SIBO or bacteria overgrowth in the small intestine

Under normal conditions the small intestine should have less than 1,000 bacteria / ml, regardless of the type of bacteria, because even an excess of beneficial bacteria in the small intestine can be problematic. SIBO occurs when there is a excess bacteria in the gut (dysbiosis)

What causes excess bacteria or SIBO?

There are multiplecauses and disorders that can end up producing abacterial overgrowth in the small intestine:

• Functional and motility disorders, caused for example by , the use of drugs such as opioids, diabetes, or intestinal pseudo-obstruction.
• Anatomical and structural alterationssuch as inflammatory bowel disease, adhesions from previous surgical interventions or radiotherapy, small bowel tumors, small bowel diverticulosis, ileocecal valve alterations, or gastric bypass performed as an intervention for the treatment of obesity morbid.
• Liver cirrhosis or exocrine pancreatic insufficiency, because the amount and composition of bile and digestive enzymes are altered, thus allowing the overgrowth of bacteria in the small intestine.
• Immune system disorderssuch as immunoglobulin A deficiency or HIV infection.
• Other causes: certain parasitosis, and alterations of gastric acidity (especially by the chronic taking of gastric protectors).

SIBO types

Whenever we talk about SIBO we mean bacteria. But there are other types of microorganisms, the archaea, which may also be involved in its appearance. To be able to make a diagnosis of SIBO it is necessary measure with a test the levels of two types of gases, the hydrogen and methane:

• Bacteria mainly produce hydrogen
• Archaea produce methane.

This means that, if in the diagnostic test we find elevated levels of methane, the microorganisms that we will have to pursue will be archaea.

Symptoms of bacterial overgrowth in the small intestine

The growth of microorganisms in the small intestine causesinflammation Y damage to the intestinal surface.

At the intestinal level

SIBO can produce multiple effects by poor digestion and malabsorption of nutrients and theimpaired intestinal motility. It is typical for the following to occur:

• Flatulence and bloating due to excess gas, especially when eating foods with certain types of sugars such as fructose or lactose.
• Diarrhea and / or constipation
• Abdominal pain.
• weight loss and malnutrition due to fat and protein malabsorption.

At the systemic level

Multiple effects have been described due to the production of toxins, producing an increase in the intestinal permeability, allowing toxins to pass into the bloodstream.

• Neurological symptomslike brain fog, confusion.
• Fibromyalgia, headache and musculoskeletal system, tiredness.
• Menstrual disturbances
• Skin symptoms
• Autoimmune diseases
• Intolerance to multiple foods, including those rich in histamine due to DAO deficiency.

However, many of these symptoms are not yet recognized as related to SIBO and, in fact, it can be difficult to know if they are caused by it or by the primary pathology that caused the development of SIBO, such as undiagnosed celiac disease. .

Who can develop it?

It has been seen that healthy people can develop SIBO up to a 20%. In groups of people with digestive symptoms like him, SIBO can be present in up to 65%.

Although his prevalence increases with age, also children can suffer it.

How is it diagnosed?

Fordiagnose SIBO the most important thing is to suspect it. Anyone who has digestive symptoms (such as those that have been described) could have it, associated or not with another digestive or systemic pathology. That is why it is important to carry out a clinic history complete information including the medication the person is taking or symptoms related to eating different foods along with a thorough physical examination.

SIBO may be suspected in certain situations, such as:

• In the case of a insufficient improvement in celiac patientswho are on a gluten-free diet.
• If there is a worsening of digestive symptoms when given probiotics, prebiotics, or a very high fiber diet.
• If there is a temporary improvement in digestive symptoms after taking antibiotics, or a worsening with drugs such as opioids or gastric protectors

The diagnosis of SIBO today is carried out mainly with the exhaled air test for bacterial overgrowth which consists of administering lactulose or lactitol and hydrogen and methane. In a healthy person, hydrogen and methane should be produced only in the large intestine, but in the case of a person with SIBO they are also produced in the small intestine.

This test may have quite a few false negatives Y false positives. If SIBO is still suspected with a negative test, one can be repeated or done.

Also, it is important look for the cause bacterial overgrowth and be aware that a patient with SIBO may have several concurrent causes.

Treatment of SIBO with the FODMAP diet

The current classic approach is based on the FODMAP diet that we explain below. However, in some cases antibiotic therapy is used. The most important thing to be able to treat it is to identify the causes or triggers.

Low FODMAP diet

Avoid fast-fermenting carbohydrates to reduce the food of the bacteria present in the small intestine. Is about control fermentable fructooligosaccharides, disaccharides, monosaccharides and monosaccharides.

Although more studies are needed on the effect of diet on gut microbiota, it is true that people with SIBO or irritable bowel may experience improvement. There is great interindividual variability in tolerance to FODMAPs and personalized nutritional counseling is the most recommended.

However, it is not convenient to discard this type of food forever, since its fermentable fiber is transformed in the large intestine into short-chain fatty acids necessary for the correct physiology of the intestine.

• • SIBO is a bacterial overgrowth in the small intestine that does not have to be harmful bacteria.
  • At the intestinal level, SIBO can produce multiple effects due to poor digestion andnutrient malabsorption and theimpaired intestinal motility.
  • At the systemic level, multiple effects have been described due to the production of toxins, producing an increase in intestinal permeability, which allows the passage

Paola Solé

Graduated in Human Nutrition and Dietetics

Clinical Nutrition Specialist