“Gut health” gets credit for a lot these days, and for many medical conditions there is a clear connection. But is gut health linked to acne and other skin problems? Can fixing gut “dysbiosis” help with clear skin?

Summary

• Science says yes, there is a connection between gut health and skin health.
• Most important, the gut microbiome is closely linked to the strength of your immune system. An imbalance of good and bad bacteria in the gut may cause systemic inflammation, contributing to acne outbreaks.
• Probiotics are considered the first line of treatment for dysbiosis (an imbalanced gut), and some good bacteria appear to be more beneficial than others when it comes to skin health.

Most people think of the stomach when they hear the word "gut", but your gastrointestinal system consists of many organs other than the stomach. Components of the gut truly include your:

• Mouth
• Esophagus
• Stomach
• Small intestine (ileum, jejunum, and duodenum)
• Large intestine
• Colon
• Rectum

The gut is home to trillions of bacteria, viruses, and other microorganisms that are collectively referred to as the gut microbiome. In fact, 50 percent of all cells in the human body reside in this microbiome! 

It’s staggering. 

Due to the high acidity of your small intestine and stomach, your colon contains most of the microorganisms that influence metabolic, nutritional, cell-signaling, and immune-specific activity in the human body.

Gut Health And Skin

Why is a healthy gut microbiome important to general health, and exactly how does gut health affect skin health? 

Responsible for a wide variety of essential physiological functions, the gut microbiome synthesizes vitamin K, all B vitamins and also performs the following:

• Breaks down and digests starches, gums, cellulose, and other complex polysaccharides that would otherwise remain indigestible
• Supports amino acid synthesis
• Chemically transforms bile into a substance that promotes cholesterol and glucose metabolism
• Helps produce short-chain fatty acids and anti-inflammatory metabolites that "good" colonic bacteria consume
• Benefits communication pathways that are involved with the normal functioning of the vagus nerve, the HPA axis, and the manufacturing of neurotransmitters and hormones mediating appetite, sleep, and mood (like serotonin, dopamine, leptin, ghrelin, and cortisol)

When the gut microbiota is balanced––that is, there are more "good" bacteria populations in the gut than "bad" (illness-causing) bacteria––the ability of the immune system to fight off inflammation is significantly strengthened. 

A healthy gut microbiome represses the colonization of infectious bacteria or viruses by providing a barrier composed of antimicrobial compounds. This barrier stops pathogens from depleting nutrients needed for "good" bacteria growth.

Gut Health and Dysbiosis

Dysbiosis is a condition in which the gut microbiome is dominated by populations of bad bacteria. 

Research into the effects dysbiosis has on human health suggests the following medical conditions have all been associated with dysbiosis:

• Inflammatory bowel disease (IBD)
• Type I and Type II diabetes (diabetes mellitus)
• Autism spectrum disorders
• Colorectal cancer
• Certain allergy disorders, such as asthma, atopic dermatitis, and allergic rhinitis

Examining the gut-skin connection is one of the more popular topics of dermatological and gastrointestinal studies. 

Moreover, emerging study results are definitively showing that the correlation between gut health and skin health is a positive one.

Does Gut Health Affect Skin?

The gut microbiome can impact skin health primarily because gut bacteria (commensals) have such a strong influence on the immune system. 

Specific metabolites (substances produced through metabolism) and gut microbes support the buildup of T cells to provide an anti-inflammatory response to infections and wounds. T cells are white blood cells that identify and attack foreign pathogens (bacteria, viruses, parasites) in the body.

Studies show that when the gut microbiome isn't sufficiently balanced, intestinal bacteria and metabolites can infiltrate the bloodstream, accumulate in one or more layers of skin and cause skin irritations. 

In fact, the gut bacteria DNA of patients with psoriasis is the same DNA found in samples of their plasma! 

Moreover, evidence is emerging that the skin's own microbiome (yes, you’ve got beneficial creepy crawlies all over you) is directly influenced by the condition of the gut microbiome!

Specifically, short-chain fatty acids produced by fermentation of fiber in the GI system may play a critical role in determining the appearance and/or severity of skin conditions such as acne, psoriasis, certain infections, and eczema.

Gut Health and Acne

Evidence supporting the influence of the gut microbiome on acne is accumulating, with most research results indicating the involvement of one pathway in particular, called the mTOR pathway.

The mTOR pathway is a cell signaling pathway that all cells use to regulate their metabolism and growth. Without the existence of the mTOR pathway, cells could not survive. This pathway allows cells to access proteins and lipids necessary for energy while preventing apoptotic (naturally programmed cell death) pathways from quickly killing trillions of cells in the body.

Scientists think the mTOR pathway aggravates acne outbreaks due to DNA and chemical interactions between gut microbiota and the mTOR pathway. 

Since the balance between good and bad gut bacteria is easily disrupted by excessive consumption of dairy products, saturated fats, and refined carbohydrates, dermatologists suggest that the Western diet is a leading precipitator and amplifier of acne.

