When brainstorming what might be behind your stomach discomfort, you might think of stress or maybe a condition like IBS or IBD. After all, they’re very common contributors.

But something a bit more complicated and less discussed might actually be what’s at hand. We’re talking about a sucrase deficiency. Basically, it affects the digestion of sugar and carbs in the body.

But let’s back up a bit. First we’ll look at what sucrase is, exactly, then dig into what you need to know about this type of deficiency.

Wait, what is sucrase?

“Sucrase is a digestive enzyme that’s produced in the small intestine and is responsible for breaking apart the sugar sucrose into the smaller sugars glucose and fructose, so they can be absorbed and used by the body,” says Kim Kulp, RDN, a dietitian, gut health expert, and owner of the Gut Health Connection in the San Francisco Bay Area.

Some people’s bodies don’t have enough sucrase. “Sucrase intolerance/deficiency correlates with the lack of enzyme used to break down sucrose,” says Tim Hadley, DO, a pediatric gastroenterologist at Pediatrix Gastroenterology of the Rocky Mountains. “It tends to fall under the umbrella of disaccharidase deficiencies, which include lactase, sucrase, and maltase.” (You may recognize that first one: A lactase deficiency leads to lactose intolerance, or trouble digesting the sugar in dairy products.)

This is where digestive problems come in. When you don’t have enough sucrase to help you break down the sucrose you’re eating, that undigested sugar ends up traveling to the large intestine, causing gastrointestinal (GI) distress.

Signs of sucrase deficiency

Symptoms of a sucrase deficiency, sometimes called a sucrose intolerance, are similar to symptoms of other digestive concerns. Kulp and Dr. Hadley list some examples:

• Cramps, particularly after eating
• Bloating or abdominal distention
• A change in your stool, with diarrhea being more likely
• Gas
• Generalized discomfort

It’s important to note that noticing those symptoms isn’t a definite sign you have a sucrase deficiency, though. “These same symptoms are seen in IBS, making it hard to distinguish the cause of the GI distress without further testing,” Kulp says.

As far as an official diagnosis, Dr. Hadley says the “gold standard” is an esophagogastroduodenoscopy (EGD), an endoscopic procedure that examines and takes biopsies (tissue samples) of the upper GI tract.

What’s the difference between sucrose intolerance in adults and congenital sucrase-isomaltase deficiency?

If you Google “sucrase deficiency,” you may find both of these conditions. Are they the same thing? Yes and no.

“Both are merely deficiencies in enzymes,” Dr. Hadley says.

However, how they start, how long they last, and how they show up can look different.

Sucrose intolerance in adults

This condition can come from intestinal damage that’s possibly caused by infections, IBD, celiac disease, SIBO, or malnutrition, according to Kulp. She says it can be temporary in some cases, in which symptoms decrease when the cause of intestinal damage improves.

Unlike kids with the condition, adults are less likely to experience weight changes, Dr. Hadley adds, and their symptoms will be more like those of IBS.

Congenital sucrase-isomaltase deficiency (CSID)

This condition is an inherited disease (hence the word “congenital”), Kulp says. It can be temporary in some cases.

Dr. Hadley adds that kids with a congenital sucrase deficiency may struggle to gain weight and have feeding difficulties, which can contribute to developmental delays and systemic symptoms. He’s found that kids’ symptoms are also more severe than adults’.

Is sucrase deficiency common?

CSID isn’t super common. Depending on what research you look at and in what area of the world, the numbers range from 0.2 percent to 10 percent¹ of kids.

However, other research and experts suggest it’s more common—at least when looking at these types of deficiencies more generally. Pointing to a 2017 study in the Journal of Parenteral and Enteral Nutrition², Dr. Hadley says that “disaccharidase deficiencies have been well-documented in children to explain abdominal pain.” That same study found about 21 percent of the kids had a sucrase deficiency.

The fact that adults can have this too, however, is a newer understanding. But it’s possible the condition is more prevalent in adults. “Until recently, it was believed this enzyme deficiency was a rare childhood disease, but now it’s understood this can also affect adults,” Kulp says. Further, she says, about 70 percent of adults³ have some form of carbohydrate malabsorption.

Foods that trigger sucrase deficiency

If you have a sucrase deficiency, sugar and foods with a good bit of it (which, remember, aren’t morally bad!) can trigger uncomfortable symptoms, Kulp says. She lists specific types of sugar—such as table, raw, and brown—as well as maple syrup, molasses, and natural sugars in fruits and veggies like apples, oranges, pineapples, carrots, onions, and sweet potatoes.

Yep, even veggies can be a no-go for your gut. Don’t feel bad if you need to avoid them (if you truly have a diagnosed sucrase deficiency, that is).

Dr. Hadley adds that foods containing sucrose, maltose, and lactose can also incite GI symptoms. “It is surprising the amount of foods that contain these products as supplements or merely preservatives,” he notes.

How to manage the symptoms of sucrase deficiency

Before you make any dietary changes or take any medications, talk to your primary care doctor or gastroenterologist about your symptoms. They can run the necessary tests to determine if you’re actually dealing with a sucrase deficiency and not another health issue, and they can help you come up with a treatment plan.

If you do indeed have a sucrase deficiency, don’t lose hope! You don’t have to stop eating foods with sugar entirely. One option is to take the enzyme supplement Sucraid with your meal, Kulp and Dr. Hadley say. (You’ll need a prescription for it.) Similar to how Lactaid works for people with lactose intolerance, Sucraid delivers sucrase enzymes to your gut, to help you digest sucrose and avoid unpleasant symptoms.

Kulp also encourages getting a better understanding of your body and how much sucrose typically leads to symptoms for you (keeping a food journal is one way to do this), and to consider working with a dietitian who can help you through that process.

Dr. Hadley agrees that working with a registered dietitian can be helpful as you navigate these modifications and learn more about how your body metabolizes various foods.

Above all, avoid self-diagnosing and seek out a healthcare professional to help you navigate your symptoms.

—medically reviewed by Jennifer Logan, MD, MPH