Fructose Intolerance

The condition is mainly categorised into two types, which are:

Fructose Malabsorption 

This is the most common type, which occurs when the small intestine has a limited ability to absorb fructose efficiently. It indicates:

• Fructose is poorly absorbed, especially when eaten in large amounts.
• Symptoms typically occur after consuming high-fructose foods or drinks.
• Common in adolescents and adults.
• Not life-threatening and usually managed with dietary modification.

Hereditary Fructose Intolerance

Although it is a rare genetic disorder, it requires a formal medical diagnosis as it is caused by a deficiency of an enzyme required to break down fructose. It involves:

• Usually presents in infancy or early childhood.
• Fructose, sucrose or sorbitol can cause severe symptoms.
• It can lead to liver and kidney damage if it is left untreated.
• Requires strict lifelong avoidance under specialist medical care.

High-fructose foods that commonly trigger symptoms

Certain foods are more likely to cause symptoms, particularly when consumed in excess or on an empty stomach, such as:

Additionally, foods high in fructans, which are a relatable carbohydrate, may also worsen symptoms in sensitive individuals.

How is Fructose Intolerance diagnosed in Singapore?

An accurate diagnosis of fructose intolerance is essential to manage symptoms effectively and improve quality of life. The diagnosis typically involves a combination of:

• Clinical assessment – the first step involves a detailed discussion of your symptoms, medical history and dietary pattern. Our gastroenterologist will ask about the timing and severity of bloating, gas, diarrhoea or nausea and which foods seem to trigger symptoms. This personalised assessment helps identify whether fructose may be contributing to your digestive discomfort.
• Hydrogen breath test – in Singapore, a hydrogen breath test is commonly used to detect fructose malabsorption. After consuming a measured amount of fructose, the breath is analysed for hydrogen, which is produced when unabsorbed fructose ferments in the colon. A significant rise in hydrogen levels suggests that your body is not absorbing fructose efficiently.
• Dietary trials – in some cases, an elimination diet is recommended. High-fructose foods are removed from the diet for a period of time, followed by a structured reintroduction of these foods. This process helps pinpoint specific triggers, establish tolerance levels and guide personalised dietary recommendations.
• Excluding other conditions – because digestive symptoms can have multiple causes, our gastroenterologist will also rule out other conditions such as irritable bowel syndrome (IBS), coeliac disease, lactose intolerance or other carbohydrate malabsorption issues. Excluding these conditions ensures that your treatment plan is targeted and effective.

How is Fructose Intolerance managed and treated in Singapore?

An effective management of fructose intolerance focuses on controlling symptoms and improving digestive comfort. While there is no cure, most patients achieve good results through dietary and lifestyle adjustments, which entail:

• Dietary modification – limit high-fructose foods and choose foods with balanced fructose-to-glucose ratios. Adjusting portion sizes rather than complete avoidance often improves tolerance.
• Structured dietary plans – following a low-FODMAP diet under dietitian guidance helps identify specific trigger foods and personalise the diet.
• Supporting fructose absorption – consuming glucose-containing foods alongside fructose can improve absorption and reduce symptoms.
• Enzyme supplements – certain enzyme products, such as xylose isomerase, may help some individuals digest fructose more effectively. These should only be used under medical supervision.