Is SIBO on Your Differential For Patients With GI Symptoms?

Is SIBO on Your Differential For Patients With GI Symptoms?

David presents to your office with constant burping, diarrhea and abdominal distention. He says he thinks he now knows how uncomfortable his wife was when she was eight months pregnant. This has been going on for six months and he can’t figure out why. He has tried probiotics and think they make him worse. He has a history of antibiotic use and has tried taking fiber products that his local health food store recommended, with no success. Diet is certainly not perfect, and he loves more than a couple of beers on the weekend. The diarrhea is affecting his daily life, as sometimes it is hard to leave the house.

“SIBO,” or small intestinal bacterial overgrowth, has become a more commonly diagnosed condition that affects the small intestine. It results from bacteria, both beneficial or unhealthy, that can migrate from other areas of the gut, setting up their home in the small intestine. This can lead to many symptoms, including abdominal pain/discomfort, constipation and/or diarrhea, flatulence, belching, weight loss and vitamin deficiencies. The bacteria will feed off undigested food in the small intestine, and the biggest culprits are sugar, simple and complex carbs, starch and alcohol. That mixture leads to fermentation with hydrogen or methane gas as the end product. Hydrogen is a direct result of fermentation and feeds the archaea (single-celled organisms) in the small intestine, which is how methane is produced. Hydrogen dominant gas usually correlates with diarrhea and methane dominant with constipation. It is important that you test for both methane and hydrogen, since with increased methane there can be a reduction in hydrogen giving you a false negative hydrogen test. (1)

Some studies suggest that between 6 to 15% of healthy, asymptomatic people have SIBO, while up to 80% of people with irritable bowel syndrome (IBS) have SIBO (2).

An association exists between SIBO and moderate alcohol consumption, defined as up to one drink per day for women and two drinks per day for men. (3) Alcohol appears to have effects on several of the normal protective mechanisms, including causing injury to the small bowel mucosal cells, contributing to leaky gut, and decreasing the muscular contractions. Additionally, alcohol may “feed” a few specific types of bacteria contributing to overgrowth (4). This could have been adding additional ammunition for the overgrowth in David’s case.

Our normal flora can be disrupted in the gut as a result of medications, such as antibiotics, acid-blocking drugs, and steroids, so the fact that David had a history of antibiotic use was a risk factor in developing SIBO.

Also common is lack of enzymes released in saliva that begin to break down food and assist with proper function of nerves, muscles and neurotransmitters to properly digest food and move it along the digestive tract. With David describing burping with any food intake, it is possible the problem also is compounded by an enzyme deficiency. We are supposed to masticate our food to the point that it is liquid. That is hard to do when we typically eat in a rush, taking two bites and swallowing. It is also common to have less digestive enzyme in saliva as we age. Those two things together can increase the potential incidence of SIBO. If we also don’t move our food through the intestines at the proper pace, we allow the possibility for bacteria to rest in the small intestine. Be aware that patients with diabetes and scleroderma have an increased risk for SIBO, since muscle in the gut in these conditions can be affected. Testing for glucose, HgA1c and insulin levels may give us an indication as to the risk and relationship of these levels to symptoms in the patient presenting with SIBO. Physical obstructions such as scarring can also lead to deposits of bacteria in the lining, and diverticula will trap the bacteria, as well not allow it to pass to the colon.

The big red flag for me with David was that he felt worse with a probiotic. The lactobacillus or bifidobacterium species can increase the levels of bacteria in the small intestine, exacerbating the symptoms. It probably isn’t that the probiotic is bad, just that the good bacteria isn’t getting to where it belongs in the colon, and there are now increases in the level of bacteria with the probiotic ingestion in the small intestine.

