Small intestine dysbiosis or SIBO, very little known and investigated in Romania but with a high prevalence especially among patients with irritable bowel syndrome .

Due to various factors, our microbiota can undergo changes that affect its diversity and / or the amount of microorganisms that form it, initiating a pathological process called bacterial overpopulation or SIBO.

If you haven't heard of this change yet, pay attention because it is estimated that by 35% of the general population can suffer from bacterial overgrowth, and prevalence may rise to 80-90% TO patients with irritable bowel syndrome or syndrome or the syndrome of a chronic cough .

In normal conditions, the small intestine it must not practically harbor bacteria because it is a area dedicated to digestion and absorption of nutrients .

Small Intestinal Bacterial Overgrowth, also known as SIBO, is considered to be an excess of bacteria in the proximal small intestine, over 10/5 CFU.

There are 3 types of SIBO:

  • Hydrogen – Occurs when there is mainly an overgrowth of bacteria
  • Methane – Occurs when there is an overgrowth of archaea
  • Sulfate – This type of SIBO is still under research.

What are the symptoms of bacterial overgrowth in the small intestine?

The fact that colonic bacteria migrate from their natural habitat, the colon, into the small intestine will cause discomfort to the affected person. The cells of the intestine will compete with the bacteria for food and this will cause various changes:

Intestinal changes deriving from gas accumulation

Caused by fermentation by bacteria and archaea, gastrointestinal discomfort will occur:

  • Abdominal distension.
  • Balloons.
  • Abdominal pain.
  • Flatulence.
  • Flatulence.
  • Belch.
  • Acidity.
  • Alterations in intestinal transit: Constipation or decomposition (depending on the microorganisms present in the small intestine), even steatorrhea.

Derived from the production of toxic metabolites

Produced by elevated microbiota, which promotes the production of pro-inflammatory cytokines. These will affect the microvilli of the intestinal mucosa (where we absorb nutrients) causing inflammation in the intestine and malabsorption, increasing the risk of:

  • Nutritional deficiencies, the most common being a deficiency of vitamin B12, vitamins A, D, E and iron which can lead to anemia or alterations of the nervous system. Folate and vitamin K levels are generally normal or elevated, given the bacteria's ability to synthesize them.
  • Food intolerances: fructose, sorbitol, lactose, other carbohydrates, histamine, gluten, etc. depending on the enzymes and transporters that are affected, the damage to the intestinal mucosa.
  • Asthenia, caused by nutritional deficiencies.
  • Weight loss, caused by malabsorption and gastrointestinal symptoms that may cause food avoidance due to discomfort that usually occurs after ingestion.
  • Increased risk of infection with Candida and other yeasts.

Derived from the fact that it is NOT treated on time

The junctions between enterocytes can break, causing intestinal permeability - leaky gut (known in English as Leaky Gut). In this situation, the contents of the gut can come into contact with the immune system and cause systemic inflammation, increasing the likelihood of autoimmune diseases (Crohn's disease, ulcerative colitis, etc.), allergies, dermatological and neurological conditions or resistance. to insulin, among others.

Causes of SIBO . Why does it appear?

There are several reasons that can lead to the pathological proliferation of microbiota in the small intestine. Below I try to summarize them:

Anatomical causes

  • Changes in the ileocecal valve or the Bauhin valve. When the "door" that separates the large and small intestines is left open (open ileocecal valve syndrome), SIBO is more likely to occur. This change has several possible causes:
  • Intestinal surgeons.
  • Short bowel syndrome with the absence of this valve.
  • Inflammatory intestinal diseases (Crohn's, Ileitis...) affecting the Bauhin valve.
  • Stress.

Blind loop syndrome

The small intestine forms a bag or handle in which food stagnates, being an ideal environment for the proliferation of microbiota. It can be produced by:

  • Abdominal surgeries (gastric bypass, gastrectomy...).
  • Intestinal adhesions.
  • Abdominal radiotherapy.
  • The presence of fistulas.
  • Diverticulosis

Deficiency of gastric acid, bile or enzyme deficiency

They have bacteriostatic properties, preventing colonic bacteria from reaching the stomach and intestine. When its quantity is reduced, there is a greater probability of microbiota colonization in these portions of the digestive tract. What can cause these deficits?