High-fat diets not only increase levels of lipopolysaccharide (LPS) in the gut but also reduce populations of good bacteria in the GI tract. One of the leading causes of low-grade, systemic inflammation, LPS contains a substance called Lipid A that enhances the inflammatory properties of lipopolysaccharide. In addition, LPS interferes with the ability of colonic microbiota to stop the release of acne-inducing cytokines.

The Gut-Brain-Skin Theory: Do Mental States Influence the Gut-Skin Connection?

Originally developed in 1930 by Stokes and Pillsbury, the gut-brain-skin theory proposed the possibility that depression, anxiety, stress, and other mental health issues disrupt the normal balance of gut microbiota. In particular, Stokes and Pillsbury thought this gut-brain-skin relationship was a primary cause of acne outbreaks due to mental illness reducing the amount of gastric acid in the stomach.

Woah.

Hypochlorida (insufficient gastric acid) may force "bad" bacteria to migrate to an area of the small intestine where this bacteria can disrupt gut health. Systemic inflammation aggravated by a stressed gut microbiome has been found to lead to skin inflammation associated with acne, dermatitis, eczema, and rosacea.

Further evidence supporting the interaction between the brain and gut microbiota comes from investigations involving good and bad gut bacteria competing to influence the CNS through the immune system, neurotransmitters, and stress hormones (cortisol and adrenaline).

Probiotics, Gut Health, and Skincare

Containing mostly live bacteria and some yeasts, probiotics exert beneficial effects in the gut by restoring the normal balance between good bacteria and bad bacteria. 

There are seven primary bacterial strains often found in probiotic supplements:

• Bacillus

• Escherichia

• Lactobacillus

• Saccharomyces

• Enterococcus

• Bifidobacterium

• Streptococcus

Consuming fermented foods that contain probiotic bacteria won't always improve gut health dramatically because food probiotics deteriorate in the small intestine when exposed to bile salts and hydrolytic enzymes. However, some probiotic strains found in yogurt may survive passage through the stomach and into the intestines and colon. 

Probiotic strains most effective at restoring gut and skin health are Lactobacillus (L. bacillus) and Bifidobacterium (B. bifidum).

In clinical studies, L. Bacillus and B. bifidium have been found to moderate inflammatory skin conditions by enhancing the condition of immune system tissues associated with the gut. 

These two bacteria also promote the production of anti-inflammatory cytokines called IL-10 and improve the function of T-cells to help support immune system responses to inflammation.

Probiotics called Streptococcus salivarius and Lactococcus may be able to suppress acne outbreaks by releasing an inhibitory substance in the gut resembling antimicrobial peptides called bacteriocins. Recently, research into topical probiotics discovered that not only did the topical improve the activity of the skin barrier but also increased the production of antimicrobial peptides.

Lactobacillus acidophilus is another type of probiotic bacteria that ferments sugars into lactic acid in the human body. Occurring naturally in the mouth and gastrointestinal tract of humans and mammals, L. acidophilus exhibit probiotic characteristics by attaching themselves to enterocytes to stop harmful pathogens from binding to gut microbiota. In addition, L. acidophilus inhibits the release of pro-inflammatory cytokines responsible for acne and general skin health. 

Gut Health and Skin: The Connection is Real

A wealth of studies have provided clinical evidence proving a direct link between skin inflammation and gut health via moderation of the immune system. Disruption of the gut microbiome could lead to a decline in skin barrier function and skin equilibrium. 

Classified as an endocrine organ, the gut microbiome is known to produce 30 hormone-like substances, cortisol, short-chain fatty acids, and a host of neurotransmitters. Chemicals similar to hormones made within the gut get released into the bloodstream, too, where they can exert minimal to substantial influence on the condition of the skin and other organs.

Consequently, acne can arise from dysbiosis or the combination of dysbiosis and other factors. Probiotic supplements may support the improvement of mild acne, while more severe acne may require multiple treatment protocols that include probiotic supplementation and prescription medications.

The bottom line on gut and skin health is to eat well, support your gut microbiome, and consider all of the factors involved in your skin's health.

References

https://www.racgp.org.au/afp/2017/april/the-gut-microbiome/#ref-1

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566439/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838534/

https://www.frontiersin.org/articles/10.3389/fimmu.2015.00639/full

https://mdpi-res.com/d_attachment/jcm/jcm-08-00987/article_deploy/jcm-08-00987-v2.pdf

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/western-diets

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780801/

https://gutpathogens.biomedcentral.com/articles/10.1186/1757-4749-3-1

https://link.springer.com/article/10.1186/1471-2180-14-189

https://ods.od.nih.gov/factsheets/Probiotics-HealthProfessional/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8439139/#:~:text=Lactobacillus%20acidophilus%28L.%20acidophilus%29%20is%20an%20important%20probiotic%20%2810%29,and%20inhibiting%20the%20production%20of%20proinflammatory%20cytokines%20%2811%29.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916842/