Small Intestinal Bacterial Overgrowth
The small intestines are divided into three parts: the duodenum which receives food from the stomach, the jejunum and the ileum which passes the undigested food into the large intestine.
The gastrointestinal tract (GI tract) contains bacteria with the highest concentration being in the colon while the small intestines have the least. The type of bacteria in the GI tract also varies with the bacteria in the large bowel being different from those in the small bowel.
These good bacteria, which are also known as friendly flora or probiotics, help keep the colon healthy and regulate the immune system.
Small intestinal bacterial overgrowth (SIBO) is a disorder characterized by the presence of numerous bacteria in the small bowel. These bacteria are those which are normally located in the part of the large intestine known as the colon.
These bacteria feed on starches, natural sugars and refined sugars in the consumed food and produce methane and hydrogen gas. This causes flatulence (intestinal gas) with symptoms like belching, bloating, abdominal distension and abdominal pain that are most marked after eating complex carbohydrates like grains and fruit.
The excessive production of intestinal gases can also cause intestinal cramps and irritable bowel syndrome (IBS) with diarrhea and vomiting. Diarrhea is usually linked to the production of hydrogen gas while constipation is usually associated with the production of methane gas.
The abnormal quantities of gas in the intestines can also lead to the development of heartburn, acid reflux, GERD and nausea. These symptoms develop as a result of the gas filled small intestines pushing upwards against the stomach and causing hiatal hernia.
Other symptoms associated with SIBO include improved bowel movements after taking antibiotics and the worsening of bowel problems after consuming fiber or taking probiotics. Bowel problems that begin after taking opiates for pain also suggest the presence of SIBO.
These excessive bacteria also inhibit enzymes in the small bowel that breakdown complex starches in consumed food into simple sugars that can be absorbed by the body. They also consume nutrients like vitamin B-12, iron and fats and can even cause nutrient deficiencies and a decline in general health.
SIBO also leads to an increase in the production of a hormone known as zonulin which increases the permeability of the small intestines, a condition which is also known as leaky gut syndrome. The absorption of abnormally large protein molecules in this condition leads to problems in the immune system like autoimmune disorders, allergies and asthma.
IS SIBO IBS in Disguise?
The diagnosis of IBS is often made after persons with diarrhea or constipation test negative for conditions like celiac disease and Crohn’s disease and have endoscopies, colonoscopies that do not reveal the cause of their symptoms.
SIBO researchers approximate that around 35-50% of the general public have SIBO. However since it is not often tested or properly diagnosed, many persons with SIBO assume they have Candida or yeast infection.
Making the diagnosis of SIBO is not easy since it is difficult to get bacterial culture from the small intestines. Other tests that can be done include the hydrogen breath test in which the patient drinks a glucose or lactose solution and samples of their breath are collected. These tests must be ordered by a doctor and the lactose test is more accurate than the glucose one.
Symptoms of leaky gut include having an autoimmune disorder, multiple joint pains, depression, chronic fatigue, allergies, long standing skin conditions and general malaise which is feeling of not being well.
If these symptoms of leaky gut are associated with chronic diarrhea or constipation, abdominal pain, bloating and belching after meals, GERD, indigestion and even IBS, the person may have SIBO.
What is SIBO?
SIBO or small intestinal bacterial overgrowth is a condition that is characterized by an increase in the number of bacteria or changes in the species of bacteria present in the small bowel.
Most patients with SIBO usually have an overgrowth of the many types of bacteria which are normally present in the colon (1) rather than just an increase of one type of bacteria.
SIBO has been proven to adversely affect the structure and function of the small intestines. It interferes with the digestion of food and absorption of nutrients mainly by damaging the mucosa which is the lining of the intestines.
These increased bacteria can also reduce the amount of fat absorbed by the body through their effects on bile acids. This can lead to deficiencies of fat soluble vitamins like A and D.
