Sucrose Intolerance: Symptoms, Causes, Diagnosis & Treatment

Sucrose is another name for table sugar, the common white or brown variety.

Symptoms of sucrose intolerance typically appear within minutes to a few hours after consuming sucrose-containing foods. They are caused by undigested sugar reaching the colon, where intestinal bacteria ferment it, producing gas.

Common Symptoms Include:

• Diarrhea (often watery)
• Bloating
• Abdominal pain or cramping
• Excessive gas
• Foul-smelling stools

These symptoms are nearly identical to those of lactose intolerance, which is why sucrose intolerance is frequently overlooked. Both conditions involve enzyme deficiency, both affect the small intestine, and both worsen when the gut lining is damaged.

1. Congenital Sucrase-Isomaltase Deficiency (CSID)

This is a rare genetic condition in which a person is born without the ability to produce the sucrase-isomaltase enzyme. Symptoms typically appear in infancy when a baby begins consuming sucrose-containing foods or beverages. Breastfed infants are generally asymptomatic, as breast milk does not contain sucrose. Because CSID is lifelong, it typically requires permanent dietary modification and may be managed with prescription enzyme replacement therapy.

2. Acquired Sucrose Intolerance

The acquired form develops when damage to the intestinal lining reduces the number of available digestive enzymes, including sucrase. Conditions that can damage the gut lining and trigger acquired sucrose intolerance include:

• Celiac disease
• Small intestinal bacterial overgrowth (SIBO)
• Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
• Gastrointestinal infections
• Other illnesses that compromise intestinal integrity

In many cases of acquired sucrose intolerance, successfully treating the underlying condition will restore enzyme levels and resolve sucrose intolerance symptoms.

The digestive symptoms are similar to the symptoms of lactose intolerance.

Lactose intolerance is the inability to digest the milk sugar called lactose. Lactose intolerance affects most of the world’s population ( 65%). Both sucrose and lactose intolerance cause bloating gas and diarrhea.

The enzymes for both sucrose and lactose digestion live in the intestine. When damage to the intestine occurs for any reason, such as infection or illness, the levels of both types of enzymes drop.

Symptoms of sucrose intolerance typically appear within minutes to a few hours after consuming sucrose-containing foods. They are caused by undigested sugar reaching the colon, where intestinal bacteria ferment it and produce gas.

Common Symptoms Include:

• Diarrhea (often watery)
• Bloating
• Abdominal pain or cramping
• Excessive gas
• Foul-smelling stools

These symptoms are nearly identical to those of lactose intolerance, which is why sucrose intolerance is frequently overlooked. Both conditions involve enzyme deficiency, both affect the small intestine, and both worsen when the gut lining is damaged.

• Apples
• Bananas
• Dates
• Grapefruit
• Honeydew melon
• Peaches
• Pineapples
• Raisins

Vegetables

• Beans
• Lentils
• Peas
• Sweet pickles

Sweeteners

• Table sugar (white and brown)
• Cane sugar
• Maple sugar and maple syrup
• Molasses

Starches and Processed Carbohydrates

• Breakfast cereals and granola bars
• Muffins, cookies, pies, and cakes
• Bread, pasta, rice, and potatoes
• Jam, pudding, and other sweetened packaged foods

Note: Some medications contain sucrose as an inactive ingredient. If you have been diagnosed with sucrose intolerance, speak with your pharmacist to review your current medications.

In specific populations, it may be as high as 5%.

Anyone with underlying digestive problems can develop the acquired form. The frequency of this form is unknown (2).

Estimates suggest that approximately 1 in 5,000 people have the congenital form of sucrose intolerance. In certain populations—particularly Indigenous populations in Alaska and Canada—prevalence may be as high as 5%. The frequency of the acquired form is not well established, as it remains underdiagnosed in clinical practice.

Research has found that sucrose intolerance may account for up to 35% of cases of IBS with diarrhea—potentially affecting more than 10 million people in the United States alone. Despite this, many gastroenterologists continue to associate sucrose intolerance primarily with infants and young children, overlooking the acquired form in adults.

Step 1: Rule Out Other Conditions

Before testing specifically for sucrose intolerance, your physician will typically evaluate for other diagnoses that share similar symptoms—including celiac disease, SIBO, inflammatory bowel disease, and intestinal infection. Treating an underlying condition may resolve sucrose intolerance entirely, rendering further testing unnecessary.

