Bacterial overgrowth in the small intestine

In recent years, problems digestive took center stage in healthcare, with a noticeable increase in diagnosis of conditions such as SIBO (small intestinal bacterial overgrowth) and food intolerances. According to data from American Journal of GastroenterologySIBO already affects 15 to 20% of the population, and the rate of food intolerances has increased by 20% in the last decade. This situation poses significant challenges for those seeking a life free of digestive discomfort and is forcing health professionals to rethink their approach to nutrition and gut wellness.

In this interview Isabel MartorellDoctor of Biomedicine and head of the nutrition and health team at Nootric, shares with Oksana her experience and knowledge about the impact of these disorders on the lives of patients, the most effective approaches to diagnosis and treatment, as well as the necessary changes in education and prevention of digestion. During the conversation, the expert offers us An Updated Look at How SIBO and Food Intolerances form lifestyle habits and what we can do to improve gut health.

QUESTION: What factors do you think have contributed to the increase in SIBO and food intolerances over the past decade?

REPLY.- The increase in cases of SIBO and food intolerances over the past decade can be attributed to several factors, starting with the fact that SIBO in many cases is a consequence of pre-existing digestive problems rather than the original cause. SIBO tends to develop due to underlying conditions, such as changes in intestinal motility often found in irritable bowel syndrome (IBS), or as a result of long-term use of certain medications that alter the microbiota. Thus, although antibiotic treatment may provide temporary relief, the problem may recur if the original cause is not treated, highlighting the importance of comprehensive and personalized diagnosis.

On the other hand, the increase in food intolerance may be related to lifestyle and changes in modern dietary patterns, richer in processed foods and less fiber intake, which affects the gut microbiota and contributes to the development of intolerance. In addition, advances in diagnostic tests have made it possible to more accurately identify these conditions, which previously could not be detected and were considered nonspecific digestive problems.

Q: What are the most common symptoms of SIBO and how can they be distinguished from other digestive conditions such as irritable bowel syndrome?

A.- The most common symptoms of SIBO include bloating, gas, abdominal pain, diarrhea, and malabsorption of nutrients. Although these symptoms are similar to those of irritable bowel syndrome, people with SIBO often experience more severe symptoms after eating foods high in fermentable carbohydrates, which is less common in IBS.

Q: In your experience, what role does the microbiota play in the development of SIBO and increased food intolerances?

A.- The gut microbiota plays a critical role in digestion and overall health. When there is an imbalance in the microbiota, gut motility and the body’s immune response can be altered, favoring conditions such as SIBO, which is a type of dysbiosis. Changes in the microbiota can also increase intestinal permeability, which contributes to food intolerances and adverse reactions to food components. Dysbiosis can promote both bacterial overgrowth in areas where there shouldn’t be bacteria, such as the small intestine, and inflammation associated with intolerance.

Q: Are there specific and reliable tests to diagnose SIBO, and how do they differ from tests used to diagnose food intolerances?

A.- Yes, the most common and reliable test for diagnosing SIBO is the lactulose or glucose breath test, which measures the production of hydrogen and methane in the exhaled air after consuming these sugars and is designed to detect excess bacteria in the small intestine. However, as nutritionist Julio Basulto notes, overuse of this type of test has led to possible overdiagnosis of SIBO, even in people without underlying digestive pathology. It is therefore important that test results are complemented by a full clinical assessment taking into account the patient’s history and symptoms.

However, for food intolerance, various tests are used, such as detection of specific enzymes (for example, lactase for lactose intolerance), blood tests, or food elimination and reintroduction protocols. These tests allow us to identify individual reactions to certain foods and avoid misdiagnoses that could lead to unnecessary dietary restrictions.

Q: What type of diet or nutrition plan is typically recommended for treating SIBO and what are the biggest challenges for patients in complying with treatment?

A.- A low FODMAP diet is often recommended in the treatment of SIBO because it limits the fermentable carbohydrates that bacteria use as food, helping to reduce symptoms. However, it is not recommended to follow a low FODMAP plan indefinitely, as limiting these foods for long periods of time can negatively impact your gut microbiota and reduce bacterial diversity, which is key to a healthy digestive system. Therefore, gradual reintroduction of FODMAPs under professional supervision is necessary to identify specific foods that may trigger symptoms and avoid nutritional deficiencies.

Additionally, anti-inflammatory therapy based on unprocessed, low-sugar foods may be recommended to reduce bowel irritation. Following these recommendations can be difficult due to restrictions, so professional support is needed to ensure proper nutritional balance and prevent long-term deficiencies.

Question: In terms of treatment, how effective are antibiotic-based approaches compared to dietary and probiotic interventions?

A.- Antibiotics, such as rifaximin, are effective in temporarily reducing the number of bacteria in the small intestine and relieving the symptoms of SIBO. However, their effectiveness is usually greater when combined with dietary changes and, in some cases, probiotics, which help restore the balance of the gut microbiota. A dietary approach is essential to maintaining long-term results, since after antibiotic treatment has ended, diet and probiotics help prevent relapses. To do this in nootricdigital nutrition service, we have a team of nutritionists specializing in various areas of healthcare who treat each patient based on their symptoms and unique conditions to establish the best nutritional regimen for each individual.

Q: Do you think stress and lifestyle play a role in the development and treatment of SIBO? What recommendations do you usually give to your patients for changing habits?

A.- Stress and lifestyle significantly influence the development and treatment of SIBO. Chronic stress can alter intestinal motility and immune response, both factors that contribute to bacterial overgrowth. I encourage patients to engage in stress management techniques such as moderate exercise, meditation or yoga, as well as good sleep hygiene. It is also important to eat mindfully and chew slowly to ease digestion and reduce stress on the digestive system.

Question: In response to the rise in food intolerances, what changes do you think should be made in nutrition education and preventative medicine to improve the digestive health of the population?

A.- To improve the health of the digestive system of the population, it is necessary to teach a varied and balanced diet from an early age. Additionally, spread knowledge about the microbiota and its role in health, as well as the impact of processed foods and lifestyle choices on the digestive system. In preventative medicine, closer collaboration between doctors and nutritionists, like the one we offer at Nootric, will help identify and treat digestive problems and intolerances early, reducing the risk of long-term complications and improving patients’ quality of life.