In addition, the increased number of the wrong bacteria in the small intestines can lead to nutritional deficiencies when these bacteria use up vitamins like B12. They can also use up amino acids which can lead to mild protein deficiency and an increase in the production of ammonia by some bacteria. This increased ammonia production puts an extra burden on the detoxification system which handles the little ammonia normally produced by the body.
In addition, the damaged small intestine mucosa causes a leaky gut which causes numerous immune reactions like food allergies, generalized inflammation and autoimmune diseases (2) by allowing large protein molecules to cross into the bloodstream.
To learn about the Foods that can Exacerbate SIBO symptoms and gain access to Dr Hagmeyers video series titled “Everything you want to know about SIBO”
What Causes SIBO?
Several factors contribute to the development of SIBO and the first of these is a deficiency of hydrochloric acid (HCl) in the stomach. HCl is an acid which helps the body digest proteins and kills bacteria consumed in the food to prevent them from colonizing the small bowel.
The second factor that contributes to the development of SIBO is a lack of intestinal motility. In the periods before eating, migrating motor complexes, which are controlled by the enteric nervous system, cause movements of the small intestines which help flush out bacteria. These migrating motor complexes (MMCs) movements cause the intestinal rumblings known as hunger pains that are experienced after a person has not eaten for some time.
MMCs can be damaged by surgical operations, intestinal scarring and infections of the intestines. Drugs that can restrict these movements of the intestines include those used for acidity like proton pump inhibitors and antacids. Opiate pain killers like morphine and antibiotics can also reduce these movements.
Stress can contribute to reduced hydrochloric acid levels as well as reduced intestinal motility. This is due to the fact that the sympathetic nervous system which controls the flight of flight response to a stressful situation inhibits the secretion of digestive juices like HCl and intestinal motility. When person is relaxed, the parasympathetic nervous system is more active and it enhances the digestive process and intestinal motility. Persons who are dealing with stress and have IBS symptoms should therefore have their levels of the hormone cortisol evaluated.
Thyroid hormones like T3 and T4, cortisol and the sex hormone estrogen should also be measured since they also affect motility and inflammation in the gastrointestinal tract as well as the production of HCl.
A poorly functioning ileocecal valve is another factor that contributes to the development of SIBO. This valve, which is located between the small and large bowel, prevents the back-flow of food material from the large intestines into the small ones.
Bloating, which can be caused by poor digestion, hormonal imbalances and inflammation can keep the ileocecal valve open. If the ileocecal valve is not closed or functioning normally, bacteria can move from the large intestines to the small ones and cause gas, bloating, general weakness and malaise.
The bacterial superinfection of SIBO can also result in a persistently open ileocecal valve perpetuating this vicious cycle.
Can Anything Be done to Improve Ileocecal Valve Function?
Massaging the ileocecal valve can help relieve severe gas and bloating by reducing its inflammation and swelling since this helps it close properly.
The ileocecal valve is located on the lower right side of the abdomen. It is half way between the belly button and the right hip bone.
Persons with severe gas and bloating can check for any swelling and tenderness in that area on their body. If present, they can massage the area several times each day until the swelling and tenderness disappear.
Natural Therapy for SIBO
If a person has SIBO one of the best things they can do is consult a Holistic Functional Medicine Practitioner who is conversant with the vicious cycle of SIBO.
In addition, they can do the following to help reduce the symptoms of SIBO:
- Eliminate food allergies or sensitivities
- Adhere to a low FODMAP diet
- Identify if you are a methane or hydrogen producer.
- Adhere to a 4R protocol (Remove, Replace, Repair, Re-Inoculate)
- Receive chiropractic care and visceral manipulation of the ileocecal valve
- Watch Dr. Hagmeyer’s free video series entitled “Everything you need to know about SIBO”
- Hydrogen Breath Testing-Frequently Asked Questions
Enter Your name and email and Dr Hagmeyer will send you a list of foods to avoid on FODMAP Diet.
How Do I Know If I Have SIBO?
Self-treatment for SIBO based on symptoms only may be unnecessary and even dangerous if it destroys the friendly bacteria. It is therefore important for a person be tested for SIBO.
