The gut-skin axis

The health of the gut microbiome and its impact on wider health has seen an explosion of research, and with the advent of DNA sequencing our understanding of the microbiome and its effects on health is growing. We now understand that the influence of the gut microbiome extends beyond the gut, impacting on distant organs and systems either positively or negatively depending on the composition of microbiota. These wider effects are known to influence skin health, and this article will review the specific influence on acne.

A cardinal function of the microbiota is to maintain intestinal barrier function as well as being important regulators of immune function and inflammatory responses. Changes in composition of the microbiota, leading to a state of microbial imbalance (dysbiosis) are associated with gut barrier dysfunction and permeability, or leaky gut. Dysbiosis can also activate the immune system and lead to inflammation, both at a local gut level and systemically, and this is effect is thought to be modulated by the degree of gut ‘leakiness’.

So how does this influence the skin? Dysbiosis has the potential to negatively impact skin health in numerous ways. The presence of pathogenic bacteria in the gut leads to an accumulation of toxic metabolites, which can access systemic circulation. These metabolites can accumulate in the skin and disrupt skin barrier integrity, reduce skin moisture content and disrupt the production of healthy skin cells (Salem, et al. 2018).

Acne is an inflammatory skin condition and it is now known that inflammation precedes pustule development, even in preclinical micro-comedones (Mochtar, et al. 2018). The concentration of certain inflammatory molecules is also linked to the severity of acne. Both the overgrowth of commensal (normal) bacteria and/or the presence of pathogens can drive inflammation systemically, which leads to increased inflammatory chemicals in the skin and thus driving acne progression (Salem, et al. 2018). This implies that they degree of dysbiosis may also influence the severity of acne in susceptible, however this has not been firmly established as yet.

There is a brain connection involved in acne pathogenesis also, and so rather than just the gut-skin axis, it can be extended to the brain-gut-skin axis. This concept is supported by the frequent association of mood disorders such as anxiety and depression, coupled with gastrointestinal complaints and acne (Kelly, et al. 2015). Psychological stress is thought to drive the gut microbiota to produce different neurotransmitters, or trigger the release of neuro-chemicals such as substance P from the specific intestinal cells. Substance P can trigger inflammatory mediators both locally and within the skin. The net effect is increased leaky gut, leading to inflammation systemically and within the skin.

So what influences negative changes in the gut microbiota? Well as mentioned above stress plays a role. Also well known is that acne is particularly influenced by both high fat and high glycemic carbohydrate diets. This pattern of eating has a strong negative influence on the gut microbiota, which thrives on high fibre, complex carbohydrates and polyphenol rich foods. Other negative influencers include alcohol, food additives, certain medications such as non-steroidal anti-inflammatory drugs and too much or too little exercise.

The dietary pattern that supports a healthy skin has been well established and correlates well to the foods that support a healthy microbiome. For more on the specifics of what to consume to help prevent or manage acne consider booking in for a consultation. If eating all the 'right' foods and avoiding those that drive acne and a dysbiotic microbiome still aren't reducing acne severity, then the factors influencing acne development and severity may be broader. If you you need more support to heal your acne I can support you to make the changes you need to feel better in a way that is manageable and works in your life.

References:

Kelly, J. R., Kennedy, P. J., Cryan, J. F., Dinan, T. G., Clarke, G., & Hyland, N. P. (2015). Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders. Frontiers in cellular neuroscience, 9, 392.

Lee, Y. B., Byun, E. J., & Kim, H. S. (2019). Potential role of the microbiome in acne: a comprehensive review. Journal of clinical medicine, 8(7), 987.

Mochtar, M., Murasmita, A., Irawanto, M. E., Julianto, I., Kariosentono, H., & Waskito, F. (2018). The Difference in Interleukin-19 Serum on Degrees of Acne Vulgaris Severity. International journal of inflammation, 2018.

Salem, I., Ramser, A., Isham, N., & Ghannoum, M. A. (2018). The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Frontiers in microbiology, 9.