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Acne & Small Intestinal Bacterial Overgrowth (SIBO) - Part 3

Your Acne May Be a Reflection of Your Gut Health - Small Intestinal Bacterial Overgrowth SIBO


Small intestinal bacterial overgrowth (SIBO) is exactly what it sounds like: an overgrowth of bacteria in the small intestine. Most of our gut bacteria is found in the large intestine. In SIBO, bacteria from the large intestine migrate into the small intestine and cause all sorts of issues. It turns out that 60% of people who have digestive issues have SIBO![1]

Currently, there are no studies examining the frequency of SIBO in those who suffer with acne. However, it is known that SIBO is ten times more prevalent in those with rosacea (acne rosacea). Once SIBO was addressed in these patients, they saw improvements in their symptoms.[2] This clearly shows that SIBO has an influence on our skin!

SIBO is a form of dysbiosis (imbalanced microbiome), which is one of the causes of systemic inflammation in the body (as discussed in this blog post). Dysbiosis can also be caused by fungal dysbiosis (i.e., Candida overgrowth) or parasitic infections.[1]

Symptoms of SIBO

SIBO is tricky because the symptoms range from being asymptomatic to extreme malabsorption. Many patients experience mild gastrointestinal symptoms such as bloating, diarrhea, abdominal pain, and constipation[3].

The symptoms of SIBO can include:

  • Bloating[3],[4],[5]

  • Diarrhea[3],[4],[5]

  • Fat-soluble vitamin malabsorption[3],[4],[5]

  • Weight loss[3],[4]

  • Constipation[4],[5]

  • Nausea[4],[5]

  • Abdominal pain[4],[5]

  • Heartburn[5]

  • Flatulence[5]

  • Belching[5]

  • Various systemic symptoms (e.g., headache, joint/muscle pain, fatigue)[5]

  • Anxiety and depression[6]

  • Skin conditions such as eczema, rosacea, rashes, and acne[7]

Causes of SIBO

Overall, there are 3 main causes of SIBO which may trigger other conditions that also act as risk factors. These main risk factors include:

  • A compromised Migrating Motor Complex (MMC) - The MMC is an internal function of the small intestine that clears out bacteria and cellular debris from the small intestine and moves everything into the large intestine. The MMC activates during a fasting state – between meals and overnight. If the body is unable to clear the debris out of the small intestine, there is a risk for bacteria overgrowth![8]

  • Structural changes to the small intestine – if there is damage to the small intestine (e.g., adhesions, compression, twists or kinks) or damage after abdominal surgery (e.g., hernia, C-section, endometriosis, etc.), the body’s ability to clear the small intestine is compromised.[8]

  • Immunodeficiency disorder – people who are immunodeficient are prone to bacterial overgrowth[9]

Other conditions that are associated with SIBO risk, although may not be the underlying cause, include:

  • Hypochlorhydria (low stomach acid)- 40% of acne patients have hypochlorhydria. It is hypothesized that the lack of stomach acid may induce the migration of bacteria that would typically reside in the colon toward the further parts of the small intestine, which also disrupts the normal intestinal flora.[10] A major cause of hypochlorhydria is the use of Proton Pump Inhibitor (PPI) medications. Research shows that SIBO is detected in half of patients on a long-term PPI treatment.[11]

  • Food poisoning – food poisoning, also known as post-infectious IBS, affects the Migrating Motor Complex (MMC). This is thought to be the most common cause of SIBO! If you’ve ever had food poisoning, that may have been what triggered your SIBO.

  • Hypothyroid – low thyroid function can affect all cells of the body, including those in the GI tract! If these cells are affected, the MMC can be compromised.[12]

  • Psychological stress – stress encourages bacterial overgrowth, slows down motility and negatively affects the intestinal barrier.[10]

  • Alcohol - Heavy drinking, as well as moderate use of alcohol, is significantly associated with increased SIBO risk.[13]

How can I find out if I have SIBO?

SIBO is typically diagnosed using a breath test. You drink a sugar mixture and breathe into several special vials at certain time increments. A lab will measure the gas mixture in each vial – this represents the gases produced by the microbial overgrowth in the gut. An excess production of hydrogen is associated with diarrhea predominant symptoms or mixed symptoms (diarrhea and constipation), while an excess of methane is associated with constipation.[14]

Therapeutic protocols for SIBO: antimicrobials & diet

Eradicating SIBO is not an easy process and requires a lot of patience and dedication. It is important to work with a qualified practitioner to determine the intricacies of the protocol that will best suite you individually. The general protocol requires the use of antimicrobial intervention to remove the infection, using a prokinetic to support motility, and a restrictive diet to starve the bacterial overgrowth. The restrictive diets are best guided by a qualified practitioner to avoid malnutrition.

SIBO is considered a bacterial infection, and we know that bacteria eat sugars and carbohydrates. Due to this, SIBO diets limit sugars and carbohydrates. Changing your diet short-term is critical in treating dysbiosis. It is important to starve the bacteria while they are treated with various antimicrobials or other medications.[1]

It is not clear how much time is needed on a restrictive diet after reducing the number of bacteria in the small intestines – there have been studies showing that 4 weeks of a diet can be successful, while sometimes 3 months or more has been recommended.[13] Below are a few of the popular SIBO diets.


