What is trehalose intolerance?
Trehalose intolerance, also known as trehalase deficiency, is a metabolic condition defined by the body's inability to break down the disaccharide trehalose. Trehalose is a sugar composed of two glucose molecules and is naturally found in small amounts in various foods, most notably mushrooms, yeast, and shellfish. For the body to process trehalose, the enzyme trehalase must be present in the small intestine to break it down into usable glucose. When trehalase is deficient, the undigested trehalose continues into the large intestine, where it is fermented by gut bacteria, causing uncomfortable gastrointestinal symptoms.
The genetic basis of trehalose deficiency
Primary trehalose intolerance is an inherited genetic condition. It is typically passed down in an autosomal recessive pattern, meaning a child must inherit a copy of the faulty TREH gene from both parents to develop the condition. However, some populations, such as the indigenous peoples of Greenland, show a higher incidence, and some studies suggest an autosomal dominant pattern in certain cases. In these cases, inheriting just one copy of the faulty gene is enough to cause the deficiency. Research also indicates that the prevalence of the trehalase gene variant (rs2276064-А*TREH) can be quite high in certain high-latitude indigenous populations.
Symptoms and effects on the body
When undigested trehalose reaches the colon, it draws water into the intestine (osmotic effect) and is fermented by gut bacteria. This process is responsible for the characteristic symptoms associated with trehalose intolerance.
Key symptoms include:
- Osmotic diarrhea: The influx of water into the colon causes loose, watery stools.
- Abdominal pain and cramps: The gas produced during fermentation can cause significant discomfort.
- Increased flatulence: Excessive gas is a direct result of bacterial fermentation.
- Bloating: The buildup of gas in the intestines can cause the abdomen to feel full and tight.
- Vomiting: In some cases, severe intolerance can lead to vomiting.
The severity of symptoms can vary widely depending on the amount of trehalose consumed and the individual's remaining trehalase activity.
Diagnosing trehalose intolerance
Due to its rarity and overlapping symptoms with other gastrointestinal issues like Irritable Bowel Syndrome (IBS) or other disaccharide deficiencies, diagnosis can be challenging and delayed. The most definitive diagnostic method is an intestinal biopsy to measure trehalase enzyme activity directly. However, less invasive methods are also used, though they are less conclusive.
- Hydrogen breath test: Patients consume a trehalose solution, and the concentration of hydrogen in their breath is measured over time. An increase in breath hydrogen indicates bacterial fermentation of undigested sugar in the colon.
- Elimination diet: A doctor may recommend a strict diet that removes trehalose-containing foods for a period to see if symptoms improve.
- Genetic testing: With the identification of the TREH gene, genetic testing for the associated variant can be used to assess risk, especially in at-risk populations.
Managing trehalose intolerance
Currently, there is no cure for trehalose deficiency. The primary management strategy is a diet that limits or completely avoids foods and products containing trehalose. Since trehalose can be used as a food additive, reading ingredient labels carefully is crucial.
Food sources to manage:
- Mushrooms: All types of mushrooms are a primary natural source of trehalose and should be avoided.
- Yeast: Baker's and brewer's yeast contain trehalose.
- Processed Foods: Trehalose is used as a stabilizer and texturizer in many products, including dried foods, baked goods, frozen desserts, and confectioneries.
- Beverages: Some fruit juices and other beverages may contain trehalose as an additive.
Comparison of Trehalose Intolerance vs. Lactose Intolerance
| Feature | Trehalose Intolerance | Lactose Intolerance |
|---|---|---|
| Cause | Deficiency of the trehalase enzyme | Deficiency of the lactase enzyme |
| Sugar | Trehalose (glucose-glucose disaccharide) | Lactose (glucose-galactose disaccharide) |
| Main Food Sources | Mushrooms, yeast, shellfish, some processed foods | Dairy products (milk, cheese, yogurt) |
| Prevalence | Very rare in most populations; higher incidence in Greenlandic Inuit | Very common globally, varies significantly by ethnicity |
| Onset | Often congenital (primary deficiency) | Can be congenital, but often develops later in life |
| Management | Avoid trehalose-containing foods | Avoid or limit dairy; use lactase enzyme supplements |
| Treatment | No cure; dietary management is the main approach | Managed with diet and enzyme supplements |
Conclusion
Trehalose intolerance, or trehalase deficiency, is a rare genetic disorder caused by a lack of the intestinal enzyme trehalase, which is necessary to break down the sugar trehalose. For affected individuals, consuming trehalose-rich foods like mushrooms or processed items containing the additive can result in uncomfortable digestive symptoms, including diarrhea, gas, and abdominal pain. While there is no cure, the condition can be effectively managed by strictly avoiding trehalose in the diet. Accurate diagnosis, often requiring an intestinal biopsy, is key to differentiating this condition from other more common gastrointestinal disorders. If you suspect you have trehalose intolerance, consulting with a healthcare professional for a proper diagnosis and guidance on dietary management is essential. Further research is needed to fully understand the prevalence and genetic factors involved, particularly in under-diagnosed populations.
Allergy Insight: Trehalose Intolerance
Symptoms of trehalose intolerance
- Digestive discomfort after consuming foods like mushrooms or baked goods made with yeast.
- Abdominal pain and cramping resulting from bacterial fermentation of undigested sugar in the gut.
- Chronic or osmotic diarrhea caused by the osmotic pull of water into the colon.
- Excessive gas and bloating from the fermentation process in the large intestine.
- Vomiting, especially with more severe cases and higher intake of trehalose.
- Fluctuations in stool consistency, from loose stools to increased flatulence.
- Possible nutrient malabsorption over time if left unmanaged.
Frequently Asked Questions
Q: What is trehalose intolerance? A: Trehalose intolerance is a rare metabolic condition where the body cannot properly digest the sugar trehalose due to a deficiency of the enzyme trehalase. This leads to uncomfortable digestive symptoms after eating foods containing the sugar.
Q: What are the main symptoms of trehalose intolerance? A: The main symptoms include abdominal pain, bloating, excessive gas, and osmotic diarrhea, which typically occur after consuming foods like mushrooms or baked goods made with yeast.
Q: What foods contain trehalose? A: Trehalose is found naturally in mushrooms, shellfish like shrimp and lobster, and baker's and brewer's yeast. It is also used as an additive in many processed foods, including certain frozen foods, confectioneries, and dried products.
Q: Is trehalose intolerance the same as a mushroom allergy? A: No, trehalose intolerance is not an allergy. It is a digestive issue caused by a lack of an enzyme, whereas an allergy involves an immune system response.
Q: How is trehalose intolerance diagnosed? A: A definitive diagnosis is typically made by measuring trehalase enzyme activity via a small intestinal biopsy. Other methods include a hydrogen breath test after consuming trehalose and an elimination diet.
Q: Is there a cure for trehalose intolerance? A: No, there is currently no cure for trehalase deficiency. The condition is managed through a lifelong dietary approach that involves avoiding or severely restricting the intake of trehalose-containing foods.
Q: Is trehalose intolerance genetic? A: Yes, primary trehalose intolerance is a genetic condition caused by mutations in the TREH gene. It is often inherited in an autosomal recessive manner, though some populations have an autosomal dominant pattern.
