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Lactose intolerance


Disease: Lactose intolerance Lactose intolerance
Category: Allergies

Disease Definition:

Also called lactase deficiency, lactose intolerance is the condition in which a person won’t be able to fully digest the milk sugar (lactose) found in dairy products. Although this condition is usually not dangerous, however, its symptoms could be uncomfortable enough to steer a person clear of dairy products.


A deficiency of lactase, which is an enzyme that is produced by the lining of the small intestine, is the cause of lactose intolerance. Not everyone with low levels of lactase is lactose intolerant, and people who think they are lactose intolerant actually don't have impaired lactose digestion. People who are considered to have lactose intolerance are only those with low lactase levels and symptoms.


A carefully chosen diet could control the symptoms of lactose intolerance. This diet should limit lactose but without cutting out calcium. Supplements should also be taken.

Work Group:

Symptoms, Causes


Usually, thirty minutes to two hours after eating or drinking foods that contain lactose, the signs and symptoms of lactose intolerance begin. Some of the common signs and symptoms of lactose intolerance may be:


  • Nausea
  • Gas
  • Diarrhea, which is the most common symptom
  • Bloating
  • Abdominal cramps


Even though these symptoms could be severe, but they're usually mild. The severity of the symptoms doesn't have anything to do with the degree of lactose malabsorption. However, they are related to other factors, such as how fast a person digests food, their ethnicity and age.


This disorder cannot be easily diagnosed only with signs and symptoms, because similar symptoms are caused by many other conditions, such as irritable bowel syndrome and stomach flu. Diarrhea, along with certain other symptoms, could be a sign of milk protein allergy in children.



An enzyme called lactase is produced by the cells that line the small intestine. Lactose will be broken down by lactase into two simple sugars, glucose and galactose, which could be absorbed into the bloodstream. Without lactase, the unprocessed lactose will move on to the colon, where the normal intestinal bacteria contend with it. This will cause gas, bloating and diarrhea, which are the hallmarks of lactose intolerance.


There are three types of lactose intolerance:

Congenital lactose intolerance:

Babies could be born with lactose intolerance. In a pattern of inheritance called autosomal recessive, this rare disorder is passed from generation to generation. However, for the child to be affected, both the mother and the father must pass on the defective form of the gene. These babies will require lactose-free infant formulas, because they will be intolerant of the lactose in their mothers' breast milk and have diarrhea from birth.

Primary lactose intolerance:

For some people, this occurs as a normal result of aging. At birth and during early childhood, when milk is the primary source of nutrition, the body produces large amounts of lactase. As a baby’s diet becomes more varied and less reliant on milk, the lactase production decreases. Symptoms of lactose intolerance could be caused by this gradual decline.

Secondary lactose intolerance:

This type could occur as a result of illness or injury. When the small intestine decreases lactase production after an illness, surgery or injury to the small intestine, this type occurs. Intestinal diseases, such as gastroenteritis, celiac disease or an inflammatory bowel disease such as Crohn's disease could cause this. This form of lactose intolerance could be completely reversible and last only a few weeks. However, it could be permanent if it's caused by a long-term illness.







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