The acronym FODMAP represents the highly fermentable, but poorly absorbed short-chain carbohydrates and polyols: Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. However, this diet was not specifically designed for SIBO and does not eliminate certain carbohydrates found in grains, starch, starchy vegetables, and sucrose.[15]

Specific Carbohydrate Diet (SCD)

The SCD diet was not created for SIBO, and it is not a low-carbohydrate diet: it allows carbohydrates consisting of monosaccharides. Complex carbohydrates are excluded by eliminating grains, starchy vegetables, lactose, and most sweeteners. The Gut and Psychology Syndrome Diet (GAPS) diet, originally intended to address autism, is a variation of SCD.

SIBO Specific Food Guide Diet (SSFG)

This is a combination of the Specific Carbohydrate Diet, the low FODMAP diet, and clinical experience with SIBO treatment.[13]

SIBO Bi-Phasic Diet

Based off the SSFG, this diet is put into phases with antimicrobial recommendations to go along the diet.

Vegetarian Bi-phasic diet

This diet is based on eliminating fermentable foods and properly preparing vegetarian proteins, such as legumes and grains, by soaking and sprouting before cooking to improve digestibility.

It is important to note that all these diets eliminate or reduce foods high in FODMAPs. FODMAPs have prebiotic functions, and their restriction may lead to reduction in beneficial bacteria.[16] Due to this, none of these diets are recommended long-term!

In the treatment of SIBO, it is crucial to find the underlying causes for repair or support of the MMC. A relapse of SIBO is expected in most cases (approximately 2/3 of cases!), unless the underlying cause can be identified and eliminated.[17] Additionally, supplements (e.g., antimicrobials, prokinetics) in combination with a diet are necessary to fully eradicate the SIBO and prevent relapse.[13]

What if it's not SIBO?

Although this post focused on SIBO, other forms of dysbiosis share many of the same causes, symptoms and therapeutic protocols of diet and herbs. The most common forms of dysbiosis other than SIBO include fungal infections, also called yeast infections or small intestinal fungal overgrowth (SIFO), and parasites. You can work with a qualified practitioner (like a Nutrition Therapist) to determine the best protocol to address these forms of dysbiosis that might be the underlying cause of your acne!

Are you on a SIBO protocol and struggling to find anti-inflammatory foods to calm your acne? Download my eBook with the 10 Best Foods for Acne that are also compliant with most SIBO diets!



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[1] Lipski E. Digestive Wellness : Strengthen the Immune System and Prevent Disease through Healthy Digestion. Mcgraw-Hill; 2020 [2] Parodi A, Paolino S, Greco A, et al. Small intestinal bacterial overgrowth in rosacea: clinical effectiveness of its eradication. Clin Gastroenterol Hepatol. 2008;6(7):759-764. doi:10.1016/j.cgh.2008.02.054 [3] Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome. World J Gastroenterol. 2010;16(24):2978-2990. [4] Grace E, Shaw C, Whelan K, Andreyev HJ. Review article: small intestinal bacterial overgrowth--prevalence, clinical features, current and developing diagnostic tests, and treatment. Aliment Pharmacol Ther. 2013;38(7):674-688. [5] Siebecker A, Sandberg-Lewis S. Small Intestine Bacterial Overgrowth: Often-Ignored Cause of Irritable Bowel Syndrome. Townsend Letter. February/March 2013. Accessed August 23, 2020. [6] Pimentel M, Chow EJ, Lin HC. Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome. Am J Gastroenterol. 2000;95(12):3503-3506. doi:10.1111/j.1572-0241.2000.03368.x [7] Bowe W, Loberg K. Dirty Looks: the Secret to Beautiful Skin. New York: Little, Brown Spark; 2019. [8] Coomes, R. Top 3 Underlying Causes of SIBO. The Healthy Gut. Published May 22, 2020. Accessed November 26, 2020. [9] Dukowicz AC, Lacy BE, Levine GM. Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterol Hepatol (N Y). 2007;3(2):112-122. [10] Bowe W, Patel NB, Logan AC. Acne vulgaris, probiotics and the gut-brain-skin axis: from anecdote to translational medicine. Benef Microbes. 2014;5(2):185-199. doi:10.3920/BM2012.0060 [11] Lombardo L, Foti M, Ruggia O, Chiecchio A. Increased incidence of small intestinal bacterial overgrowth during proton pump inhibitor therapy. Clin Gastroenterol Hepatol. 2010;8(6):504-508. doi:10.1016/j.cgh.2009.12.022 [12] Gunsar F, Yilmaz S, Bor S, et al. Effect of hypo- and hyperthyroidism on gastric myoelectrical activity. Dig Dis Sci. 2003;48(4):706-712. doi:10.1023/a:1022876423487 [13] Siebecker A, Sandberg-Lewis S. SIBO: Dysbiosis Has A New Name. Townsend Letter. February/March 2015. Accessed August 23, 2020. [14] Takakura W, Pimentel M. Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome - An Update. Front Psychiatry. 2020;11:664. Published 2020 Jul 10. doi:10.3389/fpsyt.2020.00664 [15] Ong DK, Mitchell SB, Barrett JS, et al. Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome. J Gastroenterol Hepatol. 2010;25(8):1366-1373. [16] Karakula-Juchnowicz H, Gałęcka M, Rog J, et al. The Food-Specific Serum IgG Reactivity in Major Depressive Disorder Patients, Irritable Bowel Syndrome Patients and Healthy Controls. Nutrients. 2018;10(5):548. Published 2018 Apr 28. doi:10.3390/nu10050548 [17] Siebecker A. SIBO Overview & Orientation. Presented at the: Next Steps for Treating Tough SIBO Cases: Masterclass Summit + Research Updates; November 17, 2020.

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