What is Sucrase-Isomaltase Deficiency?

People who have been diagnosed with IBS have a 50-80% chance of benefitting from the low-FODMAP diet, but if their symptoms are due to a Sucrase-Isomaltase Deficiency, they will be amongst those for whom the dietary intervention is not effective.

 

Although rare, Sucrase-Isomaltase Deficiency is a disorder that impacts the digestion of sugars and starches, which are not eliminated or challenged during the phases of the low-FODMAP diet.

Sucrase-Isomaltase Deficiency (SID) is a disorder in which the small intestines do not produce adequate (or any) enzymes to break down disaccharides such as sugar (sucrose) and starch (found in grains and potatoes, for example).  When these disaccharides do not follow the typical digestive pathway of being broken down and absorbed by the small intestines, they will pass through to the large intestines and subsequently trigger similar symptoms to ones experienced by those with Irritable Bowel Syndrome (IBS) such as gas, cramping, and abdominal pain.

There are two types of Sucrase-Isomaltase Deficiency.  The first is Congenital Sucrase-Isomaltase Deficiency and usually diagnosed in infancy.  The second is Acquired Sucrase-Isomaltase Deficiency and possible causes include a mutation of a gene, damage to the small intestines either by disease or autoimmune disorders or from extended use of antibiotics or chemotherapy.  People with the acquired form of SID are typically first diagnosed with IBS since the symptoms present similarly.

When I was at Digestive Disease Week in San Diego, California, where the premier physicians, dietitians, and researchers gathered to present and learn about the latest advances in the search for treatments and cures for all digestive diseases, Sucrase-Isomaltase Deficiency was among those topics.  Here are a few of my observations from the training I received:

IBS and SID Have a Connection
The research suggested that if you have been diagnosed with IBS and have tried the low-FODMAP diet with the help of a Registered Dietitian without success, you may have more than just IBS.

In fact, Dr. Shanti Eswaran, MD shared that people with IBS are two times more likely to carry a genetic predisposition to Sucrase-Isomaltase Deficiency than people without IBS.

While SID is not as common as IBS, those with SID or the genes that predispose them to SID may not have the same reduction in GI symptoms as someone without SID when following the low-FODMAP diet.

Sucrose may be the “Sixth FODMAP”
Sucrose, known to many as table sugar, is also found in fruits like bananas and vegetables like peas.  It is broken down by the enzyme, sucrase.  Sucrose is not currently counted as a FODMAP – or fermentable carbohydrate – on the low-FODMAP diet.  But when sucrase (the enzyme that breaks sucrase down for absorption) is not present or deficient, it can lead to similar symptoms experienced by those with IBS.  The same can be said for starches that need maltase to break them down into their absorbable component – glucose.

Although sucrose may trigger IBS-like symptoms, eliminating sugars and starches from one’s diet, in addition to the foods eliminated during the first phase of the low-FODMAP diet, would prove to be very restrictive.  The sucrose breath test can be administered by your gastroenterologist to determine if you have Sucrase-Isomaltase Deficiency.  The standard, however, is diagnosis via endoscopy with biopsy.  Should you have SID, there is a supplement that can be taken instead of completely eliminating sucrose-containing carbohydrate sources.

If you suspect that you may have Sucrase-Isomaltase Deficiency, seek out a diagnosis from your gastroenterologist. Eliminating sugars and starches from your diet could lead to vitamin and mineral deficiencies as well as insufficient energy intake.

Working with a Registered Dietitian who specializes in gut health can help you to ease your symptoms while liberalizing your food intake to improve your quality of life.

If you need help managing your gut issues, start with my free download, “Own Your IBS”: an organizer that will capture all the details of your experience and let your health practitioners help you find relief quickly.

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Beth Rosen

Eating Attitudes™ & Gut Expert

Beth Rosen, MS, RD, CDN is a Registered Dietitian and owner of Beth Rosen Nutrition. She practices a non-diet philosophy and is a Health at Every Size" practitioner. Her goal is to end the pain of diet culture, one person at a time. Beth's techniques and programs empower chronic dieters, and those who consider themselves emotional and /or stress eaters, to ditch the vicious cycle of dieting, eat fearlessly by removing Food and diet rules, and mend their relationship with food and their bodies. Beth's works face-to-face with clients in Southbury, CT, and virtually with clients, worldwide.

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