Medically reviewed by Onikepe Adegbola, MD, PhD
SIBO is also known as small intestine bacterial growth. It is a condition characterized by the exponential increase of bacteria in the small intestine. The bacteria found in SIBO is not the type of microflora found usually in the small intestine. It is also known as the ‘blind loop syndrome.’
Some of the causes of SIBO are:
- Obstruction of the intestine (constipation, scar tissue, gastric ulcers).
- Surgery (scar tissue due to gastric bypass, gastrectomy).
- Diseases that cause slowing down of the intestinal contents (radiation side effects, diabetes, scleroderma, carload disease).
- Organ anatomy issue (diverticulitis, hernia).
- Diseases of the immune system (HIV).
- Medications like the medicines used to treat irritable bowel syndrome, medicines used to reduce stomach acid, and antibiotics that change digestive flora.
- Stress can be a precipitating factor in the presence of pre-existing health conditions.
Symptoms of SIBO
SIBO can cause:
- Nausea and vomiting
- Severe abdominal pain
- Loss of hunger
- Unexplained weight loss
- Bloating and gas
- Weak bones
- Kidney stones
Why Does it Happen?
The small intestine is the longest part of the gastrointestinal tract (almost 18 to 21 feet). It is the central part of the intestine where the digestive juices and enzymes are mixed with the food, and digestion takes place. Nutrients are also majorly absorbed in the small intestine. The risk factors for developing SIBO cause the food to get lodged in this part of the small intestine, which becomes a breeding area for microorganisms. These organisms release toxins and also hamper the absorption of nutrients.
SIBO and the Menstrual Cycle
As mentioned above, SIBO hampers the absorption of nutrients in the small intestine. This leads to nutritional deficiencies over the long run. For women, dietary deficiencies lead to improper production, metabolization, and regulation of hormones in the body.
Women require progesterone and estrogen in adequate quantities to regulate a healthy menstrual cycle. When women produce estrogen, a feedback mechanism stops producing it after it reaches a certain blood level. This is because estrogen has to be metabolized in the liver via different pathways before final excretion through feces.
The liver metabolizes estrogen with the help of various enzymes and nutrients like vitamins E and vitamin B. When there is an excess bacterial growth in the small intestine, the body competes with the excess microorganisms in the small intestine(due to SIBO) to absorb nutrients. Many microbes absorb the nutrients faster than the body resulting in nutritional deficiencies.
Many studies like “Uninvited guests- the impact of small intestinal bacterial overgrowth on nutritional status,” published in Practical Gastroenterology, have shown that women who suffer from SIBO show vitamin B deficiency because the bacteria is utilizing it instead of the body. In this scenario, the estrogen is not efficiently metabolized by the body, which leads to its increase in the blood.
Women with excess amounts of circulating estrogen become estrogen dominant. Being Estrogen dominant can lead to a lot of health risk factors like:
- Low reproductive health
- Increased risk for breast cancer
- Polycystic ovarian disease
- Autoimmune diseases
When external and internal estrogen overloads the right liver, there is an excess of estrogen circulating in the blood. This effect is enhanced in individuals who are also deficient in Magnesium and vitamin E. Nutrients like vitamins B, E, and Magnesium are also essential for other things than just estrogen balance. For example, both men and women need adequate levels of B vitamins for efficient transport of oxygen in the blood, proper brain development, increased immunity, digestion, and energy production.
Vitamin E also promotes heart health and immunity. It is found and reported in studies like “Nutrition and female fertility,” published in Front Endocrinol (Lausanne) that women with magnesium deficiency undergo fatigue, muscle aches, and severe symptoms of PMS (premenstrual syndrome). The severity of PMS symptoms demonstrates how a shortage of essential nutrients can affect reproductive health and various hormone levels in the body. It also emphasizes the need and importance of diagnosing SIBO in female patients.
How Can SIBO be Treated?
There are various treatment options for SIBO depending on the severity of the condition:
1) Diagnostic tests
Diagnostic tests will be done to diagnose the presence of SIBO accurately:
- X-ray, CT, MRI
- Blood tests
- Stool tests
- Small intestinal aspirate and fluid culture test
- Lactulose breath test
2) Treatment Plans
Some cases of SIBO can be treated through medicines like:
(This also depends on breath test results of methane/hydrogen.)
- Antibiotics like neomycin, amoxicillin-clavulanate, ciprofloxacin, metronidazole, norfloxacin, and Trimethoprim
Supplements for vitamins K, E, B, and iron can be beneficial and should be considered to make up for different deficiencies.
Probiotics like kefir, miso, yogurt, kimchi, etc., can be considered to regulate bacterial flora.
Surgical treatments may be needed for anatomical problems and scar tissues.
6) Dietary regulations
You can try the SIBO diet during your menstrual cycle, which includes
- A reduction in sugar levels will help enhance beneficial bacterial growth.
- Avoid foods that trigger your SIBO symptoms.
- Avoid syrups and supplements which may have sugar contents
- Avoid lactulose – dairy and milk products
- Your doctor/nutritionist can help you chart a low FODMAP diet.
- Try the element diet: no processed or prepared foods. For e.g., to eat only clean and raw vegetables and fruits.
It is advised that any changes in diet or any new diets should always be started under the guidance of your healthcare provider.
SIBO can lead to severe PMS symptoms and can cause reproductive health issues if not diagnosed and treated at the right time. It can adversely affect the thyroid gland and cause inflammation of the GIT and Liver. Stress can also be a precipitating factor for small intestine bacterial overgrowth. Therefore, it is advised to see your doctor if you experience severe PMS or have severe abdominal discomfort during your menstrual cycles to diagnose the cause and discuss various treatment options or diet changes.
Dukowicz, A. C., Lacy, B. E., & Levine, G. M. (2007). Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterology & Hepatology, 3(2), 112–122.
Madormo, C. (2021, September 10). SIBO: Symptoms, treatment, diet, and more. Healthline. https://www.healthline.com/health/SIBO
Murphy, M. F., Sourial, N. A., Burman, J. F., Doyle, D. V., Tabaqchali, S., & Mollin, D. L. (1986). Megaloblastic anemia due to vitamin B12 deficiency caused by small intestinal bacterial overgrowth: possible role of vitamin B12 analogs. British Journal of Haematology, 62(1), 7–12. https://doi.org/10.1111/j.1365-2141.1986.tb02894.x
Zaidel, O., & Lin, H. C. (n.d.). Uninvited guests: The impact of small intestinal bacterial overgrowth on nutritional status. NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #7. Virginia.Edu. Retrieved June 16, 2022, from https://med.virginia.edu/ginutrition/wp-content/uploads/sites/199/2015/11/zaidelarticle-July-03.pdf