Glucose and galactose malabsorption / intolerance; Galactosemia Grey Shade Causes Glucose and galactose malabsorption Glucose
Glucose and galactose malabsorption / intolerance; Galactosemia
Glucose and galactose are two common sugars, which are present in many foods. They are found as free sugars, but also in combination with other sugars (e.g. sucrose – table sugar – is made up of glucose and fructose, or lactose – milk sugar – is made up of glucose and galactose). The malabsorption and secondary intolerance of glucose and galactose is due to a genetic abnormality on chromosome 22 regulating a sugar transporter protein (SGLT1) and leading to a decreased ability to absorb the sugars across the lining (mucosa) of the small intestine.
Frequency in population and natural history
- Glucose-galactose malabsorption is rare, with only a few hundred cases identified worldwide.
- Up to 10% of the population may have a slightly reduced capacity for glucose absorption without significant associated health problems. This condition may be a milder variation of glucose-galactose malabsorption.
- Malabsorption and intolerance of galacto-olicosaccharides as part of a general FODMAP intolerance is common in functional bowel syndromes, such as Irritable Bowel Syndrome (see Fructose intolerance).
- Both parents of the affected individual will be carriers of the genetic defect, but without symptoms (autosomal recessive condition)
Glucose-galactose malabsorption commonly becomes apparent in the first weeks of a baby's life. Typical symptoms are severe diarrhea leading to life-threatening dehydration, destabilization of the acidity of the blood and tissues (acidosis), stomach cramps, bloating, excess gas production, vomiting, and weight loss when fed breast milk or regular infant formulas. They can, however, digest fructose-based formulas that do not contain glucose or galactose. As they get older the affected children often tolerate glucose and galactose better.
Kidney stones or more calcium deposits in the kidneys are more frequent, as the genetic disorder can also affect the kidneys.
Testing and diagnosis
Genetic analysis is the most accurate test. Breath testing can also be performed. See Tests.
Avoid ingestion of glucose and galactose, as well as sugars containing them (e.g. lactose and sucrose). This means avoiding table and milk sugar in all forms, such as sugar cane and sugar beets, sorghum, confectioners' sugar or powdered sugar, rock candy, brown sugar (made of white sugar and molasses), cotton candy, maple syrup, Demerara and Barbados sugar, molasses, pancake syrup, gingerbreads, baked beans and pumpernickel breads, as well as dairy products. Expert dietary advice is required to implement this complicated dietary regime.
For glucose content of food see:
For galactose content of food see:
Galactosemia / Galactosaemia
Hereditary galactosemia is a genetic disease resulting in a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT). Acute manifestations occur in the neonatal period. Symptoms are related to lactose (milk sugar) ingestion and include poor feeding and growth, vomiting, jaundice, liver disease, increased bleeding, anemia, kidney disease, cataracts and brain damage. Long-term changes involve the brain (delayed language skills, speech defects and learning problems) and the ovaries (subnormal functioning) in adolescents.