What does your face say about your gut? The Microbiome and Acne
Many people have experienced annoying pimples or even full-blown acne first hand. Acne is one of the most common skin disorders and cannot be hidden as it is literally written in your face. You have probably heard us talk about the gut-brain axis before. But did you know that there is also a gut-skin axis? Let’s explore, how our gut microbes affect our skin and the implications for treating acne in a healthier way.
Factors contributing to acne
Acne is a chronic inflammatory skin disease that can be caused by a multitude of different factors like genes, metabolism, hormones, as well as psychological aspects like stress [1, 2]. Some risk factors include age, family history, BMI and skin type . It most often starts in adolescence due to changing hormone levels and increased sebum production . Interestingly, while acne is more prevalent in men during adolescence, in adulthood it is more common in women . The underlying reasons have not been studied yet .
The fact that acne is hardly found in non-westernized societies shows, that not just genetic, but also lifestyle and environmental factors must be at play. 
Another factor is incorrectly cleansing the skin: Irritating or strongly degreasing ingredients in cleansing products can attack the skin's protective layer. The same applies to excessive washing, which makes the skin more susceptible to germs and irritation.
The bacterium Cutibacterium acnes is most commonly ‘blamed’ for the development of acne. However, studies have shown that there are different types of C. acnes, which influence the skin differently and can also act as commensal/neutral bacteria. C. acnes is therefore an exacerbating rather than acne-causing factor. Also, it can form biofilms (seen more often in acne lesions than healthy skin), which can make them resistant to antibiotics. 
The gut-acne connection
Several studies show differences in the intestinal microbiota in healthy people vs. those with acne. Intestinal and skin microbiota work together to establish the right immune homeostasis for the skin. The gut is influencing skin health through modulating inflammatory processes. Intestinal dysbiosis can lead to ‘leaky gut’ which can increase systemic inflammation and thereby contribute to the development or aggravation of acne. 
The role of probiotics
As standard acne treatments are aggressive and often resort to antibiotics – which are disturbing microbial balance even further and can lead to antibiotic resistance – other ways of treatment are needed. Due to the importance of probiotics for gut health, their role is being researched with oral and topical application for skin conditions as well. Studies about topical use, however, are still scarce. Probiotics have been shown to change the gut’s microbial composition, causing an anti-inflammatory response, restoring the gut’s integrity and thereby impacting overall systemic inflammation. 
What to do about acne?
Diet is one of the best ways to impact our gut microbes. Eating an anti-inflammatory diet, meaning focusing on fruits and vegetables, and avoiding processed foods like refined sugar, simple carbohydrates, fatty foods, and dairy, benefits both our gut and skin. [6, 1]
Also, avoid harsh cleansing products and practices that disrupt microbial balance, and only use Microbiome-friendly products that respect the microbiome.
Another factor to consider is stress management. Psychological factors also contribute to the development of acne, and acne itself can lead to psychological problems like depression and low self-esteem.  Treatment approaches should also take the sex and age of patients into account. 
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