The lactose tolerance test is a test to diagnose lactose intolerance, a genetic disease in which individuals are unable to digest and absorb the sugar lactose in cow’s milk. medicinenet“.
What is lactose intolerance?
Lactose intolerance is the inability to digest the sugar in milk and lactose. Milk is an important source of nutrition for children and even some adults.
With normal lactose tolerance, the lactose is broken down (digested) in the intestine by an enzyme into two smaller sugars (galactose and glucose) and then absorbed into the body. As a result, the lactose does not usually reach the colon.
On the other hand, in people with lactose intolerance who lack the intestinal enzyme that breaks down lactose, the ingested lactose is not digested or absorbed in the small intestine and reaches the colon where it is used by bacteria in the colon.
The bacteria produce chemicals that cause diarrhea and also produce gas. Abdominal pain may also occur.
How is lactose tolerance tested?
The lactose tolerance test requires the individual to drink a liquid that contains lactose
In the small intestine among lactose-tolerant individuals, the ingested lactose is broken down into galactose and glucose and then absorbed from the intestine and into the blood.
Several blood samples are taken over two hours after lactose ingestion to measure the blood glucose level. If lactose intolerance is normal, the blood glucose level rises due to glucose uptake from the intestine. If there is lactose intolerance, the glucose level does not rise.
What other tests can detect lactose intolerance?
Many clinicians simply make this diagnosis based on improvement of symptoms when lactose is withheld from the patient’s diet and malaise when reintroduced.
Other tests used to detect lactose intolerance include the lactose-hydrogen breath test and the stool acidity test, the latter used primarily in infants.
There is also a genetic test that can determine whether or not an individual has the intestinal enzyme required to digest and absorb lactose.
