It is yet another important aspect of the so-called “gut-skin axis,” i.e., how the gut can be a major influence on skin health via the fatty acid, butyrate or butyric acid. Of course, if you’ve been following my Wheat Belly discussions, you already know that wheat and grain elimination improves skin health and appearance dramatically. But you can take it further with natural strategies that provide butyrate via the gut-skin axis.
A number of observations have hinted at this unique relationship between the gut and skin over the years:
- People with irritable bowel syndrome and inflammatory bowel diseases, ulcerative colitis and Crohn’s disease, frequently experience skin rashes, including atopic dermatitis, vitiligo, and psoriasis.
- Children with atopic dermatitis and asthma (that often go hand-in-hand) have disrupted gastrointestinal (GI) microbiomes, lacking microbial species that produce butyrate.
- People with skin rashes tend to have skin microbiomes dominated by the pathogen, Staphylococcus aureus, and lacking the normal (“commensal”) inhabitant, Staphylococcus epidermidis. S. epidermidis is a producer of the fatty acid, butyrate. Butyrate, produced by S. epidermidis, as well as that produced by GI microbes, suppresses S. aureus.
- Healthy skin is mildly acidic with a pH of around 4.0-5.0, largely due to butyrate (butyric acid). Diseased skin is less acidic or even alkaline.
- Increased ingestion and/or microbial production of butyrate thickens the epidermal layer of skin, forming a more effective barrier against injury and dryness.
- Butyrate, along with omega-3 fatty acids, EPA and DHA, are inhibitors of the intestinal enzyme, intestinal alkaline phosphatase, an enzyme that helps to deactivate the lipopolysaccharide (LPS) endotoxin released by fecal microbes. Recall that, by my estimation, half the U.S. population has fecal microbial species colonizing the 24-feet of small intestine, i.e., small intestinal bacterial overgrowth, SIBO, that yields lots of LPS endotoxin that enters the bloodstream, “endotoxemia,” that, in turn, explains how gut microbes can be experienced as brain effects such as depression, anxiety, and cognitive decline; muscle and joint effects such as fibromyalgia and rheumatoid arthritis; metabolic effects such as obesity and type 2 diabetes; cardiovascular effects such as coronary disease, atrial fibrillation, congestive heart failure, and hypertension; skin effects such as psoriasis, eczema, or rosacea. Butyrate also increases the expression of proteins that are components of the intestinal barrier. For these and other reasons, increased butyrate thereby decreases endotoxemia.
The lack of MACs and fermented foods and the dysbiosis/SIBO created by modern dietary habits due to misguided dietary advice and exploitative food company practices set you up to have skin rashes due to the lack of butyrate and less acidic skin pH. Adverse skin effects are further encouraged due to loss of butyrate-producing GI microbes in dysbiosis and SIBO. Worse, it is not uncommon for people suffering from skin rashes to have a preponderance of intestinal mucus-consuming species in their GI tracts, consuming and thinning the protective intestinal mucus barrier and adding further to deterioration in GI health, increased endotoxemia, and worsening metabolic health.
There are a number of habits that you should consider adopting that benefit skin health, as well as providing numerous other health benefits:
- Include plenty of fermented foods in your diet—Microbes used to make kefir, kimchi, sauerkraut, etc. (e.g., Leuconostoc mesenteroides, Pediococcus pentosaceus, Bacillus coagulans, etc.) do not themselves produce butyrate. But they produce metabolites such as lactate that feed butyrate-producing species (“cross-feeding”) such as Faecalibacterium prausnitzii and Akkermansia muciniphila. Intestinal and blood levels of butyrate are therefore higher in people who include plenty of fermented foods in their diet, thereby contributing to acidification of the skin.
- Including microbiota-accessible carbohydrates, MACs, such as prebiotic fibers and polysaccharides from onions, garlic, shallots, root vegetables, legumes, hyaluronic acid, mushrooms, etc. bloom butyrate-producing species. Inulin and fructooligosaccharides, FOS, are especially important here, obtained from root vegetables, as well as commercial powders for convenience. Butyrate production is increased, endotoxemia is decreased, skin pH is acidified.
- Minimize reliance on soaps and other toiletries that remove sebum and weaken the epithelial barrier, encouraging growth of microbes such as S. aureus.
While it is best to adopt the above practices that increase microbial butyrate production, you can further augment butyrate by ingesting it directly. This is not as helpful as the microbial sources, as microbes produce butyrate around-the-clock, as compared to episodic dietary intake. Nonetheless, it can help a little to ingest foods rich in butyrate, especially butter, ghee, cheeses, and other dairy products including our L. reuteri high-fat yogurt. (Note that low-fat dairy products therefore do not reduce endotoxemia—yet another item to add to the long list of blunders yielded by low-fat dietary advice).