What is SIBO syndrome?


Table of contents

We always like to remember that not all bacteria that appear or are present in our body are harmful, but that many of them also have a positive function for our organism. However, it is also important to mention that if their number is irregular, either more or less than their usual amount, we may have a problem, which is the case of SIBO syndrome. small intestine bacterial overgrowth, or small intestine bacterial overgrowth.

This dysfunction affects the small intestine, as the name suggests, and can be treated with the help of a health professional. But how do we know if we have SIBO? Today we will explain the causes, the symptoms and give some basic solutions to the problem. Here we go!

What is SIBO?

As mentioned above, this small bowel syndrome, also called blind loop or stagnant loop syndrome, produces an exaggerated amount of certain bacteria (more than 100 billion coliforms/mL) that should not be in the small intestine, but in the large intestine. The problem and pain occurs when these bacteria start to ferment food where they should not.

Although the large intestine can support this type of bacteria (in the right quantity), the small intestine is usually made up of very few bacteria, as its contents flow very quickly and contain bile. Hence, if there is an overgrowth of these components, the food ‘stagnates’ in the small intestine, creating a perfect breeding ground for the proliferation of more bacteria. One of the main dangers lies in the creation of toxins, which can interfere with the absorption of nutrients.

The patient with SIBO may experience some changes in health, such as gas and/or bloating, among other symptoms, such as:

Lack of appetite

Some people may experience a decrease in food cravings.


Nausea is also common, manifesting as a feeling of stomach discomfort with a tendency to vomiting.

Feeling of bloating

Abdominal bloating is another key symptom, with a noticeable increase in the volume of the abdomen due to gas accumulation.

Feeling of fullness after eating

In addition, people with SIBO often experience an uncomfortable feeling of fullness after eating, even after eating small portions of food.


Diarrhoea is another common symptom, with loose and frequent bowel movements.

Non-voluntary weight loss

Unintentional weight loss is an additional concern, as it may indicate inadequate nutrient absorption due to SIBO.

Food deficiency

Finally, malnutrition, rather than a symptom, is a risk, as excess bacteria and toxin production can interfere with the proper absorption of nutrients in the small intestine.

SIBO causes

Before we continue, we would like to send out a reassuring message that SIBO is not a hereditary syndrome, or at least it is not the norm. It is caused by certain factors that can be corrected to return to good health. Therefore, if SIBO is suspected, the best thing to do in this case is to see a doctor so that he or she can carry out the appropriate tests and create a suitable diet to solve the problem.

It is therefore important to know what can cause this excessive number of bacteria in the small intestine. Some of the most common or important are:

  • Chronic atrophic gastritis.
  • Taking certain proton pump inhibitors, such as omeprazole.
  • Some intestinal motility disorders (post-radiotherapy colitis, tumours, diverticula, fistulas, etc.).
  • Chronic or autoimmune pathologies.
  • A deficiency of proteolytic enzymes (proteases).
  • Excessive consumption of alcohol and/or opioid drugs.
  • Some systemic diseases that alter motility and are associated with SIBO (Parkinson’s, systemic sclerosis, hypothyroidism, cirrhosis, celiac disease, morbid obesity…).

It should also be noted that SIBO or its development is more likely to occur as we get older, so special care and monitoring is needed as we get older, especially if we have had SIBO at some point in our lives.

Additional factors to consider

In addition to the above, there are some factors that can cause an increase in bacteria in the small intestine that need to be monitored:

  • Gastric surgery to treat obesity or ulcers.
  • A structural defect in the small intestine or injury.
  • A fistula between two segments of the intestine.
  • Crohn’s disease, intestinal lymphoma or scleroderma.
  • If there has been a history of radiotherapy to the abdomen.
  • Diabetes.
  • Diverticulosis in the small intestine.
  • Adhesions caused by previous abdominal surgery.

The good news is that there are simple and accessible tests to diagnose SIBO: the hydrogen and methane breath test. To do this, a source of sugars must first be administered to the patient in order to obtain the results.

However, before a diagnosis can be made, it is necessary to go to the doctor and tell him/her about the symptoms. It will be at that point that the ‘investigation’ will begin.

It will also use the anamnesis. to reach a conclusion and to be able to offer treatment. If the patient goes to the general practitioner, he/she may refer him/her to the gastroenterologist so that he/she can order appropriate tests. It should be borne in mind that all the symptoms discussed above can overlap with those of other diseases or problems, so it is important to be discerning.

What is the treatment for SIBO?

