can small intestine bacterial overgrowth (sibo) cause weight gain?
Small intestine bacterial overgrowth, or sibo, refers to an excessive growth of bacteria in the small intestine, which is the part of the digestive tract where most nutrients are absorbed, typically causing bloating and discomfort. While sibo is most commonly associated with symptoms that lead to weight loss, such as constipation, diarrhea, and abdominal pain, there is also a potential connection to weight gain.
In fact, some studies suggest a link between sibo and obesity. A study published in 2019 found that individuals with small intestine bacterial overgrowth who experienced constipation gained more weight than those without it, after 12 weeks of treatment with rifaximin. Additionally, another study published in 2021 found that participants with sibo experienced a 9.1% increase in BMI while on rifaximin, compared to participants without sibo. Although the study found no significant BMI increase in individuals whose sibo continued to test positive after treatment, it still indicates that sibo may be associated with weight gain.
Sibo and constipation
The presence of small intestine bacterial overgrowth can lead to constipation, which itself can contribute to weight gain. As food moves through the intestines more slowly with sibo and constipation, more calories are absorbed, leading to weight gain. In addition, constipation can cause bloating and other discomforting symptoms, which can contribute to a feeling of being overweight despite changes in weight.
Sibo and nutrient deficiencies
Sibo can also lead to nutrient deficiencies due to the reduced efficiency of digestion and absorption. By 2018, researchers found that individuals with sibo and constipation had lower iron stores and higher rates of depleted B-vitamin levels, compared to those without sibo. These nutrient deficiencies can further contribute to feelings of weakness and fatigue, which can lead to weight gain.
While sibo with diarrhea may initially lead to weight loss, it is not uncommon for patients with sibo and diarrhea to experience a regain of weight over time. This is because diarrhea speeds up the digestive process, leading to faster absorption of nutrients and potentially more calorie intake.
Sibo and hormonal imbalances
In recent years, researchers have begun to explore the connection between sibo and hormonal imbalances. Sibo has been associated with higher levels of insulin resistance and hypothyroidism, which can both contribute to weight gain. Insulin resistance, for example, can lead to difficulties controlling blood sugar levels, resulting in increased appetite and weight gain.
Sibo and metabolism
Sibo has also been linked to disturbances in metabolism. A study published in 2017 found that people with sibo had lower resting energy expenditures than those without it, which can contribute to weight gain. Additionally, sibo has been associated with higher levels of thyrotropin, a hormone that regulates thyroid function.
It is important to note that the relationship between sibo and weight gain can vary from person to person. Some individuals with sibo may never experience any weight gain despite experiencing digestive symptoms, while others may gain weight due to the combination of constipation, diarrhea, and nutrient deficiencies caused by sibo.