Conditions that cause the decrease or absence of hydrochloric acid in the stomach (hypochlorhydria / achlorhydria):

  • Old age
  • Taking proton pump inhibitors or hydrogen receptor antagonists, misnamed gastric protectors or antacids, which are commonly used to treat heartburn caused by gastroesophageal reflux. Examples of such drugs are omoprazole or ranitidine.
  • Chronic atrophic gastritis (secondary to Helicobacter pylori infection or autoimmune cause).
  • Pernicious anemia.
  • Radiotherapy treatment.
  • Gastric bypass.

Conditions that cause bile to decrease (cholestasis):

  • Choledocholithiasis (gallbladder stones that obstruct the flow of bile acids).
  • Cholangitis (inflammation of the bile ducts).
  • Choledochal cyst.
  • Pancreatitis
  • Neoplasm in the head of the pancreas or bile ducts
  • Use of certain medications.
  • AIDS.
  • Biliary cirrhosis
  • Toxic, viral or autoimmune hepatitis.
  • Caroli disease.
  • Byler's disease.
  • vermin
  • Duodenal diverticulum.

Conditions leading to deficiency of digestive enzymes (lipases, peptidases, amylases):

  • Old age
  • Changes in the salivary glands.
  • Pancreatic pathologies (pancreatitis, obstruction, cancer...)
  • Liver disorders
  • Crohn's disease.
  • Cystic fibrosis.

Slowing of intestinal motility (own movements of the intestine).

Under normal conditions, our intestine has two types of movements:

  • Those associated with food consumption.
  • Those associated with periods of fasting, known as the migratory motor complex (MMC). These movements are activated between 2 and 4 hours after eating food and are very important because their function is to keep the lumen of the small intestine clear and "clean" of bacteria from food, thus reducing the risk of microbiota overgrowth.

One of the clearest symptoms of a slow motility is constipation, so finding its cause and treating it can prevent SIBO from developing.

There are several situations in which impaired motility can occur:

  • Old age
  • Consumption of certain drugs or medicines (anticholinergics, antidiarrheals, opiates such as morphine or codeine, etc.).
  • Various pathologies: hypothyroidism, autonomic neuropathy for diabetes, Parkinson's, scleroderma, radicular enteritis, polymyositis, amyloidosis, multiple sclerosis, celiac disease, inflammatory bowel disease (Crohn's, ulcerative colitis), short bowel syndrome, obesity, etc.
  • Lack of physical activity: advanced age, severe overweight (morbid or extreme obesity), people with hemiplegia / paraplegia, people with chronic fatigue syndrome and / or fibromyalgia who have great movement difficulties...
  • Some eating behaviors: low-fiber diet, chewing gum or stevia consumption.

Autoimmune pathologies

Scleroderma, type 1 diabetes, ulcerative colitis, Crohn's disease, celiac disease, autoimmune hypothyroidism (Hashimoto's hypothyroidism, Graves' disease, atrophic thyroiditis...), rheumatoid arthritis, etc.

Having one of these conditions does not mean you will have SIBO, but it does increase your risk of developing it.

How can SIBO be diagnosed?

When bacterial overgrowth is suspected, it is essential to have a confirmed diagnosis for further treatment.

The first thing you should do is a medical visit for diagnostic guidance and ordering tests. See a digestive specialist up-to-date on small intestinal bacterial overgrowth. After a clinical history, you will have the necessary information.

Testing for a precise and noninvasive diagnosis

The Airtest is a non-invasive test that consists in taking samples of exhaled air to measure, at different moments of time, the amount of hydrogen and methane from the breath after administration of a substrate (10g of lactulose/lactitol). You can order this test online

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