Does Fasting Help for SIBO? Can Fasting Cure SIBO?

While there are no studies directly investigating the effect of fasting on SIBO (Small Intestinal Bacterial Overgrowth), fasting may help with the treatment via something called migrating motor complex (MMC). MMC occurs during fasting periods and helps empty residual food and bacteria from the small intestine. Fasting may also help starve the unwanted bacteria of the foods they thrive on. That said, fasting itself is not a cure for SIBO and must only be practiced for this specific cause at the advice of a doctor.

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What is SIBO?

Small Intestinal Bacterial Overgrowth, or SIBO, refers to an abnormally high number of bacteria in the small intestine. This overgrowth disrupts the delicate balance of the gut microbiome, which is essential for digestion. As a result, this condition leads to digestive issues and even nutrient malabsorption.

Bacteria exist in the small intestines and help break down nutrients. But in SIBO, the wrong type of bacteria starts moving into and growing inside the small intestine. This excessive bacteria consumes essential nutrients and vitamins, even bile salts that help digest fats.

Other digestive conditions typically cause SIBO and co-occur with it, so treating SIBO essentially involves treating the underlying cause.

SIBO Symptoms

SIBO symptoms are very similar to other digestive issues, such as irritable bowel syndrome (IBS). You may have some or most of the following symptoms:

Bloating and abdominal distension
Gas and excessive belching
Diarrhea or constipation
Abdominal pain or discomfort
Fatigue and lethargy due to poor nutrient absorption
Weight loss or difficulty gaining weight
Malnutrition, especially deficiencies in vitamin B12, iron, and fat-soluble vitamins

SIBO Causes

For a healthy balance of gut microbiome, several mechanical or chemical functions must work just right. If one is off, the result may be an increase in the wrong bacteria in the small intestine. Here are the factors that usually contribute to SIBO development:

Impaired motility of the small intestine is often due to conditions like diabetes, hypothyroidism, or scleroderma (motility is the ability of the intestine to move its contents).
Structural abnormalities such as small intestinal diverticulosis or surgical blind loops.
Low stomach acid (hypochlorhydria) reduces the natural barrier to bacterial colonization.
Immune system deficiencies can fail to control bacterial overgrowth.
Medications, particularly long-term use of proton pump inhibitors (PPIs) or antibiotics, may alter gut flora.

Diagnosis

Since SIBO’s symptoms are similar to other more common digestive conditions, a healthcare provider may test for those. If they suspect SIBO, they’ll conduct a breath test. In this test, they measure hydrogen and methane in your breath, as gas is the most common symptom of SIBO.

Your doctor may also perform blood tests, stool tests, and imaging of the digestive tract.

Does Fasting Help Treat SIBO?

Fasting, particularly intermittent fasting, may positively impact SIBO-diagnosed patients. However, the research on the matter is essentially non-existent, and fasting isn’t part of the usual treatment options prescribed for SIBO.

That said, the migrating motor complex (MMC) may help explain the promising effect of fasting on SIBO. MMC occurs for 90 to 120 minutes after eating a meal. It occurs in phases and moves leftover/indigestible food, cellular debris, and bacteria out of the stomach and small intestine. Through a series of random contractions, it moves the leftover bits in the digestive tract toward the colon and ultimately to the rectum.

MMC is interrupted every time you eat something. One can assume that fasting may help turn on MMC, which may help move some excessive bacteria out of the small bowels. More research is needed to confirm fasting’s impact on SIBO.

Doctors also often prescribe an elimination diet to patients diagnosed with SIBO. They eliminate certain foods, like carbohydrates, that help increase the growth of bad bacteria in the small intestine. Intermittent fasting may help with such treatment options by keeping all food, including carbohydrates, out of the system for a while.

Usual Treatment Options for SIBO

Once diagnosed, SIBO is typically treated with both medications and diet. Since it can often be a complication related to another condition (for example, motility issues), your doctor may treat that condition in order to treat SIBO as well. Most commonly, antibiotics are used to control the bacteria in the small bowels. For those who have had SIBO for a while and have developed deficiencies, particularly vitamin B12, supplements may also be needed to replenish those deficient nutrients.

A healthcare practitioner may also recommend a strict diet to control certain foods that the bacteria in SIBO feed on. The so-called SIBO diet often eliminates foods high in carbs (including fiber) and sugar.

How to Use Intermittent Fasting for SIBO Treatment?

If you have been diagnosed with SIBO and practice intermittent fasting, discuss with your doctor whether you should continue doing it. It may or may not be beneficial for controlling SIBO, depending on your symptoms, severity, and other health conditions.

If your doctor approves intermittent fasting while the treatment for SIBO is ongoing, you may continue to fast, ideally for shorter periods, as you may need to eat food before taking medication.

Remember to track everything you eat or drink to identify foods that cause your symptoms to get worse. The Fastic app allows you to quickly log details about your meals and create a diet history.

Can Intermittent Fasting Cure SIBO?

Intermittent fasting, or any kind of fasting, alone may not cure SIBO. It’s a gut issue that requires medical intervention. Medication may be the quickest and most reliable way to treat it. However, you may complement the antibiotic approach with diet and fasting. Again, consult your doctor about your options and whether fasting will be safe for you to practice during treatment.

Disclaimer: Speaking with a health professional before beginning intermittent fasting or a diet program is advised. There may be side effects for people with certain medical conditions.