There is a significant concern with vitamin and mineral deficiencies as well. Common deficiencies occur with the fat-soluble vitamins A, D, E and K, vitamin B12 and iron. This occurs due to maldigestion and or malabsorption of these nutrients in the intestinal lumen. Also common is excess of folate. Findings on blood work may include hypoproteinemia and hypoalbuminemia. B12 deficiency occurs because the absorption is not permitted in the ileum without enough gastric intrinsic factor that can be affected by bacteria. (5) The folate elevates due to increased synthesis by small bowel bacteria. (6)

Patients that present to the office with symptoms typical of SIBO are assessed with a thorough blood work up, SIBO breath test, comprehensive stool analysis to evaluate levels of bacteria (both good and bad), any yeast or parasitic involvement, assessment of the ability to digest and absorb food, short chain fatty acid levels, inflammatory markers and SIgA .

Below are David’s results:

Glucose 99
HgA1c 5.3
Uric Acid 5.0
BUN 18
Creatinine .85
Sodium 140
Potassium 4.2
Chloride 104
Calcium 9.5
RBC magnesium 4.0
CO2 20
Protein 6.0
Albumin 3.2
Globulin 2.8
Alk Phos 78
LDH 185
AST 24
ALT 21
Bilirubin 1.10
Serum Iron 98
TIBC 321
Ferritin 100
RBC 4.4
HGB 14.2
HCT 38
MCV 87
MCH 29.4
MCHC 33.2
RDW 14.3
WBC 4.8
Neutrophils 61
Lymphocytes 32
Monocytes 4
Eosinophils 1
Basophils 0
Platelets 230
Triglycerides 53
Cholesterol 248
LDL 115
HDL 120
TSH 1. 24
T4 6.4
T3 92
T3 uptake 34
Ft4 1.2
TPO and thyroglobulin antibodies negative
Insulin 7
25 (OH) vitamin D 17
Vitamin B12 394
Folate >24
Homocysteine 7

The difference between his baseline reading on the breath test was 91. Anything higher than 11 is a positive test. He was significantly higher on hydrogen than methane.

The comprehensive stool analysis revealed 4+ on lactobacillus and bifidobacterium species, which is the highest amount recorded. He had imbalanced flora: 2+ alpha hemolytic strep, 1+ klebsiella pneumonia. No yeast was cultured. No parasites were found He was outside the reference range on carbohydrates, indicating carbohydrate malabsorption. His inflammatory markers revealed increased calprotectin of 85 with a reference range less than 50 ug/g, which is a reliable marker for indicating IBD vs. IBS, and certainly inflammation. Lowering that level will decrease his risk for IBD and for any sort of relapse. Secretory IgA was decreased, which makes him more vulnerable to infection and is seen in diarrhea.

Treatment for SIBO can be complicated and long, depending on how the patient responds and how compliant he or she chooses to be.
There are a few goals when treating:

  1. Correction of the underlying cause; in this case, eliminating the gut bacteria, reducing the sugar and carbohydrate load leading to the fermentation process producing the methane and hydrogen gas, replenishing enzymes and aiding in the digestive process due to low protein and poor diet choices.
  2. Nutritional support to elevate the B12 levels, using 6000mcg of B12 methylated to increase probability of absorption, with a B complex to also increase absorption rates. Magnesium threonate 800 mg to get levels above 6, and yet not affect bowel by increasing the chance for more diarrhea. Magnesium threonate crosses the blood brain barrier and doesn’t distress the GI tract, so that higher dosages may be achieved. L-glutamine at 10-40g per day in powdered form (being careful to not start too high; dosing up makes it easier on the patient to consume) and curcumin for the elevated CRP. “Glutamine has protective effects on intestinal mucosa by decreasing bacteremia and epithelial cell apoptosis, enhancing gut barrier function, and influencing gut immune response,” according to a study by Ban and Kozar published in the American Journal of Physiology Gastrointestinal and Liver Physiology, 2010. If the glutamine makes patients report they are worse, believe them, as some have trouble with this supplement based on genetics, gut flora and hormone levels. Digestive enzymes with HCL were given to be taken with meals. Ten thousand IUs of Vitamin D3 were also given with a meal that contained a healthy fat.
  3. Treating the overgrowth with products that are broad spectrum antimicrobials. The typical route is antibiotics, which do not have a large data base of research behind them. In our arsenal are easily accessible products that are successful and have some support that has been documented in the literature. In practice I have used the following successfully, coupled with dietary changes: Biocidin from Biobotanical Research, FC Cidal and Dysbiocide from Biotics and Candibactin-AR and Candibactin_BR from Metagenics. (7) Food avoidance is also important for eradication of SIBO. A low FODMAP diet with the elimination of highly fermentable fruits and vegetables, the Specific Carbohydrate diet or the Gut and Psychology Syndrome diet are good places to start by picking one of them and seeing if there are any additional triggers that need to be adjusted when monitoring symptoms.

