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When bacteria takes over: S.O.S. SIBO

Gut Health, Well Being| Views: 3944

The “new” evil : Intestinal bacterial overgrowth

Have you ever heard of SIBO (Small Intestinal Bacterial Overgrowth)? Overcrowding in the small intestine affects up to 20% of healthy people. In normal times, the vast majority of bacteria are found in the large intestine, also known as the colon. Several factors are at work to prevent bacterial overgrowth in the small intestine: acidic gastric secretions that chase certain bacterial strains, peristaltic movements that prevent their adhesion to the intestinal mucosa, the production of anti-bacterial substances by the enteric immune system, the ileocecal valve that prevents the reflux of bacteria from the colon to the ileum, one of the three parts of the small intestine1. That’s when and if everything goes as planned …

Bacterial overgrowth may occur due to a physiological change which result in alterations of the luminal pH (due to antacids or a very sweet diet for instance) or disruption of intestinal transit (a slowdown in case of diabetes or narcotics consumption, malabsorption due to pancreatic insufficiency, etc.) or the presence of structural abnormalities of the digestive system (in case of diverticulosis, stenosis, cicatrization as in Crohn’s disease or radiotherapy). Accurately diagnosing SIBO is not easy, to determine the increase in bacterial count to more than 105 active colonies per milliliter of proximal digestive fluid. A breath test, evaluating the levels of hydrogen is the least invasive and the most popular for identifying bacterial overpopulation; since high doses of sugar (glucose and lactulose) administered during the examination will be metabolized by the invading bacteria of the small intestine1,3. Typical symptoms of SIBO include: abdominal pain, flatulence, diarrhea with or without steatorrhea (presence of excess fat in feces) 3. In some more extreme cases, there is even talk of more severe gastrointestinal disorders and complications leading to malabsorption, weight loss, and possibly immune weakness2.

Link between SIBO and Irritable Bowel Syndrome

Intestinal dysbiosis – bacterial imbalance of the digestive system – causes the symptoms of the irritable bowel syndrome (IBS)1. The emergence of this syndrome after an episode of gastroenteritis suggests that IBS is infectious4. Considering the postprandial discomfort (after meals) affecting people with irritable bowel, it is believed that they suffer from unusual fermentation and overproduction of gas by their intestinal bacteria4. This is very similar to the physical manifestations of SIBO. In fact, about 40% of people with IBS also experience SIBO. This double burden will particularly affect women, older people, people affected by diarrhea and who complain of bloating, and people with anemia1.

Probiotics in all of this?

Many studies recommend antibiotics combined with probiotic therapy as a standard protocol for resolution of SIBO1,3. Bifidobacteria supplementation has been shown to be useful in combating bacterial overpopulation in patients with gastrointestinal difficulties who were related to cancer3. Further scientific observations have revealed that the addition of Lactobacilli over a 6-week period to an antibiotic prescription for SIBO has reduced the symptoms2. Our pharmaceutical grade Probaclac products offer multi-strains containing Bifidobacteria and Lactobacilli that have been clinically tested. It is clear that the combination of probiotics with antibiotics remains more effective than antibiotic therapy by itself to fight intestinal bacterial proliferation3. Note that it is important to space the intake of these two adjuvants for 3 to 4 hours to maximize their respective efficiencies.

Flash Quiz to see who the Experts are!

True or false ? To put the odds on one’s side in the fight against bacterial overgrowth, it is better to revise eating habits.

True! Since in the case of SIBO, the bacteria of the small intestine feast on simple sugars such as lactose and fructose and polysaccharides which are fermentable ... leading to both embarrassing and painful consequences. The first recommendations for treating SIBO is to avoid high consumption of carbohydrates, limit the intake of refined foods and also to moderate the intake of alcohol.

True or false ? Antibiotic therapy does not fully address the microbial dysbiosis associated with SIBO, since antibiotics will not restore the intestinal flora.

True. Although they are effective in treating bacterial overgrowth, SIBO is often recurrent and the bacteria will multiply again, unless addressing the underlying cause of the problem and looking for strategies to maintain a healthy and balanced intestinal flora.


1Ghoshal UC, Shukla R et Ghoshal U. Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy. Gut and Liver. 2017 ; 11 (2) : 196-208.

2Khalighi AR, Khalighi MR, Behdani R, Jamali J, Khosravi A, Kouhestani Sh et al. Evaluating the efficacy of probiotic on treatment in patients with small intestinal bacterial overgrowth (SIBO) : A pilot study. Indian J Med Res. 2014 ; 140 (5) : 604-608.

3Furnari M, Parodi A, Gemignani L, Giannini EG, Marenco S et al. Clinical trial : the combination of rifaximin with partially hydrolysed guar gum is more effective than Rifaximin alone in eradicating small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2010 ; 32 (8) : 1000-1006.

4Thompson JR. Is irritable bowel syndrome an infectious disease? World J Gastroenterol. 2016 ; 22 (4) : 1331-1334.

5Shah SC, Day LW, Somwouk M et Sewell JL. Meta-analysis: antibiotic therapy for small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2013 ; 38 (8) : 925-934.