Recovering, supporting, and maintaining healthy gut barrier is one of the key factors in getting and keeping your skin clear.

In the in-depth section I covered how defects in the gut barrier allow toxic substances, like lipopolysaccharides, to leak through the gut wall and enter the systemic circulation. Once in the circulation, these substances cause insulin resistance and systemic inflammation, both of which are linked to acne.

Healthy gut barrier allows nutrients to pass through and keeps toxic substances out of your body.

What is the intestinal barrier

A 2009 review describes it as the most important barrier between what’s inside and outside of you.

The intestinal epithelium is a single-cell layer that constitutes the largest and most important barrier against the external environment.

Groschwitz, K. R. & Hogan, S. P. Intestinal barrier function: molecular regulation and disease pathogenesis. J. Allergy Clin. Immunol. 124, 3–20; quiz 21–2 (2009). https://www.ncbi.nlm.nih.gov/pubmed/19560575

The intestinal barrier consists of:

• Intestinal cells and the substances they secrete (such as mucus and antimicrobial peptides)
• Probiotic bacteria and their metabolic end-products (mainly short-chain fatty acids like butyrate)

Problems in either can result in barrier defects.

Butyrate and butyrate-producing bacteria

Along with the intestinal wall, the intestinal microbiota (i.e. gut bacteria) plays a vital role in maintaining and protecting the gut barrier. Disturbances in the intestinal microbiota almost always weaken the gut barrier and lead to intestinal problems.

Butyrate

Butyrate is a short-chain fatty acid (SCFA) with a crucial role in gut health. Butyrate is produced when probiotic bacteria ferment dietary fiber. The cells lining the intestines use butyrate as energy, and without butyrate, these cells will starve and die. As such, butyrate is critical for the integrity of the gut barrier. It has also been shown to suppress inflammation in the gut and may prevent colon cancer. Finally, butyrate suppresses the growth of pathogenic bacteria in the gut.

Several studies looking at differences in gut microbiota between healthy people and people with diabetes and other metabolic diseases note significantly lower numbers of butyrate-producing bacteria in individuals with these health problems.

Butyrate has a critical role in colonic homeostasis owing to a variety of functions: inhibiting inflammation and carcinogenesis, reinforcing various components of the colonic defense barrier, decreasing oxidative stress, and providing a satiety sensation.

Chiba, M., Tsuji, T., Nakane, K. & Komatsu, M. High Amount of Dietary Fiber Not Harmful But Favorable for Crohn Disease. The Permanente Journal 19,58 (2015). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315379/

A handful of studies shows butyrate supplementation can reduce inflammation and disease activity in inflammatory bowel disease patients.

Similarly, butyrate supplementation has been shown to reduce bloating, gas, constipation and other abdominal issues in irritable bowel syndrome patients.

But don’t run to the health food store to buy butyrate supplements. Butyrate has to be either given as an enema or in a specially coated supplement that doesn’t dissolve in the stomach or small intestine. As far as I know, most commercially-available supplements lack such coating. Without such coating, butyrate from supplements is absorbed in the small intestine and thus unavailable in the large intestine where it’s needed.

The best way to supply butyrate into the large intestine is to support the butyrate-producing bacteria residing there.

Key butyrate-producing probiotics

The following probiotic strains are among the key butyrate-producing strains in the human gut:

• Faecalibacterium prausnitzii
• Roseburia intestinalis
• Butyricicoccus pullicaecorum
• Eubacterium rectale

Studies have shown that people with inflammatory bowel disease often have much lower levels faecalibacterium prausnitzii and butyricicoccus pullicaecorum than individuals with a healthy gut.

Most of the above species aren’t available as commercial probiotics. The good news is that you don’t have supplement with them.

The best way to support butyrate-producing bacteria, and thus increase butyrate production, is to feed them fiber. Fiber restricted diets have been shown to reduce the amount of butyrate and probiotic bacteria in the gut. Similarly, fiber supplemented diets have been demonstrated to boost the total number of healthy bacteria and increase butyrate levels in the colon.

In the supplements part of this section, we’ll talk more about acacia gum, which is a slowly fermenting fiber known to increase butyrate production in the gut. And in the diet part, we’ll talk about resistant starch, a particularly yummy form of starch for butyrate producing bacteria.

Takeaway

The intestinal wall is the most important barrier between you and the outside world. Defects in the intestinal barrier can cause insulin resistance, increases systemic inflammation, and lead to acne.

Fortunately, supporting and maintaining healthy intestinal barrier is not a big challenge. Based on all the research I’ve read, maintaining healthy gut bacteria is the most important factor. For most people, this doesn’t require anything beyond avoiding foods that irritate their gut (can vary from person to person) and feeding the healthy bacteria with acacia gum, resistant starch, and other types of fiber.