Be patient with the treatment, as it usually takes 3-6 months to see resolution and permanent eradication of all the symptoms, even though the patient may feel better after 3-6 weeks.

David’s protocol was easy for him to follow with supplementation; however, dietary changes were challenging, so we met every two weeks to check his progress and add changes that he felt he could accomplish. A repeat breath test was done at three months, since he had complete resolution of symptoms at that time, but the test revealed a level change of 25 points, which still indicated a positive SIBO test. This demonstrates the importance of retesting. Had we stopped treatment at that time, recurrence was probable because we had not completely eradicated the overgrowth at that time. After an additional three months of dietary restriction and nutritional support, there was complete resolution. SIBO testing returned to a steady baseline, and no imbalanced flora was found on a stool test. Absorption of carbohydrate returned to normal, as did the calprotectin and SIgA levels. We had begun to wean the patient off the antimicrobial products prior to the second retest. His symptoms had still not returned.

Repeat labs showed improvement in CRP to normal levels, Vitamin D at 85, cholesterol down to 212 and B12 up to 865. Overall, David felt great with normal bowel function, moving two times a day with solid consistency and the ability to empty. The nutritional support would be continued for another 4-6 months. He no longer experienced abdominal bloating or belching with any meals, and, with his wife pregnant with their second child, he did not have to contend with the same “feeling like he was pregnant.”

  1. Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome. World J Gastroenterol. 2010;16(24):2978-90.
  2. Dukowicz AC, Lacy BE, Levine GM. Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterol Hepatol (N Y). 2007;3(2):112-22.
  3. Hauge T, Persson J, Danielsson D: Mucosal Bacterial Growth in the Upper Gastrointestinal Tract in Alcoholics (Heavy Drinkers). Digestion 1997;58:591-595.
  4. Levin, I., Meiri, G., Peretz, M., Burstein, Y. and Frolow, F. (2004), The ternary complex of Pseudomonas aeruginosa alcohol dehydrogenase with NADH and ethylene glycol. Protein Science, 13: 1547-1556.
  5. Welkos SL, Toskes PP, Baer H. Importance of anaerobic bacteria in the cobalamin malabsorption of the experimental rat blind loop syndrome. Gastroenterology. 1981;80:313–320. [PubMed]
  6. Russell RM, Krasinski SD, Samloff IM, et al. Folic acid malabsorption in atrophic gastritis: Possible compensation by bacterial folate synthesis. Gastroenterology. 1986;91:1476–1482.
  7. Chedid V, Dhalla S, Clarke JO, et al. Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med. 2014;3(3):16-24.

Another great reference is, Dr. Allison Siebecker.

About Author


Dr. Cindy M. Howard has been in private practice since 1999. She is board certified in Internal Disorders and Nutrition and hold a fellowship in Medical Acupuncture. She is the past president of the ACA Council on Diagnosis and Internal Disorders and serves currently as the Northern Illinois Delegate for the American Chiropractic Association. She serves on the medical advisory board for The Functional Medicine University and Integrative Therapeutics. Dr. Howard is the Director of Functional Nutrition for Neurosport Elite which focuses on sports performance for serious to elite athletes. She also teaches for the diplomate program and is an Executive Board member and Instructor for POWERPlay in Sports. She is the team Chiropractic Physician for DREAMZ Elite competitive cheer.

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