsening acne. [1]
  • Rosacea: Studies show a higher prevalence of small intestinal bacterial overgrowth (SIBO) in people with rosacea. [2]
  • Eczema (Atopic Dermatitis): Children with eczema often have less microbial diversity in the gut. [3]
  • Psoriasis: Associations have been found between gut microbiota imbalance and severity of psoriasis. [4]

These findings don’t suggest the gut is the only cause, but they highlight it as a meaningful factor — and a modifiable one.

Lifestyle Changes That Support Gut and Skin Health

Science continues to show that our modern lifestyles — often high in stress, poor-quality sleep, ultra-processed foods, and sedentary habits — can contribute to gut dysbiosis. The reverse is also true: improving these areas can support both gut and skin health.

Here’s what the evidence says:

🧠 Stress

Chronic stress impacts the gut barrier (leading to ‘leaky gut’) and alters the composition of gut bacteria. Mind-body practices such as mindfulness, yoga, and even nature exposure have been shown to improve both stress resilience and gut health. [5]

🍽️ Diet

While there’s no one-size-fits-all diet, research consistently supports a diverse, fibre-rich eating pattern for gut health:

  • Aim for 30+ different plant foods per week, including fruits, vegetables, nuts, seeds, legumes, and whole grains. (Herbs and spices count too!) This target, made popular by the American Gut Project, has been linked to greater microbial diversity. [6]
  • Include fermented foods: Yogurt, kefir, sauerkraut, kimchi, tempeh, and miso contain live beneficial microbes. In a 2021 study published in Cell, participants who ate 6 servings per day of fermented foods for 10 weeks saw an increase in microbiome diversity and a reduction in inflammatory markers. [7] While this amount was part of a closely monitored clinical trial, starting with just 1–2 servings daily or a few times a week is a realistic goal.
  • If you are new to fermented foods, go slowly. Start with a tablespoon of sauerkraut or half a glass of kefir and gradually build up. If you have a history of histamine intolerance, autoimmune disease, or significant gut issues (like bloating, SIBO, or IBS), consider working with a qualified practitioner before making major dietary changes.

😴 Sleep

Poor sleep can negatively affect the gut microbiome — and vice versa. Aim for 7–9 hours of consistent, high-quality sleep per night. [8]

🏃‍♀️ Exercise

Moderate, regular exercise supports gut microbial diversity. Even brisk walking for 30 minutes daily has benefits. [9]

❤️ Emotional Wellbeing

Our emotions and gut are deeply interconnected. Practices that support mood (such as journaling, social connection, therapy) may also support gut-brain-skin health.

Nutrition: What to Focus On

Rather than prescribing one “perfect” diet, I advise a focus on diversity, fibre, and fermented foods, and limiting ultra-processed, high-sugar foods.

🍲 Plant diversity counts — and it includes herbs, spices, nuts, and legumes.

Increasing prebiotic fibre (from foods like oats, garlic, onions, bananas, and lentils) helps to feed your beneficial bacteria.

Fermented foods are particularly powerful — and for many people, accessible. Aim to include a few portions weekly, from foods like:

  • Natural live yogurt (dairy or non-dairy)
  • Kefir
  • Kimchi
  • Sauerkraut
  • Tempeh
  • Miso

Does Intermittent Fasting Help?

Emerging evidence suggests that intermittent fasting (IF) may support gut health by encouraging microbial resilience and regulating inflammation. [10]

However, it’s not suitable for everyone — including people with a history of eating disorders, certain chronic diseases, pregnant or breastfeeding women, and often those in active reproductive years (especially if not aligned with hormonal fluctuations).

It’s best approached cautiously, with medical guidance. I’ll explore this in more detail in an upcoming blog.

Probiotic Supplements: What Does the Evidence Say?

There’s significant interest in probiotics — but not all supplements are created equal.

Evidence suggests that strain-specific probiotics may help certain conditions (e.g. Lactobacillus rhamnosus GG for eczema in children, or Bifidobacterium infantis for IBS). However, broad-spectrum or general blends may not always deliver targeted benefits, and in some cases may even crowd out native beneficial strains. [11]

⚠️ Not all strains of Lactobacillus or Bifidobacterium are the same.

For example, Lactobacillus acidophilus has multiple subspecies — some have immunomodulatory effects, while others have not been shown to offer benefits. This is why professional guidance or strain-specific research is recommended before purchasing a probiotic.

More is not always better. Look for products that:

  • Identify the specific strain (not just the genus/species).
  • Indicate the colony-forming units (CFU) count and expiry.
  • Have clinical studies to back their claims.
  • Are preferably stored and packaged for stability (e.g., blister packs, cold storage if required)

Final Thoughts

Our gut and skin are deeply interconnected. From reducing stress and sleeping better, to increasing plant and fermented food intake, small shifts in your lifestyle can have a profound impact.

While probiotic supplements can be helpful in specific cases, a food-first, diverse approach remains the cornerstone of gut health — and, in turn, healthy skin.

This topic will form part of a broader resource I’m currently developing, which explores the lifestyle and medical science behind skin health in more depth. If you’ve found this post helpful, stay tuned.

Want to build a complete inside-out routine for skin health?
Check out my evidence-based morning skincare routine here to complement the lifestyle changes discussed above.

References

  1. Deng Y et al., “The microbiome and acne: a new frontier in acne research,” J Dermatol Sci. 2018. PubMed
  2. Parodi A et al., “Small intestinal bacterial overgrowth in rosacea,” Clin Gastroenterol Hepatol. 2008. PubMed
  3. West CE et al., “Gut microbiome and allergic disease: new perspectives,” Curr Opin Allergy Clin Immunol. 2015. PubMed
  4. Codoner FM et al., “Gut microbial composition in patients with psoriasis,” Sci Rep. 2018. PubMed
  5. Chrousos GP. “Stress and disorders of the stress system,” Nat Rev Endocrinol. 2009. PubMed
  6. McDonald D et al., “American Gut: an open platform for citizen science,” mSystems. 2018. PubMed
  7. Wastyk HC et al., “Gut-microbiota-targeted diets modulate human immune status,” Cell. 2021. PubMed
  8. Benedict C et al., “Gut microbiota and sleep-wake regulation,” Curr Opin Clin Nutr Metab Care. 2020. PubMed
  9. Allen JM et al., “Exercise alters gut microbiota composition and function,” J Appl Physiol. 2018. PubMed
  10. Thaiss CA et al., “The microbiome and innate immunity,” Nature. 2016. PubMed
  11. Ouwehand AC et al., “Probiotic and other functional microbes: from markets to mechanisms,” Curr Opin Biotechnol. 2018. PubMed