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08 Jun 2021
Gut health and skin health have been linked as far back as the early 20th century1. This article will look at current understanding behind this link, especially the link between gut health and acne, and the role probiotics can play in this relationship.
Teenagers are not the only age group affected by pesky, painful spots and breakouts, as acne is a common complaint amongst adults too. Acne is caused by inflammation of the skin, and particularly affects the sebaceous glands which produce sebum, the skin’s natural oil that keeps it lubricated. Excessive sebum and dead skin cells block skin follicles (appearing as blackheads). These blocked pores are breeding grounds for further infection and inflammation. Spots develop as papules (red bumps) and pustules (whiteheads). Although there are various factors that may trigger acne including hormonal, dietary and environmental factors, the impact of gut health should also be a major consideration.
A healthy gut is largely influenced by the health of the collection of microbes that live in our gut, known as the gut microbiome. The gut microbiome not only affects gut health locally but also has far-reaching effects around the body. It has been implicated in many common skin disorders such as eczema, psoriasis and acne2. To learn more about how probiotics can help with eczema, health professionals can read this article on the Probiotic Professionals site: Probiotics for Eczema.
The gut can influence skin health through what is referred to as the gut-skin axis3. As 70% of our immune cells are found in the gut, our gut microbes can affect the function of immune cells. Ideally this results in an increase in the production of anti-inflammatory messengers (cytokines) and a reduction of the levels of pro-inflammatory cytokines. However, dysbiosis, an imbalance between friendly and more harmful bacteria in the gut, is frequently present in acne4 and can have negative effects on the immune responses. To learn more, you may like to read the article What is Dysbiosis?
In response to dysbiosis, inflammation or infection in the gut, the gaps between the cells lining the gut become larger, causing what is known as “leaky gut”. Beneficial gut bacteria, known as probiotics, inhibit the growth of harmful bacteria, or pathogens, and strengthen the gut wall lining5. But when overgrowths of pathogens damage the gut wall, the contents of the gut leak through this abnormally permeable lining, and can stimulate an immune cell response, triggering inflammation in the body which may contribute to the development of acne6. Bacterial by-products can also pass through these gaps in the gut wall lining, through the bloodstream to the skin3 where they can dry and harden the skin7.
Like the gut, the skin is colonised by its own collection of microbes called the skin microbiome. Common bacteria normally found on the skin include Staphylococci, Corynebacteria, Propionibacterium, Brevibacterium and Micrococci8. The skin microbiome composition varies from person to person based on factors such as age, gender and environment.
Colonisation of the skin with the bacteria Propionibacterium acnes is associated with acne8 and can trigger an inflammatory reaction. The first line treatment for acne vulgaris is antibiotics. Unfortunately, there has been an increase in antibiotic resistant strains of Propionibacterium acnes in recent years9 and antibiotics may cause unpleasant side effects. Those who suffer with acne may find themselves looking for alternative options such as probiotics to help manage their acne, or to ameliorate the side effects of antibiotic medication – read more about this below.
There is a growing interest in the use of probiotics for acne and other skin conditions, but how might they help? Let’s look at the different ways in which they might have a benefit.
Reduce inflammation – Acne is an inflammatory condition, and Lactobacilli and Bifidobacteria strains have been shown to reduce the release of pro-inflammatory cytokines, TNF- α, IL-6 and IL-8 and increase the release of anti-inflammatory cytokines, IL-1010,11,12.
Reduce oxidative stress - The body naturally produces what are called free radicals as a result of metabolic processes in the body. Antioxidants that we consume in our diets, for example in brightly coloured fruit and vegetables, counteract these free radicals. However, there is often an imbalance with too many free radicals produced and not enough antioxidants to counteract their effects, and this is called oxidative stress. This excess of free radicals contributes to inflammation. In acne, there is an increase in oxidative stress and markers of oxidative stress such as hydroperoxide. These markers of oxidative stress including hydroperoxide have also been reduced by specific probiotics strains11.
Rebalance gut dysbiosis – Probiotic supplementation can rebalance the gut microbiome by boosting the levels of beneficial bacteria and inhibiting the growth of more harmful bacteria. Find out more by reading All about the microbiome.
Inhibit pathogenic bacteria on the skin – Natural bacterial inhabitants of the skin include Staphylococcus epidermidis and Streptococcus salivarius, both of which can inhibit the growth of Propionibacterium acnes13. Although currently these probiotic strains are not available for skin care, the pharmaceutical company, Bayer announced their plans to develop a natural skincare range containing Staphylococcus epidermidis in the near future14.
Maintain gut barrier integrity – Increased intestinal permeability, otherwise known as “leaky gut”, can contribute to the development of acne2. Probiotics can reinforce the lining of the gut wall and inhibit the growth of pathogens that damage the delicate gut lining.
Promote gut health and regulate bowel movements – Individuals with acne are more likely to suffer with digestive issues such as constipation, bloating and acid reflux15. Dysbiosis and “leaky gut” are present more frequently in those suffering with constipation compared with healthy individuals16, both of which may contribute to the development of acne. To learn more, health professionals can read this article on the Professionals site: Probiotics for constipation.
Help to manage the effects of stress – There is a link between the mental health, the gut, and skin health, known as the gut-skin-brain axis. Mental health issues such as anxiety and depression occur frequently alongside chronic skin conditions such as acne17, and stress is an important trigger of acne18. In the stress response, cortisol, our main stress hormone, is released into the bloodstream. It can bind to receptors in the skin resulting in increased sebum production and inflammation. Stress can also trigger acne indirectly by causing dysbiosis in the gut19. This upset to the gut microbiome can increase intestinal permeability causing “leaky gut” leading to inflammation2. Both dysbiosis and “leaky gut” can contribute to the development of acne and can be improved by probiotics as discussed above. To learn more about the relationship between the gut and mental health, read this article: The gut-brain axis and probiotics.
Currently, there are few clinical trials which directly assess the effects of specific strains of probiotics on skin health. However, there are several clinically researched probiotic strains that may help by addressing some of the triggers for acne.
Bifidobacterium lactis HN019 can help address gut-related triggers of acne by helping to improve the health of the gut microbiome, reduce inflammation and alleviate constipation.
Health professionals can visit the Probiotics Database to learn more about Bifidobacterium lactis HN019.
Health professionals can visit the Probiotics Database to learn more about Lactobacillus acidophilus NCFM ®.
Although they are often prescribed to treat persistent acne, antibiotics can deplete the natural friendly bacteria living in the gut resulting in dysbiosis and inflammation24, both potential contributing factors in the development of acne. To help support the gut when taking antibiotics, consider a probiotic supplement researched for use during and after antibiotic therapy such as Lactobacillus acidophilus NCFM® which has been shown to restore balance in the gut microbiome after antibiotic treatment.
To learn more about protecting the gut when taking antibiotics, read this article about taking probiotics with antibiotics.
In recent years, topical probiotics have become popular under the premise that applying probiotics directly to the skin will positively affect the local skin microbiome. Whilst to date there have not been many clinical trials looking at topical probiotics for skin conditions, research so far suggests that they may prevent growth of harmful bacteria implicated in acne such as Propionibacterium acnes6.
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