Breath Testing

Two types of breath tests are available for sucrose intolerance diagnosis:

• Hydrogen Methane Breath Test – not specific to sucrose intolerance, but may indicate fermentation in the gut
• ¹³C-Sucrose Breath Test – more specific to sucrose intolerance and preferred when available

Both tests have limitations and should be interpreted alongside clinical history.

Intestinal Biopsy

Biopsy of the small intestine remains the most accurate diagnostic test. Small tissue samples are analyzed for sucrase-isomaltase enzyme activity. However, because it requires anesthesia and carries procedural risks, biopsy is typically reserved for confirmation of CSID rather than routine workup.

The 4-4-4 Challenge

This simple at-home screening test can help identify a potential sucrose sensitivity:

1. Dissolve 4 tablespoons of plain table sugar (pure sucrose) in 4 ounces of water.
2. Drink on an empty stomach.
3. Monitor symptoms over the following 4 hours.

If this produces your typical digestive symptoms, discuss the results with your physician. Note: This test is not appropriate for young children or individuals with diabetes.

Additional Diagnostic Options

Other methods that may support diagnosis include:

• Sucrose elimination diet with symptom monitoring
• Urine sucrose testing
• Genetic testing for CSID variants
• Trial of enzyme replacement (Sucraid) with symptom assessment

Research published in peer-reviewed gastroenterology literature found that sucrose intolerance may be responsible for approximately 35% of IBS-diarrhea cases. That represents a significant proportion of the estimated 35–45 million Americans who live with IBS.

Because sucrose intolerance is rarely screened for in standard IBS evaluations, many patients cycle through multiple diets and treatments without identifying the true cause of their symptoms. Clinicians are increasingly encouraged to consider sucrose intolerance—particularly the acquired form—in adult patients with refractory IBS-D.

If you have been diagnosed with IBS with diarrhea and have not responded fully to a low-FODMAP diet, sucrose intolerance warrants consideration. Ask your physician about targeted testing.

Step-by-Step Treatment Approach

1. Treat any underlying digestive condition (celiac disease, SIBO, IBD, infection). Resolving the root cause may restore enzyme function.
2. Consider breath testing or the 4-4-4 challenge as initial screening.
3. Begin a low-sucrose diet and monitor symptom improvement.
4. If symptoms persist after eliminating sucrose, also eliminate dietary starches, as some individuals with sucrose intolerance also have impaired starch digestion.
5. Discuss enzyme replacement therapy with your physician if dietary modification alone is insufficient.

Dietary Treatment: The Low-Sucrose Diet

A low-sucrose diet is the primary dietary intervention for sucrose intolerance. Unlike a strict elimination diet, most individuals with SI can tolerate small amounts of sucrose—symptom threshold varies by person. Many individuals with sucrose intolerance have previously tried a low-FODMAP diet and experienced only partial improvement. This incomplete response is a clinically meaningful signal that sucrose intolerance may be a contributing factor. For detailed meal planning and food guidance, see our companion article: The Sucrose Intolerance Diet: How to Get Started.

Medication: Sucraid (Sacrosidase)

Sucraid is an FDA-approved prescription enzyme replacement therapy for CSID. Taken with meals, it supplies the sucrase enzyme the body is unable to produce adequately. While effective, Sucraid is expensive and can be difficult to obtain through insurance coverage. Some insurers require an intestinal biopsy for diagnosis before approving the medication. Sucraid is derived from yeast and is contraindicated in individuals with yeast allergies.

For more detailed information on the sucrose elimination diet. CLICK HERE

It presents with symptoms that closely mimic IBS, lactose intolerance, and other gastrointestinal conditions, which frequently delays accurate diagnosis.

Key takeaways for patients and clinicians:

• Sucrose intolerance has two forms: congenital (genetic, lifelong) and acquired (caused by intestinal damage)
• Symptoms include bloating, diarrhea, gas, and abdominal pain after sucrose-containing foods
• It may be responsible for up to 35% of IBS-with-diarrhea cases
• Partial response to low-FODMAP, gluten-free, or dairy-free diets may indicate sucrose as an unidentified trigger
• Treatment includes a low-sucrose diet and, where appropriate, Sucraid enzyme replacement therapy
• Always consult a qualified physician before making significant dietary changes or initiating treatment

• Overview of Sucrose Isomaltase Deficiency

• Sucrase Isomaltase Deficiency Mimicking IBS 2020

• Low FODMAP not working-may be sucrose intolerance

• Reduced efficacy of low FODMAP diet with genetic variants of CSID