After testing and confirmation that the patient has SIBO syndrome, it is time to move on to treatment. On the positive side, with a change in diet provided by a health professional who regularly monitors the patient’s health status, the problem can be solved. Let’s look at some of the keys:


The doctor will most likely prohibit the consumption of artificial or processed sugars and sweeteners for a period of time.

Foods to avoid

One of the maxims of a SIBO diet is the list of foods that we cannot eat until our doctor gives us the go-ahead. The ones mentioned below will be banned, as they help to promote microbial activity in our small intestine:

  • Fructans. Garlic, artichokes, persimmon, onion, asparagus, peas, mushrooms, inulin, peach, leek, beet, watermelon, etc.
  • Fructose. Apricot, cherries, canned fruit, pomegranate, mango, apple, peach, pear, watermelon, fruit juices, fructose sweeteners, honey, coconut sugar, nuts, etc.
  • Lactose. This includes milk and its derivatives (ice cream, dairy desserts, kefir, cream, margarine…).
  • Galactans. Pulses will also be an element to avoid, although some, if cooked, can be digested much better (such as lentils or chickpeas).
  • Polyols. Avocado, plum, lychee, sweet corn, nectarine and watermelon…

It should be borne in mind that one of the missions of the diet we are given is to help our digestive system to digest food better and more easily. In this way we are giving it a little boost and making it make as little effort as possible.

If you suffer from constipation, oats are preferable, as they provide fibre but do not contain sugars. Of course, when we are weak or have a problem, water consumption must increase, so the patient will probably also be told to drink a little more than usual.


In addition to some indications about the diet, it is also important and we wanted to highlight some applications or habits that are important to acquire when following this type of diet in order to make them more enjoyable and effective;

  • Divide meals into 5 to 7 small-volume meals/day.
  • Chew food well and eat slowly.
  • Cook foods containing carbohydrates (pasta, rice, etc.) for longer.

Taking care of emotions as well

As well as the body, when we are overcoming an illness or problem, we must also pay attention to the mind, especially to the emotions that may flourish.

It is normal (and should not be avoided) to be sad or a little more depressed when we are ill, but states such as anxiety or stress can be detrimental to rapid improvement.

It is therefore essential to also take care of these factors when going through a syndrome such as SIBO, which can cause anxiety about pain, difficulty eating or dieting. Stress can decrease hydrochloric acid production, affect intestinal motility and increase inflammation and intestinal permeability. If this persists and the vagus nerve remains constantly active, bacteria from the colon can migrate into the small intestine, thus worsening the SIBO situation.

For this reason, we have compiled some key points that you can apply, as far as your state of health allows you to do so:


Sleep quality is directly linked to stress and plays a crucial role in gut health. Disruptions in circadian rhythms have been associated with an increased risk of bowel disorders, such as irritable bowel syndrome or intestinal dysbiosis (imbalance in the intestinal flora and fauna). microbiota).

That is why it is so important to take care of the quality of sleep by changing rest habits that do not work for us for healthier ones, such as going to bed early or having light dinners. The doctor may prescribe a melatonin supplement if the patient is found to have difficulty falling asleep, although exposure to sunlight during the day may also be beneficial for this problem.


Maintaining an active lifestyle is crucial to support the natural motility of the intestines and counteract the effects of sedentary lifestyles, which promote bacterial colonisation.

We are not saying that it is necessary to go to the gym every day, but that it is often enough to go for a walk or play a sport that the patient particularly enjoys. These physical activities can provide significant benefits, not only in combating SIBO, but also in improving overall quality of life.

In addition to knowing the symptoms of SIBO so that you can see a doctor if you notice any, it is also necessary to know that there are tests and analyses available to detect the disease and provide a more specific solution. In this way, the problem will be solved more quickly. Hence, testing laboratories, such as Ambar Lab, are of particular help.

You can access our test catalogue or, if you have more specific questions, please contact our team. Whether you are a hospital, a laboratory, a drug developer or a medical researcher, we have the answer to all your needs.

Share this post!

More articles that may interest you...

Do you want to know more?

Do not hesitate to contact us

¡Contáctanos ahora!

Te ofrecemos una consulta personalizada para ti. Nuestro equipo de expertos estará encantado de asesorarte en cualquiera de nuestros servicios. 

Contact us now!

We offer a personalized consultation for you. Our team of experts will be happy to advise you on any of our services.

Get the latest news

Do you want to keep up to date with what's new in the clinical sector?

Leave us your email and you won’t miss any of our updates.