top of page

Could your SIBO be from undiagnosed Genetic Sucrase Isomaltase Deficiency?


I have hundreds of patients with SIBO (small intestinal bacterial overgrowth) and I have identified over 100 causes. If the underlying cause is not diagnosed patients often progress to recurrent/chronic SIBO. It takes a very detailed history to find out the cause. Learn more about this unusual disorder that few physicians have ever heard of!

Patients are curious if indeed this is the cause of their symptoms or could something have been missed. The short answer to this question is yes...usually something has been missed. But it takes time, a thorough history, physical exam and record review to determine the underlying cause.

What is Sucrase-Isomaltase Deficiency?

Dr. Rudert answers:

The short answer is that Sucrase-Isomaltse Deficiency is the inability to digest sucrose. If you lack the enzyme sucrase you cannot digest table sugar or other sugars from starch. It may be genetic (you are born with the deficiency), ideopathic (we don't know why) or aquired. It is more common than you think: 8% of adults are estimated to have this commonly missed disorder, and 9% of the population may be carriers of Genetic Sucrase-Isomaltase Deficiency (GSID).

What are the symptoms of Sucrase-Isomaltase Deficiency?

Dr. Rudert answers:

The symptoms are often misdiagnosed since they overlap with many other disorders that should be excluded first such as celiac disease, gluten sensitivity, lactose intolerance, SIBO (small intestinal bacterial overgrowth), pancreatic insufficiency, medication induced diarrhea and other etiologies. Symptoms may include abdominal cramping after meals, gas, bloating and episodic diarrhea. Some patients may have lifelong symptoms.

How is it (GSID) diagnosed?

Dr. Rudert answers:

First you have to have it on your radar and many physicians are not aware of it. I often say in my lectures, "If you don't think of a diagnosis you will never consider it." Small bowel biopsies can be performed which is an invasive test to analyze enzyme levels (disaccharidase assays). Breath sucrose testing is readily available and can be done at home. It is free if your physician is aware of the complimentary test. Free sucrose hydrogen breath testing is available through our office. Genetic testing looks for approximately 40 known variants. False negatives may occur; however, a positive test is diagnostic.

Is there a treatment for Sucrase-Isomaltase Deficiency?

Dr. Rudert answers:

Yes, and the therapy has been available for many years. The therapy is prescription Sucraid (sucrosidase) drops. It is the only FDA approved enzyme replacement therapy and is taken with every meal and snack.

Featured Posts

Dr. Cynthia Rudert

Recent Posts
Search By Tags
No tags yet.
Follow Us
  • Facebook Basic Square
  • Twitter App Icon
bottom of page