Trehalase deficiency is a metabolic condition in which the body lacks an enzyme called trehalase and is not able to convert trehalose, a disaccharide (sugar composed of two monosaccharides) into glucose (sugar composed of one monosaccharide). Trehalose is found naturally in mushrooms, algae and insects. Trehalose may additionally be found in manufactured food products, medications, and cosmetics. For trehalose to be digested and absorbed by the digestive system, it must be broken down into glucose. Individuals with this deficiency are therefore unable to breakdown and absorb trehalose. This may lead to vomiting, abdominal discomfort and diarrhea after eating foods containing trehalose. Trehalase deficiency is caused by mutations in the TREH gene. Both autosomal recessive and autosomal dominant inheritance patterns have been described in the medical literature. Treatment involves avoidance or restriction of products that contain trehalose.

Individuals that have trehalase deficiency experience abdominal discomfort after consuming foods that contains trehalose, a type of sugar. The symptoms are typically similar to irritable bowel syndrome and might include: bloating, abdominal pain, diarrhea, vomiting, and gas.

TREH gene. The TREH gene codes for an enzyme that breaks down trehalose, a sugar made of two glucose molecules (disaccharide) into a digestible sugar or glucose, called a monosaccharide. When there is a mutation in the TREH gene, the enzyme has reduced or absent function, which results in undigested sugar entering into the bowel (digestive system). There, it goes through a process called fermentation, where sugars are converted to acids, gases, or alcohol. This leads to the production of gases, diarrhea, and other symptoms of abdominal pain and discomfort.

Trehalose is found naturally in mushrooms, algae, and insects. Trehalose received the GRAS (Generally Recognized As Safe) status from the U.S. Food and Drug Administration as a food additive in 2000. Since that time, trehalose has been utilized in many capacities in food production due to its chemical makeup and properties including taste enhancement, food preservation, and stabilization against heat and cold. Food products that may contain trehalose or are predicted to contain trehalose in the future include: dried foods (cereal, powdered milk, beans), frozen foods, confection (candy, gum, chocolate), confectionary (cake, jam, cream), beverages (coffee, tea, fruit juices), and fermented food (bread, yogurt). Trehalose additionally might be utilized in medical and cosmetic products.

1. For food products, one should avoid the foods that naturally contain trehalose (listed above)
2. As trehalose can be an additive in many food products, it is important to check the food label to determine whether trehalose has been added. The FDA provides a factsheet on How to Understand and Use the Nutrition Facts Label
3. Trehalose has many synonyms; so it is important to familiarize oneself with other names that might be utilized. PubChem, a resource from the National Library of Medicine at the NIH, provides a list of synonyms for Trehalose
4. It may be helpful to work with a dietician or nutritionist. Genetic Metabolic Dietitians International (GMDI) may be a helpful resource.
5. For cosmetics, check labeling and/or call the manufacturer if there is concern
6. For medications, check labeling and speak with your prescribing physician if there is concern