HBT—Hydrogen Breath Testing
The hydrogen breath test (HBT), which is also used to test for lactose or fructose intolerance, is one test that can be done to determine if a person has SIBO.
The excessive bacteria in SIBO make hydrogen when they come in contact with certain foods in the intestines. These include foods that are improperly digested due to the absence of enzymes like lactase.
Drinking a lot of milk or soda after fasting from the previous night’s dinner followed by checking for an increased level of hydrogen in the exhaled air after every 15 minutes, can help make the diagnosis of lactose or fructose intolerance.
In persons with SIBO, since the bacteria have moved from the lower part of the colon to the upper part of the small intestines, drinking lactulose causes the hydrogen levels in the breath to increase earlier than expected. These levels of hydrogen in the expelled air increase after around 1 hour of drinking the solution when it reaches the small intestine and again after around 1 more hour when the solution reaches the colon. This double rise of hydrogen gas in the expelled air confirms a diagnosis of SIBO.
When Should I Get Hydrogen Breath Test (HBT)?
A hydrogen breath test should be done if a person has symptoms like abdominal bloating, abdominal cramps, flatulence, diarrhea and constipation.
Additionally, a HBT should also be done at least once on all persons with CFS/FMS since SIBO is very common in these patients. If they are found to have SIBO, they should be treated and retested after a few months.
Persons with SIBO who take the antibiotic Rifaximin will develop recurrences after a few months if the underlying causes are not treated. These persons may need to do the HBT.
Patients with lactose and fructose intolerance also need to have HBT testing if SIBO is not found in order to explain their symptoms.
How Is SIBO Testing Done?
The hydrogen breath test is based on the fact that hydrogen gas and methane gas are only produced in the body by bacteria in the intestine after they ferment sugars like lactulose.
These gases are absorbed by the intestinal mucosa and are transported to the lungs by blood vessels. They are then expelled from the body through the breath and measured in the hydrogen breath test.
SIBO hydrogen breath test involves preparing a patient for the test by fasting before a baseline breath sample is taken.
The patient then takes 10 g of the carbohydrate lactulose dissolved in water by mouth.
More breath specimens are collected 20, 40 and 60 minutes after drinking the solution. A rise of the level of hydrogen and/or methane gas above 20 parts per million in the breath within 60 minutes is diagnostic for SIBO.
Since around 15% patients have intestinal bacteria which produce methane gas instead of hydrogen, methane levels in the breath have to be measured. Each breath sample is therefore measured by metabolic solutions for both hydrogen and methane gas.
SIBO—Why Does It Keep Coming Back?
Bacteria are important for maintaining healthy small intestines and performing vital functions in the intestines. However, small intestinal bacterial overgrowth can cause leaky gut and its numerous symptoms.
Small intestines are around 20 feet long and even though bacteria are present in the whole gastrointestinal tract, relatively few inhabit the small bowel. The concentration of bacteria in the small intestines is less than 10,000 bacteria per milliliter of fluid while that in the colon, which is a part of the large intestines, is at least 1,000,000,000 bacteria per milliliter of fluid.
In addition to the differences in concentration, the species of bacteria present in the small intestines differ from those in the colon.
Why you should thank your small bowel and the beneficial bacteria that live there
The small intestines are important for digesting food and absorbing nutrients into the body. The small bowel also plays a key role in the immune system since it contains lymphoid cells that help fight infections and regulate the function of the immune system.
Are you at risk for small intestinal bacterial overgrowth? Find out what the most common risk factors and symptoms are.
The normal good bacteria help protect the body from yeasts and pathogenic (bad) bacteria that cause diseases that are consumed in the food.
These good bacteria also help the body absorb nutrients in addition to producing nutrients like short chain fatty acids, vitamin K and vitamin B9 which is also known as folate.
These good bacteria also assist in maintaining the normal muscular activity of the small intestines which moves foods along the gut.
What causes SIBO?
