Bacterial Overgrowth Syndrome

Your small intestines are where food is absorbed. Good bacteria live in your intestines. Bacterial overgrowth is when the good bacteria in the small intestines grow too much. The extra bacteria keep you from absorbing all the nutrients in your food. Not absorbing nutrients is called malabsorption.

• The extra bacteria in your intestines keep you from digesting food properly

• The bacteria also use up nutrients in your food that you need for your health

• Some people have no symptoms, but others have diarrhea, lose weight, or feel gassy and bloated

• Doctors may do a breath test, test samples of fluid from your small intestine, or do x-rays of your GI tract

• Doctors treat bacterial overgrowth syndrome with antibiotics and may suggest changes in your diet

Bacterial overgrowth syndrome is mainly caused by:

• Conditions that slow down your GI tract, which keeps your intestines from flushing out extra bacteria

The most common cause of a slow-down is:

• Diabetes

Other diseases that can cause a slow-down include an underactive thyroid (hypothyroidism), systemic sclerosis, and amyloidosis.

Certain types of surgery on your intestines and complications of surgery also can cause bacterial overgrowth.

Some people have few symptoms or only weight loss.

Common symptoms are:

• Diarrhea that is greasy and smelly

• Belly pain

• Bloating

• Passing more gas than usual

• After months and years, vitamin and mineral deficiencies

Vitamin and mineral deficiencies can cause:

• Low blood count (anemia)

• Easy bruising

• Tingling of hands and feet

Doctors diagnose bacterial overgrowth syndrome based on your symptoms and if you have conditions that favor overgrowth of bacteria in your colon. They may also:

• Look down your stomach and intestines with a flexible viewing scope (endoscopy)

• Take a sample of intestinal fluid and culture the fluid to measure the amount of bacteria

• Measure certain chemicals in your breath

• Take x-rays of your stomach after you swallow a liquid contrast agent

Treatments can include:

• Antibiotics

• Eating less carbohydrates and fiber

• Vitamins or minerals to correct specific deficiencies

Most people get better after taking antibiotics for 10 to 14 days.

Doctors may suggest you eat a diet that's higher in fat and lower in carbohydrates and fiber to slow down the bacteria's regrowth.