In my last post, I discussed the “gut-brain-skin” axis theory—which suggests that what we eat, what lives in our gut, our mood and the health of our skin are all intimately related.

In the 1930’s it was popular to treat acne internally with the use of L. acidophilus and L. acidophilus –fermented milk products, though there was little research into this approach and interest waned despite its apparent effectiveness.  More recently, studies have shown that many patients with acne vulgaris and acne rosacea have low stomach acid (hypochlorhydria), small intestinal bacterial overgrowth (SIBO) and disturbances in normal gastrointestinal microflora.  In 1961, a physician by the name of Robert Silver conducted a study in which he orally administered L. acidophilus and L. bulgaricus—and showed that 80% of the 300 patients studied had some degree of clinical improvement in their acne.  Since that time, advances in molecular biology have shown that probiotics can regulate the release of inflammatory cytokines within the skin, including substance P—which may be a primary mediator of inflammation and sebum production in acne.  Both Bifidobacterium longum and Lactobacillus paracasei can reduce the inflammation mediated by substance P.  Certain bacterial strains such as Streptococcus salivarius secrete substances with antimicrobial properties, which limit the growth of Propionibacterium acnes, thought to play a major role in the development of acne lesions.

Probiotics may also act in the “gut-brain-skin” axis via glycemic control.  New research shows that gut flora contribute to glucose tolerance—for example, Bifidobacterium lactis improved fasting insulin levels and glucose turnover rates.

Of note, milk may play a role in acne development via insulin-like growth factor 1 (IGF-1), which is absorbed across colonic mucosa but reduced in fermented dairy products.  Thus, avoidance of milk (and substituting fermented milk products such as cheese, yogurt, kefir) may help improve acne in some patients.

More research is forthcoming with regard to the specific molecular mechanisms at play, but so far the evidence is quite compelling that dietary changes and modification of gut microflora can have an impact on skin inflammation and acne.

TIP:  A topically applied yogurt mask (which contains the lactic acid bacteria Streptococcus thermophilus) can increase ceramide production—which have activity against P. acnes and a direct anti-inflammatory effect.

BOTTOM LINE:  Acne may respond to changes in diet (increased fermented dairy consumption and nutrient rich foods; reduce sugar, carbohydrates, processed foods) as a result of normalization of gut microbiota.


PROBIOTICS and your mood

How does diet affect our mood?

Some scientists believe that what we eat encourages certain types of microbes to thrive in our gastrointestinal tract, and these microbes can affect our mood, skin, weight, immune system and risk for chronic diseases such as autoimmune disease and cancer.  The “gut-brain-skin” theory has been around since 1930 when dermatologists John H. Stokes and Donald M. Pillsbury noted that skin conditions such as acne are often associated with mood disorders and gastrointestinal disturbances—which increase gut permeability and lead to systemic inflammation.

Since the 1930’s, animal and human research has supported the idea that mental health disorders are frequently associated with low levels of Lactobacillus and Bifidobacterium, an omega-3 deficient diet and low stomach acid (hypochlorhydria).  The microflora of our GI tract is intimately involved in gut permeability—which when breached can allow foreign proteins across the gut’s barrier and trigger immune reactions and systemic inflammation, leading to inflammatory acne lesions and depressed mood/ anxiety.  In fact, it has been shown in animal studies that a circulating endotoxin, E. coli lipopolysaccharide (LPS)—which is usually not present in blood but can be if the intestinal barrier is not working proprerly—can itself produce depression-like behavior in animals.  In addition, if the gut is not populated with beneficial microbes (or they’re not in the appropriate location), small intestinal bacterial overgrowth (SIBO) can result—which has been associated with fibromyalgia, chronic fatigue syndrome, constipation, depression and anxiety.  One cause of this disturbance of normal gut microflora is hypochlorhydria, sometimes caused by medication (e.g. proton pump inhibitors, H2 blockers), hypothyroidism, atrophic gastritis, naturally occurring with age, or other less common conditions such as tumors, mucolipidosis or pellagra (niacin deficiency).

Probiotics including Lactobacillus and Bifidobacterium species have been shown to limit systemic oxidative stress and reduce inflammatory cytokines in various tissues of the body, inhibit the release of substance P and decrease monoamine oxidase activity—resulting in decreased anxiety- like behavior in animals.  Stress hormones and substance P are known to cause anxiety, depression and aggression.  The addition of probiotics to lab animal feed increases tissue levels of omega-3 fatty acids, peripheral tryptophan levels, and increase serotonin and dopamine turnover in the frontal cortex and limbic system—which can have a positive impact mental health.

This “gut-brain-skin” theory also works in reverse—stress and anxiety can adversely affect the gut microflora, as can a poor diet.  In the Western diet, which is typically high in fat, sugar as well as processed foods, the loss of Bifidobacteria can lead to increased intestinal permeability, encroachment of LPS endotoxins through the intestinal barrier, low grade inflammation, insulin resistance and mood disorders.  As we learn more about the prebiotic-probiotic-mood relationship, perhaps physicians will consider treating mood disorders with a prescription for a certain diet or HCl supplement, as opposed to a psychopharmaceutical drug.

BOTTOM LINE:  Prebiotics and probiotics can have a positive impact on mood.  Anyone who wishes to lead a healthier lifestyle and promote a normal mood state should eat a healthy diet and consider consuming fermented dairy products daily (see PROBIOTICS overview).