The body has numerous mechanisms of preventing SIBO. These include the secretion of hydrochloric acid by the stomach which maintains an acidic environment. The waves of muscular activity in the intestines also help prevent SIBO. Immunoglobulins produced by the immune system that are present in the intestines also help prevent SIBO. The ileocecal valve which is located between the small and large intestines also helps prevent SIBO by reducing the backflow of bacteria from the large intestines into the small ones.
The causes of SIBO are complex and they often affect several of the above mentioned protective mechanisms simultaneously.
Risk factors for SIBO
The risk factors of SIBO include:
- Low concentration of hydrochloric acid in the stomach
- IBS or irritable bowel syndrome
- Long standing celiac disease
- Crohn’s disease
- Previous operations on the intestines
- Diabetes mellitus types I and II
- Taking many courses of antibiotics
- Dysfunctions of other organs in the body like liver cirrhosis, chronic pancreatitis and kidney failure.
Moderate alcohol consumption and oral contraceptive pills (OCPs) also increase the risk for SIBO
Heavy consumption of alcohol has been linked to SIBO for long time (3). This study also found a link between SIBO and moderate alcohol consumption which is defined as consuming one alcoholic drink per day for women and two alcoholic drinks per day for men.
Alcohol is thought to adversely affect the body’s SIBO protective mechanisms by damaging the small intestine mucosal cells, aiding the development of a leaky gut and decreasing the muscular contractions of the intestines. In addition, it is also thought to contribute to the bacterial overgrowth by feeding some bacteria (4).
There is a moderate association between oral contraceptives (OCPs or birth control pills) and inflammatory bowel diseases like Crohn’s disease (5). This risk is reversed by ceasing to use OCPs.
Regardless of the fact that no studies link OCPs to SIBO, there is a possibility that OCPs can also contribute to the development of SIBO due to the relationship between SIBO and IBD.
How do you know if you have SIBO?
Though the exact number of people in the general public with SIBO is not known, some studies suggest that between 6 to 15% of healthy people without symptoms have SIBO while up to 80% of people with IBS have SIBO (6).
SIBO remains a largely under-diagnosed condition because many doctors are not aware of how common it is. In addition, many persons do not consult doctors for their SIBO symptoms which include:
- Abdominal discomfort or pain
- Bloating and abdominal distension after eating starches and sugars
- Gas and bloating
- In severe cases, weight loss and symptoms arising from nutrient deficiencies
In addition to this, the breath tests used to measure hydrogen and methane gas have high false negative rates. This means that the tests come back as negative in patients who have SIBO (7).
Why SIBO can be difficult to treat
Antibiotics are frequently used to treat SIBO but studies show that recurrence develops in almost 50% of patients treated with antibiotics within one year.
One study which compared the use of rifaximin, which is the most frequently used antibiotic, with botanical antimicrobials found that the botanical protocols had better outcomes but treatment was only successful in around 50% of patients after one course of treatment.
These research findings suggest that the treatment of bacterial overgrowth alone is not enough for most patients with SIBO. Successful treatment must therefore be tailored to each patient and include managing underlying conditions and dealing with predisposing factors.
How Can A Natural Approach To SIBO Help put an end to Bloating, Gas, Constipation, Diarrhea, Fatigue and Nutritional Mal-absorption?
Unlike conventional medical treatments whose main goal is to kill the infection, Functional and Holistic Medicine approach is to get to the underlying cause of your GI Problems and Understand why they developed in the first place. While the conventional approach to SIBO is antibiotics, this may not be the best course of action in every case. Most cases have reinfection rates as high as 90% within a years period of time. Our Goal is to detect the “why” behind SIBO and truly correct the many causes.
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Have Questions? Dr Hagmeyer offers a limited number of Free 15 minute phone consults for SIBO sufferers who are interested in becoming a patient.
Other Articles You May Want to Read About SIBO
- Preparing for Your Small Intestinal Bacterial Overgrowth Test-(These Mistakes could affect your Test Result)
- Heal Your Gut, Balance Your SIgA Levels