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.



The concept of probiotics—live microorganisms which when administered in adequate amounts confer a health benefit to the host—is not new.  It has only been recently that the scientific community has taken a closer look at probiotics and their practical applications.  There are too many areas under investigation to discuss, so here’s a brief list of possible uses of probiotics in the medical arena (the items at the top of the list have more supporting evidence than the more speculative/ uncertain items toward the end):

• Infectious diarrhea (antibiotic associated, rotavirus, c. diff, traveller’s)

• Irritable Bowel Syndrome (IBS)

• Lactose intolerance

• Hyperlipidemia

• Small intestinal bacterial overgrowth (post op gastric bypass or Crohn’s Disease)

• Helicobater pylori

• Bacterial vaginosis

• Necrotizing Enterocolitis (NEC) in pre-term infants

• Colon cancer (prevention and possibly treatment)

• Metabolic syndrome (obesity, hyperlipidemia, hypertension)—and thus type 2 diabetes and coronary artery disease

• Dermatologic conditions: acne, rosacea

• Inflammatory Bowel Disease (IBD)–Crohn’s Disease and Ulcerative Colitis

• Prevention of the common cold

• Hypertension (high blood pressure)

• Hepatic encephalopathy (due to liver disease)

• Nursing Home Care: decreased febrile episodes, reduced constipation and diarrhea, reduced MRSA

• Autoimmune disorders—such as multiple sclerosis, Type 1 Diabetes (still under investigation; demonstrated in mice)

• Allergic conditions—food allergies, atopic dermatitis (still under investigation)

• Anxiety, depression (still under investigation)

Though it might seem like wishful thinking that these bacteria can be so helpful, it makes absolute sense.  Humans have evolved with these bacteria living symbiotically inside our guts, which have come to serve as an organ within an organ—aiding digestion, improving nutrient absorption, warding off infection, regulating gut permeability, and modulating the host’s immune system.   As a result of our modern industrialized society, practices such as surgical childbirth, use of pasteurized food products, synthetically supplemented food, cleaner homes, overuse of antibiotics, etc. have affected the microenvironments on our skin and in our gastrointestinal tract.  This may very well be contributing to the surge in modern diseases such as diabetes, allergies and autoimmune disorders that we are currently witnessing.

Note:  the relationship between host and gut microflora is extremely complex and the strains of bacteria studied for the above conditions are very specific.  Much of the research thus far has investigated Lactobacillus and Bifidobacterium species.   If you were interested in incorporating probiotics in your daily life, you may consider adding fermented milk products (such as yogurt or kefir with live active cultures) to your diet.   These usually contain many beneficial strains of bacteria including L. acidophilus, B. bifidus, S. thermophilus, and are generally regarded as safe.

BOTTOM LINE:  We have been big yogurt fans for years, but have added homemade kefir to our diet.   Making your own kefir is very simple and has no added sugars–you can flavor with banana & strawberry or other fruit in a smoothie.  Many websites walk you through the process and have great tips & videos, including: and .  There are also many online sites where individuals offer kefir grains for free–look for a local donor.  Tips:  avoid using any metal(spoons, strainers) and avoid ultra- pasteurized milk (use pasteurized milk instead).