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Content: Lactose intolerance - Wikipedia
Lactose intolerance
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Not to be confused with Milk allergy. Medical condition
Lactose intolerance
Other names
Lactase deficiency, hypolactasia, alactasia, lactose challenged
Lactose is made up of two simple sugars
Specialty
Gastroenterology
Symptoms
Abdominal pain, bloating, diarrhea, flatulence, nausea[1]
Complications
Does not cause damage to the GI tract[2]
Usual onset
30–120 min after dairy products[1]
Causes
Decreased ability to digest lactose(genetic, small intestine injury)[1]
Diagnostic method
Symptoms resolve following eliminating lactose[1]
Differential diagnosis
Irritable bowel syndrome, celiac disease, inflammatory bowel disease, milk allergy[1]
Treatment
Decreasing lactose in the diet, lactase supplements, treat the underlying cause[1]
Frequency
~65% of people (less common in Europeans)[3]
Lactose intoleranceis a common condition caused by a decreased ability to digest lactose, a sugar found in dairy products.[1] Those affected vary in the amount of lactose they can tolerate before symptoms develop.[1] Symptoms may include abdominal pain, bloating, diarrhea, gas, and nausea.[1] These symptoms typically start thirty minutes to two hours after eating or drinking milk-based food.[1] Their severity typically depends on the amount a person eats or drinks.[1] Lactose intolerance does not cause damage to the gastrointestinal tract. [ 2]
Lactose intolerance is due to the lack of the enzymelactasein the small intestinesto break lactose down into glucoseand galactose.[3] There are four types: primary, secondary, developmental, and congenital.[1] Primary lactose intolerance occurs as the amount of lactase declines as people age.[1] Secondary lactose intolerance is due to injury to the small intestine. Such injury could be the result of infection, celiac disease, inflammatory bowel disease, or other diseases. [ 1][4]Developmental lactose intolerance may occur in premature babiesand usually improves over a short period of time.[1] Congenital lactose intolerance is an extremely rare genetic disorderin which little or no lactase is made from birth.[1] The onset of primary lactose intolerance, the most common type, is typically in late childhood or early adulthood,[1]but prevalence increases with age. [ 5]
Diagnosis may be confirmed if symptoms resolve following eliminating lactose from the diet.[1] Other supporting tests include a hydrogen breath testand a stool acidity test.[1] Other conditions that may produce similar symptoms include irritable bowel syndrome, celiac disease, and inflammatory bowel disease.[1] Lactose intolerance is different from a milk allergy.[1] Management is typically by decreasing the amount of lactose in the diet, taking lactase supplements, or treating the underlying disease. [ 1][6]People are usually able to drink at least one cup of milk per sitting without developing significant symptoms, with greater amounts tolerated if drunk with a meal or throughout the day. [ 1][7]
Most adults (around 65–70% of the world's population) are lactose intolerant. [ 5][8]Other mammalsnormally lose the ability to digest lactose after weaningand this was the ancestral stateof all humans before the recent evolutionof lactase persistence, which extends lactose tolerance into adulthood.[9] Lactase persistence evolved in several populations independently, probably as an adaptation to the domesticationof dairy animalsaround 10,000 years ago. [